Firework Model: Time Dependent Spectral Evolution of GRB

NASA Astrophysics Data System (ADS)

Barbiellini, Guido; Longo, Francesco; Ghirlanda, G.; Celotti, A.; Bosnjak, Z.

2004-09-01

The energetics of the long duration GRB phenomenon is compared with models of a rotating BH in a strong magnetic field generated by an accreting torus. The GRB energy emission is attributed to magnetic field vacuum breakdown that gives origin to a e +/- fireball. Its subsequent evolution is hypothesized in analogy with the in-flight decay of an elementary particle. An anisotropy in the fireball propagation is thus naturally produced. The recent discovery in some GRB of an initial phase characterized by a thermal spectrum could be interpreted as the photon emission of the fireball photosphere when it becomes transparent. In particular, the temporal evolution of the emission can be explained as the effect of a radiative deceleration of the out-moving ejecta.

The Development of the Spanish Fireball Network Using a New All-Sky CCD System

NASA Astrophysics Data System (ADS)

Trigo-Rodríguez, J. M.; Castro-Tirado, A. J.; Llorca, J.; Fabregat, J.; Martínez, V. J.; Reglero, V.; Jelínek, M.; Kubánek, P.; Mateo, T.; Postigo, A. De Ugarte

2004-12-01

We have developed an all-sky charge coupled devices (CCD) automatic system for detecting meteors and fireballs that will be operative in four stations in Spain during 2005. The cameras were developed following the BOOTES-1 prototype installed at the El Arenosillo Observatory in 2002, which is based on a CCD detector of 4096 × 4096 pixels with a fish-eye lens that provides an all-sky image with enough resolution to make accurate astrometric measurements. Since late 2004, a couple of cameras at two of the four stations operate for 30 s in alternate exposures, allowing 100% time coverage. The stellar limiting magnitude of the images is +10 in the zenith, and +8 below ~ 65° of zenithal angle. As a result, the images provide enough comparison stars to make astrometric measurements of faint meteors and fireballs with an accuracy of ~ 2°arcminutes. Using this prototype, four automatic all-sky CCD stations have been developed, two in Andalusia and two in the Valencian Community, to start full operation of the Spanish Fireball Network. In addition to all-sky coverage, we are developing a fireball spectroscopy program using medium field lenses with additional CCD cameras. Here we present the first images obtained from the El Arenosillo and La Mayora stations in Andalusia during their first months of activity. The detection of the Jan 27, 2003 superbolide of ± 17 ± 1 absolute magnitude that overflew Algeria and Morocco is an example of the detection capability of our prototype.

On the energy deposition into the plasma for an inverted fireball geometry

NASA Astrophysics Data System (ADS)

Levko, Dmitry; Gruenwald, Johannes

2017-10-01

Energy deposition into a plasma for an inverted fireball geometry is studied using a self-consistent two-dimensional Particle-in-Cell Monte Carlo collision model. In this model, the cathode is a pin which injects the fixed electron current and the anode is a hollow metal tube covered with the metal grid. We obtain an almost constant ratio between the densities of plasmas generated in the cathode-grid gap and inside the hollow anode. The results of the simulations show that there is no energy exchange between the beam and plasma electrons at low emission currents. For increasing current, however, we observe the increasing coupling between the electron beam and the thermal plasma electrons. This leads to the heating of plasma electrons and the generation of the so-called supra-thermal electrons.

Galileo Infrared Observations of the Shoemaker Levy 9 G and R Fireballs and Splash

NASA Technical Reports Server (NTRS)

Carlson, R. W.; Weissman, P. R.; Hui, J.; Segura, M.; Baines, K. H.; Johnson, T. V.; Dossart, P.; Encrenaz, T.; Leader, F.; Mehlman, R.

1995-01-01

The Galileo spacecraft was fortuitously situated for a direct view of the impacts of comet Shoemaker(ka)evy 9 in Jupiter's atmosphere and measurements were recorded by the Near Infrared Mapping Spectrometer (NIMS) instrument for several of the impact events. Seventeen discrete wavelength channels were used between 0.7 to 5.0 microns, obtained with a time resolution of 5 seconds. Two phases of the impact phenomena are found in the data: the initial fireball, which was evident for one minute, and subsequent fallback of impact ejecta onto the atmosphere, starting six minutes after fireball initiation.

Autonomous spectrographic system to analyse the main elements of fireballs and meteors

NASA Astrophysics Data System (ADS)

Espartero, Francisco Ángel; Martínez, Germán; Frías, Marta; Montes Moya, Francisco Simón; Castro-Tirado, Alberto Javier

2018-01-01

We present a meteor observation system based on imaging CCD cameras, wide-field optics and a diffraction grating. This system is composed of two independent spectrographs with different configurations, which allows us to capture images of fireballs and meteors with several fields of view and sensitivities. The complete set forms a small autonomous observatory, comprised of a sealed box with a sliding roof, weather station and computers for data storing and reduction. Since 2014, several meteors have been studied using this facility, such as the Alcalá la Real fireball recorded on 30 September 2016.

Modelling of dispersal and deposition of impact glass spherules from the Cretaceous-Tertiary boundary deposit

NASA Technical Reports Server (NTRS)

Espindola, J. M.; Carey, S.; Sigurdsson, H.

1993-01-01

The dispersal of glass spherules or tektites from a bolide impact with the Earth is modelled as ballistic trajectories in standard atmosphere. Ballistic dispersal of Cretaceous-Tertiary boundary impact glass spherules found in Haiti and Mimbral, Mexico requires a fireball radius in excess of 50 km but less than 100 km to account for the observed distribution. Glass spherules from 1 and up to 8 mm in diameter have been found at the KT boundary at Beloc in Haiti, at Mimbral, Mexico, and at DSDP Sites 536 and 540 in the Gulf of Mexico corresponding to paleodistances of 600 to 1000 km from the Chicxulub crater. In Haiti the basal and major glass-bearing unit at the KT boundary is attributed to fallout on basis of sedimentologic features. When compared with theoretical and observed dispersal of volcanic ejecta, the grain size versus distance relationship of the KT boundary tektite fallout is extreme, and rules out a volcanic fallout origin. At a comparable distance from source, the KT impact glass spherules are more than an order of mangitude coarser than ejecta of the largest known volcanic events. We model the dispersal of KT boundary impact glass spherules as ballistic ejecta from a fireball generated by the impact of a 10 km diameter bolide. Mass of ejecta in the fireball is taken as twice the bolide mass. Melt droplets are accelerated by gas flow in the fireball cloud, and leave the fireball on ballistic trajectories within the atmosphere, subject to drag, depending on angle of ejection and altitude. The model for ballistic dispersal is based on equations of motion, drag and ablation for silicate spheres in standard atmosphere.

The end height of fireball as a function of their residual kinetic energy

NASA Technical Reports Server (NTRS)

Revelle, D. O.

1987-01-01

Previous analyses of meteoroid compositional groupings have utilized the end height of fireballs as a diagnostic tool. From an observational perspective this definition is straight forward, but from a theoretical viewpoint there are problems with using this operational definition. In order to realistically assess the estimated geometric uncertainty of + 1 km in the observed end height, a theoretical definition of the end height of meteoritic fireballs is proposed using the results from the integral radiation efficiency model of ReVelle. Three photographed and recovered meteorites are used as a calibration for this proposed definition. This definition was used to evaluate the end height of all fireballs that were deduced by Wetherill and ReVelle as being meteoritic. In almost all cases the theoretical values are lower than the observed values, in some cases as much as 5 km lower. A preliminary summary of results are given.

Fireball multi object spectrograph: as-built optic performances

NASA Astrophysics Data System (ADS)

Grange, R.; Milliard, B.; Lemaitre, G.; Quiret, S.; Pascal, S.; Origné, A.; Hamden, E.; Schiminovich, D.

2016-07-01

Fireball (Faint Intergalactic Redshifted Emission Balloon) is a NASA/CNES balloon-borne experiment to study the faint diffuse circumgalactic medium from the line emissions in the ultraviolet (200 nm) above 37 km flight altitude. Fireball relies on a Multi Object Spectrograph (MOS) that takes full advantage of the new high QE, low noise 13 μm pixels UV EMCCD. The MOS is fed by a 1 meter diameter parabola with an extended field (1000 arcmin2) using a highly aspherized two mirror corrector. All the optical train is working at F/2.5 to maintain a high signal to noise ratio. The spectrograph (R 2200 and 1.5 arcsec FWHM) is based on two identical Schmidt systems acting as collimator and camera sharing a 2400 g/mm aspherized reflective Schmidt grating. This grating is manufactured from active optics methods by double replication technique of a metal deformable matrix whose active clear aperture is built-in to a rigid elliptical contour. The payload and gondola are presently under integration at LAM. We will present the alignment procedure and the as-built optic performances of the Fireball instrument.

Annual Occurrence of Meteorite-Dropping Fireballs

NASA Astrophysics Data System (ADS)

Konovalova, Natalia; Jopek, Tadeusz J.

2016-07-01

The event of Chelyabinsk meteorite has brought about change the earlier opinion about limits of the sizes of potentially dangerous asteroidal fragments that crossed the Earth's orbit and irrupted in the Earth's atmosphere making the brightest fireball. The observations of the fireballs by fireball networks allows to get the more precise data on atmospheric trajectories and coordinates of predicted landing place of the meteorite. For the reason to search the periods of fireball activity is built the annual distribution of the numbers of meteorites with the known fall dates and of the meteorite-dropping fireballs versus the solar longitude. The resulting profile of the annual activity of meteorites and meteorite-dropping fireballs shows several periods of increased activity in the course of the year. The analysis of the atmospheric trajectories and physical properties of sporadic meteorite-dropping fireballs observed in Tajikistan by instrumental methods in the summer‒autumn periods of increased fireballs activity has been made. As a result the structural strength, the bulk density and terminal mass of the studied fireballs that can survive in the Earth atmosphere and became meteorites was obtained. From the photographic IAU MDC_2003 meteor database and published sources based on the orbit proximity as determined by D-criterion of Southworth and Hawkins the fireballs that could be the members of group of meteorite-dropping fireballs, was found. Among the near Earth's objects (NEOs) the searching for parent bodies for meteorite-dropping fireballs was made and the evolution of orbits of these objects in the past on a long interval of time was investigated.

2015 Southern Taurid fireballs and asteroids 2005 UR and 2005 TF50

NASA Astrophysics Data System (ADS)

Olech, A.; Żołądek, P.; Wiśniewski, M.; Rudawska, R.; Bęben, M.; Krzyżanowski, T.; Myszkiewicz, M.; Stolarz, M.; Gawroński, M.; Gozdalski, M.; Suchodolski, T.; Węgrzyk, W.; Tymiński, Z.

2016-09-01

On the night of October 31, 2015 two bright Southern Taurid fireballs occurred over Poland, being one of the most spectacular bolides of this shower in recent years. The first fireball - PF311015a Okonek - was detected by six video stations of Polish Fireball Network (PFN) and photographed by several bystanders, allowing for precise determination of the trajectory and orbit of the event. The PF311015a Okonek entered Earth's atmosphere with the velocity of 33.2 ± 0.1 km s-1 and started to shine at height of 117.88 ± 0.05 km. The maximum brightness of -16.0 ± 0.4 mag was reached at height of 82.5 ± 0.1 km. The trajectory of the fireball ended at height of 60.2 ± 0.2 km with terminal velocity of 30.2 ± 1.0 km s-1. The second fireball - PF311015b Ostrowite - was detected by six video stations of PFN. It started with velocity of 33.2 ± 0.1 km s-1 at height of 108.05 ± 0.02 km. The peak brightness of -14.8 ± 0.5 mag was recorded at height of 82.2 ± 0.1 km. The terminal velocity was 31.8 ± 0.5 km s-1 and was observed at height of 57.86 ± 0.03 km. The orbits of both fireballs are similar not only to orbits of Southern Taurids and comet 2P/Encke, but even closer resemblance was noticed for orbits of 2005 UR and 2005 TF50 asteroids. Especially the former object is interesting because of its close flyby during spectacular Taurid maximum in 2005. We carried out a further search to investigate the possible genetic relationship of Okonek and Ostrowite fireballs with both asteroids, that are considered to be associated with Taurid complex. Although, we could not have confirmed unequivocally the relation between fireballs and these objects, we showed that both asteroids could be associated, having the same origin in a disruption process that separates them.

HUBBLE STAYS ON TRAIL OF FADING GAMMA-RAY BURST FIREBALL

NASA Technical Reports Server (NTRS)

2002-01-01

A Hubble Space Telescope image of the fading fireball from one of the universe's most mysterious phenomena, a gamma-ray burst. Though the visible component has faded to 1/500th its brightness (27.7 magnitude) from the time it was first discovered by ground- based telescopes last March (the actual gamma-ray burst took place on February 28), Hubble continues to clearly see the fireball and discriminated a surrounding nebulosity (at 25th magnitude) which is considered a host galaxy. The continued visibility of the burst, and the rate of its fading, support theories that the light from a gamma-ray burst is an expanding relativistic (moving near the speed of light) fireball, possibly produced by the collision of two dense objects, such as an orbiting pair of neutron stars. If the burst happened nearby, within our own galaxy, the resulting fireball should have had only enough energy to propel it into space for a month. The fact that this fireball is still visible after six months means the explosion was truly titanic and, to match the observed brightness, must have happened at the vast distances of galaxies. The energy released in a burst, which can last from a fraction of a second to a few hundred seconds, is equal to all of the Sun's energy generated over its 10 billion year lifetime. The false-color image was taken Sept. 5, 1997 with the Space Telescope Imaging Spectrograph. Credit: Andrew Fruchter (STScI), Elena Pian (ITSRE-CNR), and NASA

Event-by-event distribution of the ratio of magnetic field energy to initial fluid energy density in √{sN N}=200 GeV Au-Au collisions

NASA Astrophysics Data System (ADS)

Roy, Victor; Pu, Shi

2015-12-01

We estimate the event-by-event (e-by-e) distribution of the ratio (σ ) of the magnetic and electric field energy density to the fluid energy density in the transverse plane of Au-Au collisions at √{sN N}=200 GeV. A Monte Carlo (MC) Glauber model is used to calculate σ in the transverse plane for impact parameter b =0 , 12 fm at time τi˜0.5 fm. The fluid energy density is obtained by using Gaussian smoothing with two different smoothing parameter σg=0.25 , 0.5 fm. For b =0 fm collisions σ is found to be ≪1 in the central region of the fireball and σ ≳1 at the periphery. For b =12 fm collisions σ ≳1 is observed for some events. The e-by-e correlation between σ and the fluid energy density (ɛ ) is studied. We did not find strong correlation between σ and ɛ at the center of the fireball, whereas they are mostly anticorrelated at the periphery of the fireball.

Observations of Leonids 2009 by the Tajikistan Fireball Network

NASA Technical Reports Server (NTRS)

Borovicka, J.; Borovicka, J.

2011-01-01

The fireball network in Tajikistan has operated since 2009. Five stations of the network covering the territory of near eleven thousands square kilometers are equipped with all-sky cameras with the Zeiss Distagon "fish-eye" objectives and by digital SLR cameras Nikon with the Nikkor "fish-eye" objectives. Observations of the Leonid activity in 2009 were carried out during November 13-21. In this period, 16 Leonid fireballs have been photographed. As a result of astrometric and photometric reductions, the precise data including atmospheric trajectories, velocities, orbits, light curves, photometric masses and densities were determined for 10 fireballs. The radiant positions during the maximum night suggest that the majority of the fireball activity was caused by the annual stream component with only minor contribution from the 1466 trail. According to the PE criterion, the majority of Leonid fireballs belonged to the most fragile and weak fireball group IIIB. However, one detected Leonid belonged to the fireball group I. This is the first detection of an anomalously strong Leonid individual.

Which fireballs are meteorites - A study of the Prairie Network photographic meteor data

NASA Astrophysics Data System (ADS)

Wetherill, G. W.; Revelle, D. O.

1981-11-01

With the exception of three recovered meteorites with photographic fireball data (Pribram, Lost City, Innisfree), there is generally little information regarding the location of meteorites in the solar system prior to their impact on the earth. An investigation is conducted with the objective to identify those fireballs (bright meteor) data from the Prairie Network. The investigation is based on the belief that many small ordinary chondrites must be present among the photographed bright fireballs. Observations of the recovered fireballs are used to identify characteristics of their dynamics while passing through the atmosphere. In this way criteria are established for identifying those fireballs with similar dynamical characteristics. On the basis of the studies, a catalog is provided of fireballs which have a high probability of being ordinary chondrites or other strong meteorites.

Precise multi-instrument data on exceptional fireballs recorded over Central Europe in the period 2012-2014

NASA Astrophysics Data System (ADS)

Spurny, P.; Borovicka, J.

2014-07-01

Introduction: Instrumental recordings of fireballs provide an excellent means of examining the physical and structural properties of larger meteoroids, as well as their temporal and spatial distribution in the Solar System. Except direct information about this component of interplanetary bodies this study also yields very valuable knowledge about their parent bodies, asteroids and comets. In some special and very rare cases, when such instrumentally observed fireball terminates by a meteorite fall, we have even direct information about the composition, structure and mineralogy not only of this particular meteorite but also of its parent body. The most efficient systems for systematic fireball observations are so-called fireball networks. In this work we present precise and complex data on several exceptional fireballs based on photographic and photoelectric records taken by the Czech Fireball Network, which is the longest continuously operated and the most developed part of the European Fireball Network (EN). Instruments and data processing: The Czech part of the EN has been entirely modernized in the last decade and its operation was in the large extent automatized [1]. This change significantly increased not only efficiency but also quality and complexity of our observations. However, this observing system, which provides us with photographic and photoelectric data about fireballs brighter than -4 magnitude, still uses photographic films, which brings some limitations for the data processing. Primarily it implies a non-negligible delay between data acquisition and their analysis as we had to transport photographic films physically from remote stations and only then to develop and digitize them. There is also much lower efficiency of observations during the full Moon period than during moonless nights. Taking the advantage of fast progress of digital photography, we have constructed a new generation of the Digital Autonomous Fireball Observatory (DAFO), which provides us with high-resolution digital images available immediately after their recording. This observatory, developed during the last 2 years, sorted out all the above-mentioned disadvantages. These sophisticated digital cameras are currently being deployed on the stations of the Czech Fireball Network. In this work, we present the first data from this new observing system and the comparison with the previous one. Along with this significant modernization we also improved our software for positional and photometric measurement of photographic records, which partly automatizes this time consuming work and make it much more efficient, easier, and even more precise. This observing system based on the DAFO's, provides us not only with the similarly precise dataset of fireballs as the previous large format film system but thanks to the different observing strategy and higher sensitivity limit, significantly increased effective observing time and number of recorded fireballs. Average absolute positional accuracy for the recorded fireballs stayed similar for both systems and it is about 15 m for each point on a fireball luminous trajectory. Results: To demonstrate this fact, we present complete and precise data on atmospheric trajectories, orbits, lightcurves and dynamics for several fireballs, which are in some sense exceptional and which were recorded by both systems in the last two years. This sample contains, among others the cases which very probably terminate by the fall of a small meteorite, the cases with interesting internal structure and orbital characteristics and also the cases with interesting orbits with respect to their structural properties (i.e. cometary material on a typical asteroidal orbit and vice versa). As the examples of uniqueness of our data we can mention recording of the deep penetrating Geminid fireball (EN141212) which certainly terminated by the fall of a small, only tens of grams meteorite. This unique case with very precise trajectory, dynamic and orbital data (one of the most precise Geminid ever observed) proved that in some special cases even meteoroids with a high initial velocity of 36 km/s can produce a meteorite and that there is real possibility that we could find a piece of Phaethon, the parent of Geminids. Another example is the fireball designated EN130114 which was recorded only by our new digital cameras (it was during the full Moon period). The main exceptionality of this case consists in its lowest ever observed initial velocity which we recorded for natural interplanetary body. Its initial speed of only 11.090 km/s means among others that this meteoroid orbited Sun on a very Earth-like orbit. All presented fireballs well document the high standard of our observations and their usefulness for better knowledge of properties of meteoroids and their parents as well as their distribution in the Solar System.

FIREBall-2: Trailblazing observations of the space UV circumgalactic medium

NASA Astrophysics Data System (ADS)

Martin, Christopher

The Faint Intergalactic-medium Redshifted Emission Balloon (FIREBall-2) is designed to discover and map faint emission from the circumgalactic medium of low redshift galaxies (0.3

A statistical method to estimate low-energy hadronic cross sections

NASA Astrophysics Data System (ADS)

Balassa, Gábor; Kovács, Péter; Wolf, György

2018-02-01

In this article we propose a model based on the Statistical Bootstrap approach to estimate the cross sections of different hadronic reactions up to a few GeV in c.m.s. energy. The method is based on the idea, when two particles collide a so-called fireball is formed, which after a short time period decays statistically into a specific final state. To calculate the probabilities we use a phase space description extended with quark combinatorial factors and the possibility of more than one fireball formation. In a few simple cases the probability of a specific final state can be calculated analytically, where we show that the model is able to reproduce the ratios of the considered cross sections. We also show that the model is able to describe proton-antiproton annihilation at rest. In the latter case we used a numerical method to calculate the more complicated final state probabilities. Additionally, we examined the formation of strange and charmed mesons as well, where we used existing data to fit the relevant model parameters.

A fireball analysis from Spanish meteor observations

NASA Astrophysics Data System (ADS)

Benítez Sánchez, O.; Ocaña González, F.

2004-03-01

Naked eye meteor records from Spain are used for an analysis of 3240 fireballs reported by members of the Sociedad de Observadores de Meteoros Y Cometas de España (SOMYCE) and by casual eye-witnesses from 1982 to 2000. This analysis concerns various areas, such as statistical studies of the colours and the frequency of fireballs in annual meteor showers. Annual and diurnal variations are also discussed. We describe the population index r for magnitudes brighter than m=-2 for ORI, VIR, AQU, TAU, CAP, QUA, GEM, LYR, LEO, KCG, PER and sporadic fireballs. The typical population index is always in the range ≃ 1.2 to 1.9, except for Perseids and Geminids. An investigation of visual fireballs radiants was attempted with the Radiant software. The sample of fireballs (282 fireballs with the path reported) only shows evidence for the Perseids and Leonids.

Analysis of mixing in high-explosive fireballs using small-scale pressurised spheres

NASA Astrophysics Data System (ADS)

Courtiaud, S.; Lecysyn, N.; Damamme, G.; Poinsot, T.; Selle, L.

2018-02-01

After the detonation of an oxygen-deficient homogeneous high explosive, a phase of turbulent combustion, called afterburning, takes place at the interface between the rich detonation products and air. Its modelling is instrumental for the accurate prediction of the performance of these explosives. Because of the high temperature of detonation products, the chemical reactions are mixing-driven. Modelling afterburning thus relies on the precise description of the mixing process inside fireballs. This work presents a joint numerical and experimental study of a non-reacting reduced-scale set-up, which uses the compressed balloon analogy and does not involve the detonation of a high explosive. The set-up produces a flow similar to the one caused by a spherical detonation and allows focusing on the mixing process. The numerical work is composed of 2D and 3D LES simulations of the set-up. It is shown that grid independence can be reached by imposing perturbations at the edge of the fireball. The results compare well with the existing literature and give new insights on the mixing process inside fireballs. In particular, they highlight the fact that the mixing layer development follows an energetic scaling law but remains sensitive to the density ratio between the detonation products and air.

Dynamic Monte Carlo simulations of radiatively accelerated GRB fireballs

NASA Astrophysics Data System (ADS)

Chhotray, Atul; Lazzati, Davide

2018-05-01

We present a novel Dynamic Monte Carlo code (DynaMo code) that self-consistently simulates the Compton-scattering-driven dynamic evolution of a plasma. We use the DynaMo code to investigate the time-dependent expansion and acceleration of dissipationless gamma-ray burst fireballs by varying their initial opacities and baryonic content. We study the opacity and energy density evolution of an initially optically thick, radiation-dominated fireball across its entire phase space - in particular during the Rph < Rsat regime. Our results reveal new phases of fireball evolution: a transition phase with a radial extent of several orders of magnitude - the fireball transitions from Γ ∝ R to Γ ∝ R0, a post-photospheric acceleration phase - where fireballs accelerate beyond the photosphere and a Thomson-dominated acceleration phase - characterized by slow acceleration of optically thick, matter-dominated fireballs due to Thomson scattering. We quantify the new phases by providing analytical expressions of Lorentz factor evolution, which will be useful for deriving jet parameters.

Diffusive mass transport in agglomerated glassy fallout from a near-surface nuclear test

NASA Astrophysics Data System (ADS)

Weisz, David G.; Jacobsen, Benjamin; Marks, Naomi E.; Knight, Kim B.; Isselhardt, Brett H.; Matzel, Jennifer E.

2018-02-01

Aerodynamically-shaped glassy fallout is formed when vapor phase constituents from the nuclear device are incorporated into molten carriers (i.e. fallout precursor materials derived from soil or other near-field environmental debris). The effects of speciation and diffusive transport of condensing constituents are not well defined in models of fallout formation. Previously we reported observations of diffuse micrometer scale layers enriched in Na, Fe, Ca, and 235U, and depleted in Al and Ti, at the interfaces of agglomerated fallout objects. Here, we derive the timescales of uranium mass transport in such fallout as it cools from 2500 K to 1500 K by applying a 1-dimensional planar diffusion model to the observed 235U/30Si variation at the interfaces. By modeling the thermal transport between the fireball and the carrier materials, the time of mass transport is calculated to be <0.6 s, <1 s, <2 s, and <3.5 s for fireball yields of 0.1 kt, 1 kt, 10 kt, and 100 kt respectively. Based on the calculated times of mass transport, a maximum temperature of deposition of uranium onto the carrier material of ∼2200 K is inferred (1σ uncertainty of ∼200 K). We also determine that the occurrence of micrometer scale layers of material enriched in relatively volatile Na-species as well as more refractory Ca-species provides evidence for an oxygen-rich fireball based on the vapor pressure of the two species under oxidizing conditions. These results represent the first application of diffusion-based modeling to derive material transport, thermal environments, and oxidation-speciation in near-surface nuclear detonation environments.

Diffusive mass transport in agglomerated glassy fallout from a near-surface nuclear test

DOE PAGES

Weisz, David G.; Jacobsen, Benjamin; Marks, Naomi E.; ...

2017-12-15

Aerodynamically-shaped glassy fallout is formed when vapor phase constituents from the nuclear device are incorporated into molten carriers (i.e. fallout precursor materials derived from soil or other near-field environmental debris). The effects of speciation and diffusive transport of condensing constituents are not well defined in models of fallout formation. Previously we reported observations of diffuse micrometer scale layers enriched in Na, Fe, Ca, and 235U, and depleted in Al and Ti, at the interfaces of agglomerated fallout objects. Here in this paper, we derive the timescales of uranium mass transport in such fallout as it cools from 2500 K tomore » 1500 K by applying a 1-dimensional planar diffusion model to the observed 235U/ 30Si variation at the interfaces. By modeling the thermal transport between the fireball and the carrier materials, the time of mass transport is calculated to be <0.6 s, <1 s, <2 s, and <3.5 s for fireball yields of 0.1 kt, 1 kt, 10 kt, and 100 kt respectively. Based on the calculated times of mass transport, a maximum temperature of deposition of uranium onto the carrier material of ~2200 K is inferred (1σ uncertainty of ~200 K). We also determine that the occurrence of micrometer scale layers of material enriched in relatively volatile Na-species as well as more refractory Ca-species provides evidence for an oxygen-rich fireball based on the vapor pressure of the two species under oxidizing conditions. These results represent the first application of diffusion-based modeling to derive material transport, thermal environments, and oxidation-speciation in near-surface nuclear detonation environments.« less

Diffusive mass transport in agglomerated glassy fallout from a near-surface nuclear test

DOE Office of Scientific and Technical Information (OSTI.GOV)

Weisz, David G.; Jacobsen, Benjamin; Marks, Naomi E.

Aerodynamically-shaped glassy fallout is formed when vapor phase constituents from the nuclear device are incorporated into molten carriers (i.e. fallout precursor materials derived from soil or other near-field environmental debris). The effects of speciation and diffusive transport of condensing constituents are not well defined in models of fallout formation. Previously we reported observations of diffuse micrometer scale layers enriched in Na, Fe, Ca, and 235U, and depleted in Al and Ti, at the interfaces of agglomerated fallout objects. Here in this paper, we derive the timescales of uranium mass transport in such fallout as it cools from 2500 K tomore » 1500 K by applying a 1-dimensional planar diffusion model to the observed 235U/ 30Si variation at the interfaces. By modeling the thermal transport between the fireball and the carrier materials, the time of mass transport is calculated to be <0.6 s, <1 s, <2 s, and <3.5 s for fireball yields of 0.1 kt, 1 kt, 10 kt, and 100 kt respectively. Based on the calculated times of mass transport, a maximum temperature of deposition of uranium onto the carrier material of ~2200 K is inferred (1σ uncertainty of ~200 K). We also determine that the occurrence of micrometer scale layers of material enriched in relatively volatile Na-species as well as more refractory Ca-species provides evidence for an oxygen-rich fireball based on the vapor pressure of the two species under oxidizing conditions. These results represent the first application of diffusion-based modeling to derive material transport, thermal environments, and oxidation-speciation in near-surface nuclear detonation environments.« less

Onset of normal and inverse homoclinic bifurcation in a double plasma system near a plasma fireball

DOE Office of Scientific and Technical Information (OSTI.GOV)

Mitra, Vramori; Sarma, Bornali; Sarma, Arun

Plasma fireballs are generated due to a localized discharge and appear as a luminous glow with a sharp boundary, which suggests the presence of a localized electric field such as electrical sheath or double layer structure. The present work reports the observation of normal and inverse homoclinic bifurcation phenomena in plasma oscillations that are excited in the presence of fireball in a double plasma device. The controlling parameters for these observations are the ratio of target to source chamber (n{sub T}/n{sub S}) densities and applied electrode voltage. Homoclinic bifurcation is noticed in the plasma potential fluctuations as the system evolvesmore » from narrow to long time period oscillations and vice versa with the change of control parameter. The dynamical transition in plasma fireball is demonstrated by spectral analysis, recurrence quantification analysis (RQA), and statistical measures, viz., skewness and kurtosis. The increasing trend of normalized variance reflects that enhancing n{sub T}/n{sub S} induces irregularity in plasma dynamics. The exponential growth of the time period is strongly indicative of homoclinic bifurcation in the system. The gradual decrease of skewness and increase of kurtosis with the increase of n{sub T}/n{sub S} also reflect growing complexity in the system. The visual change of recurrence plot and gradual enhancement of RQA variables DET, L{sub max}, and ENT reflects the bifurcation behavior in the dynamics. The combination of RQA and spectral analysis is a clear evidence that homoclinic bifurcation occurs due to the presence of plasma fireball with different density ratios. However, inverse bifurcation takes place due to the change of fireball voltage. Some of the features observed in the experiment are consistent with a model that describes the dynamics of ionization instabilities.« less

On the spectrum and polarization of magnetar flare emission

NASA Astrophysics Data System (ADS)

Taverna, R.; Turolla, R.

2017-08-01

Bursts and flares are among the distinctive observational manifestations of magnetars, isolated neutron stars endowed with an ultrastrong magnetic field (B ≈ 1014-1015 G). It is believed that these events arise in a hot electron-positron plasma that remains trapped within the closed magnetic field lines. We developed a simple radiative transfer model to simulate magnetar flare emission in the case of a steady trapped fireball. After dividing the fireball surface in a number of plane-parallel slabs, the local spectral and polarization properties are obtained integrating the radiative transfer equations for the two normal modes. We assume that magnetic Thomson scattering is the dominant source of opacity, and neglect contributions from second-order radiative processes, although double-Compton scattering is accounted for in establishing local thermal equilibrium in the fireball atmospheric layers. The observed spectral and polarization properties as measured by a distant observer are obtained by summing the contributions from the patches that are visible for a given viewing geometry by means of a ray-tracing code. The spectra we obtained in the 1-100 keV energy range are thermal and can be described in terms of the superposition of two blackbodies. The blackbody temperature and the emitting area ratio are in broad agreement with the available observations. The predicted linear polarization degree is, in general, greater than 80 per cent over the entire energy range and should be easily detectable by new-generation X-ray polarimeters, such as IXPE, XIPE and eXTP.

Fireballs in the Sky

NASA Astrophysics Data System (ADS)

Day, B. H.; Bland, P.

2016-12-01

Fireballs in the Sky is an innovative Australian citizen science program that connects the public with the research of the Desert Fireball Network (DFN). This research aims to understand the early workings of the solar system, and Fireballs in the Sky invites people around the world to learn about this science, contributing fireball sightings via a user-friendly app. To date, more than 23,000 people have downloaded the app world-wide and participated in planetary science. The Fireballs in the Sky app allows users to get involved with the Desert Fireball Network research, supplementing DFN observations and providing enhanced coverage by reporting their own meteor sightings to DFN scientists. Fireballs in the Sky reports are used to track the trajectories of meteors - from their orbit in space to where they might have landed on Earth. Led by Phil Bland at Curtin University in Australia, the Desert Fireball Network (DFN) uses automated observatories across Australia to triangulate trajectories of meteorites entering the atmosphere, determine pre-entry orbits, and pinpoint their fall positions. Each observatory is an autonomous intelligent imaging system, taking 1000×36Megapixel all-sky images throughout the night, using neural network algorithms to recognize events. They are capable of operating for 12 months in a harsh environment, and store all imagery collected. We developed a completely automated software pipeline for data reduction, and built a supercomputer database for storage, allowing us to process our entire archive. The DFN currently stands at 50 stations distributed across the Australian continent, covering an area of 2.5 million km^2. Working with DFN's partners at NASA's Solar System Exploration Research Virtual Institute, the team is expanding the network beyond Australia to locations around the world. Fireballs in the Sky allows a growing public base to learn about and participate in this exciting research.

Optical spectroscopy to study confined and semi-closed explosions of homogeneous and composite charges

NASA Astrophysics Data System (ADS)

Maiz, Lotfi; Trzciński, Waldemar A.; Paszula, Józef

2017-01-01

Confined and semi-closed explosions of new class of energetic composites as well as TNT and RDX charges were investigated using optical spectroscopy. These composites are considered as thermobarics when used in layered charges or enhanced blast explosives when pressed. Two methods to estimate fireball temperature histories of both homogeneous and metallized explosives from the spectroscopic data are also presented, compared and analyzed. Fireball temperature results of the charges detonated in a small explosion chamber under air and argon atmospheres, and detonated in a semi-closed bunker are presented and compared with theoretical ones calculated by a thermochemical code. Important conclusions about the fireball temperatures and the physical and chemical phenomena occurring after the detonation of homogeneous explosives and composite formulations are deduced.

FIREBall-2: Trailblazing observations of the space UV circumgalactic medium (Columbia University, Co-I Proposal)

NASA Astrophysics Data System (ADS)

Schiminovich, David

Columbia University is a Co-I institution in a collaborative research program with Caltech, the Lead Institution (PI: Christopher Martin). The Faint Intergalactic-medium Redshifted Emission Balloon (FIREBall-2) is designed to discover and map faint emission from the circumgalactic medium of low redshift galaxies (0.3

The Fireball integrated code package

DOE Office of Scientific and Technical Information (OSTI.GOV)

Dobranich, D.; Powers, D.A.; Harper, F.T.

1997-07-01

Many deep-space satellites contain a plutonium heat source. An explosion, during launch, of a rocket carrying such a satellite offers the potential for the release of some of the plutonium. The fireball following such an explosion exposes any released plutonium to a high-temperature chemically-reactive environment. Vaporization, condensation, and agglomeration processes can alter the distribution of plutonium-bearing particles. The Fireball code package simulates the integrated response of the physical and chemical processes occurring in a fireball and the effect these processes have on the plutonium-bearing particle distribution. This integrated treatment of multiple phenomena represents a significant improvement in the state ofmore » the art for fireball simulations. Preliminary simulations of launch-second scenarios indicate: (1) most plutonium vaporization occurs within the first second of the fireball; (2) large non-aerosol-sized particles contribute very little to plutonium vapor production; (3) vaporization and both homogeneous and heterogeneous condensation occur simultaneously; (4) homogeneous condensation transports plutonium down to the smallest-particle sizes; (5) heterogeneous condensation precludes homogeneous condensation if sufficient condensation sites are available; and (6) agglomeration produces larger-sized particles but slows rapidly as the fireball grows.« less

The Pribram, Lost City, Innisfree, and Neuschwanstein falls: An analysis of the atmospheric trajectories

NASA Astrophysics Data System (ADS)

Gritsevich, M. I.

2008-10-01

To date, several meteorites have been found for which their flight in the atmosphere was recorded by special fireball camera networks. Because of this, a thorough analysis of the instrumentally registered falls is of current importance. For such fireballs, not only the high-quality photo images of the motion in the atmosphere exist, but also the density and the shape of the meteor body fragments reached the Earth’s surface are known for sure. In the present study, for the Innisfree, Lost City, and Pribram fireballs, new models of the entry to the atmosphere have been built. The values of the ballistic coefficient and the mass-loss parameter providing the best approximation for the observations of the luminous trajectory segment with the analytical solution of the meteor physics equations have been obtained. From recent results of the numerical experiments on the supersonic airflow of bodies of various shapes, the preatmospheric masses of the fireballs, as well as the dynamic estimates of the mass at the other trajectory points, were obtained. In particular, the terminal mass of the fireballs in the lower segment of the analyzed trajectories is in good agreement with the total mass of the meteorite material recovered in all of the cases considered. Moreover, to calculate the acceleration of the meteor bodies, a new analytical formula has been suggested, which allows the obtained theoretical time dependencies of the velocity and altitude to be compared with the observational data.

Absolute mass scale calibration in the inverse problem of the physical theory of fireballs.

NASA Astrophysics Data System (ADS)

Kalenichenko, V. V.

A method of the absolute mass scale calibration is suggested for solving the inverse problem of the physical theory of fireballs. The method is based on the data on the masses of the fallen meteorites whose fireballs have been photographed in their flight. The method may be applied to those fireballs whose bodies have not experienced considerable fragmentation during their destruction in the atmosphere and have kept their form well enough. Statistical analysis of the inverse problem solution for a sufficiently representative sample makes it possible to separate a subsample of such fireballs. The data on the Lost City and Innisfree meteorites are used to obtain calibration coefficients.

A Practical Quantum Mechanics Molecular Mechanics Method for the Dynamical Study of Reactions in Biomolecules.

PubMed

Mendieta-Moreno, Jesús I; Marcos-Alcalde, Iñigo; Trabada, Daniel G; Gómez-Puertas, Paulino; Ortega, José; Mendieta, Jesús

2015-01-01

Quantum mechanics/molecular mechanics (QM/MM) methods are excellent tools for the modeling of biomolecular reactions. Recently, we have implemented a new QM/MM method (Fireball/Amber), which combines an efficient density functional theory method (Fireball) and a well-recognized molecular dynamics package (Amber), offering an excellent balance between accuracy and sampling capabilities. Here, we present a detailed explanation of the Fireball method and Fireball/Amber implementation. We also discuss how this tool can be used to analyze reactions in biomolecules using steered molecular dynamics simulations. The potential of this approach is shown by the analysis of a reaction catalyzed by the enzyme triose-phosphate isomerase (TIM). The conformational space and energetic landscape for this reaction are analyzed without a priori assumptions about the protonation states of the different residues during the reaction. The results offer a detailed description of the reaction and reveal some new features of the catalytic mechanism. In particular, we find a new reaction mechanism that is characterized by the intramolecular proton transfer from O1 to O2 and the simultaneous proton transfer from Glu 165 to C2. Copyright © 2015 Elsevier Inc. All rights reserved.

Fireballs in the Sky: an Augmented Reality Citizen Science Program

NASA Astrophysics Data System (ADS)

Day, B. H.; Bland, P.; Sayers, R.

2017-12-01

Fireballs in the Sky is an innovative Australian citizen science program that connects the public with the research of the Desert Fireball Network (DFN). This research aims to understand the early workings of the solar system, and Fireballs in the Sky invites people around the world to learn about this science, contributing fireball sightings via a user-friendly augmented reality mobile app. Tens of thousands of people have downloaded the app world-wide and participated in the science of meteoritics. The Fireballs in the Sky app allows users to get involved with the Desert Fireball Network research, supplementing DFN observations and providing enhanced coverage by reporting their own meteor sightings to DFN scientists. Fireballs in the Sky reports are used to track the trajectories of meteors - from their orbit in space to where they might have landed on Earth. Led by Phil Bland at Curtin University in Australia, the Desert Fireball Network (DFN) uses automated observatories across Australia to triangulate trajectories of meteorites entering the atmosphere, determine pre-entry orbits, and pinpoint their fall positions. Each observatory is an autonomous intelligent imaging system, taking 1000×36Megapixel all-sky images throughout the night, using neural network algorithms to recognize events. They are capable of operating for 12 months in a harsh environment, and store all imagery collected. We developed a completely automated software pipeline for data reduction, and built a supercomputer database for storage, allowing us to process our entire archive. The DFN currently stands at 50 stations distributed across the Australian continent, covering an area of 2.5 million km^2. Working with DFN's partners at NASA's Solar System Exploration Research Virtual Institute, the team is expanding the network beyond Australia to locations around the world. Fireballs in the Sky allows a growing public base to learn about and participate in this exciting research.

Fireballs in the Sky: An Augmented Reality Citizen Science Program

NASA Technical Reports Server (NTRS)

Day, Brian

2017-01-01

Fireballs in the Sky is an innovative Australian citizen science program that connects the public with the research of the Desert Fireball Network (DFN). This research aims to understand the early workings of the solar system, and Fireballs in the Sky invites people around the world to learn about this science, contributing fireball sightings via a user-friendly augmented reality mobile app. Tens of thousands of people have downloaded the app world-wide and participated in the science of meteoritics. The Fireballs in the Sky app allows users to get involved with the Desert Fireball Network research, supplementing DFN observations and providing enhanced coverage by reporting their own meteor sightings to DFN scientists. Fireballs in the Sky reports are used to track the trajectories of meteors - from their orbit in space to where they might have landed on Earth. Led by Phil Bland at Curtin University in Australia, the Desert Fireball Network (DFN) uses automated observatories across Australia to triangulate trajectories of meteorites entering the atmosphere, determine pre-entry orbits, and pinpoint their fall positions. Each observatory is an autonomous intelligent imaging system, taking 1000 by 36 megapixel all-sky images throughout the night, using neural network algorithms to recognize events. They are capable of operating for 12 months in a harsh environment, and store all imagery collected. We developed a completely automated software pipeline for data reduction, and built a supercomputer database for storage, allowing us to process our entire archive. The DFN currently stands at 50 stations distributed across the Australian continent, covering an area of 2.5 million square kilometers. Working with DFN's partners at NASA's Solar System Exploration Research Virtual Institute, the team is expanding the network beyond Australia to locations around the world. Fireballs in the Sky allows a growing public base to learn about and participate in this exciting research.

Analysis of identified iron meteoroids: Possible relation with M-type Earth-crossing asteroids?

NASA Astrophysics Data System (ADS)

Revelle, D. O.; Ceplecha, Z.

1994-12-01

We have used two different techniques to analyze the U. S. Prairie Network (PN) fireballs in order to search for possible nickel-iron meteoroids. The first approach used is that of ReVelle and Rajan which is similar to the analysis carried out earlier by Wetherill and ReVelle in a series of papers relating first to the chondrites and later to fireballs of cometary origin. The second approach is a new technique developed by Ceplecha and co-workers that can simultaneously determine the presence and location of gross fragmentation events and also determine an effective ablation parameter during the fireball entry. Using this combined approach we have determined that seven fireballs among the 287 that were analyzed are likely to be iron in composition. Using the method of Ceplecha we have determined that none of these objects experienced any gross fragmentation events during their entry to the atmosphere and most of the meteoroids also exhibited rather large ablation coefficients during entry as well, a feature that is also characteristic of the ReVelle and Rajan approach. For all of these objects for which we currently have available data, we have determined that gross fragmentation events did not occur during the entry.

Orbit analysis of a bright Southern sigma Sagittariids fireball

NASA Astrophysics Data System (ADS)

Koukal, Jakub

2018-02-01

During twilight on June 14, 2017, CEMeNt network cameras recorded a long and bright fireball with an absolute magnitude of -7.9 ± 0.2m, whose atmospheric path began over the northwest of Romania and ended up above southern Poland. This fireball belongs to the Southern sigma Sagittariids meteor shower and was recorded from 9 cameras of the CEMeNt network. The atmospheric path of the fireball as well as the heliocentric orbit of the meteoroid are analyzed in this article.

IMO Fireball report form: results and prospects

NASA Astrophysics Data System (ADS)

Hankey, M.; Perlerin, V.

2015-01-01

At the 2014 IMC, we presented the new IMO (International Meteor Organization) online, Fireball report (available at fireballs.imo.net). This fireball report form was specifically designed for use by people with no astronomy experience who witnessed a fireball, a bolide or a suspected similar phenomenon. The IMO version of the form has been officially launched in February 2015. Since then, the form has been translated in different languages and customized for organizations around the world. In this paper, we will present preliminary results of the form and provide tips to improve the online presence of local organizations, in order to promote usage. We will also highlight procedures to be followed by local organizations to get a custom version of the form.

Beyond the Band Function Paradigm : a New Model for GRB Prompt Emission and Possible Impact in Cosmology

NASA Astrophysics Data System (ADS)

Guiriec, Sylvain

Gamma Ray Bursts (GRBs) are the most violent phenomenons in the Universe. They are associated with the birth of stellar mass black holes either from the collapse of hypermassive stars or the merger of compact objects. The Fireball model is the most popular scenario to explain GRBs. In this theoretical framework, GRB central engines release collimated, bipolar and highly relativistic jets mainly composed of electrons, positrons, photons, and a small amount of baryons. During the first phase of the Fireball model, charged particles are accelerated and release non-thermal radiations. The Fireball model also predicts a thermal like component coming from the jet photosphere. This first phase would be responsible for the GRB prompt emission observed by gamma ray telescopes such as Fermi/GBM in the keV-MeV energy range and which is the only phase discussed in this talk. Until now, GRB prompt emission spectra were considered as adequately fitted with the empirical Band function, which is a smoothly broken power law. However, its parameters are very often incompatible with the Fireball model predictions for both the thermal and non-thermal components. We will see that observation with the Fermi Gamma Ray Space Telescope break the paradigm of the Band function and that deviations from this function exists in many GRBs. Those deviations are adequately fitted with an additional thermal-like component -that we consider as the jet photosphere- and/or an additional power law. Importantly, with the three components together, theory and observations are much more in agreement. We will also see how this new model for prompt emission spectra may have an impact beyond the physics of GRBs. Indeed, this work may confirm a relation between the hardness of the GRB prompt emission and its luminosity which may be used to scale GRBs as standard-like candles for use in cosmology.

The Valec fireball and predicted meteorite fall

NASA Technical Reports Server (NTRS)

Ceplecha, Z.; Spurny, P.

1987-01-01

A fireball was photographed with a luminous trajectory below a height of 20 km. On Aug. 3, 1984, seven stations photographed this slow moving fireball, which traversed 94 km of luminous trajectory in 9.2 sec and terminated its visible flight at a height of 19.1 km. The computed dark flight trajectory intersected the surface close to Valec, a small village 40 km west of Brno. The Valec fireball was the lowest photographed fireball ever. The Valec fireball was photographed by fish eye cameras. The positional precision of all the records were within the range of 1 to 2 minutes of arc. All computations were done using the FIRBAL program, a set of almost 4000 Fortran statements run on EC 1040 computer. The average computed mass at the terminal point, i.e., the predicted mass of the biggest meteorite, was 16 kg. This number is based on the dynamical data at the terminal point solely. Visual data was also collected from occasional observers. This observed phenomenon is discussed.

Meteor fireball sounds identified

NASA Technical Reports Server (NTRS)

Keay, Colin

1992-01-01

Sounds heard simultaneously with the flight of large meteor fireballs are electrical in origin. Confirmation that Extra/Very Low Frequency (ELF/VLF) electromagnetic radiation is produced by the fireball was obtained by Japanese researchers. Although the generation mechanism is not fully understood, studies of the Meteorite Observation and Recovery Project (MORP) and other fireball data indicate that interaction with the atmosphere is definitely responsible and the cut-off magnitude of -9 found for sustained electrophonic sounds is supported by theory. Brief bursts of ELF/VLF radiation may accompany flares or explosions of smaller fireballs, producing transient sounds near favorably placed observers. Laboratory studies show that mundane physical objects can respond to electrical excitation and produce audible sounds. Reports of electrophonic sounds should no longer be discarded. A catalog of over 300 reports relating to electrophonic phenomena associated with meteor fireballs, aurorae, and lightning was assembled. Many other reports have been cataloged in Russian. These may assist the full solution of the similar long-standing and contentious mystery of audible auroral displays.

250 Fireballs Observed in Norway 100 Years Ago

NASA Astrophysics Data System (ADS)

Skorve, J.

2014-07-01

In 1941 the Norwegian Academy of Sciences, presented a study in the Mathematcal-Natural Sciences section, by the Norwegian astronomer Sigurd Einbu. In this report, the information of each fireball is presented in a table containing eight parameters, including their radiants. The report also contains several illustrations. For about 60 of the most interesting fireballs, Einbu included additional information, as describing them in more details. Like, those fireballs producing infrasonic sounds, and/or having superbolide brightness. Also, the strong smell of sulfur, have been reported by a number of persons in a meteorite drop zone. Also, a unique incident of four bright fireballs that were observed within a period of 12 hours, all with the same radiant. During this period, we also experienced the brightest fireball that ever has been observed in Norway, the Trysil superbolide, of 1927. This paper discusses Einbu's report. With respect to when it was published, is surprisingly well suited to also to be read and studied by interested researchers.

Cloud heights and stratospheric injections resulting from a thermonuclear war

NASA Astrophysics Data System (ADS)

Manins, P. C.

Two consequences of a major thermonuclear war are the injection of fireball material into the atmosphere and the production of vast quantities of dense smoke from fires which are ignited by the blasts. A major concern for assessment of impact on the environment is the height reached by this material. Fireball rise data are presented and a model for the plume rise from large fires in standard ambient conditions is validated with available data. It is concluded that injection of bomb debris into the stratosphere at mid and high latitudes should take place for all explosions with yield greater than approx. 30 kt of TNT equivalent. At low latitudes yields greater than 1 Mt are evidently required. Thus most fireball material would reach into the stratosphere under recently postulated scenarios. Fires would require a power output of 1.5 × 10 7 MW at middle and higher latitudes and 8 × 10 7 MW at low latitudes for significant injection of smoke into the stratosphere in standard conditions. Study of possible fires ignited in a thermonuclear war in rural and urban areas suggests that smoke from rural fires would reach the tropopause but that significant injections into the stratosphere are unlikely. Conflagration of large, medium- and high-density city-centres would, it is predicted, result in much smoke reaching to the tropopause and into the lower stratosphere at higher but not at low latitudes.

An Analysis of the Atmospheric Trajectories of the Famous Meteorite Producing Fireballs

NASA Astrophysics Data System (ADS)

Gritsevich, M. I.

2010-08-01

In the present study the modern analytical model of the atmospheric entry (Gritsevich, 2007) is applied to well-known real impacts. These are Pribram, Lost City, Innisfree, and Neuschwanstein meteorite falls. For each of the events preatmospheric mass is calculated using the data of actual observations, by selecting the parameters describing deceleration and ablation of fireballs along the luminous segment of the trajectory. Mathematical model is based on the best fitting of the observational data by the analytical solution of the equations of meteor physics. Other estimations of preatmospheric mass for Pribram, Lost City, Innisfree, and Neuschwanstein fireballs are also presented. The majority of them considerably differs from each other. The greater difference is appreciable between the estimations received by dynamic and photometric methods. In the paper (Ceplecha, ReVelle, 2005) the mixed approach is presented. However, the found terminal mass has been accepted by authors (Ceplecha, ReVelle, 2005) as the given condition. When this study was prepared, the terminal mass has been calculated analytically. And it is exceptionally important, that results have appeared quite close to their real values.

Neutrino emission from gamma-ray burst fireballs, revised.

PubMed

Hümmer, Svenja; Baerwald, Philipp; Winter, Walter

2012-06-08

We review the neutrino flux from gamma-ray bursts, which is estimated from gamma-ray observations and used for the interpretation of recent IceCube data, from a particle physics perspective. We numerically calculate the neutrino flux for the same astrophysical assumptions as the analytical fireball neutrino model, including the dominant pion and kaon production modes, flavor mixing, and magnetic field effects on the secondary muons, pions, and kaons. We demonstrate that taking into account the full energy dependencies of all spectra, the normalization of the expected neutrino flux reduces by about one order of magnitude and the spectrum shifts to higher energies, where we can pin down the exact origin of the discrepancies by the recomputation of the analytical models. We also reproduce the IceCube-40 analysis for exactly the same bursts and same assumptions and illustrate the impact of uncertainties. We conclude that the baryonic loading of the fireballs, which is an important control parameter for the emission of cosmic rays, can be constrained significantly with the full-scale experiment after about ten years.

Large-amplitude late-time radio variability in GRB 151027B

NASA Astrophysics Data System (ADS)

Greiner, J.; Bolmer, J.; Wieringa, M.; van der Horst, A. J.; Petry, D.; Schulze, S.; Knust, F.; de Bruyn, G.; Krühler, T.; Wiseman, P.; Klose, S.; Delvaux, C.; Graham, J. F.; Kann, D. A.; Moin, A.; Nicuesa-Guelbenzu, A.; Schady, P.; Schmidl, S.; Schweyer, T.; Tanga, M.; Tingay, S.; van Eerten, H.; Varela, K.

2018-06-01

Context. Deriving physical parameters from gamma-ray burst (GRB) afterglow observations remains a challenge, even 20 years after the discovery of afterglows. The main reason for the lack of progress is that the peak of the synchrotron emission is in the sub-mm range, thus requiring radio observations in conjunction with X-ray/optical/near-infrared data in order to measure the corresponding spectral slopes and consequently remove the ambiguity with respect to slow vs. fast cooling and the ordering of the characteristic frequencies. Aims: We have embarked on a multifrequency, multi-epoch observing campaign to obtain sufficient data for a given GRB that allows us to test the simplest version of the fireball afterglow model. Methods: We observed GRB 151027B, the 1000th Swift-detected GRB, with GROND in the optical-near-IR, ALMA in the sub-millimeter, ATCA in the radio band; we combined this with public Swift/XRT X-ray data. Results: While some observations at crucial times only return upper limits or surprising features, the fireball model is narrowly constrained by our data set, and allows us to draw a consistent picture with a fully determined parameter set. Surprisingly, we find rapid, large-amplitude flux density variations in the radio band which are extreme not only for GRBs, but generally for any radio source. We interpret them as scintillation effects, though their extreme nature requires the scattering screen to be at a much smaller distance than usually assumed, multiple screens, or a combination of the two. Conclusions: The data are consistent with the simplest fireball scenario for a blast wave moving into a constant-density medium, and slow-cooling electrons. All fireball parameters are constrained at or better than a factor of 2, except for the density and the fraction of the energy in the magnetic field which has a factor of 10 uncertainty in both directions. This paper makes use of the following data: ATCA: Proposal C2955 (PI: Greiner), ALMA: ADS/JAO.ALMA#2015.1.01558.T (PI: Schulze).

Origin and diagenesis of K/T impact spherules - from Haiti to Wyoming and beyond

USGS Publications Warehouse

Bohor, B.F.; Glass, B.P.

1995-01-01

Impact spherules in Cretaceous/Tertiary (K/T) boundary clays and claystones consist of two types; each type is confined to its own separate layer of the boundary couplet in the Western Hemisphere. The form and composition of each of the spherule types result from its own unique mode of origin during the K/T event. Type 1 splash-form spherules occur only in the melt-ejecta (basal) layer of the K/T couplet. This layer was deposited from a ballistic ejecta curtain composed of melt-glass droplets transported mostly within the atmosphere. In contrast, Type 2 spherules are accreted, partially crystalline, spheroidal bodies that formed by condensation of vaporized bolide and target-rock materials in an expanding fireball cloud, from which they settled out of buoyant suspension to form the fireball layer. Dendritic and skeletal Ni-rich spinel crystals are unique to these Type 2 spherules in the fireball layer. -from Authors

Absolute calibration of the mass scale in the inverse problem of the physical theory of fireballs

NASA Astrophysics Data System (ADS)

Kalenichenko, V. V.

1992-08-01

A method of the absolute calibration of the mass scale is proposed for solving the inverse problem of the physical theory of fireballs. The method is based on data on the masses of fallen meteorites whose fireballs have been photographed in flight. The method can be applied to fireballs whose bodies have not experienced significant fragmentation during their flight in the atmosphere and have kept their shape relatively well. Data on the Lost City and Innisfree meteorites are used to calculate the calibration coefficients.

Submillisecond fireball timing using de Bruijn timecodes

NASA Astrophysics Data System (ADS)

Howie, Robert M.; Paxman, Jonathan; Bland, Philip A.; Towner, Martin C.; Sansom, Eleanor K.; Devillepoix, Hadrien A. R.

2017-08-01

Long-exposure fireball photographs have been used to systematically record meteoroid trajectories, calculate heliocentric orbits, and determine meteorite fall positions since the mid-20th century. Periodic shuttering is used to determine meteoroid velocity, but up until this point, a separate method of precisely determining the arrival time of a meteoroid was required. We show it is possible to encode precise arrival times directly into the meteor image by driving the periodic shutter according to a particular pattern—a de Bruijn sequence—and eliminate the need for a separate subsystem to record absolute fireball timing. The Desert Fireball Network has implemented this approach using a microcontroller driven electro-optic shutter synchronized with GNSS UTC time to create small, simple, and cost-effective high-precision fireball observatories with submillisecond timing accuracy.

Fireball data analysis: bridging the gap between small solar system bodies and meteorite studies

NASA Astrophysics Data System (ADS)

Gritsevich, Maria; Moreno-Ibáñez, Manuel; Kuznetsova, Daria; Bouquet, Alexis; Trigo-Rodríguez, Josep; Peltoniemi, Jouni; Koschny, Detlef

2015-08-01

One of the important steps in identification of meteorite-producing fireballs and prediction of impact threat to Earth raised by potentially hazardous asteroids is the understanding and modeling of processes accompanying the object’s entry into the terrestrial atmosphere (Gritsevich et al., 2012). Such knowledge enables characterization, simulation and classification of possible impact consequences with further reommendation for potential meteorite searches. Using dimensionless expressions, which involve the pre-atmospheric meteoroid parameters, we have built physically based parametrisation to describe changes in mass, height, velocity and luminosity of the object along its atmospheric path (Gritsevich and Koschny, 2011; Bouquet et al., 2014). The developed model is suitable to estimate a number of crucial unknown values including shape change coefficient, ablation rate, and surviving meteorite mass. It is also applicable to predict the terminal height of the luminous flight and therefore, duration of the fireball (Moreno-Ibáñez et al., 2015). Besides the model description, we demonstrate its application using the wide range of observational data from meteorite-producing fireballs appearing annually (such as Košice) to larger scale impacts (such as Chelyabinsk, Sikhote-Alin and Tunguska).REFERENCESBouquet A., Baratoux D., Vaubaillon J., Gritsevich M.I., Mimoun D., Mousis O., Bouley S. (2014): Planetary and Space Science, 103, 238-249, http://dx.doi.org/10.1016/j.pss.2014.09.001Gritsevich M., Koschny D. (2011): Icarus, 212(2), 877-884, http://dx.doi.org/10.1016/j.icarus.2011.01.033Gritsevich M.I., Stulov V.P., Turchak L.I. (2012): Cosmic Research, 50(1), 56-64, http://dx.doi.org/10.1134/S0010952512010017Moreno-Ibáñez M., Gritsevich M., Trigo-Rodríguez J.M. (2015): Icarus, 250, 544-552, http://dx.doi.org/10.1016/j.icarus.2014.12.027

The NASA Fireball Network Database

NASA Technical Reports Server (NTRS)

Moser, Danielle E.

2011-01-01

The NASA Meteoroid Environment Office (MEO) has been operating an automated video fireball network since late-2008. Since that time, over 1,700 multi-station fireballs have been observed. A database containing orbital data and trajectory information on all these events has recently been compiled and is currently being mined for information. Preliminary results are presented here.

Blast wave mitigation by dry aqueous foams

NASA Astrophysics Data System (ADS)

Del Prete, E.; Chinnayya, A.; Domergue, L.; Hadjadj, A.; Haas, J.-F.

2013-02-01

This paper presents results of experiments and numerical modeling on the mitigation of blast waves using dry aqueous foams. The multiphase formalism is used to model the dry aqueous foam as a dense non-equilibrium two-phase medium as well as its interaction with the high explosion detonation products. New experiments have been performed to study the mass scaling effects. The experimental as well as the numerical results, which are in good agreement, show that more than an order of magnitude reduction in the peak overpressure ratio can be achieved. The positive impulse reduction is less marked than the overpressures. The Hopkinson scaling is also found to hold particularly at larger scales for these two blast parameters. Furthermore, momentum and heat transfers, which have the main dominant role in the mitigation process, are shown to modify significantly the classical blast wave profile and thereafter to disperse the energy from the peak overpressure due to the induced relaxation zone. In addition, the velocity of the fireball, which acts as a piston on its environment, is smaller than in air. Moreover, the greater inertia of the liquid phase tends to project the aqueous foam far from the fireball. The created gap tempers the amplitude of the transmitted shock wave to the aqueous foam. As a consequence, this results in a lowering of blast wave parameters of the two-phase spherical decaying shock wave.

Detection of the large meteoroid/NEO flux using infrasound: recent detection of the November 21, 1995, Colorado fireball

NASA Astrophysics Data System (ADS)

Revelle, Douglas O.; Whitaker, Rodney W.

1996-10-01

During the early morning of November 21, 1995, a fireball as bright as the full moon entered the atmosphere over southeastern Colorado and initially produced audible sonic boom reports from Texas to Wyoming. The event was detected locally by a security video camera which showed the reflection of the fireball event on the hood of a truck. The camera also recorded tree shadows cast by the light of the fireball. This recording includes the audio signal of a strong double boom as well. Subsequent investigation of the array near Los Alamos, New Mexico operated by the Los Alamos National Laboratory as part of its commitment to the Comprehensive Test Ban Treaty negotiations, showed the presence of an infrasonic signal from the proper direction at about the correct time for this fireball. The Los Alamos array is a four-element infrasonic system in near-continuous operation on the laboratory property. The nominal spacing between the array elements is 212 m. The basic sensor is a Globe Universal Sciences Model 100C microphone whose response is flat from about 0.1 to 300 Hz (which we filter at the high frequency end to be limited to 20 Hz). Each low frequency microphone is connected to a set of twelve porous hoses to reduce wind noise. The characteristics of the observed signal include the onset arrival time of 0939:20 UT (0239:20 MST), with a maximum timing uncertainty of plus or minus 2 minutes, the signal onset time delay from the appearance of the fireball of 21 minutes, 20 seconds, total signal duration of 2 minutes 10 seconds, the source location determined to be toward 31 degrees from true north, the horizontal trace velocity of 429 m/sec, the signal velocity of 0.29 plus or minus 0.03 km/sec, assuming a 375 km horizontal range to the fireball, the dominant signal frequency content of 0.25 to 0.84 Hz (analyzed in the frequency interval from 0.2 to 2.0 Hz), the maximum signal cross-correlation of 0.97 and the maximum signal amplitude of 2.0 plus or minus 0.1 microbars. Also, on the basis of the signal period at maximum amplitude, we estimate a probable source energy for this event of between 10 to 100 tons of TNT (53.0 tons nominal).

A New Analysis of Fireball Data from the Meteorite Observation and Recovery Project (MORP)

NASA Astrophysics Data System (ADS)

Campbell-Brown, M. D.; Hildebrand, A.

2004-12-01

Sixty fireball cameras operated in Western Canada from 1971 to 1985. Over one thousand (1016) fireballs were recorded at more than one station, but only 367 were reduced, of which 285 have been published, including that of the Innisfree meteorite. Digitization of all the data is underway, and procedures are being developed which will allow the automatic reduction of events not previously examined. The results of the analysis of 80 fireballs reduced but not previously published are presented. When the new analysis is complete, the MORP archive will be a valuable source of information on meteoroid orbits.

Mass Transport of Condensed Species in Aerodynamic Fallout Glass from a Near-Surface Nuclear Test

NASA Astrophysics Data System (ADS)

Weisz, David Gabriel

In a near-surface nuclear explosion, vaporized device materials are incorporated into molten soil and other carrier materials, forming glassy fallout upon quenching. Mechanisms by which device materials mix with carrier materials have been proposed, however, the specific mechanisms and physical conditions by which soil and other carrier materials interact in the fireball, as well as the subsequent incorporation of device materials with carrier materials, are not well constrained. A surface deposition layer was observed preserved at interfaces where two aerodynamic fallout glasses agglomerated and fused. Eleven such boundaries were studied using spatially resolved analyses to better understand the vaporization and condensation behavior of species in the fireball. Using nano-scale secondary ion mass spectrometry (NanoSIMS), we identified higher concentrations of uranium from the device in 7 of the interface layers, as well as isotopic enrichment (>75% 235U) in 9 of the interface layers. Major element analysis of the interfaces revealed the deposition layer to be chemically enriched in Fe-, Ca- and Na-bearing species and depleted in Ti- and Al-bearing species. The concentration profiles of the enriched species at the interface are characteristic of diffusion. Three of the uranium concentration profiles were fit with a modified Gaussian function, representative of 1-D diffusion from a planar source, to determine time and temperature parameters of mass transport. By using a historical model of fireball temperature to simulate the cooling rate at the interface, the temperature of deposition was estimated to be 2200 K, with 1? uncertainties in excess of 140 K. The presence of Na-species in the layers at this estimated temperature of deposition is indicative of an oxygen rich fireball. The notable depletion of Al-species, a refractory oxide that is highly abundant in the soil, together with the enrichment of Ca-, Fe-, and 235U-species, suggests an anthropogenic source of the enriched species, together with a continuous chemical fractionation process as these species condensed.

The FIREBall-2 UV sample grating efficiency at 200-208nm

NASA Astrophysics Data System (ADS)

Quiret, S.; Milliard, B.; Grange, R.; Lemaitre, G. R.; Caillat, A.; Belhadi, M.; Cotel, A.

2014-07-01

The FIREBall-2 (Faint Intergalactic Redshifted Emission Balloon-2) is a balloon-borne ultraviolet spectro-imaging mission optimized for the study of faint diffuse emission around galaxies. A key optical component of the new spectrograph design is the high throughput cost-effective holographic 2400 ℓ =mm, 110x130mm aspherized reflective grating used in the range 200 - 208nm, near 28°deviation angle. In order to anticipate the efficiency in flight conditions, we have developed a PCGrate model for the FIREBall grating calibrated on linearly polarized measurements at 12° deviation angle in the range 240-350nm of a 50x50mm replica of the same master selected for the flight grating. This model predicts an efficiency within [64:7; 64:9]+/-0:7% (S polarization) and [38:3; 45]+/-2:2% (P-polarization) for the baseline aluminum coated grating with an Al2O3 natural oxidation layer and within [63:5; 65] +/-1% (S-polarization) and [51:3; 54:8] +/-2:8% (P-polarization) for an aluminum plus a 70nm MgF2 coating, in the range 200 - 208nm and for a 28°deviation angle. The model also shows there is room for significant improvements at shorter wavelengths, of interest for future deep UV spectroscopic missions.

Determination of trajectories of fireballs using seismic network data

NASA Astrophysics Data System (ADS)

Ishihara, Y.

2006-12-01

Fireballs, Bolides, which are caused by high velocity passages of meteoroids through the atmosphere, generate shockwaves. Meteor shockwave provide us very important information (arrival time and amplitude) to study meteor physics. The shockwave arrival time data enable us to determine trajectories of the fireballs. On the other hand, the shockwave amplitude tells us size and ablation history of the meteoroid. Infrasound observation is one of the ways of detecting bolide shockwaves. However, we have no infrasound observational networks extends for large area with enough spatial distribution for determination of trajectories and estimate ablation histories. We have only a few infrasound arrays that have three or four elements, in the Japanese islands. Last decade, digital seismic networks are greatly improved for the purpose of monitoring micro earthquakes. Those seismic networks are quite sensitive for detecting micro ground vibration, and then those networks could detect not only seismic wave generated by earthquakes, but also ground oscillations generated by coupling of meteor shockwave with the ground near station. Last years, I analyses this kind of ground motion data recorded by seismic network, as meteor shockwave signals. For example, we estimate some great fireball's aerial path from arrival times of shockwaves (e.g., Ishihara et. al., 2003 Earth Planets, and Space, 2004 Geophysical Research. Letters.; Pujol et al., 2006 Planetary and Space Science), and we estimate sizes and ablation history of some great fireball and a meteorite fall (Ishihara et al., 2004 Meteoroids2004). In Japan, some great fireball falls occurred during 2004 to 2005. In this presentation, I show the trajectories of these fireballs determined from shockwave analysis. Some fireballs trajectories are also determined from photographic records. The trajectories determined from shockwave and that from photos show good agreement.

Detailed analysis of the fireball 20160317_031654 over the United Kingdom

NASA Astrophysics Data System (ADS)

Koukal, Jakub

2018-03-01

On March 17, 2016 in the early morning hours the UKMON network (United Kingdom Meteor Observation Network) cameras recorded a bright fireball with an absolute magnitude of -12.5 ± 0.4m, its atmospheric path began above the Dorset County and ended up above the Oxford County in the southern part of England. This fireball belonging to the Northern March gamma Virginids (IAU MDC #749 NMV) meteor shower was recorded from 8 cameras of the UKMON network. The atmospheric path of the bolide and the heliocentric orbit of the meteoroid are analyzed in this article. The flight of the fireball, whose absolute magnitude was comparable with the brightness of the Full Moon, was also observed by numerous random observers from the public in the United Kingdom, the Netherlands, Belgium and France. Numerical integration of the heliocentric orbit of the body and its clones was performed to find the potential parent body of the fireball and also the potential parent body of the meteor shower #749 NMV. However, no potential parent body of the fireball 20160317_031654 was found in the comets (periodic, non-periodic and lost) and asteroids database.

Acoustic analysis of shock production by very high-altitude meteors—I: infrasonic observations, dynamics and luminosity

NASA Astrophysics Data System (ADS)

Brown, P. G.; Edwards, W. N.; Revelle, D. O.; Spurny, P.

2007-04-01

Four very high-velocity and high-altitude meteors (a Leonid, two Perseids and a high-speed sporadic fireball) have been unambiguously detected at the ground both optically using precision all-sky cameras and acoustically via infrasound and seismic signals. Infrasound arriving from altitudes of over 100 km is not very common, but has been previously observed for re-entering spacecraft. This, however, is the first reported detection of such high-altitude infrasound unambiguously from meteors to our knowledge. These fragile meteoroids were found to generate acoustic waves at source heights ranging from 80 to 110 km, with most acoustic energy being generated near the lowest heights. Time residuals between observed acoustic onset and model predictions based on ray-tracing points along the photographically determined trajectories indicate that the upper winds given by the UK meteorological office (UKMO) model systematically produce lower residuals for first arrivals than those from the Naval Research Laboratory Horizontal Wind Model (HWM). Average source energies for three of the four events from acoustic data alone are found to be in the range of 2×108-9 J. One event, EN010803, had unusually favorable geometry for acoustic detection at the ground and therefore has the smallest photometric source energy (10-5 kt; 6×107 J) of any meteor detected infrasonically. When compared to the total optical radiation recorded by film, the results for the three events produce equivalent integral panchromatic luminous efficiencies of 3 7%, within a factor of two of the values proposed by Ceplecha and McCrosky [1976. Fireball end heights—a diagnostic for the structure of meteoric material. Journal of Geophysical Research 81, 6257 6275] for the velocity range (55 70 km s-1) appropriate to our events. Application of these findings to meteor showers in general suggest that the Geminid shower should be the most prolific producer of infrasound detectable meteors at the ground of all the major showers, with one Geminid fireball producing detectable infrasound from a given location every ˜400 h of observation.

High baryon and energy densities achievable in heavy-ion collisions at √{sN N}=39 GeV

NASA Astrophysics Data System (ADS)

Ivanov, Yu. B.; Soldatov, A. A.

2018-02-01

Baryon and energy densities, which are reached in central Au+Au collisions at collision energy of √{sN N}= 39 GeV, are estimated within the model of three-fluid dynamics. It is shown that the initial thermalized mean proper baryon and energy densities in a sizable central region approximately are nB/n0≈ 10 and ɛ ≈ 40 GeV/fm3, respectively. The study indicates that the deconfinement transition at the stage of interpenetration of colliding nuclei makes the system quite opaque. The final fragmentation regions in these collisions are formed not only by primordial fragmentation fireballs, i.e., the baryon-rich matter passed through the interaction region (containing approximately 30% of the total baryon charge), but also by the baryon-rich regions of the central fireball pushed out to peripheral rapidities by the subsequent almost one-dimensional expansion of the central fireball along the beam direction.

MacBurn's cylinder test problem

DOE Office of Scientific and Technical Information (OSTI.GOV)

Shestakov, Aleksei I.

2016-02-29

This note describes test problem for MacBurn which illustrates its performance. The source is centered inside a cylinder with axial-extent-to-radius ratio s.t. each end receives 1/4 of the thermal energy. The source (fireball) is modeled as either a point or as disk of finite radius, as described by Marrs et al. For the latter, the disk is divided into 13 equal area segments, each approximated as a point source and models a partially occluded fireball. If the source is modeled as a single point, one obtains very nearly the expected deposition, e.g., 1/4 of the flux on each end andmore » energy is conserved. If the source is modeled as a disk, both conservation and energy fraction degrade. However, errors decrease if the source radius to domain size ratio decreases. Modeling the source as a disk increases run-times.« less

Suzaku Finds "Fossil" Fireballs from Supernovae

NASA Image and Video Library

2017-12-08

Suzaku Finds "Fossil" Fireballs from Supernovae In a supernova remnant known as the Jellyfish Nebula, Suzaku detected X-rays from fully ionized silicon and sulfur -- an imprint of higher-temperature conditions immediately following the star's explosion. The nebula is about 65 light-years across. (12/30/2009) Credit: JAXA/NASA/Suzaku To learn more go to: www.nasa.gov/mission_pages/astro-e2/news/fossil-fireballs...

The force exerted by a fireball

DOE Office of Scientific and Technical Information (OSTI.GOV)

Makrinich, G.; Fruchtman, A.

The force exerted by a fireball was deduced both from the change of the equilibrium position of a pendulum and from the change in the pendulum oscillation period. That measured force was found to be several times larger than the force exerted by the ions accelerated across the double layer that is assumed to surround the fireball. The force enhancement that is expected by ion-neutral collisions in the fireball is evaluated to be too small to explain the measured enhanced force. Gas pressure increase, due to gas heating through electron-neutral collisions, as recently suggested [Stenzel et al., J. Appl. Phys.more » 109, 113305 (2011)], is examined as the source for the force enhancement.« less

Strange fireball as an explanation of the muon excess in Auger data

NASA Astrophysics Data System (ADS)

Anchordoqui, Luis A.; Goldberg, Haim; Weiler, Thomas J.

2017-03-01

We argue that ultrahigh-energy cosmic-ray collisions in Earth's atmosphere can probe the strange quark density of the nucleon. These collisions have center-of-mass energies ≳1 04.6A GeV , where A ≥14 is the nuclear baryon number. We hypothesize the formation of a deconfined thermal fireball which undergoes a sudden hadronization. At production the fireball has a very high matter density and consists of gluons and two flavors of light quarks (u , d ). Because the fireball is formed in the baryon-rich projectile fragmentation region, the high baryochemical potential damps the production of u u ¯ and d d ¯ pairs, resulting in gluon fragmentation mainly into s s ¯. The strange quarks then become much more abundant and upon hadronization the relative density of strange hadrons is significantly enhanced over that resulting from a hadron gas. Assuming the momentum distribution functions can be approximated by Fermi-Dirac and Bose-Einstein statistics, we estimate a kaon-to-pion ratio of about 3 and expect a similar (total) baryon-to-pion ratio. We show that, if this were the case, the excess of strange hadrons would suppress the fraction of energy which is transferred to decaying π0's by about 20%, yielding an ˜40 % enhancement of the muon content in atmospheric cascades, in agreement with recent data reported by the Pierre Auger Collaboration.

The Status of the NASA All Sky Fireball Network

NASA Technical Reports Server (NTRS)

Cooke, William J.; Moser, Danielle E.

2011-01-01

Established by the NASA Meteoroid Environment Office, the NASA All Sky Fireball Network consists of 6 meteor video cameras in the southern United States, with plans to expand to 15 cameras by 2013. As of mid-2011, the network had detected 1796 multi-station meteors, including meteors from 43 different meteor showers. The current status of the NASA All Sky Fireball Network is described, alongside preliminary results.

Could a plasma in quasi-thermal equilibrium be associated to the "orphan" TeV flares?

NASA Astrophysics Data System (ADS)

Fraija, N.

2015-12-01

TeV γ-ray detections in flaring states without activity in X-rays from blazars have attracted much attention due to the irregularity of these "orphan" flares. Although the synchrotron self-Compton model has been very successful in explaining the spectral energy distribution and spectral variability of these sources, it has not been able to describe these atypical flaring events. On the other hand, an electron-positron pair plasma at the base of the AGN jet was proposed as the mechanism of bulk acceleration of relativistic outflows. This plasma in quasi-thermal equilibrium called Wein fireball emits radiation at MeV-peak energies serving as target of accelerated protons. In this work we describe the "orphan" TeV flares presented in blazars 1ES 1959+650 and Mrk 421 assuming geometrical considerations in the jet and evoking the interactions of Fermi-accelerated protons and MeV-peak target photons coming from the Wein fireball. After describing successfully these "orphan" TeV flares, we correlate the TeV γ-ray, neutrino and UHECR fluxes through pγ interactions and calculate the number of high-energy neutrinos and UHECRs expected in IceCube/AMANDA and TA experiment, respectively. In addition, thermal MeV neutrinos produced mainly through electron-positron annihilation at the Wein fireball will be able to propagate through it. By considering two- (solar, atmospheric and accelerator parameters) and three-neutrino mixing, we study the resonant oscillations and estimate the neutrino flavor ratios as well as the number of thermal neutrinos expected on Earth.

Asteroid/meteorite streams

NASA Astrophysics Data System (ADS)

Drummond, J.

The independent discovery of the same three streams (named alpha, beta, and gamma) among 139 Earth approaching asteroids and among 89 meteorite producing fireballs presents the possibility of matching specific meteorites to specific asteroids, or at least to asteroids in the same stream and, therefore, presumably of the same composition. Although perhaps of limited practical value, the three meteorites with known orbits are all ordinary chondrites. To identify, in general, the taxonomic type of the parent asteroid, however, would be of great scientific interest since these most abundant meteorite types cannot be unambiguously spectrally matched to an asteroid type. The H5 Pribram meteorite and asteroid 4486 (unclassified) are not part of a stream, but travel in fairly similar orbits. The LL5 Innisfree meteorite is orbitally similar to asteroid 1989DA (unclassified), and both are members of a fourth stream (delta) defined by five meteorite-dropping fireballs and this one asteroid. The H5 Lost City meteorite is orbitally similar to 1980AA (S type), which is a member of stream gamma defined by four asteroids and four fireballs. Another asteroid in this stream is classified as an S type, another is QU, and the fourth is unclassified. This stream suggests that ordinary chondrites should be associated with S (and/or Q) asteroids. Two of the known four V type asteroids belong to another stream, beta, defined by five asteroids and four meteorite-dropping (but unrecovered) fireballs, making it the most probable source of the eucrites. The final stream, alpha, defined by five asteroids and three fireballs is of unknown composition since no meteorites have been recovered and only one asteroid has an ambiguous classification of QRS. If this stream, or any other as yet undiscovered ones, were found to be composed of a more practical material (e.g., water or metalrich), then recovery of the associated meteorites would provide an opportunity for in-hand analysis of a potential near-Earth resource.

Asteroid/meteorite streams

NASA Technical Reports Server (NTRS)

Drummond, J.

1991-01-01

The independent discovery of the same three streams (named alpha, beta, and gamma) among 139 Earth approaching asteroids and among 89 meteorite producing fireballs presents the possibility of matching specific meteorites to specific asteroids, or at least to asteroids in the same stream and, therefore, presumably of the same composition. Although perhaps of limited practical value, the three meteorites with known orbits are all ordinary chondrites. To identify, in general, the taxonomic type of the parent asteroid, however, would be of great scientific interest since these most abundant meteorite types cannot be unambiguously spectrally matched to an asteroid type. The H5 Pribram meteorite and asteroid 4486 (unclassified) are not part of a stream, but travel in fairly similar orbits. The LL5 Innisfree meteorite is orbitally similar to asteroid 1989DA (unclassified), and both are members of a fourth stream (delta) defined by five meteorite-dropping fireballs and this one asteroid. The H5 Lost City meteorite is orbitally similar to 1980AA (S type), which is a member of stream gamma defined by four asteroids and four fireballs. Another asteroid in this stream is classified as an S type, another is QU, and the fourth is unclassified. This stream suggests that ordinary chondrites should be associated with S (and/or Q) asteroids. Two of the known four V type asteroids belong to another stream, beta, defined by five asteroids and four meteorite-dropping (but unrecovered) fireballs, making it the most probable source of the eucrites. The final stream, alpha, defined by five asteroids and three fireballs is of unknown composition since no meteorites have been recovered and only one asteroid has an ambiguous classification of QRS. If this stream, or any other as yet undiscovered ones, were found to be composed of a more practical material (e.g., water or metalrich), then recovery of the associated meteorites would provide an opportunity for in-hand analysis of a potential near-Earth resource.

American Meteor Society Fireball reporting system and mobile application

NASA Astrophysics Data System (ADS)

Hankey, M.

2014-07-01

The American Meteor Society (AMS) founded in 1911 pioneered the visual study of meteors and has collected data relating to meteor observations and bright fireballs for over 100 years. In December 2010, the online fireball reporting system was upgraded to an interactive application that utilizes Google Maps and other programmatic methods to pinpoint the observer's location, azimuth and elevation values with a high degree of precision. The AMS has collected 10s of 1000s of witness reports relating to 100s of events each year since the new application was released. Three dimensional triangulation methods that average the data collected from witnesses have been developed that can determine the start and end points of the meteor with an accuracy of <50 km (when compared to published solutions provided by operators of all sky cameras). RA and DEC radiant estimates can also be computed for all significant events reported to the AMS. With the release of the mobile application, the AMS is able to collect more precise elevation angles than through the web application. Users can file a new report directly on the phone or update the values submitted through a web report. After web users complete their fireball report online, they are prompted to download the app and update their observation with the more precise data provided by the sensors in the mobile device. The mobile app also provides an accurate means for the witness to report the elapsed time of the fireball. To log this value, the user drags the device across the sky where they saw the fireball. This process is designed to require no button click or user interaction to start and stop the time recording. A count down initiates the process and once the user's phone crosses the plane of azimuth for the end point of the fireball the velocity timer automatically stops. Users are asked to log the recording three times in an effort to minimize error. The three values are then averaged into a final score. Once enough witnesses have filed reports, elapsed time data collected from the mobile phone can be used to determine the velocity of the fireball. With the velocity, trajectory solution and RA/DEC the AMS can plot orbital estimates for significant fireball events reported to the society. Our hope is that overtime this catalog of events will reveal patterns relating to the origins of bright fireballs at certain times of year. The AMS also hopes to be able to associate fireball events reported to the society with known meteor showers when RA/DEC radiant estimates fall close enough to those of known showers. In addition to the enhanced fireball reporting application, the AMS Mobile App provides a meteor shower calendar with information, radiant maps and moon conditions for all upcoming showers. There is also a meteor observing function inside the app that enables meteor observers to log meteor observations directly on the phone and have that data uploaded to the AMS online database and associated with that users observing profile. To record observations the user simply points the device at the part of the sky where they saw the meteor. They then drag their finger across the screen in the direction the meteor traveled. The user is then prompted to enter the magnitude of the event and associate the meteor with a known shower that is active for that date. When the user completes their session, all of the data for each meteor along with the information relating to the session is uploaded to the AMS website. Users can then review the data online in the AMS member's area. Data across all users can be aggregated for statistical analysis and ZHR estimates. Currently the AMS has over 10,000 registered users and facebook followers. In 2013 over 680,000 people visited the AMS website and the society received over 18,000 witness reports relating to 713 confirmed unique fireball events.

Charged particle spectra in 32S + 32S interactions at 200 GeV/nucleon from CCD-imaged nuclear collisions in a streamer chamber

DOE Office of Scientific and Technical Information (OSTI.GOV)

Teitelbaum, Lawrence Paul

1992-04-01

We have measured the transverse momentum spectra 1/p T dN/dp T and rapidity distributions dN/dy of negatively charged hadrons and protons for central 32S + 32S interactions at 200 GeV/nucleon incident energy. The negative hadron dN/dy distribution is too broad to be accounted for by thermal models which demand isotropic particle emission. It is compatible with models which emphasize longitudinal dynamics, by either a particle production mechanism, as in the Lund fragmentation model, or by introducing one-dimensional hydrodynamic expansion, as in the Landau model. The proton dN/dy distribution, although showing no evidence for a peak in the target fragmentation region,more » exhibits limited nuclear stopping power. We estimate the mean rapidity shift of participant target protons to be Δy ~ 1.5, greater than observed for pp collisions, less than measured in central pA collisions, and much less than would be observed for a single equilibrated fireball at midrapidity. Both the negative hadron and proton dN/dy distributions can be fit by a symmetric Landau two-fireball model. Although the spectrum possesses a two-component structure, a comparison to pp data at comparable center-of-mass energy shows no evidence for enhanced production at low p T. The two-component structure can be explained by a thermal and chemical equilibrium model which takes into account the kinematics of resonance decay. Using an expression motivated by longitudinal expansion we find the same temperature for both the protons and negative hadrons at freezeout, T f ~ 170 MeV. We conclude that the charged particle spectra of negative hadrons and protons can be accommodated in a simple collision picture of limited nuclear stopping, evolution through a state of thermal equilibrium, followed by longitudinal hydrodynamic expansion until freezeout.« less

Charged particle spectra in [sup 32]S + [sup 32]S interactions at 200 GeV/nucleon from CCD-imaged nuclear collisions in a streamer chamber

DOE Office of Scientific and Technical Information (OSTI.GOV)

Teitelbaum, L.P.

1992-04-01

We have measured the transverse momentum spectra 1/p[sub T] dN/dp[sub T] and rapidity distributions dN/dy of negatively charged hadrons and protons for central [sup 32]S + [sup 32]S interactions at 200 GeV/nucleon incident energy. The negative hadron dN/dy distribution is too broad to be accounted for by thermal models which demand isotropic particle emission. It is compatible with models which emphasize longitudinal dynamics, by either a particle production mechanism, as in the Lund fragmentation model, or by introducing one-dimensional hydrodynamic expansion, as in the Landau model. The proton dN/dy distribution, although showing no evidence for a peak in the targetmore » fragmentation region, exhibits limited nuclear stopping power. We estimate the mean rapidity shift of participant target protons to be [Delta]y [approximately] 1.5, greater than observed for pp collisions, less than measured in central pA collisions, and much less than would be observed for a single equilibrated fireball at midrapidity. Both the negative hadron and proton dN/dy distributions can be fit by a symmetric Landau two-fireball model. Although the spectrum possesses a two-component structure, a comparison to pp data at comparable center-of-mass energy shows no evidence for enhanced production at low p[sub T]. The two-component structure can be explained by a thermal and chemical equilibrium model which takes into account the kinematics of resonance decay. Using an expression motivated by longitudinal expansion we find the same temperature for both the protons and negative hadrons at freezeout, T[sub f] [approximately] 170 MeV. We conclude that the charged particle spectra of negative hadrons and protons can be accommodated in a simple collision picture of limited nuclear stopping, evolution through a state of thermal equilibrium, followed by longitudinal hydrodynamic expansion until freezeout.« less

Enhancements to the Sentinel Fireball Network Video Software

NASA Astrophysics Data System (ADS)

Watson, Wayne

2009-05-01

The Sentinel Fireball Network that supports meteor imaging of bright meteors (fireballs) has been in existence for over ten years. Nearly five years ago it moved from gathering meteor data with a camera and VCR video tape to a fisheye lens attached to a hardware device, the Sentinel box, which allowed meteor data to be recorded on a PC operating under real-time Linux. In 2006, that software, sentuser, was made available on Apple, Linux, and Window operating systems using the Python computer language. It provides basic video and management functionality and a small amount of analytic software capability. This paper describes the new and attractive future features of the software, and, additionally, it reviews some of the research and networks from the past and present using video equipment to collect and analyze fireball data that have applicability to sentuser.

On the spectrum and polarization of magnetar flare emission

NASA Astrophysics Data System (ADS)

Taverna, R.; Turolla, R.

2017-12-01

Bursts and flares are among the distinctive observational manifestations of magnetars, isolated neutron stars endowed with an ultra-strong magnetic field (B ≈ 1014-1015 G). It is believed that these events arise in a hot electron-positron plasma, injected in the magnetosphere, due to a magnetic field instability, which remains trapped within the closed magnetic field lines (the “trapped-fireball” model). We have developed a simple radiative transfer model to simulate magnetar flare emission in the case of a steady trapped fireball. We assume that magnetic Thomson scattering is the dominant source of opacity in the fireball medium, and neglect contributions from second-order radiative processes. The spectra we obtained in the 1-100 keV energy range are in broad agreement with those of available observations. The large degree of polarization (≳ 80%) predicted by our model should be easily measured by new-generation X-ray polarimeters, like IXPE, XIPE and eXTP, allowing one to confirm the model predictions.

Fireball Flash over Russia

NASA Image and Video Library

2013-02-16

This image shows the flash above Chelyabinsk, Russia, from the fireball streaking through the sky on Feb. 15, 2013. The small asteroid was approximately 56 to 66 feet in diameter. The picture was taken by a local, M. Ahmetvaleev.

Olivier Chesneau's Work on Novae

NASA Astrophysics Data System (ADS)

Millour, F.; Lagadec, E.

2015-12-01

Olivier Chesneau founded a brand new field of observational astrophysics with his attempts to resolve the novae expanding fireball from the very first days of the explosion. With the images he could get, he showed that novae do indeed explode in an aspherical way, leading to a change of paradigm for the physics of these yet-poorly understood catastrophic systems. He also set the stage for a new way of estimating novae distances, by directly measuring the sky-size of the fireball and comparing it with spectroscopic scales, taking into account the tremendous effects of the fireball geometry.

Threshold current for fireball generation

NASA Astrophysics Data System (ADS)

Dijkhuis, Geert C.

1982-05-01

Fireball generation from a high-intensity circuit breaker arc is interpreted here as a quantum-mechanical phenomenon caused by severe cooling of electrode material evaporating from contact surfaces. According to the proposed mechanism, quantum effects appear in the arc plasma when the radius of one magnetic flux quantum inside solid electrode material has shrunk to one London penetration length. A formula derived for the threshold discharge current preceding fireball generation is found compatible with data reported by Silberg. This formula predicts linear scaling of the threshold current with the circuit breaker's electrode radius and concentration of conduction electrons.

Fireball Over Tennessee and North Carolina

NASA Image and Video Library

2016-05-05

We observed a fireball the morning of May 4 around 12:50am EDT, traveling southwest at about 77,000 mph over the Nantahala National Forest on the Tennessee/North Carolina state line. At its brightest point, it rivaled the full moon. According to Dr. Bill Cooke in NASA's Meteoroid Environment Office at NASA's Marshall Space Flight Center in Huntsville, Ala. , "The fireball was bright enough to be seen through clouds, which is an attention getter. In Chickamauga, Ga., one would have thought it was a flash of lightning lighting up the clouds beneath."

Video observations, atmospheric path, orbit and fragmentation record of the fall of the Peekskill meteorite.

PubMed

Ceplecha, Z; Brown, P; Hawkes, R L; Wetherill, G; Beech, M; Mossman, K

1996-02-01

Large Near-Earth-Asteroids have played a role in modifying the character of the surface geology of the Earth over long time scales through impacts. Recent modeling of the disruption of large meteoroids during atmospheric flight has emphasized the dramatic effects that smaller objects may also have on the Earth's surface. However, comparison of these models with observations has not been possible until now. Peekskill is only the fourth meteorite to have been recovered for which detailed and precise data exist on the meteoroid atmospheric trajectory and orbit. Consequently, there are few constraints on the position of meteorites in the solar system before impact on Earth. In this paper, the preliminary analysis based on 4 from all 15 video recordings of the fireball of October 9, 1992 which resulted in the fall of a 12.4 kg ordinary chondrite (H6 monomict breccia) in Peekskill, New York, will be given. Preliminary computations revealed that the Peekskill fireball was an Earth-grazing event, the third such case with precise data available. The body with an initial mass of the order of 10(4) kg was in a pre-collision orbit with a = 1.5 AU, an aphelion of slightly over 2 AU and an inclination of 5 degrees. The no-atmosphere geocentric trajectory would have lead to a perigee of 22 km above the Earth's surface, but the body never reached this point due to tremendous fragmentation and other forms of ablation. The dark flight of the recovered meteorite started from a height of 30 km, when the velocity dropped below 3 km/s, and the body continued 50 km more without ablation, until it hit a parked car in Peekskill, New York with a velocity of about 80 m/s. Our observations are the first video records of a bright fireball and the first motion pictures of a fireball with an associated meteorite fall.

The relationship between fireballs and HRO Long Echos

NASA Astrophysics Data System (ADS)

Yanagida, E.; Amikura, S.

Ham-band Radio Observation (HRO) is one of the major methods used to observe meteor activity in Japan. We receive certain types of meteor echoes. One of the types is the long-lasting echo called a ``Long Echo''. We have the impression that Long Echoes correspond to fireballs. The present research found this relation and tried to identify fireball data from visual observations with Long Echo data of the 2002 Leonids, Geminids, and Quadrantids. From these data, we found that the identification percentage tended to be higher for fainter magnitudes, but that the percentage is small, the percentages of each meteor stream being less than 30 %. From these results, this research found that we could not simply say that brighter meteors were received as Long Echoes. It depends on the geocentric velocity of the meteor stream, with a possibility that Long Echoes correspond to darker as well as brighter fireballs.

On the Polarization Properties of Magnetar Giant Flare Pulsating Tails

NASA Astrophysics Data System (ADS)

Yang, Yuan-Pei; Zhang, Bing

2015-12-01

Three giant flares have been detected so far from soft gamma-ray repeaters, each characterized by an initial short hard spike and a pulsating tail. The observed pulsating tails are characterized by a duration of ˜100 s, an isotropic energy of ˜1044 erg, and a pulse period of a few seconds. The pulsating tail emission likely originates from the residual energy after the intense energy release during the initial spike, which forms a trapped fireball composed of a photon-pair plasma in a closed-field-line region of the magnetars. Observationally the spectra of pulsating tails can be fitted by the superposition of a thermal component and a power-law component, with the thermal component dominating the emission in the early and late stages of the pulsating-tail observations. In this paper, assuming that the trapped fireball is from a closed-field-line region in the magnetosphere, we calculate the atmospheric structure of the optically thick trapped fireball and the polarization properties of the trapped fireball. By properly treating the photon propagation in a hot, highly magnetized, electron-positron pair plasma, we tally photons in two modes (O mode and E mode) at a certain observational angle through Monte Carlo simulations. Our results suggest that the polarization degree depends on the viewing angle with respect to the magnetic axis of the magnetar, and can be as high as Π ≃ 30% in the 1-30 keV band, and Π ≃ 10% in the 30-100 keV band, if the line of sight is perpendicular to the magnetic axis.

Two Very Precisely Instrumentally Documented Meteorite Falls: Zdar nad Sazavou and Stubenberg - Prediction and Reality

NASA Astrophysics Data System (ADS)

Spurny, P.; Borovicka, J.; Haloda, J.; Shrbeny, L.; Heinlein, D.

2016-08-01

Recently two bright bolides Zdar nad Sazavou (Czechia) and Stubenberg (Germany) were recorded by the cameras of the Czech Fireball Network. Basic data and comparison of the predicted impact areas and real positions of the meteorites will be presented.

Hydrodynamic collimation of gamma-ray-burst fireballs

PubMed

Levinson; Eichler

2000-07-10

Analytic solutions are presented for the hydrodynamic collimation of a relativistic fireball by a surrounding baryonic wind emanating from a torus. The opening angle is shown to be the ratio of the power output of the inner fireball to that of the exterior baryonic wind. The gamma ray burst 990123 might thus be interpreted as a baryon-poor jet (BPJ) with an energy output of order 10(50) erg or less, collimated by a baryonic wind from a torus with an energy output of order 10(52.5) erg, roughly the geometric mean of the BPJ and its isotropic equivalent.

AMSNEXRAD-Automated detection of meteorite strewnfields in doppler weather radar

NASA Astrophysics Data System (ADS)

Hankey, Michael; Fries, Marc; Matson, Rob; Fries, Jeff

2017-09-01

For several years meteorite recovery in the United States has been greatly enhanced by using Doppler weather radar images to determine possible fall zones for meteorites produced by witnessed fireballs. While most fireball events leave no record on the Doppler radar, some large fireballs do. Based on the successful recovery of 10 meteorite falls 'under the radar', and the discovery of radar on more than 10 historic falls, it is believed that meteoritic dust and or actual meteorites falling to the ground have been recorded on Doppler weather radar (Fries et al., 2014). Up until this point, the process of detecting the radar signatures associated with meteorite falls has been a manual one and dependent on prior accurate knowledge of the fall time and estimated ground track. This manual detection process is labor intensive and can take several hours per event. Recent technological developments by NOAA now help enable the automation of these tasks. This in combination with advancements by the American Meteor Society (Hankey et al., 2014) in the tracking and plotting of witnessed fireballs has opened the possibility for automatic detection of meteorites in NEXRAD Radar Archives. Here in the processes for fireball triangulation, search area determination, radar interfacing, data extraction, storage, search, detection and plotting are explained.

Fall and Recovery of the Murrili Meteorite, and an Update on the Desert Fireball Network

NASA Astrophysics Data System (ADS)

Bland, P. A.; Towner, M. C.; Sansom, E. K.; Devillepoix, H.; Howie, R. M.; Paxman, J. P.; Cupak, M.; Benedix, G. K.; Cox, M. A.; Jansen-Sturgeon, T.; Stuart, D.; Strangway, D.

2016-08-01

The Murrili meteorite was recovered from Lake Eyre, South Australia, on 31 December 2015. It is the third meteorite recovered by the Desert Fireball Network, and the first since the network was upgraded and expanded.

The Chelyabinsk event

NASA Astrophysics Data System (ADS)

Borovička, Jiří

2016-10-01

On February 15, 2013, 3:20 UT, an asteroid of the size of about 19 meters and mass of 12,000 metric tons entered the Earth's atmosphere unexpectedly near the border of Kazakhstan and Russia. It was the largest confirmed Earth impactor since the Tunguska event in 1908. The body moved approximately westwards with a speed of 19 km s-1, on a trajectory inclined 18 degrees to the surface, creating a fireball of steadily increasing brightness. Eleven seconds after the first sightings, the fireball reached its maximum brightness. At that point, it was located less than 40 km south from Chelyabinsk, a Russian city of population more than one million, at an altitude of 30 km. For people directly underneath, the fireball was 30 times brighter than the Sun. The cosmic body disrupted into fragments; the largest of them was visible for another five seconds before it disappeared at an altitude of 12.5 km, when it was decelerated to 3 km s-1. Fifty six second later, that ~600 kg fragment landed in Lake Chebarkul and created a 8 m wide hole in the ice. Small meteorites landed in an area 80 km long and several km wide and caused no damage. The meteorites were classified as LL ordinary chondrites and were interesting by the presence of two phases, light and dark. More material remained, however, in the atmosphere forming a dust trail up to 2 km wide and extending along the fireball trajectory from altitude 18 to 70 km. The dust then circled the Earth within few days and formed a ring around the northern hemisphere. In Chelyabinsk and its surroundings a very strong blast wave arrived 90 - 150 s after the fireball passage (depending on location). The wave was produced by the supersonic flight of the body and broke ~10% of windows in Chelyabinsk (~40% of buildings were affected). More than 1600 people were injured, mostly from broken glass. The whole event was well documented by video cameras, seismic and infrasonic records, and satellite observations. The total energy was 500 kT TNT (2 × 1015 J).

ON THE POLARIZATION PROPERTIES OF MAGNETAR GIANT FLARE PULSATING TAILS

DOE Office of Scientific and Technical Information (OSTI.GOV)

Yang, Yuan-Pei; Zhang, Bing, E-mail: yypspore@gmail.com, E-mail: zhang@physics.unlv.edu

Three giant flares have been detected so far from soft gamma-ray repeaters, each characterized by an initial short hard spike and a pulsating tail. The observed pulsating tails are characterized by a duration of ∼100 s, an isotropic energy of ∼10{sup 44} erg, and a pulse period of a few seconds. The pulsating tail emission likely originates from the residual energy after the intense energy release during the initial spike, which forms a trapped fireball composed of a photon-pair plasma in a closed-field-line region of the magnetars. Observationally the spectra of pulsating tails can be fitted by the superposition ofmore » a thermal component and a power-law component, with the thermal component dominating the emission in the early and late stages of the pulsating-tail observations. In this paper, assuming that the trapped fireball is from a closed-field-line region in the magnetosphere, we calculate the atmospheric structure of the optically thick trapped fireball and the polarization properties of the trapped fireball. By properly treating the photon propagation in a hot, highly magnetized, electron–positron pair plasma, we tally photons in two modes (O mode and E mode) at a certain observational angle through Monte Carlo simulations. Our results suggest that the polarization degree depends on the viewing angle with respect to the magnetic axis of the magnetar, and can be as high as Π ≃ 30% in the 1–30 keV band, and Π ≃ 10% in the 30–100 keV band, if the line of sight is perpendicular to the magnetic axis.« less

On the development of new SPMN diurnal video systems for daylight fireball monitoring

NASA Astrophysics Data System (ADS)

Madiedo, J. M.; Trigo-Rodríguez, J. M.; Castro-Tirado, A. J.

2008-09-01

Daylight fireball video monitoring High-sensitivity video devices are commonly used for the study of the activity of meteor streams during the night. These provide useful data for the determination, for instance, of radiant, orbital and photometric parameters ([1] to [7]). With this aim, during 2006 three automated video stations supported by Universidad de Huelva were set up in Andalusia within the framework of the SPanish Meteor Network (SPMN). These are endowed with 8-9 high sensitivity wide-field video cameras that achieve a meteor limiting magnitude of about +3. These stations have increased the coverage performed by the low-scan allsky CCD systems operated by the SPMN and, besides, achieve a time accuracy of about 0.01s for determining the appearance of meteor and fireball events. Despite of these nocturnal monitoring efforts, we realised the need of setting up stations for daylight fireball detection. Such effort was also motivated by the appearance of the two recent meteorite-dropping events of Villalbeto de la Peña [8,9] and Puerto Lápice [10]. Although the Villalbeto de la Peña event was casually videotaped, and photographed, no direct pictures or videos were obtained for the Puerto Lápice event. Consequently, in order to perform a continuous recording of daylight fireball events, we setup new automated systems based on CCD video cameras. However, the development of these video stations implies several issues with respect to nocturnal systems that must be properly solved in order to get an optimal operation. The first of these video stations, also supported by University of Huelva, has been setup in Sevilla (Andalusia) during May 2007. But, of course, fireball association is unequivocal only in those cases when two or more stations recorded the fireball, and when consequently the geocentric radiant is accurately determined. With this aim, a second diurnal video station is being setup in Andalusia in the facilities of Centro Internacional de Estudios y Convenciones Ecológicas y Medioambientales (CIECEM, University of Huelva), in the environment of Doñana Natural Park (Huelva province). In this way, both stations, which are separated by a distance of 75 km, will work as a double video station system in order to provide trajectory and orbit information of mayor bolides and, thus, increase the chance of meteorite recovery in the Iberian Peninsula. The new diurnal SPMN video stations are endowed with different models of Mintron cameras (Mintron Enterprise Co., LTD). These are high-sensitivity devices that employ a colour 1/2" Sony interline transfer CCD image sensor. Aspherical lenses are attached to the video cameras in order to maximize image quality. However, the use of fast lenses is not a priority here: while most of our nocturnal cameras use f0.8 or f1.0 lenses in order to detect meteors as faint as magnitude +3, diurnal systems employ in most cases f1.4 to f2.0 lenses. Their focal length ranges from 3.8 to 12 mm to cover different atmospheric volumes. The cameras are arranged in such a way that the whole sky is monitored from every observing station. Figure 1. A daylight event recorded from Sevilla on May 26, 2008 at 4h30m05.4 +-0.1s UT. The way our diurnal video cameras work is similar to the operation of our nocturnal systems [1]. Thus, diurnal stations are automatically switched on and off at sunrise and sunset, respectively. The images taken at 25 fps and with a resolution of 720x576 pixels are continuously sent to PC computers through a video capture device. The computers run a software (UFOCapture, by SonotaCo, Japan) that automatically registers meteor trails and stores the corresponding video frames on hard disk. Besides, before the signal from the cameras reaches the computers, a video time inserter that employs a GPS device (KIWI-OSD, by PFD Systems) inserts time information on every video frame. This allows us to measure time in a precise way (about 0.01 sec.) along the whole fireball path. EPSC Abstracts, Vol. 3, EPSC2008-A-00319, 2008 European Planetary Science Congress, Author(s) 2008 However, one of the issues with respect to nocturnal observing stations is the high number of false detections as a consequence of several factors: higher activity of birds and insects, reflection of sunlight on planes and helicopters, etc. Sometimes some of these false events follow a pattern which is very similar to fireball trails, which makes absolutely necessary the use of a second station in order to discriminate between them. Other key issue is related to the passage of the Sun before the field of view of some of the cameras. In fact, special care is necessary with this to avoid any damage to the CCD sensor. Besides, depending on atmospheric conditions (dust or moisture, for instance), the Sun may saturate most of the video frame. To solve this, our automated system determines which camera is pointing towards the Sun at a given moment and disconnects it. As the cameras are endowed with autoiris lenses, its disconnection means that the optics is fully closed and, so, the CCD sensor is protected. This, of course, means that when this happens the atmospheric volume covered by the corresponding camera is not monitored. It must be also taken into account that, in general, operation temperatures are higher for diurnal cameras. This results in higher thermal noise and, so, poses some difficulties to the detection software. To minimize this effect, it is necessary to employ CCD video cameras with proper signal to noise ratio. Refrigeration of the CCD sensor with, for instance, a Peltier system, can also be considered. The astrometric reduction procedure is also somewhat different for daytime events: it requires that reference objects are located within the field of view of every camera in order to calibrate the corresponding images. This is done by allowing every camera to capture distant buildings that, by means of said calibration, would allow us to obtain the equatorial coordinates of the fireball along its path by measuring its corresponding X and Y positions on every video frame. Such calibration can be performed from stars positions measured from nocturnal images taken with the same cameras. Once made, if the cameras are not moved it is possible to estimate the equatorial coordinates of any future fireball event. We don't use any software for automatic astrometry of the images. This crucial step is made via direct measurements of the pixel position as in all our previous work. Then, from these astrometric measurements, our software estimates the atmospheric trajectory and radiant for each fireball ([10] to [13]). During 2007 and 2008 the SPMN has also setup other diurnal stations based on 1/3' progressive-scan CMOS sensors attached to modified wide-field lenses covering a 120x80 degrees FOV. They are placed in Andalusia: El Arenosillo (Huelva), La Mayora (Málaga) and Murtas (Granada). They have also night sensitivity thanks to a infrared cut filter (ICR) which enables the camera to perform well in both high and low light condition in colour as well as provide IR sensitive Black/White video at night. Conclusions First detections of daylight fireballs by CCD video camera are being achieved in the SPMN framework. Future expansion and set up of new observing stations is currently being planned. The future establishment of additional diurnal SPMN stations will allow an increase in the number of daytime fireballs detected. This will also increase our chance of meteorite recovery.

Buoyancy of the ''Y2K'' Persistent Train and the Trajectory of the 04:00:29 UT Leonid Fireball

NASA Technical Reports Server (NTRS)

Jenniskens, Peter; Rairden, Rick L.; DeVincenzi, Donald L. (Technical Monitor)

2000-01-01

The atmospheric trajectory is calculated of a particularly well studied fireball and train during the 1999 Leonid Multi-Instrument Aircraft Campaign. Less than a minute after the meteor's first appearance, the train curves into a '2'-shape, which persisted until at least 13 minutes after the fireball. We conclude that the shape results because of horizontal winds from gravity waves with a scale height of 8.3 km at 79-91 km altitude, as well as a westerly wind gradient with altitude. In addition, there is downward drift that affects the formation of loops in the train early on.

Buoyancy of the "Y2K" Persistent Train and the Trajectory of the 04:00:29 UT Leonid Fireball

NASA Astrophysics Data System (ADS)

Jenniskens, Peter; Rairden, Rick L.

The atmospheric trajectory is calculated of a particularly well studied fireball and train during the 1999 Leonid Multi-Instrument Aircraft Campaign. Less than a minute after the meteor's first appearance, the train curves into a "2"-shape, which persisted until at least 13 minutes after the fireball. We conclude that the shape results because of horizontal winds from gravity waves with a scale height of 8.3 km at 79-91 km altitude, as well as a westerly wind gradient with altitude. In addition, there is downward drift that affects the formation of loops in the train early on.

New aspects in single-body meteor physics

NASA Astrophysics Data System (ADS)

Pecina, P.; Ceplecha, Z.

1983-03-01

An exact analytical solution of the atmospheric meteoroid single-body problem is presented expressing the distance along the trajectory as a function of time, which yields a least-square fit of the observed trajectory, and analytical expressions for the velocity at the point of maximum deceleration are derived. These results are used to determine the ablation coefficient from observations. These methods are applied to 17 Prairie Network fireballs observed below the maximum deceleration point and to the Innisfree fireball, and the results are found to be superior to the ones obtained with the usual interpolation formula. A model of luminous efficiencies for small velocities and for masses up to several hundred grams based on data on Innisfree and on artificial rocketry meteors is proposed and applied to separate the shape-density coefficient from the meteoroid mass.

The Multi-Universe Cosmos. The Origin and Fate of our Universe

NASA Astrophysics Data System (ADS)

Velan, Karel

18 billion yers ago our Universe, one of many in the Cosmos, emerged from a hot, dense fireball of matter and energy created in the 4-dimensional cosmic space-time from virtual particles receiving their rest mass from a powerful primordial radiation field, the missing link to any viable theory of creation. The cloud of elementary particles and radiation collapsed by gravity into a fireball until its trappped thermal radiation caused a titanic explosion that initiated the expansion and evolution of ours universe. As the universe expanded and cooled it spawned galaxies, stars, planets and life. Proven laws of physics, observationsl data and mathematical computations support the new cosmological model which proposes a large number of universes in the cosmos in varying stages of evolution

Viscous Particle Breakup within a Cooling Nuclear Fireball

DOE Office of Scientific and Technical Information (OSTI.GOV)

Wilkinson, J. T.; Knight, K. B.; Dai, Z.

2016-10-04

Following the surface detonation of a nuclear weapon, the Earth’s crust and immediate surroundings are drawn into the fireball and form melts. Fallout is formed as these melts incorporate radioactive material from the bomb vapor and cool rapidly. The resultant fallout plume and dispersion of radioactive contamination is a function of several factors including weather patterns and fallout particle shapes and size distributions. Accurate modeling of the size distributions of fallout forms an important data point for dispersion codes that calculate the aerial distribution of fallout. While morphological evidence for aggregation of molten droplets is well documented in fallout glassmore » populations, the breakup of these molten droplets has not been similarly studied. This study documents evidence that quenched fallout populations preserve evidence of molten breakup mechanisms.« less

Electron-positron outflow from black holes.

PubMed

van Putten, M H

2000-04-24

Cosmological gamma-ray bursts (GRBs) appear as the brightest transient phenomena in the Universe. The nature of their central engine is a missing link in the theory of fireballs to stellar mass progenitors, and may be associated with low mass black holes. In contact with an external magnetic field B, black hole spin produces a gravitational potential on the wave function of charged particles. We show that a rapidly rotating black hole of mass M produces outflow from initially electrostatic equilibrium with normalized isotropic emission approximately 10(48)(B/B(c))(2)(M/7M)(2)sin (2) theta erg/s, where B(c) = 4.4x10(13) G. The half-opening angle satisfies theta >or = square root[B(c)/3B]. The outflow proposed as input to GRB fireball models.

A model of early formation of uranium molecular oxides in laser-ablated plasmas

NASA Astrophysics Data System (ADS)

Finko, Mikhail; Curreli, Davide; Azer, Magdi; Weisz, David; Crowhurst, Jonathan; Rose, Timothy; Koroglu, Batikan; Radousky, Harry; Zaug, Joseph; Armstrong, Mike

2017-10-01

An important problem within the field of nuclear forensics is fractionation: the formation of post-detonation nuclear debris whose composition does not reflect that of the source weapon. We are investigating uranium fractionation in rapidly cooling plasma using a combined experimental and modeling approach. In particular, we use laser ablation of uranium metal samples to produce a low-temperature plasma with physical conditions similar to a condensing nuclear fireball. Here we present a first plasma-chemistry model of uranium molecular species formation during the early stage of laser ablated plasma evolution in atmospheric oxygen. The system is simulated using a global kinetic model with rate coefficients calculated according to literature data and the application of reaction rate theory. The model allows for a detailed analysis of the evolution of key uranium molecular species and represents the first step in producing a uranium fireball model that is kinetically validated against spatially and temporally resolved spectroscopy measurements. This project was sponsored by the DoD, Defense Threat Reduction Agency, Grant HDTRA1-16- 1-0020. This work was performed in part under the auspices of the U.S. DoE by Lawrence Livermore National Laboratory under Contract DE-AC52- 07NA27344.

Atmospheric Dispersion of Hypergolic Liquid Rocket Fuels. Volume 1

DTIC Science & Technology

1984-11-01

hydrazlnes by nitrosonium ton (NO+), formed from the ionization of nitrogen tetroxide which is promoted by donor solvents such as aminen and hydrazines. 10... ion ). C. CALCULATION OF FIREBALL SIZE AND QUANTIFICATION OF HEAT FLUX Mie fireball size and heat flux calculations presented here are based on the

Fireball as the result of self-organization of an ensemble of diamagnetic electron-ion nanoparticles in molecular gas

DOE Office of Scientific and Technical Information (OSTI.GOV)

Lopasov, V. P., E-mail: lopas@iao.ru

The conditions for dissipative self-organization of a fireball (FB) is a molecular gas by means of a regular correction of an elastic collision of water and nitrogen molecules by the field of a coherent bi-harmonic light wave (BLW) are presented. The BWL field is generated due to conversion of energy of a linear lightning discharge into light energy. A FB consists of two components: an ensemble of optically active diamagnetic electron-ion nanoparticles and a standing wave of elliptical polarization (SWEP). It is shown that the FB lifetime depends on the energies accumulated by nanoparticles and the SWEP field and onmore » the stability of self-oscillations of the energy between nanoparticles and SWEP.« less

SPH Calculations of Comet Shoemaker-Levy-9/Jupiter Impact

NASA Astrophysics Data System (ADS)

Wingate, C. A.; Hoffman, N. M.; Stellingwerf, R. F.

1994-05-01

The impact of Comet Shoemaker-Levy 9 has been simulated in 2D axisymmetric geometry and full 3D using the Los Alamos Smooth Particle Hydrodynamics code (SPHINX). The objective of this study is to calculate energy deposition profiles and fireball evolution histories for a range of comet parameters. We hope to use these results to infer comet properties from observations. The modeling proceeds in two phases. In Phase I, the collision of the incoming fragment, or bolide, is calculated, and its kinetic energy profile is differentiated to give an energy deposition profile. The deposition profile is used as input to Phase II (see companion paper by Stellingwerf et al.) in which the fireball evolution is calculated. Two different bolide densities were simulated, 0.2 g/cm(3) and 0.92 g/cm(3) . The incoming bolide velocity was 60 km/sec and the impact angle was taken to be 45 degrees. Since the calculation is 2D, this means simply that the bolide's depth in the atmosphere is equal to its distance traveled times the cosine of 45 degrees. The baseline calculation assumed a spherical bolide with a diameter of 1 km. Various physical models were used for the bolide including perfect gas equations of state (eos), more realistic eos's and strength of materials. The model for the Jupiter atmosphere was a fit to the Orton atmosphere. The eos for the atmosphere for most of the calculations was taken to be a perfect gas with a gamma of 1.2. A sesame tabular eos was also used. Rather than modeling the entire atmosphere, small sections were modeled using blocks of particles with blocks being shuffled in and out as the calculation progressed. Calculations were done with different size sections to test the sensitivity of the results to this procedure. The results indicate energy deposition for the 0.2 density, 1 km diameter case occurring between 50-200 km. The penetration is seen to increase somewhat as the bolide resolution is improved.

Deposition of vaporized species onto glassy fallout from a near-surface nuclear test

DOE Office of Scientific and Technical Information (OSTI.GOV)

Weisz, David G.; Jacobsen, Benjamin; Marks, Naomi E.

In a near-surface nuclear explosion where the resultant fireball can interact with the surface, vaporized materials from the nuclear device can be incorporated into molten soil and other carrier materials from that surface. This mixed material becomes a source of glassy fallout upon quenching and is locally deposited. Fallout formation models have been proposed; however, the specific mechanisms and physical conditions by which soil and other carrier materials interact in the fireball, as well as the subsequent incorporation of device materials with carrier materials, are not well constrained. We observe a surface deposition layer preserved at interfaces where two aerodynamicmore » fallout glasses agglomerated and fused, and characterized 11 such boundaries using spatial analyses to better understand the vaporization and condensation behavior of species in the fireball. Using nanoscale secondary ion mass spectrometry (NanoSIMS), we identify higher enrichments of uranium from the device ( 235U/ 238U ratio >7.5) in 8 of the interface layers. Major element analysis of the interfaces reveals the deposition layer to be enriched in Fe, Ca, Mg, Mn, and Na-bearing species and depleted in Ti and Al-bearing species. Most notably, the Fe and Ca-bearing species are enriched approximately 50% at the interface layer relative to the average concentrations measured within the fallout glasses, while Ti and Al-bearing species are depleted by approximately 20%. SiO 2 is found to be relatively invariable across the samples and interfaces (~3% standard deviation). The notable depletion of Al, a refractory oxide abundant in the soil, together with the enrichment of 235U and Fe, suggests an anthropogenic source of the enriched species or an unexpected vaporization/condensation behavior. The presence of both refractory (e.g., Ca and U) and volatile (e.g., Na) species approximately co-located in most of the observed layers (within 1.5 μm) suggests a continuous condensation process may also be occurring. Lastly, these fallout formation processes deviate from historical models of fallout formation, and have not been previously recognized in the literature.« less

Deposition of vaporized species onto glassy fallout from a near-surface nuclear test

NASA Astrophysics Data System (ADS)

Weisz, David G.; Jacobsen, Benjamin; Marks, Naomi E.; Knight, Kim B.; Isselhardt, Brett H.; Matzel, Jennifer E.; Weber, Peter K.; Prussin, Stan G.; Hutcheon, Ian D.

2017-03-01

In a near-surface nuclear explosion where the resultant fireball can interact with the surface, vaporized materials from the nuclear device can be incorporated into molten soil and other carrier materials from that surface. This mixed material becomes a source of glassy fallout upon quenching and is locally deposited. Fallout formation models have been proposed; however, the specific mechanisms and physical conditions by which soil and other carrier materials interact in the fireball, as well as the subsequent incorporation of device materials with carrier materials, are not well constrained. We observe a surface deposition layer preserved at interfaces where two aerodynamic fallout glasses agglomerated and fused, and characterized 11 such boundaries using spatial analyses to better understand the vaporization and condensation behavior of species in the fireball. Using nanoscale secondary ion mass spectrometry (NanoSIMS), we identify higher enrichments of uranium from the device (235U/238U ratio >7.5) in 8 of the interface layers. Major element analysis of the interfaces reveals the deposition layer to be enriched in Fe, Ca, Mg, Mn, and Na-bearing species and depleted in Ti and Al-bearing species. Most notably, the Fe and Ca-bearing species are enriched approximately 50% at the interface layer relative to the average concentrations measured within the fallout glasses, while Ti and Al-bearing species are depleted by approximately 20%. SiO2 is found to be relatively invariable across the samples and interfaces (∼3% standard deviation). The notable depletion of Al, a refractory oxide abundant in the soil, together with the enrichment of 235U and Fe, suggests an anthropogenic source of the enriched species or an unexpected vaporization/condensation behavior. The presence of both refractory (e.g., Ca and U) and volatile (e.g., Na) species approximately co-located in most of the observed layers (within 1.5 μm) suggests a continuous condensation process may also be occurring. These fallout formation processes deviate from historical models of fallout formation, and have not been previously recognized in the literature.

Deposition of vaporized species onto glassy fallout from a near-surface nuclear test

DOE PAGES

Weisz, David G.; Jacobsen, Benjamin; Marks, Naomi E.; ...

2016-10-29

In a near-surface nuclear explosion where the resultant fireball can interact with the surface, vaporized materials from the nuclear device can be incorporated into molten soil and other carrier materials from that surface. This mixed material becomes a source of glassy fallout upon quenching and is locally deposited. Fallout formation models have been proposed; however, the specific mechanisms and physical conditions by which soil and other carrier materials interact in the fireball, as well as the subsequent incorporation of device materials with carrier materials, are not well constrained. We observe a surface deposition layer preserved at interfaces where two aerodynamicmore » fallout glasses agglomerated and fused, and characterized 11 such boundaries using spatial analyses to better understand the vaporization and condensation behavior of species in the fireball. Using nanoscale secondary ion mass spectrometry (NanoSIMS), we identify higher enrichments of uranium from the device ( 235U/ 238U ratio >7.5) in 8 of the interface layers. Major element analysis of the interfaces reveals the deposition layer to be enriched in Fe, Ca, Mg, Mn, and Na-bearing species and depleted in Ti and Al-bearing species. Most notably, the Fe and Ca-bearing species are enriched approximately 50% at the interface layer relative to the average concentrations measured within the fallout glasses, while Ti and Al-bearing species are depleted by approximately 20%. SiO 2 is found to be relatively invariable across the samples and interfaces (~3% standard deviation). The notable depletion of Al, a refractory oxide abundant in the soil, together with the enrichment of 235U and Fe, suggests an anthropogenic source of the enriched species or an unexpected vaporization/condensation behavior. The presence of both refractory (e.g., Ca and U) and volatile (e.g., Na) species approximately co-located in most of the observed layers (within 1.5 μm) suggests a continuous condensation process may also be occurring. Lastly, these fallout formation processes deviate from historical models of fallout formation, and have not been previously recognized in the literature.« less

Phenomenological Model for Infrared Emissions from High-Explosive Detonation Fireballs

DTIC Science & Technology

2007-09-01

concentrations for H2O, CO2, CO, and HCl. Fitting this model to the observed MWIR spectra affords a compact, high-fidelity representation with... concentrations separates the TNT and ENE events. Spectrally-determined R values are somewhat consistent with stoichiometric expectations. Comparing...78 4.7.2 Atmospheric Water Vapor Concentration . . . . . . . . . . . . . . . . . 79 4.7.3 Spectral Resolution

On mini-cluster observed by Chacaltaya emulsion chamber experiment

NASA Technical Reports Server (NTRS)

Tati, T.

1985-01-01

Bundles of electromagnetic showers with very small tranverse momenta (approx. 10 MeV) accompanied by decay products of Chiron-type fireballs, have been observed. These bundles are called Miniclusters. This phenomenon supports the picture of fireballs made up of hadronic matter and based on the theory of the finite degree of freedom.

What Do We Know About the "Carancas-Desaguadero" Fireball, Meteorite and Impact Crater?

NASA Astrophysics Data System (ADS)

Tancredi, G.; Ishitsuka, J.; Rosales, D.; Vidal, E.; Dalmau, A.; Pavel, D.; Benavente, S.; Miranda, P.; Pereira, G.; Vallejos, V.; Varela, M. E.; Brandstätter, F.; Schultz, P. H.; Harris, R. S.; Sánchez, L.

2008-03-01

On September 15, 2007, at noon local time, a fireball was observed and heard in the southern shore of the Lake Titicaca, close to the border between Peru and Bolivia. A crater was formed due to the impact of a chondrite meteorite weighing more than 2 tons.

Meteor reporting made easy- The Fireballs in the Sky smartphone app

NASA Astrophysics Data System (ADS)

Sansom, E.; Ridgewell, J.; Bland, P.; Paxman, J.

2016-01-01

Using smartphone technology, the award-winning 'Fireballs in the Sky' app provides a new approach to public meteor reporting. Using the internal GPS and sensors of a smartphone, a user can record the start and end position of a meteor sighting with a background star field as reference. Animations are used to visualize the duration and characteristics of the meteor. The intuitive application can be used in situ, providing a more accurate eye witness account than after-the-fact reports (although reports may also be made through a website interface). Since its launch in 2013, the app has received over 2000 submissions, including 73 events which were reported by multiple users. The app database is linked to the Desert Fireball Network in Australia (DFN), meaning app reports can be confirmed by DFN observatories. Supporting features include an integrated meteor shower tool that provides updates on active showers, their visibility based on moon phase, as well as a tool to point the user toward the radiant. The locations of reports are also now shown on a live map on the Fireballs in the Sky webpage.

PF120916 Piecki fireball and Reszel meteorite fall

NASA Astrophysics Data System (ADS)

Olech, A.; Żołądek, P.; Tymiński, Z.; Stolarz, M.; Wiśniewski, M.; Bęben, M.; Lewandowski, T.; Polak, K.; Raj, A.; Zaręba, P.

2017-06-01

On September 12, 2016, at 21:44:07 UT, a -9.2±0.5 mag fireball appeared over northeastern Poland. The precise orbit and atmospheric trajectory of the event are presented, based on the data collected by six video stations of the Polish Fireball Network (PFN). The PF120916 Piecki fireball entered the Earth's atmosphere with the velocity of 16.7±0.3 km/s and started to shine at a height of 81.9 ± 0.3 km. Clear deceleration started after first three seconds of the flight, and the terminal velocity of the meteor was only 5.0±0.3 km/s at a height of 26.0 ± 0.2 km. Such a low value of the terminal velocity indicates that fragments with the total mass of around 10-15 kg could survive the atmospheric passage and cause fall of the meteorites. The predicted area of possible meteorite impact is computed and it is located south of Reszel city at the Warmian-Masurian region. The impact area was extensively searched by experienced groups of meteorite hunters, but without any success.

Exploring Solar System Origins With The Desert Fireball Network

NASA Astrophysics Data System (ADS)

Day, B. H.; Bland, P.

2016-12-01

Fireball camera networks are designed to recover meteorites with orbits. A geological context is a prerequisite for understanding terrestrial rocks. An improved dynamical context would benefit our understanding of extraterrestrial geology. A dozen projects - professional and amateur - have pursued this goal over the years. The effort has yielded 10 meteorites with orbits. Why so few? All these projects were in the temperate zone of the northern hemisphere: areas where meteorite recovery is marginal. Deserts are one of the few places on Earth where field searches for meteorites can be mounted with a realistic chance of success. This was the driver behind the Desert Fireball Network. The Desert Fireball Network (DFN) uses automated observatories across Australia to triangulate trajectories of meteorites entering the atmosphere, determine pre-entry orbits, and pinpoint their fall positions. Each observatory is an autonomous intelligent imaging system, taking 1000×36Megapixel all-sky images throughout the night, using neural network algorithms to recognise events. They are capable of operating for 12 months in a harsh environment, and store all imagery collected. We developed a completely automated software pipeline for data reduction, and built a supercomputer database for storage, allowing us to process our entire archive. We successfully recovered a meteorite from Lake Eyre on 31st December 2015, using this pipeline. By February 2016 we had reduced our complete fireball dataset, deriving precise orbits for >350 events: a dataset that provides a unique window on the dynamics of material in the inner solar system. The DFN currently stands at 50 stations distributed across the Australian continent, covering an area of 2.5 million km2. The fireball and meteorite orbital data that it can provide will deliver a new dynamical window on the inner solar system, and new insights into solar system origins. Working with DFN's partners at NASA's Solar System Exploration Research Virtual Institute, the team is now working to expand the network beyond Australia to locations around the world.

Preliminary Experimental Results using a Steady State ICP Flow Reactor to Investigate Condensation Chemistry for Nuclear Forensics

NASA Astrophysics Data System (ADS)

Koroglu, Batikan; Armstrong, Mike; Cappelli, Mark; Chernov, Alex; Crowhurst, Jonathan; Mehl, Marco; Radousky, Harry; Rose, Timothy; Zaug, Joe

2016-10-01

The high temperature chemistry of rapidly condensing matter is under investigation using a steady state inductively coupled plasma (ICP) flow reactor. The objective is to study chemical processes on cooling time scales similar to that of a low yield nuclear fireball. The reactor has a nested set of gas flow rings that provide flexibility in the control of hydrodynamic conditions and mixing of chemical components. Initial tests were run using two different aqueous solutions (ferric nitrate and uranyl nitrate). Chemical reactants passing through the plasma torch undergo non-linear cooling from 10,000K to 1,000K on time scales of <0.1 to 0.5s depending on flow conditions. Optical spectroscopy measurements were taken at different positions along the flow axis to observe the in situ spatial and temporal evolution of chemical species at different temperatures. The current data offer insights into the changes in oxide chemistry as a function of oxygen fugacity. The time resolved measurements will also serve as a validation target for the development of kinetic models that will be used to describe chemical fractionation during nuclear fireball condensation. This work was performed under the auspices of the U.S. Department of Energy by Lawrence Livermore National Laboratory under Contract DE-AC52-07NA27344.

Fireball Observations in Visible and Sodium Bands

NASA Astrophysics Data System (ADS)

Fletcher, Sandra

On November 17th at 1:32am MST, a large Leonid fireball was simultaneously imaged by two experiments, a visible band CCD camera and a 590nm filtered band equi-angle fisheye and telecentric lens assembly. The visible band camera, ROTSE (Robotic Optical Transient Search Experiment) is a two by two f/1.9 telephoto lens array with 2k x2k Thompson CCD and is located at 35.87 N, 106.25 W at an altitude of 2115m. One-minute exposures along the radiant were taken of the event for 30 minutes after the initial explosion. The sodium band experiment was located at 35.29 N,106.46 W at an altitude of 1860m. It took ninety second exposures and captured several events throughout the night. Triangulation from two New Mexico sites resulted in an altitude of 83km over Wagon Mound, NM. Two observers present at the ROTSE site saw a green flash and a persistent glow up to seven minutes after the explosion. Cataloging of all sodium trails for comparison with lidar and infrasonic measurements is in progress. The raw data from both experiments and the atmospheric chemistry interpretation of them will be presented.

The Chelyabinsk event

NASA Astrophysics Data System (ADS)

Borovička, Jiri

2015-08-01

On February 15, 2013, 3:20 UT, an asteroid of the size of about 19 meters and mass of 12,000 metric tons entered the Earth's atmosphere unexpectedly near the border of Kazakhstan and Russia. It was the largest confirmed Earth impactor since the Tunguska event in 1908. The body moved approximately westwards with a speed of 19 km/s, on a trajectory inclined 18 degrees to the surface, creating a fireball of steadily increasing brightness. Eleven seconds after the first sightings, the fireball reached its maximum brightness. At that point, it was located less than 40 km south from Chelyabinsk, a Russian city of population more than one million, at an altitude of 30 km. For people directly underneath, the fireball was 30 times brighter than the Sun. The cosmic body disrupted into fragments; the largest of them was visible for another five seconds before it disappeared at an altitude of 12.5 km, when it was decelerated to 3 km/s. Fifty six second later, that ~ 600 kg fragment landed in Lake Chebarkul and created an 8 m wide hole in the ice. More material remained, however, in the atmosphere forming a dust trail up to 2 km wide and extending along the fireball trajectory from altitude 18 to 70 km. People observing the dust trail from Chelyabinsk and other places were surprised by the arrival of a very strong blast wave 90 - 150 s after the fireball passage (depending on location). The wave, produced by the supersonic flight of the body, broke ~10% of windows in Chelyabinsk (~40% of buildings were affected). More than 1600 people were injured, mostly from broken glass. Small meteorites landed in an area 60 km long and several km wide and caused no damage. The meteorites were classified as LL ordinary chondrites and were interesting by the presence of two phases, light and dark. The dust left in the atmosphere circled the Earth within few days and formed a ring around the northern hemisphere.The whole event was well documented by video cameras, seismic and infrasonic records, and satellite observations. The total energy was 500 kT TNT (2×1015 J). Details of the atmospheric fragmentations and implication for the asteroid impact hazard will be discussed in this review..

5-10 GeV neutrinos from gamma-Ray burst fireballs

PubMed

Bahcall; Meszaros

2000-08-14

A gamma-ray burst fireball is likely to contain an admixture of neutrons. Inelastic collisions between differentially streaming protons and neutrons in the fireball produce nu(&mgr;) (nu;(&mgr;)) of approximately 10 GeV as well as nu(e) (nu;(e)) of approximately 5 GeV, which could produce approximately 7 events/year in km(3) detectors, if the neutron abundance is comparable to that of protons. Photons of approximately 10 GeV from pi(0) decay and approximately 100 MeV nu;(e) from neutron decay are also produced, but will be difficult to detect. Photons with energies less, similar1 MeV from shocks following neutron decay produce a characteristic signal which may be distinguishable from the proton-related MeV photons.

Robustness of the filamentation instability as shock mediator in arbitrarily oriented magnetic field

DOE Office of Scientific and Technical Information (OSTI.GOV)

Bret, A.; Alvaro, E. Perez

2011-08-15

The filamentation instability (sometimes also referred to as ''Weibel'') is a key process in many astrophysical scenario. In the Fireball model for gamma ray bursts, this instability is believed to mediate collisionless shock formation from the collision of two plasma shells. It has been known for long that a flow aligned magnetic field can completely cancel this instability. We show here that in the general case where there is an angle between the field and the flow, the filamentation instability can never be stabilized, regardless of the field strength. The presented model analyzes the stability of two symmetric counter-streaming coldmore » electron/proton plasma shells. Relativistic effects are accounted for, and various exact analytical results are derived. This result guarantees the occurrence of the instability in realistic settings fulfilling the cold approximation.« less

The makings of meteor astronomy: part VII.

NASA Astrophysics Data System (ADS)

Beech, M.

1994-08-01

The idea that meteors might be some form of "electrical manifestation" was a popular one for several decades near the end of the 18th century. The great fireball of August 18, 1783, prompted one researcher, Charles Blagden, to develop a detailed empirical model which described all manner of meteoric phenomena.

Did Earth-approaching asteroids 3551, 3908, or 4055 produce meteorites?

NASA Technical Reports Server (NTRS)

Gustafson, Bo A. S.; Williams, I. P.

1992-01-01

Orbital integrations show that Amor asteroid 3908 could have ejected one out of four plausible groups of meteorite producing fireballs during a collision in the asteroid belt. It was suggested by others that such a collision may also have split asteroids 3551 and 3908. A member of this group of fireballs is listed as one of the better possibilities for recovery.

The NASA Fireball Network

NASA Technical Reports Server (NTRS)

Cooke, William J.

2013-01-01

In the summer of 2008, the NASA Meteoroid Environments Office (MEO) began to establish a video fireball network, based on the following objectives: (1) determine the speed distribution of cm size meteoroids, (2) determine the major sources of cm size meteoroids (showers/sporadic sources), (3) characterize meteor showers (numbers, magnitudes, trajectories, orbits), (4) determine the size at which showers dominate the meteor flux, (5) discriminate between re-entering space debris and meteors, and 6) locate meteorite falls. In order to achieve the above with the limited resources available to the MEO, it was necessary that the network function almost fully autonomously, with very little required from humans in the areas of upkeep or analysis. With this in mind, the camera design and, most importantly, the ASGARD meteor detection software were adopted from the University of Western Ontario's Southern Ontario Meteor Network (SOMN), as NASA has a cooperative agreement with Western's Meteor Physics Group. 15 cameras have been built, and the network now consists of 8 operational cameras, with at least 4 more slated for deployment in calendar year 2013. The goal is to have 15 systems, distributed in two or more groups east of automatic analysis; every morning, this server also automatically generates an email and a web page (http://fireballs.ndc.nasa.gov) containing an automated analysis of the previous night's events. This analysis provides the following for each meteor: UTC date and time, speed, start and end locations (longitude, latitude, altitude), radiant, shower identification, light curve (meteor absolute magnitude as a function of time), photometric mass, orbital elements, and Tisserand parameter. Radiant/orbital plots and various histograms (number versus speed, time, etc) are also produced. After more than four years of operation, over 5,000 multi-station fireballs have been observed, 3 of which potentially dropped meteorites. A database containing data on all these events, including the videos and calibration information, has been developed and is being modified to include data from the SOMN and other camera networks.

Correlation of high energy muons with primary composition in extensive air shower

NASA Technical Reports Server (NTRS)

Chou, C.; Higashi, S.; Hiraoka, N.; Ozaki, S.; Sato, T.; Suwada, T.; Takahasi, T.; Umeda, H.

1985-01-01

An experimental investigation of high energy muons above 200 GeV in extensive air showers has been made for studying high energy interaction and primary composition of cosmic rays of energies in the range 10 to the 14th power approx. 10 to the 15th power eV. The muon energies are estimated from the burst sizes initiated by the muons in the rock, which are measured by four layers of proportional counters, each of area 5 x 2.6 sq m, placed at 30 m.w.e. deep, Funasaka tunnel vertically below the air shower array. These results are compared with Monte Carlo simulations based on the scaling model and the fireball model for two primary compositions, all proton and mixed.

Limits on Neutrino Emission from Gamma-Ray Bursts with the 40 String IceCube Detector

NASA Astrophysics Data System (ADS)

Abbasi, R.; Abdou, Y.; Abu-Zayyad, T.; Adams, J.; Aguilar, J. A.; Ahlers, M.; Andeen, K.; Auffenberg, J.; Bai, X.; Baker, M.; Barwick, S. W.; Bay, R.; Bazo Alba, J. L.; Beattie, K.; Beatty, J. J.; Bechet, S.; Becker, J. K.; Becker, K.-H.; Benabderrahmane, M. L.; Benzvi, S.; Berdermann, J.; Berghaus, P.; Berley, D.; Bernardini, E.; Bertrand, D.; Besson, D. Z.; Bindig, D.; Bissok, M.; Blaufuss, E.; Blumenthal, J.; Boersma, D. J.; Bohm, C.; Bose, D.; Böser, S.; Botner, O.; Braun, J.; Brown, A. M.; Buitink, S.; Carson, M.; Chirkin, D.; Christy, B.; Clem, J.; Clevermann, F.; Cohen, S.; Colnard, C.; Cowen, D. F.; D'Agostino, M. V.; Danninger, M.; Daughhetee, J.; Davis, J. C.; de Clercq, C.; Demirörs, L.; Depaepe, O.; Descamps, F.; Desiati, P.; de Vries-Uiterweerd, G.; Deyoung, T.; Díaz-Vélez, J. C.; Dierckxsens, M.; Dreyer, J.; Dumm, J. P.; Ehrlich, R.; Eisch, J.; Ellsworth, R. W.; Engdegård, O.; Euler, S.; Evenson, P. A.; Fadiran, O.; Fazely, A. R.; Fedynitch, A.; Feusels, T.; Filimonov, K.; Finley, C.; Fischer-Wasels, T.; Foerster, M. M.; Fox, B. D.; Franckowiak, A.; Franke, R.; Gaisser, T. K.; Gallagher, J.; Geisler, M.; Gerhardt, L.; Gladstone, L.; Glüsenkamp, T.; Goldschmidt, A.; Goodman, J. A.; Grant, D.; Griesel, T.; Groß, A.; Grullon, S.; Gurtner, M.; Ha, C.; Hallgren, A.; Halzen, F.; Han, K.; Hanson, K.; Heinen, D.; Helbing, K.; Herquet, P.; Hickford, S.; Hill, G. C.; Hoffman, K. D.; Homeier, A.; Hoshina, K.; Hubert, D.; Huelsnitz, W.; Hülß, J.-P.; Hulth, P. O.; Hultqvist, K.; Hussain, S.; Ishihara, A.; Jacobsen, J.; Japaridze, G. S.; Johansson, H.; Joseph, J. M.; Kampert, K.-H.; Kappes, A.; Karg, T.; Karle, A.; Kelley, J. L.; Kemming, N.; Kenny, P.; Kiryluk, J.; Kislat, F.; Klein, S. R.; Köhne, J.-H.; Kohnen, G.; Kolanoski, H.; Köpke, L.; Kopper, S.; Koskinen, D. J.; Kowalski, M.; Kowarik, T.; Krasberg, M.; Krings, T.; Kroll, G.; Kuehn, K.; Kuwabara, T.; Labare, M.; Lafebre, S.; Laihem, K.; Landsman, H.; Larson, M. J.; Lauer, R.; Lehmann, R.; Lünemann, J.; Madsen, J.; Majumdar, P.; Marotta, A.; Maruyama, R.; Mase, K.; Matis, H. S.; Meagher, K.; Merck, M.; Mészáros, P.; Meures, T.; Middell, E.; Milke, N.; Miller, J.; Montaruli, T.; Morse, R.; Movit, S. M.; Nahnhauer, R.; Nam, J. W.; Naumann, U.; Nießen, P.; Nygren, D. R.; Odrowski, S.; Olivas, A.; Olivo, M.; O'Murchadha, A.; Ono, M.; Panknin, S.; Paul, L.; Pérez de Los Heros, C.; Petrovic, J.; Piegsa, A.; Pieloth, D.; Porrata, R.; Posselt, J.; Price, P. B.; Prikockis, M.; Przybylski, G. T.; Rawlins, K.; Redl, P.; Resconi, E.; Rhode, W.; Ribordy, M.; Rizzo, A.; Rodrigues, J. P.; Roth, P.; Rothmaier, F.; Rott, C.; Ruhe, T.; Rutledge, D.; Ruzybayev, B.; Ryckbosch, D.; Sander, H.-G.; Santander, M.; Sarkar, S.; Schatto, K.; Schmidt, T.; Schoenwald, A.; Schukraft, A.; Schultes, A.; Schulz, O.; Schunck, M.; Seckel, D.; Semburg, B.; Seo, S. H.; Sestayo, Y.; Seunarine, S.; Silvestri, A.; Slipak, A.; Spiczak, G. M.; Spiering, C.; Stamatikos, M.; Stanev, T.; Stephens, G.; Stezelberger, T.; Stokstad, R. G.; Stoyanov, S.; Strahler, E. A.; Straszheim, T.; Sullivan, G. W.; Swillens, Q.; Taavola, H.; Taboada, I.; Tamburro, A.; Tarasova, O.; Tepe, A.; Ter-Antonyan, S.; Tilav, S.; Toale, P. A.; Toscano, S.; Tosi, D.; Turčan, D.; van Eijndhoven, N.; Vandenbroucke, J.; van Overloop, A.; van Santen, J.; Vehring, M.; Voge, M.; Voigt, B.; Walck, C.; Waldenmaier, T.; Wallraff, M.; Walter, M.; Weaver, C.; Wendt, C.; Westerhoff, S.; Whitehorn, N.; Wiebe, K.; Wiebusch, C. H.; Williams, D. R.; Wischnewski, R.; Wissing, H.; Wolf, M.; Woschnagg, K.; Xu, C.; Xu, X. W.; Yodh, G.; Yoshida, S.; Zarzhitsky, P.

2011-04-01

IceCube has become the first neutrino telescope with a sensitivity below the TeV neutrino flux predicted from gamma-ray bursts if gamma-ray bursts are responsible for the observed cosmic-ray flux above 1018eV. Two separate analyses using the half-complete IceCube detector, one a dedicated search for neutrinos from pγ interactions in the prompt phase of the gamma-ray burst fireball and the other a generic search for any neutrino emission from these sources over a wide range of energies and emission times, produced no evidence for neutrino emission, excluding prevailing models at 90% confidence.

The NASA Fireball Network All-Sky Cameras

NASA Technical Reports Server (NTRS)

Suggs, Rob M.

2011-01-01

The construction of small, inexpensive all-sky cameras designed specifically for the NASA Fireball Network is described. The use of off-the-shelf electronics, optics, and plumbing materials results in a robust and easy to duplicate design. Engineering challenges such as weather-proofing and thermal control and their mitigation are described. Field-of-view and gain adjustments to assure uniformity across the network will also be detailed.

When the Sky Falls: Performing Initial Assessments of Bright Atmospheric Events

NASA Technical Reports Server (NTRS)

Cooke, William J.; Brown, Peter; Blaauw, Rhiannon; Kingery, Aaron; Moser, Danielle

2015-01-01

The 2013 Chelyabinsk super bolide was the first "significant" impact event to occur in the age of social media and 24 hour news. Scientists, used to taking many days or weeks to analyze fireball events, were hard pressed to meet the immediate demands (within hours) for answers from the media, general public, and government officials. Fulfilling these requests forced many researchers to exploit information available from various Internet sources - videos were downloaded from sites like Youtube, geolocated via Google Street View, and quickly analyzed with improvised software; Twitter and Facebook were scoured for eyewitness accounts of the fireball and reports of meteorites. These data, combined with infrasound analyses, enabled a fairly accurate description of the Chelyabinsk event to be formed within a few hours; in particular, any relationship to 2012 DA14 (which passed near Earth later that same day) was eliminated. Results of these analyses were quickly disseminated to members of the NEO community for press conferences and media interviews. Despite a few minor glitches, the rapid initial assessment of Chelyabinsk was a triumph, permitting the timely conveyance of accurate information to the public and the incorporation of social media into fireball analyses. Beginning in 2008, the NASA Meteoroid Environments Office, working in cooperation with Western's Meteor Physics Group, developed processes and software that permit quick characterization - mass, trajectory, and orbital properties - of fireball events. These tools include automated monitoring of Twitter to establish the time of events (the first tweet is usually no more than a few seconds after the fireball), mining of Youtube and all sky camera web archives to locate videos suitable for analyses, use of Google Earth and Street View to geolocate the video locations, and software to determine the fireball trajectory and object orbital parameters, including generation of animations suitable for popular media and presentations. This presentation will give a short description of the characterization procedure and show applications of the tools, which have become vital to answering the question of "What was that bright light in the sky?" in the post-Chelyabinsk, 24/7 news world.

Tidal heating and mass loss in neutron star binaries - Implications for gamma-ray burst models

NASA Technical Reports Server (NTRS)

Meszaros, P.; Rees, M. J.

1992-01-01

A neutron star in a close binary orbit around another neutron star (or stellar-mass black hole) spirals inward owing to gravitational radiation. We discuss the effects of tidal dissipation during this process. Tidal energy dissipated in the neutron star's core escapes mainly as neutrinos, but heating of the crust, and outward diffusion of photons, blows off the outer layers of the star. This photon-driven mass loss precedes the final coalescence. The presence of this eject material impedes the escape of gamma-rays created via neutrino interactions. If an e(+) - e(-) fireball, created in the late stages of coalescence, were loaded with (or surrounded by) material with the mean column density of the ejecta, it could not be an efficient source of gamma-rays. Models for cosmologically distant gamma-rays burst that involve neutron stars must therefore be anisotropic, so that the fireball expands preferentially in directions where the column density of previously blown-off material is far below the spherically averaged value which we have calculated. Some possible 'scenarios' along these lines are briefly discussed.

Vigie Ciel a collaborative project to study fireballs and organise meteorite recoveries

NASA Astrophysics Data System (ADS)

Colas, F.; Zanda, B.; Bouley, S.; Lewin, E.; Vaubaillon, J.; Marmo, C.; Rotaru, M.; Labenne, L.; Julien, J. F.; Linares, M.; Steinhausser, A.; Rault, J. L.; Vernazza, P.

2015-10-01

Research on fireballs and meteorites has always been of interest to the public, due to the beauty of shooting stars in the night sky and to the extraterrestrial origin of meteorites. A fireball observation network called FRIPON [1] (Colas et al, 2015) is currently being setup, funded by ANR (Agence Nationale pour la Recherche). It will cover France with 100 cameras and is expected to be operational for the end of 2015. FRIPON will detect fireballs and hence allow us to define meteorite strewn fields within 24h, so that meteorite searches can be launched very early on. Because of the need to search all over France, including in private land, it is important that the general public be aware of our project and be willing to help or participate. Indeed, as the main goal of FRIPON is to recover fresh meteorites (within a few days), our aim is to be able to organize a search with at least 50 persons to scan an area of a few km2 within a week. Help from the public would hence be most helpful but it is also important to have an operational and trained research team. This project thus appears as a unique occasion to involve the public in a scientific project while promoting informal scientific education. This prompted us to set up Vigie-Ciel, a citizen science network centered on meteorite recovery. FRIPON is an open network based on open-source software, it will accept citizenrun cameras. In addition to fireballs, it will allow scientists and Vigie-Ciel participants to study anything that can be observed by all-sky cameras: bird migrations, bats, clouds, lightning, etc. The data will be freely available to all.

The Spanish Fireball Network: Popularizing Interplanetary Matter

NASA Astrophysics Data System (ADS)

Trigo-Rodríguez, J. M.; Castro-Tirado, A.; Llorca, J.; Fabregat, J.

In order to increase in Spain the social interest in the study of interplanetary matter (asteroids, comets and meteoroids) we created the Spanish Photographic Meteor Network (SPMN) in 1997. This network has been dedicated to studying interplanetary matter with participation of researchers from three universities (Universitat Jaume I, Universitat de Barcelona and Universitat de València), the Institut d'Estudis Espacials de Catalunya (IEEC) and the Instituto de Astrofísica de Andalucía and it is also supported by the Atmospheric Sounding Station at El Arenosillo (INTA-CEDEA) and by the Experimental Station La Mayora (EELM-CSIC). In order to promote the participation of amateurs, our homepage (www.spmn.uji.es) presents public information about our research explains how amateur astronomers can participate in our network. In this paper we give some examples of the social role of a Fireball Network in order to give a coherent explanation to bright fireball events. Moreover, we also discuss the role of this kind of research project as a promoter of amateur participation and contribution to science. In fact, meteor astronomy can become an excellent area to form young researchers because systematic observation of meteors using photographic, video and CCD techniques has become one of the rare fields in astronomy in which amateurs can work together with professionals to make important contributions. We present here some results of the campaigns realized from the formation of the network. Finally, in a new step of development of our network, the all-sky CCD automatic cameras will be continuously detecting meteors and fireballs from four stations located in the Andalusia and Valencian communities by the end of 2005. Additionally, during important meteor showers we plan to develop fireball spectroscopy using medium field lenses.

Collected Extraterrestrial Materials: Constraints on Meteor and Fireball Compositions

NASA Astrophysics Data System (ADS)

Rietmeijer, Frans J. M.; Nuth, Joseph A., III

The bulk density and bulk porosity of IDPs and various meteorite classes show that protoplanet accretion and evolution were arrested at different stages as a function of parent body modification. The collected IDPs, micrometeorites and meteorites are aggregates of different structural entities that were inherited from the earliest times of solar system evolution. These structural entities and the extent of parent body lithification will determine the material strength of the meteoroids entering the Earth's atmosphere. There is a need for measurements of the material strength of collected extraterrestrial materials because they will in part determine the nature of the chemical interactions of descending meteors and fireballs in the atmosphere. High-precision determinations of meteor and fireball compositions are required to search for anhydrous, carbon-rich proto-CI material that has survived in the boulders of comet nuclei.

Current status of Polish Fireball Network

NASA Astrophysics Data System (ADS)

Wiśniewski, M.; Żołądek, P.; Olech, A.; Tyminski, Z.; Maciejewski, M.; Fietkiewicz, K.; Rudawska, R.; Gozdalski, M.; Gawroński, M. P.; Suchodolski, T.; Myszkiewicz, M.; Stolarz, M.; Polakowski, K.

2017-09-01

The Polish Fireball Network (PFN) is a project to monitor regularly the sky over Poland in order to detect bright fireballs. In 2016 the PFN consisted of 36 continuously active stations with 57 sensitive analogue video cameras and 7 high resolution digital cameras. In our observations we also use spectroscopic and radio techniques. A PyFN software package for trajectory and orbit determination was developed. The PFN project is an example of successful participation of amateur astronomers who can provide valuable scientific data. The network is coordinated by astronomers from Copernicus Astronomical Centre in Warsaw, Poland. In 2011-2015 the PFN cameras recorded 214,936 meteor events. Using the PFN data and the UFOOrbit software 34,609 trajectories and orbits were calculated. In the following years we are planning intensive modernization of the PFN network including installation of dozens of new digital cameras.

Asymmetric Fireballs in Symmetric Collisions

DOE PAGES

Bialas, A.; Bzdak, A.; Zalewski, K.

2013-01-01

Here, this contribution reports on the results obtained in the two recently published papers demonstrating that data of the STAR Collaboration show a substantial asymmetric component in the rapidity distribution of the system created in central Au-Au collisions, implying that boost invariance is violated on the event-by-event basis even at the mid c.m. rapidity.

Fireball flickering: the case for indirect measurement of meteoroid rotation rates

NASA Astrophysics Data System (ADS)

Beech, Martin; Brown, Peter

2000-08-01

Data collected during the Meteorite Observation and Recovery Program (MORP) indicate that 4% of bright fireballs show a periodic variation or flickering in brightness. The observed flickering frequencies vary from a few Hz to as high as 500 Hz. We interpret the flickering phenomenon in terms of meteoroid rotation. The MORP data does not reveal any apparent correlation between the flickering frequency and the properties of the meteoroid or the atmospheric flow conditions under which ablation is taking place. It is argued that the most likely cause of the flickering phenomenon is the rotational modulation of the cross-section area presented by the meteoroid to the on-coming airflow. A study is made of the Peekskill fireball and it is concluded that the meteoroid was spun-up during its long flight through the Earth's atmosphere, and that its initial brake up was due to rotational bursting. We also argue that the Peekskill event provides the best observational evidence that the flickering phenomenon is truly related to the rotation rate of the impinging meteoroid. We find that the observed rotation rates of the MORP fireballs are clustered just below the allowed limit set by rotational bursting, but argue that this is due to an observational selection effect that mitigates against the detection of low-frequency flickering.

A relativistic neutron fireball from a supernova explosion as a possible source of chiral influence.

PubMed

Gusev, G A; Saito, T; Tsarev, V A; Uryson, A V

2007-06-01

We elaborate on a previously proposed idea that polarized electrons produced from neutrons, released in a supernova (SN) explosion, can cause chiral dissymmetry of molecules in interstellar gas-dust clouds. A specific physical mechanism of a relativistic neutron fireball with Lorentz factor of the order of 100 is assumed for propelling a great number of free neutrons outside the dense SN shell. A relativistic chiral electron-proton plasma, produced from neutron decays, is slowed down owing to collective effects in the interstellar plasma. As collective effects do not involve the particle spin, the electrons can carry their helicities to the cloud. The estimates show high chiral efficiency of such electrons. In addition to this mechanism, production of circularly polarized ultraviolet photons through polarized-electron bremsstrahlung at an early stage of the fireball evolution is considered. It is shown that these photons can escape from the fireball plasma. However, for an average density of neutrals in the interstellar medium of the order of 0.2 cm(-3) and at distances of the order of 10 pc from the SN, these photons will be absorbed with a factor of about 10(-7) due to the photoeffect. In this case, their chiral efficiency will be about five orders of magnitude less than that for polarized electrons.

Impact detections of temporarily captured natural satellites

NASA Astrophysics Data System (ADS)

Clark, David; Spurný, Pavel; Wiegert, Paul; Brown, Peter G.; Borovicha, Jiri; Tagliaferri, Ed; Shrbeny, Lukas

2016-10-01

Temporarily Captured Orbiters (TCOs) are Near-Earth Objects (NEOs) which make a few orbits of Earth before returning to heliocentric orbits. Only one TCO has been observed to date, 2006 RH120, captured by Earth for one year before escaping. Detailed modeling predicts capture should occur from the NEO population predominantly through the Sun-Earth L1 and L2 points, with 1% of TCOs impacting Earth and approximately 0.1% of meteoroids being TCOs. Although thousands of meteoroid orbits have been measured, none until now have conclusively exhibited TCO behaviour, largely due to difficulties in measuring initial meteoroid speed with sufficient precision. We report on a precise meteor observation of January 13, 2014 by a new generation of all-sky fireball digital camera systems operated in the Czech Republic as part of the European Fireball Network, providing the lowest natural object entry speed observed in decades long monitoring by networks world-wide. Modeling atmospheric deceleration and fragmentation yields an initial mass of ~5 kg and diameter of 15 cm, with a maximum Earth-relative velocity just over 11.0 km/s. Spectral observations prove its natural origin. Back-integration across observational uncertainties yields a 92 - 98% probability of TCO behaviour, with close lunar dynamical interaction. The capture duration varies across observational uncertainties from 48 days to 5+ years. We also report on two low-speed impacts recorded by US Government sensors, and we examine Prairie Network event PN39078 from 1965 having an extremely low entry speed of 10.9 km/s. In these cases uncertainties in measurement and origin make TCO designation uncertain.

Two populations and models of gamma ray bursts

NASA Technical Reports Server (NTRS)

Katz, J. I.

1993-01-01

Gamma-ray burst statistics are best explained by a source population at cosmological distances, while spectroscopy and intensity histories of some individual bursts imply an origin on Galactic neutron stars. To resolve this inconsistency I suggest the presence of two populations, one at cosmological distances and the other Galactic. I build on ideas of Shemi and Piran (1990) and of Rees and Mesozaros (1992) involving the interaction of fireball debris with surrounding clouds to explain the observed intensity histories in bursts at cosmological distances. The distances to the Galactic population are undetermined because they are too few to affect the statistics of intensity and direction; I explain them as resulting from magnetic reconnection in neutron star magnetospheres. An appendix describes the late evolution of the debris as a relativistic blast wave.

A New Analysis of Data from the Meteorite Observation and Recovery Project

NASA Astrophysics Data System (ADS)

Campbell-Brown, M. D.; Hildebrand, A.

2004-11-01

Sixty fireball cameras operated in Western Canada from 1971-1985. Over one thousand fireballs were recorded at more than one station, but only of order 350 were reduced, including that of the Innisfree meteorite. The negatives are being scanned and procedures are being developed which will allow the reduction of the other events. When finished, the MORP archive will be a valuable source of information on meteoroid orbits.

Infrasound and seismic detections associated with the 7 September 2015 Bangkok fireball

DOE PAGES

Caudron, Corentin; Taisne, Benoit; Perttu, Anna; ...

2016-08-22

A bright fireball was reported at 01:43:35 UTC on September 7, 2015 at a height of ~30 km above 14.5°N, 98.9°E near Bangkok, Thailand. It had a TNT yield equivalent of 3.9 kilotons (kt), making it the largest fireball detected in South–East Asia since the ~50 kt 2009 Sumatra bolide. Infrasonic signals were observed at four infrasound arrays that are part of the International Monitoring System (IMS) and one infrasound array located in Singapore. Acoustic bearings and event origin times inferred from array processing are consistent with the eyewitness accounts. A seismic signal associated with this event was also likelymore » recorded at station SRDT, in Thailand. As a result, an acoustic energy equivalent of 1.15 ± 0.24 kt is derived from the Singaporean acoustic data using the period of the peak energy.« less

Infrasound and seismic detections associated with the 7 September 2015 Bangkok fireball

DOE Office of Scientific and Technical Information (OSTI.GOV)

Caudron, Corentin; Taisne, Benoit; Perttu, Anna

A bright fireball was reported at 01:43:35 UTC on September 7, 2015 at a height of ~30 km above 14.5°N, 98.9°E near Bangkok, Thailand. It had a TNT yield equivalent of 3.9 kilotons (kt), making it the largest fireball detected in South–East Asia since the ~50 kt 2009 Sumatra bolide. Infrasonic signals were observed at four infrasound arrays that are part of the International Monitoring System (IMS) and one infrasound array located in Singapore. Acoustic bearings and event origin times inferred from array processing are consistent with the eyewitness accounts. A seismic signal associated with this event was also likelymore » recorded at station SRDT, in Thailand. As a result, an acoustic energy equivalent of 1.15 ± 0.24 kt is derived from the Singaporean acoustic data using the period of the peak energy.« less

The 2013 Russian fireball largest ever detected by CTBTO infrasound sensors

NASA Astrophysics Data System (ADS)

Le Pichon, Alexis; Ceranna, Lars; Pilger, Christoph; Mialle, Pierrick; Brown, David; Herry, Pascal; Brachet, Nicolas

2013-07-01

15 February 2013, a large Earth-impacting fireball disintegrated over the Ural Mountains. This extraordinary event is, together with the 1908 Tunguska fireball, among the most energetic events ever instrumentally recorded. It generated infrasound returns, after circling the globe, at distances up to ~85,000 km, and was detected at 20 infrasonic stations of the global International Monitoring System (IMS). For the first time since the establishment of the IMS infrasound network, multiple arrivals involving waves that traveled twice round the globe have been clearly identified. A preliminary estimate of the explosive energy using empirical period-yield scaling relations gives a value of 460 kt of TNT equivalent. In the context of the future verification of the Comprehensive Nuclear-Test-Ban Treaty, this event provides a prominent milestone for studying in detail infrasound propagation around the globe for almost 3 days as well as for calibrating the performance of the IMS network.

The FIREBall fiber-fed UV spectrograph

NASA Astrophysics Data System (ADS)

Tuttle, Sarah E.; Schiminovich, David; Milliard, Bruno; Grange, Robert; Martin, D. Christopher; Rahman, Shahinur; Deharveng, Jean-Michel; McLean, Ryan; Tajiri, Gordon; Matuszewski, M.

2008-07-01

FIREBall (Faint Intergalactic Redshifted Emission Balloon) had a successful first engineering flight in July of 2007 from Palestine, Texas. Here we detail the design and construction of the spectrograph. FIREBall consists of a 1m telescope coupled to a fiber-fed ultraviolet spectrograph flown on a short duration balloon. The spectrograph is designed to map hydrogen and metal line emission from the intergalactic medium at several redshifts below z=1, exploiting a small window in atmospheric oxygen absorption at balloon altitudes. The instrument is a wide-field IFU fed by almost 400 fibers. The Offner mount spectrograph is designed to be sensitive in the 195-215nm window accessible at our altitudes of 35-40km. We are able to observe Lyα, as well as OVI and CIV doublets, from 0.3 < z < 0.9. Observations of UV bright B stars and background measurements allow characterization of throughput for the entire system and will inform future flights.

Limits on neutrino emission from gamma-ray bursts with the 40 string IceCube detector.

PubMed

Abbasi, R; Abdou, Y; Abu-Zayyad, T; Adams, J; Aguilar, J A; Ahlers, M; Andeen, K; Auffenberg, J; Bai, X; Baker, M; Barwick, S W; Bay, R; Bazo Alba, J L; Beattie, K; Beatty, J J; Bechet, S; Becker, J K; Becker, K-H; Benabderrahmane, M L; BenZvi, S; Berdermann, J; Berghaus, P; Berley, D; Bernardini, E; Bertrand, D; Besson, D Z; Bindig, D; Bissok, M; Blaufuss, E; Blumenthal, J; Boersma, D J; Bohm, C; Bose, D; Böser, S; Botner, O; Braun, J; Brown, A M; Buitink, S; Carson, M; Chirkin, D; Christy, B; Clem, J; Clevermann, F; Cohen, S; Colnard, C; Cowen, D F; D'Agostino, M V; Danninger, M; Daughhetee, J; Davis, J C; De Clercq, C; Demirörs, L; Depaepe, O; Descamps, F; Desiati, P; de Vries-Uiterweerd, G; DeYoung, T; Díaz-Vélez, J C; Dierckxsens, M; Dreyer, J; Dumm, J P; Ehrlich, R; Eisch, J; Ellsworth, R W; Engdegård, O; Euler, S; Evenson, P A; Fadiran, O; Fazely, A R; Fedynitch, A; Feusels, T; Filimonov, K; Finley, C; Fischer-Wasels, T; Foerster, M M; Fox, B D; Franckowiak, A; Franke, R; Gaisser, T K; Gallagher, J; Geisler, M; Gerhardt, L; Gladstone, L; Glüsenkamp, T; Goldschmidt, A; Goodman, J A; Grant, D; Griesel, T; Gross, A; Grullon, S; Gurtner, M; Ha, C; Hallgren, A; Halzen, F; Han, K; Hanson, K; Heinen, D; Helbing, K; Herquet, P; Hickford, S; Hill, G C; Hoffman, K D; Homeier, A; Hoshina, K; Hubert, D; Huelsnitz, W; Hülss, J-P; Hulth, P O; Hultqvist, K; Hussain, S; Ishihara, A; Jacobsen, J; Japaridze, G S; Johansson, H; Joseph, J M; Kampert, K-H; Kappes, A; Karg, T; Karle, A; Kelley, J L; Kemming, N; Kenny, P; Kiryluk, J; Kislat, F; Klein, S R; Köhne, J-H; Kohnen, G; Kolanoski, H; Köpke, L; Kopper, S; Koskinen, D J; Kowalski, M; Kowarik, T; Krasberg, M; Krings, T; Kroll, G; Kuehn, K; Kuwabara, T; Labare, M; Lafebre, S; Laihem, K; Landsman, H; Larson, M J; Lauer, R; Lehmann, R; Lünemann, J; Madsen, J; Majumdar, P; Marotta, A; Maruyama, R; Mase, K; Matis, H S; Meagher, K; Merck, M; Mészáros, P; Meures, T; Middell, E; Milke, N; Miller, J; Montaruli, T; Morse, R; Movit, S M; Nahnhauer, R; Nam, J W; Naumann, U; Niessen, P; Nygren, D R; Odrowski, S; Olivas, A; Olivo, M; O'Murchadha, A; Ono, M; Panknin, S; Paul, L; Pérez de los Heros, C; Petrovic, J; Piegsa, A; Pieloth, D; Porrata, R; Posselt, J; Price, P B; Prikockis, M; Przybylski, G T; Rawlins, K; Redl, P; Resconi, E; Rhode, W; Ribordy, M; Rizzo, A; Rodrigues, J P; Roth, P; Rothmaier, F; Rott, C; Ruhe, T; Rutledge, D; Ruzybayev, B; Ryckbosch, D; Sander, H-G; Santander, M; Sarkar, S; Schatto, K; Schmidt, T; Schoenwald, A; Schukraft, A; Schultes, A; Schulz, O; Schunck, M; Seckel, D; Semburg, B; Seo, S H; Sestayo, Y; Seunarine, S; Silvestri, A; Slipak, A; Spiczak, G M; Spiering, C; Stamatikos, M; Stanev, T; Stephens, G; Stezelberger, T; Stokstad, R G; Stoyanov, S; Strahler, E A; Straszheim, T; Sullivan, G W; Swillens, Q; Taavola, H; Taboada, I; Tamburro, A; Tarasova, O; Tepe, A; Ter-Antonyan, S; Tilav, S; Toale, P A; Toscano, S; Tosi, D; Turčan, D; van Eijndhoven, N; Vandenbroucke, J; Van Overloop, A; van Santen, J; Vehring, M; Voge, M; Voigt, B; Walck, C; Waldenmaier, T; Wallraff, M; Walter, M; Weaver, C; Wendt, C; Westerhoff, S; Whitehorn, N; Wiebe, K; Wiebusch, C H; Williams, D R; Wischnewski, R; Wissing, H; Wolf, M; Woschnagg, K; Xu, C; Xu, X W; Yodh, G; Yoshida, S; Zarzhitsky, P

2011-04-08

IceCube has become the first neutrino telescope with a sensitivity below the TeV neutrino flux predicted from gamma-ray bursts if gamma-ray bursts are responsible for the observed cosmic-ray flux above 10(18)  eV. Two separate analyses using the half-complete IceCube detector, one a dedicated search for neutrinos from pγ interactions in the prompt phase of the gamma-ray burst fireball and the other a generic search for any neutrino emission from these sources over a wide range of energies and emission times, produced no evidence for neutrino emission, excluding prevailing models at 90% confidence.

Large Meteoroid Impact on the Moon on 17 March 2013

NASA Technical Reports Server (NTRS)

Moser, Danielle E.; Suggs, Robert M.; Suggs, Ronnie J.

2014-01-01

Since early 2006, NASA's Marshall Space Flight Center has observed over 300 impact flashes on the Moon, produced by meteoroids striking the lunar surface. On 17 March 2013 at 03:50:54.312 UTC, the brightest flash of an 8-year routine observing campaign was observed in two 0.35 m telescopes outfitted with Watec 902H2 Ultimate monochrome CCD cameras recording interleaved 30 fps video. Standard CCD photometric techniques, described in [1], were applied to the video after saturation correction, yielding a peak R magnitude of 3.0 +/- 0.4 in a 1/30 second video exposure. This corresponds to a luminous energy of 7.1 × 10(exp 6) J. Geographic Information System (GIS) tools were used to georeference the lunar impact imagery and yielded a crater location at 20.60 +/- 0.17deg N, 23.92 +/- 0.30deg W. The camera onboard the Lunar Reconnaissance Orbiter (LRO), a NASA spacecraft mapping the Moon from lunar orbit, discovered the fresh crater associated with this impact by comparing post-impact images from 28 July 2013 to pre-impact images on 12 Feb 2012. The images show fresh, bright ejecta around an 18 m diameter circular crater, with a 15 m inner diameter measured from the level of pre-existing terrain, at 20.7135deg N, 24.3302deg W. An asymmetrical ray pattern with both high and low reflectance ejecta zones extends 1-2 km beyond the crater, and a series of mostly low reflectance splotches can be seen within 30 km of the crater - likely due to secondary impacts [2]. The meteoroid impactor responsible for this event may have been part of a stream of large particles encountered by the Earth/Moon associated with the Virginid Meteor Complex, as evidenced by a cluster of 5 fireballs seen in Earth's atmosphere on the same night by the NASA All Sky Fireball Network [3] and the Southern Ontario Meteor Network [4]. Assuming a velocity-dependent luminous efficiency (ratio of luminous energy to kinetic energy) from [5] and an impact velocity of 25.6 km/s derived from fireball measurements, the impactor kinetic energy was 5.4 × 10(exp 9) J and the impactor mass was 16 kg. Assuming an impact angle of 56deg from horizontal (based on fireball orbit measurements), a regolith density of 1500 kg/m(exp 3), and impactor density between 1800 and 3000 kg/m(exp 3), the impact crater diameter was estimated to be 8-18 m at the pre-impact surface and 10-23 m rim-to-rim using the Holsapple [6] and Gault [7] models, a result consistent with the observed crater.

Orbital and physical characteristics of meter-scale impactors from airburst observations

NASA Astrophysics Data System (ADS)

Brown, P.; Wiegert, P.; Clark, D.; Tagliaferri, E.

2016-03-01

We have analyzed the orbits and ablation characteristics in the atmosphere of 59 Earth-impacting fireballs, produced by meteoroids 1 m in diameter or larger, described here as meter-scale. Using heights at peak luminosity as a proxy for strength, we determine that there is roughly an order of magnitude spread in strengths of the population of meter-scale impactors at the Earth. We use fireballs producing recovered meteorites and well documented fireballs from ground-based camera networks to calibrate our ablation model interpretation of the observed peak height of luminosity as a function of speed. The orbits and physical strength of these objects are consistent with the majority being asteroidal bodies originating from the inner main asteroid belt. This is in contrast to earlier suggestions by Ceplecha (Ceplecha, Z. [1994]. Astron. Astrophys. 286, 967-970) that the majority of meter-tens of meter sized meteoroids are ;… cometary bodies of the weakest known structure;. We find a lower limit of ∼10-15% of our objects have a possible cometary (Jupiter-Family comet and/or Halley-type comet) origin based on orbital characteristics alone. Only half this number, however, also show evidence for weaker than average structure. Two events, Sumava and USG 20131121, have exceptionally high (relative to the remainder of the population) heights of peak brightness. These are physically most consistent with high microporosity objects, though both were on asteroidal-type orbits. We also find three events, including the Oct 8, 2009 airburst near Sulawesi, Indonesia, which display comparatively low heights of peak brightness, consistent with strong monolithic stones or iron meteoroids. Based on orbital similarity, we find a probable connection among several events in our population with the Taurid meteoroid complex; no other major meteoroid streams show probable linkages to the orbits of our meter-scale population. Our impactors cover almost four orders of magnitude in mass, but no trend in height of peak brightness as a function of mass is evident, suggesting no strong trend in strength with size for meter-scale impactors consistent with the results of Popova et al. (Popova, O.P. et al. [2011]. Meteorit. Planet. Sci. 46, 1525-1550).

IceCube's Search for Neutrinos from Gamma-Ray Bursts

NASA Astrophysics Data System (ADS)

Kohler, Susanna

2016-07-01

In a cubic kilometer of volume of ice under Antarctica, an observatory called IceCube is taking measurements that may help us to determine what causes the ultra-high-energy cosmic rays (UHECRs) we occasionally observe from Earth. A recent study reports on its latest results.Atomic BaseballsCosmic rays are high-energy radiation primarily composed of protons and atomic nuclei. When these charged and extremely energetic particles impact the Earths atmosphere on their journey through space, they generate showers of secondary particles that we then detect.A UHECR is any cosmic-ray particle with a kinetic energy exceeding 1018 eV and some have been detected with energies of more than 1020 eV! In practical terms, this is an atomic nucleus with the same kinetic energy as a baseball pitched at 60mph. These unbelievably energetic particlesare quite rare, but weve observed them for decades. Yet in spite of this, the source of UHECRs is unknown.Illustration of a gamma-ray burst in a star-forming region. Could these phenomena accelerate UHECRs to their enormous energies? [NASA/Swift/Mary Pat Hrybyk-Keith and John Jones]Gamma-Ray Burst FireballsOne proposed source that could accelerate particles to these energies is a gamma-ray burst (GRB). In some models for GRBs, the explosion is envisioned as a relativistically expanding fireball of electrons, photons and protons. Internal shock fronts accelerate electrons and protons within the fireball, generating UHECRs, gamma rays, and neutrinos in the process.Because the charged cosmic-ray particles can be easily deflected as they travel, its difficult to identify where they came from. Neutrinos and photons, on the other hand, both travel largely undeflected through the universe. As a result, if we detect high-energy neutrinos that are correlated with gamma-ray photons from a GRB, this would providestrong support for GRBfireball models for UHECR production.Heading Under the IceThe IceCube Laboratory in Antarctica. Beneath the Antarctic ice lie more than5,000 detectors over a cubic kilometer of volume. [IceCube/NSF/S. Lidstrom]How do we search for these neutrinos? Enter IceCube, an neutrino observatory that consists of a cubic kilometer of detectors lying deep under the Antarctic ice. This observatory is designed to detect the by-products of the rare interactions neutrinos passing through the Earth might have with molecules of water in the ice.In a recently published study by the IceCube Collaboration, the team performed a three-year search for neutrinos that were correlated with the locations and times of more than 800 known GRBs during that period.Three different fireball models for GRBs, and the predicted neutrino flux from each. The neutrinos potentially detectable by IceCube are shown with solid segments. IceCubes detections (and lack thereof) place new constraints on these models. [Aartsen et al. 2016]New ConstraintsFrom three years of data, the collaboration reports the detection of five low-significance events correlated with five GRBs. But these events are also consistent with the background of charged particles generated in Earths atmosphere. What does this mean? These detections could indicate a small number of real neutrinos generated by GRBs or they could just be background noise.Either way, these results from IceCube provide a new upper limit on the association of neutrinos with gamma-ray bursts. This constrains which production mechanisms are possible, eliminating some models for UHECR acceleration by GRB fireballs.Whats next? The collaboration indicates that the next generation IceCube-Gen2 detector, planned for the future, will be even more sensitive which will either result in the detection of more subtle neutrino events associated with GRBs, or it will further disfavor GRBs as the production mechanism for UHECRs.CitationM. G. Aartsen et al 2016 ApJ 824 115. doi:10.3847/0004-637X/824/2/115

The Taranaki daylight fireball, 1999 July 7

NASA Astrophysics Data System (ADS)

McCormick, Jennie

2006-10-01

The New Zealand Taranaki Daylight Fireball was observed on 1999 July 7 from various areas across the North and South Islands of New Zealand and had an apparent magnitude brighter than -20. The event produced more than one hundred handwritten reports, drawings, and paintings from eyewitnesses; video and audio recordings, seismic trace data, and confirmation of detection by the United States Defense Department satellites. A detailed case study based on this data shows that observations by the public are invaluable when compiling a formal history of such events.

“Ripples” on a relativistically expanding fluid

DOE PAGES

Shi, Shuzhe; Liao, Jinfeng; Zhuang, Pengfei

2014-12-29

Recent studies have shown that fluctuations of various types play important roles in the evolution of the fireball created in relativistic heavy ion collisions and bear many phenomenological consequences for experimental observables. In addition, the bulk dynamics of the fireball is well described by relativistic hydrodynamic expansion and the fluctuations on top of such expanding background can be studied within the linearized hydrodynamic framework. In this paper we present complete and analytic sound wave solutions on top of both Bjorken flow and Hubble flow backgrounds.

Groups of meteorite-producing meteoroids containing carbonaceous chondrite meteorites

NASA Astrophysics Data System (ADS)

Konovalova, N. A.; A.. Ibrohimov, A.; Kalashnikova, T. M.

2017-09-01

Proposed probable links of meteorite and meteorite-producing fireballs were been considered. Group associations between meteorite-producing meteoroids and meteorites were been determined for four carbonaceous chondrites Murchison, Maribo, Shutters Mill and Tagish Lake and potentially meteorite-producing bolides on the basis of links of their orbits. In result the several meteorite-producing sporadic slowly fireballs were found as the possible members of groups of four studied carbonaceous chondrite meteorites. One can presume that at present the identified groups may still contain large meteorite-dropping bodies.

Chelyabinsk and other February superfireballs

NASA Astrophysics Data System (ADS)

Zamora, S.; Sánchez de Miguel, A.; Ocana, F.

2017-03-01

Superfireballs are rare and a fascinating natural phenomenon. The number of them is limited, their reports have been scarce and estimating their statistics is difficult. With the increased publication of newspapers during the mid XIX century, the registration of meteorrelated news grew dramatically. In addition, the digitalization of these sources opens up huge possibilities on the meteor research. The research is based on the reports which appeared in the newspapers dating back from more than 150 years ago and other databases such as the British Association for the Advancement of Science (BAAS), SAO/NASA Astrophysics Data System (ADS) and NASA-Fireball and Bolide Reports. At the end of the compilation process there are a total of 2393 registries of fireballs. We have made a descriptive statistical analysis on the data, based on the mean and dispersion of the sample and on meteor shower properties. For the moment, we have found a number of abnormally concentrated events that can not be explained by a Poisson distribution. We have analyzed statistically two significant overabundance peaks that we found in February. They are very interesting because during this period we found no evidence of fireball. These intervals are centered around February 12 and 22 (323° and 333° solar longitude) and it is probable that the first are connected with the Chelyabinsk event date. In addition, the last detections of NASA Bolide Reports support that these superbolide streams are real. We start to pinpoint the radiant in order to characterize these concentrations and to determine their origin scenario. Some preliminary result were published on [1] and [2].

Meteoroid rotation and fireball flickering: a case study of the Innisfree fireball

NASA Astrophysics Data System (ADS)

Beech, Martin

2001-09-01

Some 5 per cent of bright meteors show rapid, quasi-periodic brightness variations. It is argued that this effect, observationally known as flickering, is a manifestation of the rotational modulation of surface mass loss through ablation of a non-spherical meteoroid. We develop a set of time-dependent, single-body ablation equations that include the effect of cross-section area modulation. We present a discussion of the effects that the rotation of a non-spherical meteoroid has on the resultant meteor light curve, and we look in depth at the data related to the fireball associated with the fall of the Innisfree meteorite. We find that the parent object to the Innisfree meteorite was spinning at a rotation frequency of 2.5Hz when it encountered the Earth's upper atmosphere. We also find that the Innisfree parent body had an initial mass of about 20kg and that the ratio of its semiminor and semimajor axes was about 0.5.

New Mars meteorite fall in Morocco: collecting observations and determining the spatial distribution in the strewnfield

NASA Astrophysics Data System (ADS)

Ibhi, Abderrahmane

2013-01-01

The existence of Martian meteorites in the region of Tissint (Tata, Morocco) dropped by a very bright fireball on July 18, 2011, had been notified to a group of scientists of the Ibn Zohr University of Agadir, Morocco, at the beginning of January 2012, by a nomad of Tata who had found a small fragment in the region. As soon as a scientific expedition arrived at the place of the meteorite fall, the members of the laboratory of Geo-heritage and Geo-materials Science started gathering information and collecting the debris of this Martian meteorite. The Tissint fireball has been observed and reported by numerous witnesses across the southeastern Morocco. The event was extremely valuable to the scientific community: it was the brightest and most comprehensively observed fireball in Morocco's known astronomical history. We are now in a position to draw the distribution ellipse of the fall, which starts at Jbel Al Gallab and continues in east-southeastern direction, above big rocky plateaus.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Geng, J. J.; Huang, Y. F., E-mail: hyf@nju.edu.cn

Fast radio bursts (FRBs) are newly discovered radio transient sources. Their high dispersion measures indicate an extragalactic origin. However, due to the lack of observational data in other wavelengths, their progenitors still remain unclear. Here we suggest that the collisions between neutron stars (NSs) and asteroids/comets are promising mechanisms for FRBs. During the impact process, a hot plasma fireball forms after the material of the small body penetrates into the NS surface. The ionized matter inside the fireball then expands along the magnetic field lines. Coherent radiation from the thin shell at the top of the fireball will account formore » the observed FRBs. Our scenario can reasonably explain the main features of FRBs, such as their durations, luminosities, and the event rate. We argue that for a single NS, FRBs are not likely to happen repeatedly in a forseeable timespan since such impacts are of low probability. We predict that faint remnant X-ray emissions should be associated with FRBs, but it may be too faint to be detected by detectors at work.« less

Modeling Gamma Ray Bursts in the Megnetically Dominated Regime

NASA Astrophysics Data System (ADS)

Zhang, Bing

Recent observations of broad-band prompt emission spectra of gamma-ray bursts (GRBs) by the Fermi Gamma-Ray Telescope suggest that they do not comply with the predictions of the standard fireball internal shock model. Several independent observations (including detections of high polarization degree of gamma-ray emission and early optical emission of some GRBs, as well as non-detection of PeV neutrinos from GRBs by IceCube) support or are consistent with the hypothesis that at least some GRBs have magnetically dominated jets. This calls for serious, detailed investigations of GRB models in the magnetically dominated regime, which interpret GRB emission as dissipation of strong magnetic fields entrained in the ejecta. On the other hand, because of their complexity, magnetic models are so far much less developed than the baryonic fireball models. Here we propose to tackle this difficult problem, aiming at making solid progress in this direction through a set of numerical investigations. Specifically, we propose to carry out the following simulations. (1) Using a relativistic MHD code, we will perform a global simulation to investigate whether efficient magnetic dissipation would occur when two high-σ magnetic blobs collide with a relativistic speed. (2) We will perform a local simulation of the relativistic collisions between two high-σ fluids, and track the evolution of magnetic field configuration in the colliding region and the interplay between magnetic reconnection and development of magnetic turbulence. (3) Through injecting test particles in the simulation box, we will study how electrons get accelerated in the turbulent reconnection regions. (4) Built upon the above-mentioned numerical simulation results, along with a Monte Carlo code and a synchrotron radiation code developed in our group before, we will develop a full numerical model to simulate lightcurves, time-dependent spectra, and polarization properties of GRB prompt emission within the framework of magnetically dominated jets. The results of this proposal will greatly advance our understanding of GRB physics in the magnetically dominated regime. The numerical simulations of collision-induced magnetic dissipation will be also relevant to many other astrophysical phenomena, such as active galactic nuclei, X-ray binary ``micro-quasars'', Crab nebula flares, and jets from tidal disruption events. The program conforms to NASA's Strategic Plan, and is highly relevant to the past and current NASA missions, such as CGRO/BATSE, Fermi, and Swift, as well as some future mission concepts, such as POET.

DRoplet and hAdron generator for nuclear collisions: An update

NASA Astrophysics Data System (ADS)

Tomášik, Boris

2016-10-01

The Monte Carlo generator DRAGON simulates hadron production in ultrarelativistic nuclear collisions. The underlying theoretical description is provided by the blast-wave model. DRAGON includes second-order angular anisotropy in transverse shape and the amplitude of the transverse expansion velocity. It also allows to simulate hadron production from a fragmented fireball, e.g. as resulting from spinodal decomposition happening at the first-order phase transition.

Beam On Target (BOT) Produces Gamma Ray Burst (GRB) Fireballs and Afterglows

NASA Astrophysics Data System (ADS)

Greyber, H. D.

1997-12-01

Unlike the myriads of ad hoc models that have been offered to explain GRB, the BOT process is simply the very common process used worldwide in accelerator laboratories to produce gamma rays. The Strong Magnetic Field (SMF) model postulates an extremely intense, highly relativistic current ring formed during the original gravitational collapse of a distant galaxy when the plasma cloud was permeated by a primordial magnetic field. GRB occur when solid matter (asteroid, white dwarf, neutron star, planet) falls rapidly through the Storage Ring beam producing a very strongly collimated electromagnetic shower, and a huge amount of matter from the target, in the form of a giant, hot, expanding plasma cloud, or ``Fireball,'' is blown off. BOT satisfies all the ``severe constraints imposed on the source of this burst --'' concluded by the CGRO team (Sommer et al, Astrophys. J. 422 L63 (1994)) for the huge intense burst GRB930131, whereas neutron star merger models are ``difficult to reconcile.'' BOT expects the lowest energy gamma photons to arrive very slightly later than higher energy photons due to the time for the shower to penetrate the target. The millisecond spikes in bursts are due to the slender filaments of current that make up the Storage Ring beam. Delayed photons can be explained by a broken target ``rock.'' See H. Greyber in the book ``Compton Gamma Ray Observatory,'' AIP Conf. Proc. 280, 569 (1993).

Gamma-ray bursts from stellar mass accretion disks around black holes

NASA Technical Reports Server (NTRS)

Woosley, S. E.

1993-01-01

A cosmological model for gamma-ray bursts is explored in which the radiation is produced as a broadly beamed pair fireball along the rotation axis of an accreting black hole. The black hole may be a consequence of neutron star merger or neutron star-black hole merger, but for long complex bursts, it is more likely to come from the collapse of a single Wolf-Rayet star endowed with rotation ('failed' Type Ib supernova). The disk is geometrically thick and typically has a mass inside 100 km of several tenths of a solar mass. In the failed supernova case, the disk is fed for a longer period of time by the collapsing star. At its inner edge the disk is thick to its own neutrino emission and evolves on a viscous time scale of several seconds. In a region roughly 30 km across, interior to the accretion disk and along its axis of rotation, a pair fireball is generated by neutrino annihilation and electron-neutrino scattering which deposit approximately 10 exp 50 ergs/s.

The Collision of Comet Shoemaker-Levy 9 and Jupiter

NASA Astrophysics Data System (ADS)

Noll, Keith S.; Weaver, Harold A.; Feldman, Paul D.

2006-11-01

Participants; Preface; 1. The orbital motion and impact circumstances of Comet Shoemaker-Levy 9 Paul W. Chodas and Donald K. Yeomans; 2. Observational constraints on the composition and nature of Comet D/Shoemaker-Levy 9 Jacques Crovisier; 3. Tidal breakup of the nucleus of Comet Shoemaker-Levy 9 Zdenek Sekanina; 4. Earth-based observations of impact phenomena Philip D. Nicholson; 5. HST imaging of Jupiter shortly after each impact: plumes and fresh sites Heidi B. Hammel; 6. Galileo observations of the impacts Clark R. Chapman; 7. Models of fragment penetration and fireball evolution David A. Crawford; 8. Entry and fireball models vs. observations: what have we learned? Mordecai-Mark Mac Low; 9. Dynamics and chemistry of SL9 plumes Kevin Zahnle; 10. Chemistry induced by the impacts: observations Emmanuel Lellouch; 11. SL9 impact chemistry: long-term photochemical evolution Julianne I. Moses; 12. Particulate matter in Jupiter's atmosphere from the impacts of Comet P/Shoemaker-Levy 9 Robert A. West; 13. Jupiter's post-impact atmospheric thermal response Barney J. Conrath; 14. Growth and dispersion of the Shoemaker-Levy 9 impact features from HST imaging Reta F. Beebe; 15. Waves from the Shoemaker-Levy 9 impacts Andrew P. Ingersoll and Hiroo Kanamori; 16. Jovian magnetospheric and auroral effects of the SL9 impacts Wing-Huen Ip.

Fragmentation of the Chelyabinsk Fireball

NASA Astrophysics Data System (ADS)

Melosh, J.

2013-12-01

The most intense bolide since the 1908 Tunguska event occurred in the early morning hours of 15 February 2013 near the Russian town of Chelyabinsk. The impacting asteroid ranged between 17 and 20 m diameter with a mass of about 10,000 tons. Its estimated pre-atmospheric velocity was about 18.6 km/sec at a low angle of 20° from the horizontal. The resulting airburst occurred at an altitude of about 23 km and released an estimated total energy of about 440 kT (1.7 x 1015 J). The blast wave shattered windows on the ground over a wide area and collapsed the roof of a zinc factory. In spite of the size of the initital asteroid, only small fragments (a few kg, so far) have been recovered. The entry of an asteroid into Earth's atmosphere and its aerodynamic fragmentation and deceleration has been modeled by a number of authors over the past few decades. Full-featured numerical simulations are presently limited in their ability to simultaneously incorporate fragmentation, energy coupling between solid fragments and the atmosphere, and thermal radiation, but an approximate treatment of the fragmentation and dispersion of a large entering meteoroid called the 'pancake model' has achieved good fits to other observed events, including the Tunguska explosion, the 1947 Shikote-Alin fall and strewn fields from larger iron meteorite falls, such as the Henbury craters. Simulations using the pancake model can fit the overall observations of the Chelyabinsk event using an 18 m diameter asteroid of density 3000 kg/m3 following the observed trajectory and possessing an initial strength of about 7 MPa, which is relatively high for a stony meteoroid. This suggests that the asteroid was not a strengthless rubble pile, but in fact possessed considerable strength, compared to other stony meteorites of similar type. Aerodynamic breakup begins at an altitude of 31 km and the final airburst occurs at 22 km, releasing about 250 kT at this time. Subsequent to this airburst, large fragments continue with a velocity of about 10 km/sec and thence undergo secondary fragmentation events above the surface which release most of the remaining energy. This accords well with reports of multiple explosion sounds. The specific energy release at the time of breakup is about 100 MJ/kg, nearly 10 times more than necessary to vaporize silicate rocks, which may account for the very small amount of solid material that finally reached the surface and the 'smoke' (condensed silicate vapor) that accompanied the event. The survival of any material at all (albeit partly melted: Some recovered specimens are remarkable in that their fusion crust is uniform over their entire surface) suggests that these fragments were in the outer part of the fireball. In spite of the simplicity of the pancake model, it can successfully account for the gross observations of the Chelyabinsk event. Nevertheless, the model is very simplistic and much more remains to be done to accurately model fireballs. That fact that most of the mass of the bolide vaporized accords well with the lack of any recovered meteorites from the ca. 10X larger Tunguska event. It appears that in this size range the fireball is energetic enough to largely or completely vaporize the incoming asteroid before it strikes the surface, a result that seems not to have been previously anticipated.

Ultraviolet Laser-induced ignition of RDX single crystal

PubMed Central

Yan, Zhonghua; Zhang, Chuanchao; Liu, Wei; Li, Jinshan; Huang, Ming; Wang, Xuming; Zhou, Guorui; Tan, Bisheng; Yang, Zongwei; Li, Zhijie; Li, Li; Yan, Hongwei; Yuan, Xiaodong; Zu, Xiaotao

2016-01-01

The RDX single crystals are ignited by ultraviolet laser (355 nm, 6.4 ns) pulses. The laser-induced damage morphology consisted of two distinct regions: a core region of layered fracture and a peripheral region of stripped material surrounding the core. As laser fluence increases, the area of the whole crack region increases all the way, while both the area and depth of the core region increase firstly, and then stay stable over the laser fluence of 12 J/cm2. The experimental details indicate the dynamics during laser ignition process. Plasma fireball of high temperature and pressure occurs firstly, followed by the micro-explosions on the (210) surface, and finally shock waves propagate through the materials to further strip materials outside and yield in-depth cracks in larger surrounding region. The plasma fireball evolves from isotropic to anisotropic under higher laser fluence resulting in the damage expansion only in lateral direction while maintaining the fixed depth. The primary insights into the interaction dynamics between laser and energetic materials can help developing the superior laser ignition technique. PMID:26847854

Tracking Radionuclide Fractionation in the First Atomic Explosion Using Stable Elements

DOE PAGES

Bonamici, Chloë E.; Hervig, Richard L.; Kinman, William S.

2017-08-25

Compositional analysis of postdetonation fallout is a tool for forensic identification of nuclear devices. However, the relationship between device composition and fallout composition is difficult to interpret because of the complex combination of physical mixing, nuclear reactions, and chemical fractionations that occur in the chaotic nuclear fireball. By using a combination of in situ microanalytical techniques (electron microprobe analysis and secondary ion mass spectrometry), we show that some heavy stable elements (Rb, Sr, Zr, Ba, Cs, Ba, La, Ce, Nd, Sm, Dy, Lu, U, Th) in glassy fallout from the first nuclear test, Trinity, are reliable chemical proxies for radionuclidesmore » generated during the explosion. Stable-element proxies show that radionuclides from the Trinity device were chemically, but not isotopically, fractionated by condensation. Moreover, stable-element proxies delineate chemical fractionation trends that can be used to connect present-day fallout composition to past fireball composition. Stable-element proxies therefore offer a novel approach for elucidating the phenomenology of the nuclear fireball as it relates to the formation of debris and the fixation of device materials within debris.« less

Tracking Radionuclide Fractionation in the First Atomic Explosion Using Stable Elements

DOE Office of Scientific and Technical Information (OSTI.GOV)

Bonamici, Chloë E.; Hervig, Richard L.; Kinman, William S.

Compositional analysis of postdetonation fallout is a tool for forensic identification of nuclear devices. However, the relationship between device composition and fallout composition is difficult to interpret because of the complex combination of physical mixing, nuclear reactions, and chemical fractionations that occur in the chaotic nuclear fireball. By using a combination of in situ microanalytical techniques (electron microprobe analysis and secondary ion mass spectrometry), we show that some heavy stable elements (Rb, Sr, Zr, Ba, Cs, Ba, La, Ce, Nd, Sm, Dy, Lu, U, Th) in glassy fallout from the first nuclear test, Trinity, are reliable chemical proxies for radionuclidesmore » generated during the explosion. Stable-element proxies show that radionuclides from the Trinity device were chemically, but not isotopically, fractionated by condensation. Moreover, stable-element proxies delineate chemical fractionation trends that can be used to connect present-day fallout composition to past fireball composition. Stable-element proxies therefore offer a novel approach for elucidating the phenomenology of the nuclear fireball as it relates to the formation of debris and the fixation of device materials within debris.« less

Tracking Radionuclide Fractionation in the First Atomic Explosion Using Stable Elements.

PubMed

Bonamici, Chloë E; Hervig, Richard L; Kinman, William S

2017-09-19

Compositional analysis of postdetonation fallout is a tool for forensic identification of nuclear devices. However, the relationship between device composition and fallout composition is difficult to interpret because of the complex combination of physical mixing, nuclear reactions, and chemical fractionations that occur in the chaotic nuclear fireball. Using a combination of in situ microanalytical techniques (electron microprobe analysis and secondary ion mass spectrometry), we show that some heavy stable elements (Rb, Sr, Zr, Ba, Cs, Ba, La, Ce, Nd, Sm, Dy, Lu, U, Th) in glassy fallout from the first nuclear test, Trinity, are reliable chemical proxies for radionuclides generated during the explosion. Stable-element proxies show that radionuclides from the Trinity device were chemically, but not isotopically, fractionated by condensation. Furthermore, stable-element proxies delineate chemical fractionation trends that can be used to connect present-day fallout composition to past fireball composition. Stable-element proxies therefore offer a novel approach for elucidating the phenomenology of the nuclear fireball as it relates to the formation of debris and the fixation of device materials within debris.

Featured Image: Fireball After a Temporary Capture?

NASA Astrophysics Data System (ADS)

Kohler, Susanna

2016-06-01

This image of a fireball was captured in the Czech Republic by cameras at a digital autonomous observatory in the village of Kunak. This observatory is part of a network of stations known as the European Fireball Network, and this particular meteoroid detection, labeled EN130114, is notable because it has the lowest initial velocity of any natural object ever observed by the network. Led by David Clark (University of Western Ontario), the authors of a recent study speculate that before this meteoroid impacted Earth, it may have been a Temporarily Captured Orbiter (TCO). TCOs are near-Earth objects that make a few orbits of Earth before returning to heliocentric orbits. Only one has ever been observed to date, and though they are thought to make up 0.1% of all meteoroids, EN130114 is the first event ever detected that exhibits conclusive behavior of a TCO. For more information on EN130114 and why TCOs are important to study, check out the paper below!CitationDavid L. Clark et al 2016 AJ 151 135. doi:10.3847/0004-6256/151/6/135

Beam-energy-dependent two-pion interferometry and the freeze-out eccentricity of pions measured in heavy ion collisions at the STAR detector

NASA Astrophysics Data System (ADS)

Adamczyk, L.; Adkins, J. K.; Agakishiev, G.; Aggarwal, M. M.; Ahammed, Z.; Alekseev, I.; Alford, J.; Anson, C. D.; Aparin, A.; Arkhipkin, D.; Aschenauer, E. C.; Averichev, G. S.; Banerjee, A.; Beavis, D. R.; Bellwied, R.; Bhasin, A.; Bhati, A. K.; Bhattarai, P.; Bichsel, H.; Bielcik, J.; Bielcikova, J.; Bland, L. C.; Bordyuzhin, I. G.; Borowski, W.; Bouchet, J.; Brandin, A. V.; Brovko, S. G.; Bültmann, S.; Bunzarov, I.; Burton, T. P.; Butterworth, J.; Caines, H.; Calderón de la Barca Sánchez, M.; Cebra, D.; Cendejas, R.; Cervantes, M. C.; Chaloupka, P.; Chang, Z.; Chattopadhyay, S.; Chen, H. F.; Chen, J. H.; Chen, L.; Cheng, J.; Cherney, M.; Chikanian, A.; Christie, W.; Chwastowski, J.; Codrington, M. J. M.; Contin, G.; Cramer, J. G.; Crawford, H. J.; Cui, X.; Das, S.; Davila Leyva, A.; De Silva, L. C.; Debbe, R. R.; Dedovich, T. G.; Deng, J.; Derevschikov, A. A.; Derradi de Souza, R.; Dhamija, S.; di Ruzza, B.; Didenko, L.; Dilks, C.; Ding, F.; Djawotho, P.; Dong, X.; Drachenberg, J. L.; Draper, J. E.; Du, C. M.; Dunkelberger, L. E.; Dunlop, J. C.; Efimov, L. G.; Engelage, J.; Engle, K. S.; Eppley, G.; Eun, L.; Evdokimov, O.; Eyser, O.; Fatemi, R.; Fazio, S.; Fedorisin, J.; Filip, P.; Finch, E.; Fisyak, Y.; Flores, C. E.; Gagliardi, C. A.; Gangadharan, D. R.; Garand, D.; Geurts, F.; Gibson, A.; Girard, M.; Gliske, S.; Greiner, L.; Grosnick, D.; Gunarathne, D. S.; Guo, Y.; Gupta, A.; Gupta, S.; Guryn, W.; Haag, B.; Hamed, A.; Han, L.-X.; Haque, R.; Harris, J. W.; Heppelmann, S.; Hirsch, A.; Hoffmann, G. W.; Hofman, D. J.; Horvat, S.; Huang, B.; Huang, H. Z.; Huang, X.; Huck, P.; Humanic, T. J.; Igo, G.; Jacobs, W. W.; Jang, H.; Judd, E. G.; Kabana, S.; Kalinkin, D.; Kang, K.; Kauder, K.; Ke, H. W.; Keane, D.; Kechechyan, A.; Kesich, A.; Khan, Z. H.; Kikola, D. P.; Kisel, I.; Kisiel, A.; Koetke, D. D.; Kollegger, T.; Konzer, J.; Koralt, I.; Kosarzewski, L. K.; Kotchenda, L.; Kraishan, A. F.; Kravtsov, P.; Krueger, K.; Kulakov, I.; Kumar, L.; Kycia, R. A.; Lamont, M. A. C.; Landgraf, J. M.; Landry, K. D.; Lauret, J.; Lebedev, A.; Lednicky, R.; Lee, J. H.; LeVine, M. J.; Li, C.; Li, W.; Li, X.; Li, X.; Li, Y.; Li, Z. M.; Lisa, M. A.; Liu, F.; Ljubicic, T.; Llope, W. J.; Lomnitz, M.; Longacre, R. S.; Luo, X.; Ma, G. L.; Ma, Y. G.; Madagodagettige Don, D. M. M. D.; Mahapatra, D. P.; Majka, R.; Margetis, S.; Markert, C.; Masui, H.; Matis, H. S.; McDonald, D.; McShane, T. S.; Minaev, N. G.; Mioduszewski, S.; Mohanty, B.; Mondal, M. M.; Morozov, D. A.; Mustafa, M. K.; Nandi, B. K.; Nasim, Md.; Nayak, T. K.; Nelson, J. M.; Nigmatkulov, G.; Nogach, L. V.; Noh, S. Y.; Novak, J.; Nurushev, S. B.; Odyniec, G.; Ogawa, A.; Oh, K.; Ohlson, A.; Okorokov, V.; Oldag, E. W.; Olvitt, D. L.; Pachr, M.; Page, B. S.; Pal, S. K.; Pan, Y. X.; Pandit, Y.; Panebratsev, Y.; Pawlak, T.; Pawlik, B.; Pei, H.; Perkins, C.; Peryt, W.; Pile, P.; Planinic, M.; Pluta, J.; Poljak, N.; Poniatowska, K.; Porter, J.; Poskanzer, A. M.; Pruthi, N. K.; Przybycien, M.; Pujahari, P. R.; Putschke, J.; Qiu, H.; Quintero, A.; Ramachandran, S.; Raniwala, R.; Raniwala, S.; Ray, R. L.; Riley, C. K.; Ritter, H. G.; Roberts, J. B.; Rogachevskiy, O. V.; Romero, J. L.; Ross, J. F.; Roy, A.; Ruan, L.; Rusnak, J.; Rusnakova, O.; Sahoo, N. R.; Sahu, P. K.; Sakrejda, I.; Salur, S.; Sandweiss, J.; Sangaline, E.; Sarkar, A.; Schambach, J.; Scharenberg, R. P.; Schmah, A. M.; Schmidke, W. B.; Schmitz, N.; Seger, J.; Seyboth, P.; Shah, N.; Shahaliev, E.; Shanmuganathan, P. V.; Shao, M.; Sharma, B.; Shen, W. Q.; Shi, S. S.; Shou, Q. Y.; Sichtermann, E. P.; Singaraju, R. N.; Skoby, M. J.; Smirnov, D.; Smirnov, N.; Solanki, D.; Sorensen, P.; Spinka, H. M.; Srivastava, B.; Stanislaus, T. D. S.; Stevens, J. R.; Stock, R.; Strikhanov, M.; Stringfellow, B.; Sumbera, M.; Sun, X.; Sun, X. M.; Sun, Y.; Sun, Z.; Surrow, B.; Svirida, D. N.; Symons, T. J. M.; Szelezniak, M. A.; Takahashi, J.; Tang, A. H.; Tang, Z.; Tarnowsky, T.; Thomas, J. H.; Timmins, A. R.; Tlusty, D.; Tokarev, M.; Trentalange, S.; Tribble, R. E.; Tribedy, P.; Trzeciak, B. A.; Tsai, O. D.; Turnau, J.; Ullrich, T.; Underwood, D. G.; Van Buren, G.; van Nieuwenhuizen, G.; Vandenbroucke, M.; Vanfossen, J. A.; Varma, R.; Vasconcelos, G. M. S.; Vasiliev, A. N.; Vertesi, R.; Videbæk, F.; Viyogi, Y. P.; Vokal, S.; Vossen, A.; Wada, M.; Wang, F.; Wang, G.; Wang, H.; Wang, J. S.; Wang, X. L.; Wang, Y.; Wang, Y.; Webb, G.; Webb, J. C.; Westfall, G. D.; Wieman, H.; Wissink, S. W.; Witt, R.; Wu, Y. F.; Xiao, Z.; Xie, W.; Xin, K.; Xu, H.; Xu, J.; Xu, N.; Xu, Q. H.; Xu, Y.; Xu, Z.; Yan, W.; Yang, C.; Yang, Y.; Yang, Y.; Ye, Z.; Yepes, P.; Yi, L.; Yip, K.; Yoo, I.-K.; Yu, N.; Zawisza, Y.; Zbroszczyk, H.; Zha, W.; Zhang, J. B.; Zhang, J. L.; Zhang, S.; Zhang, X. P.; Zhang, Y.; Zhang, Z. P.; Zhao, F.; Zhao, J.; Zhong, C.; Zhu, X.; Zhu, Y. H.; Zoulkarneeva, Y.; Zyzak, M.; STAR Collaboration

2015-07-01

We present results of analyses of two-pion interferometry in Au +Au collisions at √{sNN}=7.7 , 11.5, 19.6, 27, 39, 62.4, and 200 GeV measured in the STAR detector as part of the BNL Relativistic Heavy Ion Collider Beam Energy Scan program. The extracted correlation lengths (Hanbury-Brown-Twiss radii) are studied as a function of beam energy, azimuthal angle relative to the reaction plane, centrality, and transverse mass (mT) of the particles. The azimuthal analysis allows extraction of the eccentricity of the entire fireball at kinetic freeze-out. The energy dependence of this observable is expected to be sensitive to changes in the equation of state. A new global fit method is studied as an alternate method to directly measure the parameters in the azimuthal analysis. The eccentricity shows a monotonic decrease with beam energy that is qualitatively consistent with the trend from all model predictions and quantitatively consistent with a hadronic transport model.

Beam-energy-dependent two-pion interferometry and the freeze-out eccentricity of pions measured in heavy ion collisions at the STAR detector

DOE PAGES

Adamczyk, L.

2015-07-10

In this study, we present results of analyses of two-pion interferometry in Au+Au collisions at √s NN = 7.7, 11.5, 19.6, 27, 39, 62.4, and 200 GeV measured in the STAR detector as part of the RHIC Beam Energy Scan program. The extracted correlation lengths (HBT radii) are studied as a function of beam energy, azimuthal angle relative to the reaction plane, centrality, and transverse mass ( mT) of the particles. The azimuthal analysis allows extraction of the eccentricity of the entire fireball at kinetic freeze-out. The energy dependence of this observable is expected to be sensitive to changes inmore » the equation of state. A new global fit method is studied as an alternate method to directly measure the parameters in the azimuthal analysis. The eccentricity shows a monotonic decrease with beam energy that is qualitatively consistent with the trend from all model predictions and quantitatively consistent with a hadronic transport model.« less

Beam-energy-dependent two-pion interferometry and the freeze-out eccentricity of pions measured in heavy ion collisions at the STAR detector

DOE Office of Scientific and Technical Information (OSTI.GOV)

Adamczyk, L.

In this study, we present results of analyses of two-pion interferometry in Au+Au collisions at √s NN = 7.7, 11.5, 19.6, 27, 39, 62.4, and 200 GeV measured in the STAR detector as part of the RHIC Beam Energy Scan program. The extracted correlation lengths (HBT radii) are studied as a function of beam energy, azimuthal angle relative to the reaction plane, centrality, and transverse mass ( mT) of the particles. The azimuthal analysis allows extraction of the eccentricity of the entire fireball at kinetic freeze-out. The energy dependence of this observable is expected to be sensitive to changes inmore » the equation of state. A new global fit method is studied as an alternate method to directly measure the parameters in the azimuthal analysis. The eccentricity shows a monotonic decrease with beam energy that is qualitatively consistent with the trend from all model predictions and quantitatively consistent with a hadronic transport model.« less

A complex of meteorite-forming bodies (the Innisfree - Ridgedale family).

NASA Astrophysics Data System (ADS)

Shestaka, I. S.

1994-12-01

For the first time a swarm of meteorite-forming bodies was identified. Yearly this swarm's orbit approaches the Earth's orbit in early February. This swarm contains the Innisfree and Ridgedale fireballs, 9 small meteoric swarms, several asteroids and 12 fireballs photographed by the cameras of the Prairie Network and Canadian Meteorite Observation and Discovery Project. The discovery of this complex, intensive bombardments of the Moon's surface recorded by means of seismographs left on the Moon, the analysis of the time distributions of meteorite falls on the Earth and other established facts confirm the existence of swarms of meteorite-forming bodies which are crossing the Earth's orbit.

Open-source meteor detection software for low-cost single-board computers

NASA Astrophysics Data System (ADS)

Vida, D.; Zubović, D.; Šegon, D.; Gural, P.; Cupec, R.

2016-01-01

This work aims to overcome the current price threshold of meteor stations which can sometimes deter meteor enthusiasts from owning one. In recent years small card-sized computers became widely available and are used for numerous applications. To utilize such computers for meteor work, software which can run on them is needed. In this paper we present a detailed description of newly-developed open-source software for fireball and meteor detection optimized for running on low-cost single board computers. Furthermore, an update on the development of automated open-source software which will handle video capture, fireball and meteor detection, astrometry and photometry is given.

Digamma diagnostics for the mixed-phase generation at NICA

NASA Astrophysics Data System (ADS)

Kukulin, V. I.; Platonova, M. N.

2017-03-01

A novel type of diagnostics for dense and/or hot nuclear matter produced in heavy-ion collisions at NICA and similar future colliders (FAIR, etc.) is suggested. The diagnostics is based on an assumption (confirmed in many experiments worldwide) about intensive generation of light scalar mesons (σ) the consequent decay of which produces γγ pairs with the mass and width dependent upon density and temperature of the fireball produced in the collision process. Thus, measurements of the absolute yield, mass and width of the γγ signal carry valuable information about the state of fireball generated during the high-energy nuclear collision.

Jet-driven and jet-less fireballs from compact binary mergers

NASA Astrophysics Data System (ADS)

Salafia, O. S.; Ghisellini, G.; Ghirlanda, G.

2018-02-01

During a compact binary merger involving at least one neutron star (NS), a small fraction of the gravitational energy could be liberated in such a way to accelerate a small fraction (˜10-6) of the NS mass in an isotropic or quasi-isotropic way. In presence of certain conditions, a pair-loaded fireball can form, which undergoes accelerated expansion reaching relativistic velocities. As in the standard fireball scenario, internal energy is partly transformed into kinetic energy. At the photospheric radius, the internal radiation can escape, giving rise to a pulse that lasts for a time equal to the delay time since the merger. The subsequent interaction with the interstellar medium can then convert part of the remaining kinetic energy back into radiation in a weak isotropic afterglow at all wavelengths. This scenario does not require the presence of a jet: the associated isotropic prompt and afterglow emission should be visible for all NS-NS and BH-NS mergers within 90 Mpc, independent of their inclination. The prompt emission is similar to that expected from an off-axis jet, either structured or much slower than usually assumed (Γ ˜ 10), or from the jet cocoon. The predicted afterglow emission properties can discriminate among these scenarios.

Heavy quarkonium suppression in a fireball

NASA Astrophysics Data System (ADS)

Brambilla, Nora; Escobedo, Miguel A.; Soto, Joan; Vairo, Antonio

2018-04-01

We perform a comprehensive study of the time evolution of heavy-quarkonium states in an expanding hot QCD medium by implementing effective field theory techniques in the framework of open quantum systems. The formalism incorporates quarkonium production and its subsequent evolution in the fireball including quarkonium dissociation and recombination. We consider a fireball with a local temperature that is much smaller than the inverse size of the quarkonium and much larger than its binding energy. The calculation is performed at an accuracy that is leading order in the heavy-quark density expansion and next-to-leading order in the multipole expansion. Within this accuracy, for a smooth variation of the temperature and large times, the evolution equation can be written as a Lindblad equation. We solve the Lindblad equation numerically both for a weakly coupled quark-gluon plasma and a strongly coupled medium. As an application, we compute the nuclear modification factor for the ϒ (1 S ) and ϒ (2 S ) states. We also consider the case of static quarks, which can be solved analytically. Our study fulfills three essential conditions: it conserves the total number of heavy quarks, it accounts for the non-Abelian nature of QCD, and it avoids classical approximations.

Video Meteor Fluxes

NASA Technical Reports Server (NTRS)

Campbell-Brown, M. D.; Braid, D.

2011-01-01

The flux of meteoroids, or number of meteoroids per unit area per unit time, is critical for calibrating models of meteoroid stream formation and for estimating the hazard to spacecraft from shower and sporadic meteors. Although observations of meteors in the millimetre to centimetre size range are common, flux measurements (particularly for sporadic meteors, which make up the majority of meteoroid flux) are less so. It is necessary to know the collecting area and collection time for a given set of observations, and to correct for observing biases and the sensitivity of the system. Previous measurements of sporadic fluxes are summarized in Figure 1; the values are given as a total number of meteoroids striking the earth in one year to a given limiting mass. The Gr n et al. (1985) flux model is included in the figure for reference. Fluxes for sporadic meteoroids impacting the Earth have been calculated for objects in the centimeter size range using Super-Schmidt observations (Hawkins & Upton, 1958); this study used about 300 meteors, and used only the physical area of overlap of the cameras at 90 km to calculate the flux, corrected for angular speed of meteors, since a large angular speed reduces the maximum brightness of the meteor on the film, and radiant elevation, which takes into account the geometric reduction in flux when the meteors are not perpendicular to the horizontal. They bring up corrections for both partial trails (which tends to increase the collecting area) and incomplete overlap at heights other than 90 km (which tends to decrease it) as effects that will affect the flux, but estimated that the two effects cancelled one another. Halliday et al. (1984) calculated the flux of meteorite-dropping fireballs with fragment masses greater than 50 g, over the physical area of sky accessible to the MORP fireball cameras, counting only observations in clear weather. In the micron size range, LDEF measurements of small craters on spacecraft have been used to estimate the flux (Love & Brownlee, 1993); here the physical area of the detector is well known, but the masses depend strongly on the unknown velocity distribution. In the same size range, Thomas & Netherway (1989) used the narrow-beam radar at Jindalee to calculate the flux of sporadics. In between these very large and very small sizes, a number of video and photographic observations were reduced by Ceplecha (2001). These fluxes were calculated (details are given in Ceplecha, 1988) taking the Halliday et al. (1984) MORP fireball fluxes, slightly corrected in mass, as a calibration, and adjusting the flux of small cameras to overlap with the number/mass relation from that work.

When the dust settles: stable xenon isotope constraints on the formation of nuclear fallout.

PubMed

Cassata, W S; Prussin, S G; Knight, K B; Hutcheon, I D; Isselhardt, B H; Renne, P R

2014-11-01

Nuclear weapons represent one of the most immediate threats of mass destruction. In the event that a procured or developed nuclear weapon is detonated in a populated metropolitan area, timely and accurate nuclear forensic analysis and fallout modeling would be needed to support attribution efforts and hazard assessments. Here we demonstrate that fissiogenic xenon isotopes retained in radioactive fallout generated by a nuclear explosion provide unique constraints on (1) the timescale of fallout formation, (2) chemical fractionation that occurs when fission products and nuclear fuel are incorporated into fallout, and (3) the speciation of fission products in the fireball. Our data suggest that, in near surface nuclear tests, the presence of a significant quantity of metal in a device assembly, combined with a short time allowed for mixing with the ambient atmosphere (seconds), may prevent complete oxidation of fission products prior to their incorporation into fallout. Xenon isotopes thus provide a window into the chemical composition of the fireball in the seconds that follow a nuclear explosion, thereby improving our understanding of the physical and thermo-chemical conditions under which fallout forms. Copyright © 2014 Elsevier Ltd. All rights reserved.

Studies on High Energy Radiation Mechanisms and Gamma-Ray Burst Prompt Emissions

NASA Astrophysics Data System (ADS)

Zhang, B.

2014-07-01

Gamma-Ray Bursts (GRBs) are the most violent high-energy explosion in the universe. They are randomly happened, pulse-like phenomena with short durations. Since its discovery in 1960's by Vela satellite, GRBs have become a hot topic for astrophysical research. In 1997 the BeppoSAX satellite discovered afterglows of GRBs, and then helped to measure GRB redshifts. Thus it was found that GRBs are the events occurred at cosmological distances. Now it is widely accepted that the long bursts with durations longer than 2 s are from the collapsing massive stars, while the short bursts with durations less than 2 s are results of the merging compact binaries. By studying GRBs, the physical processes in ultrarelativistic and very high energy conditions can be investigated, and the researches on other fields, including constraining the cosmological models, can also get helped. The goal of this thesis is to present some discussions on possible radiation mechanisms and prompt light curves of GRBs. Since radiation mechanisms and prompt emissions are related to GRB central engines directly, studying these topics can help us to get a better understanding of some properties of the central engine. In Chapter 1, we review the discovery and observations of GRBs, presenting major achievements from major GRB-monitoring satellites including Compton Gamma-ray Observatory, BeppoSAX satellite, Swift satellite, as well as the latest Fermi Gamma-ray Space Telescope. The multi-wavelength properties of prompt emission as well as afterglows of GRBs are also summarized in Chapter 1. In Chapter 2 the current GRB standard model is presented. According to standard model, a fireball is ejected by the central engine. The internal shock is produced by collisions between various shells with different velocities inside the fireball. The directional kinetic energy of the fireball is then converted to internal energy, and finally the non-thermal radiation (the prompt emission) is produced by internal shocks. And the interaction between the fireball and the outer medium gives rise to external forward and reverse shocks, producing the observed afterglow. In the framework of standard model, we introduce the properties of the fireball, the evolution of shocks, some possible radiation mechanisms, as well as some post-standard effects. Also we present a brief introduction of central engines. And since the internal shock model for prompt emission has some problems hard to be solved, we also introduce some possible alternatives, including the electromagnetic model, the turbulent model, as well as the Internal-Collision-induced Magnetic Reconnection and Turbulence (ICMART) model. In Chapter 3, we present the spectrum of synchro-curvature self-Compton (SCSC) radiation of relativistic electrons with a power-law distribution of Lorentz factors. Synchro-curvature radiation from relativistic electrons moving around curved magnetic field lines and its self-Compton radiation are possible radiation mechanisms in the GRB enviroment. We find that the resulting SCSC spectrum is significantly different from that of either synchrotron self-Compton or curvature self-Compton radiation if both the curvature radius of the magnetic field and the cyclotron radius of the electrons are within some proper ranges. The effects of electrons' cooling and drifting, the low-energy self absorption in seed spectra, and the Klein-Nishina cutoff are also discussed, in order to get an accurate picture. We take GRBs as our example environment for discussions. The results would be considered as a universal approach of the self-Compton emission of relativistic electrons moving in curved magnetic fields, and thus could be applied to many astrophysical phenomena, including active galactic nuclei (AGNs), pulsars, as well as GRBs. In Chapter 4, we simulate the prompt emission light curves of GRBs within the framework of the ICMART model. This model is applied to GRBs with a moderately-high magnetization parameter σ in the emission region. We show that this model can produce highly variable light curves with both fast and slow components. The rapid variability is caused by many locally Doppler-boosted mini-emitters due to turbulent magnetic reconnection in a moderately-high-σ ejecta. The run-away growth and subsequent depletion of these mini-emitters as a function of time define a broad slow component for each ICMART event. A GRB light curve is usually composed of multiple ICMART events fundamentally driven by the erratic GRB central engine activity. Allowing variations of model parameters, including initial Lorentz factor, orientation and size distributions of reconnection regions, jet opening angle, radius of emission region, as well as observing energy band, one is able to reproduce a variety of light curves and the power density spectra (PDS) as observed. We also discuss the effects of these parameters on PDS . Finally in Chapter 5 we present our discussions, and list some remaining problems to be solved, as well as observing instruments to be commissioned in the future. We also present calculations of synchro-curvature radiation in Appendix A, and some discussions on ICMART model in Appendix B.

Photo-induced reactions from efficient molecular dynamics with electronic transitions using the FIREBALL local-orbital density functional theory formalism.

PubMed

Zobač, Vladimír; Lewis, James P; Abad, Enrique; Mendieta-Moreno, Jesús I; Hapala, Prokop; Jelínek, Pavel; Ortega, José

2015-05-08

The computational simulation of photo-induced processes in large molecular systems is a very challenging problem. Firstly, to properly simulate photo-induced reactions the potential energy surfaces corresponding to excited states must be appropriately accessed; secondly, understanding the mechanisms of these processes requires the exploration of complex configurational spaces and the localization of conical intersections; finally, photo-induced reactions are probability events, that require the simulation of hundreds of trajectories to obtain the statistical information for the analysis of the reaction profiles. Here, we present a detailed description of our implementation of a molecular dynamics with electronic transitions algorithm within the local-orbital density functional theory code FIREBALL, suitable for the computational study of these problems. As an example of the application of this approach, we also report results on the [2 + 2] cycloaddition of ethylene with maleic anhydride and on the [2 + 2] photo-induced polymerization reaction of two C60 molecules. We identify different deactivation channels of the initial electron excitation, depending on the time of the electronic transition from LUMO to HOMO, and the character of the HOMO after the transition.

FRIPON, the French fireball network

NASA Astrophysics Data System (ADS)

Colas, F.; Zanda, B.; Bouley, S.; Vaubaillon, J.; Marmo, C.; Audureau, Y.; Kwon, M. K.; Rault, J. L.; Caminade, S.; Vernazza, P.; Gattacceca, J.; Birlan, M.; Maquet, L.; Egal, A.; Rotaru, M.; Gruson-Daniel, Y.; Birnbaum, C.; Cochard, F.; Thizy, O.

2015-10-01

FRIPON (Fireball Recovery and InterPlanetary Observation Network) [4](Colas et al, 2014) was recently founded by ANR (Agence Nationale de la Recherche). Its aim is to connect meteoritical science with asteroidal and cometary science in order to better understand solar system formation and evolution. The main idea is to set up an observation network covering all the French territory to collect a large number of meteorites (one or two per year) with accurate orbits, allowing us to pinpoint possible parent bodies. 100 all-sky cameras will be installed at the end of 2015 forming a dense network with an average distance of 100km between stations. To maximize the accuracy of orbit determination, we will mix our optical data with radar data from the GRAVES beacon received by 25 stations [5](Rault et al, 2015). As both the setting up of the network and the creation of search teams for meteorites will need manpower beyond our small team of professionals, we are developing a citizen science network called Vigie-Ciel [6](Zanda et al, 2015). The public at large will thus be able to simply use our data, participate in search campaigns or even setup their own cameras.

Gamma-Ray Bursts and Fast Transients. Multi-wavelength Observations and Multi-messenger Signals

NASA Astrophysics Data System (ADS)

Willingale, R.; Mészáros, P.

2017-07-01

The current status of observations and theoretical models of gamma-ray bursts and some other related transients, including ultra-long bursts and tidal disruption events, is reviewed. We consider the impact of multi-wavelength data on the formulation and development of theoretical models for the prompt and afterglow emission including the standard fireball model utilizing internal shocks and external shocks, photospheric emission, the role of the magnetic field and hadronic processes. In addition, we discuss some of the prospects for non-photonic multi-messenger detection and for future instrumentation, and comment on some of the outstanding issues in the field.

Proceedings of Conference on Applications of Chemistry to Nuclear Weapons Effects (2nd). Held on 12-14 September 1972. Abstracts of Papers

DTIC Science & Technology

1974-12-23

16 Effects of turbulent entrainment and nonuniform mixing on fireball chemistry -------------------- 17 Entrainment by intermediate altitude...reaction rate models (*) ----------------------- 40 IV Nuclear bursts effects in the E- and F-regions ---------- 41 Shock enhanced LWIR at 151 from the C0...Regions CHAIRMAN: W. WHITAKER, AFWL 1525-1545 Shock Enhanced LWIR at 15p from the CO 2-N 2 T. McLaren System. Mount Auburn 1545-1600 CHECKMATE

Investigation of uranium molecular species using laser ablation

DOE Office of Scientific and Technical Information (OSTI.GOV)

Curreli, Davide

2017-07-12

The goal of this project is to investigate the dynamic evolution of uranium oxide (UOx) molecular species in a rapidly cooling low-temperature plasma using a coupled experimental and modeling approach. Our purpose is to develop quantitative constraints on the UOx phase chemistry under physical conditions similar to that of a nuclear fireball at the time of debris condensation. This work is motivated by a need to better understand the factors controlling uranium chemical fractionation in post-detonation nuclear debris.

Traces on sky. Unexpected results of regular observations

NASA Astrophysics Data System (ADS)

Churyumov, K. I.; Steklov, A. F.; Vidmachenko, A. P.; Dashkiev, N. G.; Steklov, E. A.

2016-08-01

If the fireball's track has noticeable angular size, it can be seen even in the daytime. After the flight, bolide remains a noticeable trace of a dust, dark against the light sky. If such a dust trail illuminated by the rays of the Sun, which had just hid behind the horizon (or even in the moonlight), it is visible as bright lanes in the night sky or in twilight. That's why we call it the twilight bolides. Usually, astronomical observations using of meteor patrols, carried out at night after the evening astronomical twilight. But from March 2013 to October 2015, the authors have obtained several thousands of different tracks in the sky over Kiev. Therefore, we have identified a special class of twilight observations of fireballs. We register the traces of invading to atmosphere of meteoroids of natural and artificial origin. At the same time, observe the traces of fireballs at the day-time are also possible. But they are less effective than in the twilight. Night observations of bright meteoric tracks can usually observe some seconds. While traces of the twilight bolides we observed from some minutes up to two hours, before they be scattered by atmospheric currents. It opens the great prospects for low-cost direct experiments probing of these tracks by using, for example, the astronomical aviation. We propose the twilight tracks are classified into the following types: AMT - aero-meteorological tracks, AST - aero-space, ATT - aero-technical, and NST - not yet classified tracks of unknown nature. During the short period of our observations (from March 2013 to 2016), was fixed falling at least a dozen fragments of cometary nuclei, at least five of sufficiently large and dozens of smaller fragments of meteoroids. The results of our observations also showed that during the morning and evening twilight over Kiev clearly visible the plume of aerosols of technical nature from the plants, factories and other production facilities.

New Exact Solutions of Relativistic Hydrodynamics for Longitudinally Expanding Fireballs

NASA Astrophysics Data System (ADS)

Csörgő, Tamás; Kasza, Gábor; Csanád, Máté; Jiang, Zefang

2018-06-01

We present new, exact, finite solutions of relativistic hydrodynamics for longitudinally expanding fireballs for arbitrary constant value of the speed of sound. These new solutions generalize earlier, longitudinally finite, exact solutions, from an unrealistic to a reasonable equation of state, characterized by a temperature independent (average) value of the speed of sound. Observables like the rapidity density and the pseudorapidity density are evaluated analytically, resulting in simple and easy to fit formulae that can be matched to the high energy proton-proton and heavy ion collision data at RHIC and LHC. In the longitudinally boost-invariant limit, these new solutions approach the Hwa-Bjorken solution and the corresponding rapidity distributions approach a rapidity plateaux.

A Simple Model for the Light Curve Generated by a Shoemaker-Levy 9 Impact

NASA Technical Reports Server (NTRS)

Zahnle, Kevin; Mordecai-Mark, Mac Low

1995-01-01

The impact of a typical Shoemaker-Levy 9 fragment produced three light peaks as seen from Earth. The first peak is related to the entry of the fragment into the Jovian atmosphere. The second peak occurs when the exploding fireball rises above Jupiter's limb into direct view from Earth. The third peak, much the brightest, occurs when the ejecta plume falls back on the atmosphere. By contrast, Galileo, which had a direct view of the impacts, saw two peaks, one at entry, and one at plumefall. Here we present a simple, highly idealized model of a ballistic plume, which we then use to fit the observed light curve of the R impact as recorded at Mauna Kea and Mount Palomar. From the light curve we find that the nominal R fragment had diameter 450-500 m and mass approx. 2-3 x 10(exp 13) g. The uncertainty in the mass is probably about a factor of 3, with a smaller event more likely than a larger one.

Self-organized criticality in a two-dimensional cellular automaton model of a magnetic flux tube with background flow

NASA Astrophysics Data System (ADS)

Dănilă, B.; Harko, T.; Mocanu, G.

2015-11-01

We investigate the transition to self-organized criticality in a two-dimensional model of a flux tube with a background flow. The magnetic induction equation, represented by a partial differential equation with a stochastic source term, is discretized and implemented on a two-dimensional cellular automaton. The energy released by the automaton during one relaxation event is the magnetic energy. As a result of the simulations, we obtain the time evolution of the energy release, of the system control parameter, of the event lifetime distribution and of the event size distribution, respectively, and we establish that a self-organized critical state is indeed reached by the system. Moreover, energetic initial impulses in the magnetohydrodynamic flow can lead to one-dimensional signatures in the magnetic two-dimensional system, once the self-organized critical regime is established. The applications of the model for the study of gamma-ray bursts (GRBs) is briefly considered, and it is shown that some astrophysical parameters of the bursts, like the light curves, the maximum released energy and the number of peaks in the light curve can be reproduced and explained, at least on a qualitative level, by working in a framework in which the systems settles in a self-organized critical state via magnetic reconnection processes in the magnetized GRB fireball.

Gasdynamics of relativistically expanding gamma-ray burst sources - Kinematics, energetics, magnetic fields, and efficiency

NASA Technical Reports Server (NTRS)

Meszaros, P.; Laguna, P.; Rees, M. J.

1993-01-01

We calculate both analytically and numerically the evolution of highly relativistic fireballs through the stages of free expansion and coasting, and determine the dependence of the thermodynamic and radiation variables in the comoving and laboratory flames. The dynamics and the comoving geometry change at the (lab) expansion factors r/r(0) greater than eta and r/r(0) greater than eta-squared, respectively, where eta = E(0)/M(0)c-squared is the initial Lorentz factor. In the lab, the gas appears concentrated in a thin shell of width r(0) until r/r(0) of less than about eta-squared, and increases linearly after that. Magnetic fields may have been important in the original impulsive event. We discuss their effect on the fireball dynamics and also consider their effects on the radiation emitted when the fireball runs into an external medium and is decelerated. The inverse synchro-Compton mechanism can then yield high radiative efficiency in the reverse shock (and through turbulent instabilities and mixing also in the forward blast wave), producing a burst of nonthermal radiation mainly in the MeV to GeV range. The energy and duration depend on eta, the magnetic field strength, and the external density, and can match the range of properties observed in cosmic gamma-ray bursts.

Gamma-ray bursts as the death throes of massive binary stars

NASA Technical Reports Server (NTRS)

Narayan, Ramesh; Paczynski, Bohdan; Piran, Tsvi

1992-01-01

We propose that gamma-ray bursts are created in the mergers of double neutron star binaries and black hole neutron star binaries at cosmological distances. Two different processes provide the electromagnetic energy for the bursts: neutrino-antineutrino annihilation into electron-position pairs during the merger, and magnetic flares generated by the Parker instability in a postmerger differentially rotating disk. In both cases, an optically thick fireball of size less than or approximately equal to 100 km is initially created, which expands ultrarelativistically to large radii before radiating. The scenario is only qualitative at this time, but it eliminates many previous objections to the cosmological merger model. The strongest bursts should be found close to, but not at the centers of, galaxies at redshifts of order 0.1, and should be accompanied by bursts of gravitational radiation from the spiraling-in binary which could be detected by LIGO.

Supernova Remnant W49B

NASA Image and Video Library

2017-12-08

Release date Dec. 30, 2009 In the supernova remnant W49B, Suzaku found another fossil fireball. It detected X-rays produced when heavily ionized iron atoms recapture an electron. This view combines infrared images from the ground (red, green) with X-ray data from NASA's Chandra X-Ray Observatory (blue). Credit: Caltech/SSC/J. Rho and T. Jarrett and NASA/CXC/SSC/J. Keohane et al. To learn more about this image go to: www.nasa.gov/mission_pages/astro-e2/news/fossil-fireballs... NASA Goddard Space Flight Center is home to the nation's largest organization of combined scientists, engineers and technologists that build spacecraft, instruments and new technology to study the Earth, the sun, our solar system, and the universe.

Emission of Gas and Al2O3 Smoke in Gas-Al Particle Deflagration: Experiments and Emission Modeling for Explosive Fireballs

NASA Astrophysics Data System (ADS)

Ranc-Darbord, Isabelle; Baudin, Gérard; Genetier, Marc; Ramel, David; Vasseur, Pierre; Legrand, Julien; Pina, Vincent

2018-03-01

Emission of gas and Al2O3 smoke within the deflagration of H2{-}O2-{N2{-}CO2}-Al particles has been studied in a closed combustion chamber at pressures of up to 18 bar and at gas temperatures of up to 3700 K. Measurements of radiance intensity were taken using a five wavelength pyrometer (0.660 μ m, 0.850 μ m, 1.083 μ m, 1.260 μ m, 1.481 μ m) and a grating spectrometer in the range (4.10 μ m to 4.30 μ m). In order to characterize the aluminum oxide smoke size and temperature, an inversion method has been developed based on the radiation transfer equation and using pyrometer measurements and thermochemical calculations of Al2O3 smoke volume fractions. Temperatures in combustion gas have been determined using a method based on the assumed blackbody head of the 4.26 μ m CO2 emission line and on its spectral shift with pressure and temperature. For validation purpose, this method has been applied to measurements obtained when calibrated alumina particles are injected in a combustion chamber prior to gaseous deflagrations. This mathematical inversion method was developed to investigate explosive fireballs.

Photoacoustic sounds from meteors

DOE PAGES

Spalding, Richard; Tencer, John; Sweatt, William; ...

2017-02-01

Concurrent sound associated with very bright meteors manifests as popping, hissing, and faint rustling sounds occurring simultaneously with the arrival of light from meteors. Numerous instances have been documented with –11 to –13 brightness. These sounds cannot be attributed to direct acoustic propagation from the upper atmosphere for which travel time would be several minutes. Concurrent sounds must be associated with some form of electromagnetic energy generated by the meteor, propagated to the vicinity of the observer, and transduced into acoustic waves. Previously, energy propagated from meteors was assumed to be RF emissions. This has not been well validated experimentally.more » Herein we describe experimental results and numerical models in support of photoacoustic coupling as the mechanism. Recent photometric measurements of fireballs reveal strong millisecond flares and significant brightness oscillations at frequencies ≥40 Hz. Strongly modulated light at these frequencies with sufficient intensity can create concurrent sounds through radiative heating of common dielectric materials like hair, clothing, and leaves. This heating produces small pressure oscillations in the air contacting the absorbers. Calculations show that –12 brightness meteors can generate audible sound at ~25 dB SPL. As a result, the photoacoustic hypothesis provides an alternative explanation for this longstanding mystery about generation of concurrent sounds by fireballs.« less

Early evolution of the extraordinary Nova Delphini 2013 (V339 Del)

NASA Astrophysics Data System (ADS)

Skopal, A.; Drechsel, H.; Tarasova, T.; Kato, T.; Fujii, M.; Teyssier, F.; Garde, O.; Guarro, J.; Edlin, J.; Buil, C.; Antao, D.; Terry, J.-N.; Lemoult, T.; Charbonnel, S.; Bohlsen, T.; Favaro, A.; Graham, K.

2014-09-01

Aims: We determine the temporal evolution of the luminosity (LWD), radius (RWD) and effective temperature (Teff) of the white dwarf (WD) pseudophotosphere of V339 Del from its discovery to around day 40. Another main objective was studying the ionization structure of the ejecta. Methods: These aims were achieved by modelling the optical/near-IR spectral energy distribution (SED) using low-resolution spectroscopy (3500-9200 Å), UBVRCIC and JHKLM photometry. Important insights in the physical conditions of the ejecta were gained from an analysis of the evolution of the Hα and Raman-scattered 6825 Å O vi line using medium-resolution spectroscopy (R ~ 10 000). Results: During the fireball stage (Aug. 14.8-19.9, 2013), Teff was in the range of 6000-12 000 K, RWD was expanding non-uniformly in time from ~66 to ~300 (d/ 3 kpc) R⊙, and LWD was super-Eddington, but not constant. Its maximum of ~9 × 1038 (d/ 3 kpc)2 erg s-1 occurred around Aug. 16.0, at the maximum of Teff, half a day before the visual maximum. After the fireball stage, a large emission measure of 1.0-2.0 × 1062 (d/ 3 kpc)2 cm-3 constrained the lower limit of LWD to be well above the super-Eddington value. The mass of the ionized region was a few × 10-4 M⊙, and the mass-loss rate was decreasing from ~5.7 (Aug. 22) to ~0.71 × 10-4 M⊙ yr-1 (Sept. 20). The evolution of the Hα line and mainly the transient emergence of the Raman-scattered O vi 1032 Å line suggested a biconical ionization structure of the ejecta with a disk-like H i region persisting around the WD until its total ionization, around day 40. On Sept. 20 (day 35), the model SED indicated a dust emission component in the spectrum. The dust was located beyond the H i zone, where it was shielded from the hard, ≳105 K, radiation of the burning WD at that time. Conclusions: Our extensive spectroscopic observations of the classical nova V339 Del allowed us to map its evolution from the very early phase after its explosion. It is evident that the nova was not evolving according to the current theoretical prediction. The unusual non-spherically symmetric ejecta of nova V339 Del and its extreme physical conditions and evolution during and after the fireball stage represent interesting new challenges for the theoretical modelling of the nova phenomenon. Based on data collected by amateur astronomers.

Bose-Einstein correlation within the framework of hadronic mechanics

DOE Office of Scientific and Technical Information (OSTI.GOV)

Burande, Chandrakant S.

The Bose-Einstein correlation is the phenomenon in which protons and antiprotons collide at extremely high energies; coalesce one into the other resulting into the fireball of finite dimension. They annihilate each other and produces large number of mesons that remain correlated at distances very large compared to the size of the fireball. It was believed that Einstein’s special relativity and relativistic quantum mechanics are the valid frameworks to represent this phenomenon. Although, these frameworks are incomplete and require arbitrary parameters (chaoticity) to fit the experimental data which are prohibited by the basic axioms of relativistic quantum mechanics, such as thatmore » for the vacuum expectation values. Moreover, correlated mesons can not be treated as a finite set of isolated point-like particles because it is non-local event due to overlapping of wavepackets. Therefore, the Bose-Einstein correlation is incompatible with the axiom of expectation values of quantum mechanics. In contrary, relativistic hadronic mechanics constructed by Santilli allows an exact representation of the experimental data of the Bose-Einstein correlation and restore the validity of the Lorentz and Poincare symmetries under nonlocal and non-Hamiltonian internal effects. Further, F. Cardone and R. Mignani observed that the Bose-Einstein two-point correlation function derived by Santilli is perfectly matched with experimental data at high energy.« less

U-Pb isotopic results for single shocked and polycrystalline zircons record 550-65.5-Ma ages for a K-T target site and 2700-1850-Ma ages for the Sudbury impact event

NASA Technical Reports Server (NTRS)

Krogh, T. E.; Kamo, S. L.; Bohor, B. F.

1992-01-01

The refractory mineral zircon develops distinct morphological features during shock metamorphism and retains these features under conditions that would anneal them in other minerals. In addition, weakly shocked zircon grains give primary ages for the impact site, while highly reconstituted (polycrystalline) single grains give ages that approach the age of the impact event. Data for a series of originally coeval grains will define a mixing line that gives both of these ages providing that no subsequent geological disturbances have overprinted the isotopic systematics. In this study, we have shown that the three zircon grain types described by Bohor, from both K-T distal ejecta (Fireball layer, Raton Basin, Colorado) and the Onaping Formation, represent a progressive increase in impact-related morphological change that coincides with a progressive increase in isotopic resetting in zircons from the ejecta and basement rocks. Unshocked grains are least affected by isotopic resetting while polycrystalline grains are most affected. U-Pb isotopic results for 12 of 14 single zircon grains from the Fireball layer plot on or close to a line recording a primary age of 550 +/- 10 Ma and a secondary age of 65.5 +/- 3 Ma. Data for the least and most shocked grains plot closest to the primary and secondary ages respectively. The two other grains each give ages between 300 and 350 Ma. This implies that the target ejecta was dominated by 550-Ma rocks and that the recrystallization features of the zircon were superimposed during the impact event at 65.5 Ma. A predominant age of 550 Ma for zircons from the Fireball layer provides an excellent opportunity to identify the impact site and to test the hypothesis that multiple impacts occurred at this time. A volcanic origin for the Fireball layer is ruled out by shock-related morphological changes in zircon and the fact that the least shocked grains are old. Basement Levack gneisses north of the Sudbury structure have a primary age of 2711 Ma. Data for three single zircons from this rock, which record a progressive increase in shock features, are displaced 24, 36, and 45 percent along a Pb-loss line toward the 1850 +/- 1 Ma minimum age for the impact as defined by the age of the norite. Southeast of the structure three shocked grains from the Murray granite record a primary age of 2468 Ma and are displaced 24, 41, and 56 percent toward the 1853 +/- 4 Ma even as defined by coexisting titanite.

The Trajectory, Orbit and Preliminary Fall Data of the JUNE BOOTID Superbolide of July 23, 2008

NASA Technical Reports Server (NTRS)

Konovalova, N. A.; Madiedo, J. M.; Trigo-Rodriguez, J. M.

2011-01-01

The results of the atmospheric trajectory, radiant, orbit and preliminary fall data calculations of an extremely bright slow-moving fireball are presented. The fireball had a -20.7 maximum absolute magnitude and the spectacular long-persistence dust trail (Fig 1 and 2) was observed in a widespread region of Tajikistan twenty eight minutes after sunset, precisely at 14h 45m 25s UT on July 23, 2008. The bolide was first recorded at a height of 38.2 km, and attained its maximum brightness at a height of 35.0 km and finished at a height of 19.6 km. These values are very much in line with other well-known fireballs producing meteorites. The first break-up must have occurred under an aerodynamic pressure Pdyn of about 1.5 MPa, similar to those derived from the study of atmospheric break-ups of previously reported meteorite-dropping bolides. Our trajectory, and dynamic results suggest that one might well expect to find meteorites on the ground in this case. The heliocentric orbit of the meteoroid determined from the observations is very similar to the mean orbit of the June Bootid meteor shower, whose parental comet is 7P/Pons-Winnecke (Lindblad et al. 2003). If the parent was indeed a comet, this has implications for the internal structure of comets, and for the survivability of cometary meteorites.

The cali meteorite fell: A new H/L ordinary chondrite

USGS Publications Warehouse

Rodriguez, J.M.T.; Llorca, J.; Rubin, A.E.; Grossman, J.N.; Sears, D.W.G.; Naranjo, M.; Bretzius, S.; Tapia, M.; Sepulveda, M.H.G.

2009-01-01

The fall of the Cali meteorite took place on 6 July 2007 at 16 h 32 ?? 1 min local time (21 h 32 ?? 1 min UTC). A daylight fireball was witnessed by hundreds of people in the Cauca Valley in Colombia from which 10 meteorite samples with a total mass of 478 g were recovered near 3??24.3'N, 76??30.6'W. The fireball trajectory and radiant have been reconstructed with moderate accuracy. From the computed radiant and from considering various plausible velocities, we obtained a range of orbital solutions that suggest that the Cali progenitor meteoroid probably originated in the main asteroid belt. Based on petrography, mineral chemistry, magnetic susceptibility, fhermoluminescence, and bulk chemistry, the Cali meteorite is classified as an H/L4 ordinary chondrite breccia.

Earth-approaching asteroid streams

NASA Astrophysics Data System (ADS)

Drummond, J. D.

1991-01-01

Three association patterns have been noted among 139 earth-approaching asteroids on the basis of current orbital similarity; these asteroid streams, consisting of two groups of five members and one of four, can be matched to three of the four meteorite-producing fireball streams determined by Halliday et al. (1990). If the asteroid streams are true nonrandom associations, the opportunity arises for studies of an 'exploded' asteroid in the near-earth environment. Near-earth asteroid-search projects are encouraged to search the mean orbit of the present streams in order to discover additional association members.

Detecting NEO Impacts using the International Monitoring System

NASA Astrophysics Data System (ADS)

Brown, Peter G.; Dube, Kimberlee; Silber, Elizabeth

2014-11-01

As part of the verification regime for the Comprehensive Nuclear Test Ban Treaty an International Monitoring System (IMS) consisting of seismic, hydroacoustic, infrasound and radionuclide technologies has been globally deployed beginning in the late 1990s. The infrasound network sub-component of the IMS consists of 47 active stations as of mid-2014. These microbarograph arrays detect coherent infrasonic signals from a range of sources including volcanoes, man-made explosions and bolides. Bolide detections from IMS stations have been reported since ~2000, but with the maturation of the network over the last several years the rate of detections has increased substantially. Presently the IMS performs semi-automated near real-time global event identification on timescales of 6-12 hours as well as analyst verified event identification having time lags of several weeks. Here we report on infrasound events identified by the IMS between 2010-2014 which are likely bolide impacts. Identification in this context refers to an event being included in one of the event bulletins issued by the IMS. In this untargeted study we find that the IMS globally identifies approximately 16 events per year which are likely bolide impacts. Using data released since the beginning of 2014 of US Government sensor detections (as given at http://neo.jpl.nasa.gov/fireballs/ ) of fireballs we find in a complementary targeted survey that the current IMS system is able to identify ~25% of fireballs with E > 0.1 kT energy. Using all 16 US Government sensor fireballs listed as of July 31, 2014 we are able to detect infrasound from 75% of these events on at least one IMS station. The high ratio of detection/identification is a product of the stricter criteria adopted by the IMS for inclusion in an event bulletin as compared to simple station detection.We discuss energy comparisons between infrasound-estimated energies based on amplitudes and periods and estimates provided by US Government sensors. Specific impact events of interest will be discussed as well as the utility of the global IMS infrasound system for location and timing of future NEAs detected prior to impact.

Bulk Lorentz factors of gamma-ray bursts

NASA Astrophysics Data System (ADS)

Ghirlanda, G.; Nappo, F.; Ghisellini, G.; Melandri, A.; Marcarini, G.; Nava, L.; Salafia, O. S.; Campana, S.; Salvaterra, R.

2018-01-01

Knowledge of the bulk Lorentz factor Γ0 of gamma-ray bursts (GRBs) allows us to compute their comoving frame properties shedding light on their physics. Upon collisions with the circumburst matter, the fireball of a GRB starts to decelerate, producing a peak or a break (depending on the circumburst density profile) in the light curve of the afterglow. Considering all bursts with known redshift and with an early coverage of their emission, we find 67 GRBs (including one short event) with a peak in their optical or GeV light curves at a time tp. For another 106 GRBs we set an upper limit tpUL. The measure of tp provides the bulk Lorentz factor Γ0 of the fireball before deceleration. We show that tp is due to the dynamics of the fireball deceleration and not to the passage of a characteristic frequency of the synchrotron spectrum across the optical band. Considering the tp of 66 long GRBs and the 85 most constraining upper limits, we estimate Γ0 or a lower limit Γ0LL. Using censored data analysis methods, we reconstruct the most likely distribution of tp. All tp are larger than the time Tp,γ when the prompt γ-ray emission peaks, and are much larger than the time Tph when the fireball becomes transparent, that is, tp>Tp,γ>Tph. The reconstructed distribution of Γ0 has median value 300 (150) for a uniform (wind) circumburst density profile. In the comoving frame, long GRBs have typical isotropic energy, luminosity, and peak energy ⟨ Eiso ⟩ = 3(8) × 1050 erg, ⟨ Liso ⟩ = 3(15) × 1047 erg s-1, and ⟨ Epeak ⟩ = 1(2) keV in the homogeneous (wind) case. We confirm that the significant correlations between Γ0 and the rest frame isotropic energy (Eiso), luminosity (Liso), and peak energy (Ep) are not due to selection effects. When combined, they lead to the observed Ep-Eiso and Ep-Liso correlations. Finally, assuming a typical opening angle of 5 degrees, we derive the distribution of the jet baryon loading which is centered around a few 10-6M⊙.

Fireball Streaking over Russia

NASA Image and Video Library

2013-02-16

This photograph of the meteor streaking through the sky above Chelyabinsk, Russia, on Feb. 15, 2013, was taken by a local, M. Ahmetvaleev. The small asteroid was about 56 to 66 feet 17 to 20 meters wide.

UCM Meteor and Fireball Research group: Results 2012--2014

NASA Astrophysics Data System (ADS)

Ocaña, F.; Sánchez de Miguel, A.; Zamorano, J.; Izquierdo, J.; Pascual, S.; Palos, M. F.; Oré, S.; Rodríguez-Coira, G.; Zamora, S.; Lorenzo, C.; San Juan, R.; Muñoz-Ibáñez, B.; Vázquez, C.; Alonso-Moragón, A.; Gallego, J.; Trigo-Rodríguez, J. M.; Madiedo, J. M.

2015-05-01

Most of the activity of the group is based on the Fireball Detection Station located at the Observatorio UCM, a system consisting of 6 high-sensitivity videocameras covering the whole sky with wide-angle lenses during nighttime. Another 15 cameras have been placed by the researchers between 10 and 200 km away from Madrid for multiple station observations. It works as a node in the SPanish Meteor and Fireball Network (SPMN), a network of similar stations covering the atmosphere over Spain. Besides the continuous monitoring, the group has worked on the recording and analysis of some meteor showers. Most of the attention was focused on the Draconids 2011 campaign at Observatorio de Sierra Nevada (Trigo-Rodríguez, J. M., Madiedo, J. M., Williams, I. P., et al. 2013, MNRAS, 433, 560; Ocaña, F., Palos, M. F., Zamorano, J., et al. 2013, Proceedings of the International Meteor Conference, 31st IMC, La Palma, Canary Islands, Spain, 2012, 70), and the 2012 Geminids balloon-borne mission over Spain (Sánchez de Miguel, A., Ocaña, F., Madiedo, J. M., et al. 2013, Lunar and Planetary Science Conference, 44, 2202). The products of the station have been used for undergraduate thesis projects at the Physics Faculty (Ocaña, F., 2011, UCM e-prints, 13292) and other undergraduate projects. In 2013 the station received new equipment thanks to the Certamen Arquímedes award, complementing the detection with spectroscopic and frame-integrating devices.

Afterglows and Kilonovae Associated with Nearby Low-luminosity Short-duration Gamma-Ray Bursts: Application to GW170817/GRB 170817A

NASA Astrophysics Data System (ADS)

Xiao, Di; Liu, Liang-Duan; Dai, Zi-Gao; Wu, Xue-Feng

2017-12-01

Very recently, the gravitational-wave (GW) event GW170817 was discovered to be associated with the short gamma-ray burst (GRB) 170817A. Multi-wavelength follow-up observations were carried out, and X-ray, optical, and radio counterparts to GW170817 were detected. The observations undoubtedly indicate that GRB 170817A originates from a binary neutron star merger. However, the GRB falls into the low-luminosity class that could have a higher statistical occurrence rate and detection probability than the normal (high-luminosity) class. This implies the possibility that GRB 170817A is intrinsically powerful, but we are off-axis and only observe its side emission. In this Letter, we provide a timely modeling of the multi-wavelength afterglow emission from this GRB and the associated kilonova signal from the merger ejecta, under the assumption of a structured jet, a two-component jet, and an intrinsically less-energetic quasi-isotropic fireball, respectively. Comparing the afterglow properties with the multi-wavelength follow-up observations, we can distinguish between these three models. Furthermore, a few model parameters (e.g., the ejecta mass and velocity) can be constrained.

Using optical techniques to measure aluminum burning in post-detonation explosive fireballs

NASA Astrophysics Data System (ADS)

Peuker, Jennifer Mott

The objectives of the current study are twofold: (1) to further the understanding of aluminum combustion in an explosive fireball, specifically where, when, and with what the aluminum is reacting; and (2) to characterize AlO emission measurements from aluminized explosive fireballs in order to determine when and how AlO emission can be used as an indicator of aluminum combustion. Experiments were completed in six different environments using four distinct aluminized charges of varying aluminum particle size---3 microm, 10 microm and 40 microm---and loading amount---20 and 50 percent by mass---to determine with what the aluminum is reacting. In addition, a charge containing 20 percent aluminum oxide (Al2O3) was used as an inert comparison. The effect of the aluminum particle location with respect to the explosive material was tested by using end-loaded charges, and by placing a layer of grease on the aluminized charge tip. Time-resolved overpressure measurements are used to determine when the aluminum is burning. Experiments employing an air-gap between the explosive charge and aluminum powder aid in determining how and when aluminum is activated and combusted in the initial blast wave and the subsequent fireball containing high pressure and high temperature detonation products. Tests in four environments show that even when AlO emission intensity is lower by 90 percent in N2 or CO2 than it is in air for a charge, it is possible to have significant---60 to 70 percent---aluminum particle oxidation. In addition, substantial AlO emission was measured in the absence of unburned aluminum---almost half of the peak AlO emission measured when unburned aluminum was present. Results show that AlO emission intensity measurements are skewed to higher AlO intensities by high transient temperatures within the first 30 micros when the peak AlO emission is usually measured. The aluminum particle location also affects the amount of AlO emission measured such that when more particles are on the fireball surface, then more AlO emission is measured. However, the end-loaded aluminum does not add to the energy output enhancement as much as the pre-loaded aluminum charges since the peak pressures and initial impulse are similar for different amounts of aluminum. A grease layer on the tip of the charge reduces the amount of AlO emission measured by 90 percent, but has the same energy output in the initial blast wave as the same charge not having a grease layer, indicating that the material at the tip of a charge changes the breakout and subsequent AlO emission production. In addition, the overpressure measurements indicate that four distinct stages of aluminum combustion exist. The first stage is the detonation and the activation of the aluminum. In the second stage the aluminum burns to enhance the blast wave which is indicated by higher peak pressures and initial impulses than a charge not containing aluminum. During the third stage, the aluminum continues to burn to increase the overpressure of the chamber. The fireball cools during the fourth stage and any aluminum oxidation does not add to the energy release. The variations in how much AlO emission is measured indicate that interpreting AlO emission measurements from explosive fireballs is not straightforward with respect to correctly determining the amount of aluminum combusted, how long the aluminum reacted, or the energy released. If aluminum is available to burn and AlO emission is measured, then the aluminum is burning---even taking into account AlO emission from the oxide layer. However, when no AlO emission is measured, it does not necessarily mean that the aluminum is not burning. When AlO emission is measured it indicates that the temperatures are high enough to sustain aluminum combustion which produces AlO, and that oxidizers are present which react to produce the AlO emission. The relative intensities for the same time frame of AlO emission measured could be indicators about the temperature or number of reactions occurring. (Abstract shortened by UMI.)

Spatially-Resolved Analyses of Aerodynamic Fallout from a Uranium-Fueled Nuclear Test

DOE PAGES

Lewis, L. A.; Knight, K. B.; Matzel, J. E.; ...

2015-07-28

The fiive silicate fallout glass spherules produced in a uranium-fueled, near-surface nuclear test were characterized by secondary ion mass spectrometry, electron probe microanalysis, autoradiography, scanning electron microscopy, and energy-dispersive x-ray spectroscopy. Several samples display compositional heterogeneity suggestive of incomplete mixing between major elements and natural U ( 238U/ 235U = 0.00725) and enriched U. Samples exhibit extreme spatial heterogeneity in U isotopic composition with 0.02 < 235U/ 238U < 11.84 among all five spherules and 0.02 < 235U/ 238U < 7.41 within a single spherule. Moreover, in two spherules, the 235U/ 238U ratio is correlated with changes in major elementmore » composition, suggesting the agglomeration of chemically and isotopically distinct molten precursors. Two samples are nearly homogenous with respect to major element and uranium isotopic composition, suggesting extensive mixing possibly due to experiencing higher temperatures or residing longer in the fireball. Linear correlations between 234U/ 238U, 235U/ 238U, and 236U/ 238U ratios are consistent with a two-component mixing model, which is used to illustrate the extent of mixing between natural and enriched U end members.« less

Status of the Desert Fireball Network

NASA Astrophysics Data System (ADS)

Devillepoix, H. A. R.; Bland, P. A.; Towner, M. C.; Cupák, M.; Sansom, E. K.; Jansen-Sturgeon, T.; Howie, R. M.; Paxman, J.; Hartig, B. A. D.

2016-01-01

A meteorite fall precisely observed from multiple locations allows us to track the object back to the region of the Solar System it came from, and sometimes link it with a parent body, providing context information that helps trace the history of the Solar System. The Desert Fireball Network (DFN) is built in arid areas of Australia: its observatories get favorable observing conditions, and meteorite recovery is eased thanks to the mostly featureless terrain. After the successful recovery of two meteorites with 4 film cameras, the DFN has now switched to a digital network, operating 51 cameras, covering 2.5 million km2 of double station triangulable area. Mostly made of off-the-shelf components, the new observatories are cost effective while maintaining high imaging performance. To process the data (~70TB/month), a significant effort has been put to writing an automated reduction pipeline so that all events are reduced with little human intervention. Innovative techniques have been implemented for this purpose: machine learning algorithms for event detection, blind astrometric calibration, and particle filter simulations to estimate both physical properties and state vector of the meteoroid. On 31 December 2015, the first meteorite from the digital systems was recovered: Murrili (the 1.68 kg H5 ordinary chondrite was observed to fall on 27 November 2015). Another 11 events have been flagged as potential meteorites droppers, and are to be searched in the coming months.

Shock Wave Dynamics of Novel Aluminized Detonations and Empirical Model for Temperature Evolution from Post-Detonation Combustion Fireballs

DTIC Science & Technology

2011-03-01

Aerospace Corporation and had both an imager and a spectrometer [34, p. 4] that employed a 60-element mercury-cadmium-telluride ( MCT ) detector array...resolution (∆λ/λ) of 0.01. Using the CVIF and the MCT detector array, they concluded the following: Table 1. Summary of previous research on...304LN FTS using HgCdTe ( MCT ) (667–2500cm−1) and InSb (1,800–10,000 cm−1) detectors , with the InSb channel fitted with an optical density (OD) filter

Early optical polarization of a gamma-ray burst afterglow.

PubMed

Mundell, Carole G; Steele, Iain A; Smith, Robert J; Kobayashi, Shiho; Melandri, Andrea; Guidorzi, Cristiano; Gomboc, Andreja; Mottram, Chris J; Clarke, David; Monfardini, Alessandro; Carter, David; Bersier, David

2007-03-30

We report the optical polarization of a gamma-ray burst (GRB) afterglow, obtained 203 seconds after the initial burst of gamma-rays from GRB 060418, using a ring polarimeter on the robotic Liverpool Telescope. Our robust (2sigma) upper limit on the percentage of polarization, less than 8%, coincides with the fireball deceleration time at the onset of the afterglow. The combination of the rate of decay of the optical brightness and the low polarization at this critical time constrains standard models of GRB ejecta, ruling out the presence of a large-scale ordered magnetic field in the emitting region.

Dilepton production from hot hadronic matter in nonequilibrium

DOE Office of Scientific and Technical Information (OSTI.GOV)

Schenke, B.; Greiner, C.

2006-03-15

The influence of time-dependent medium modifications of low-mass vector mesons on dilepton production is investigated within a nonequilibrium quantum field-theoretical description on the basis of the Kadanoff-Baym equations. Time scales for the adaption of the spectral properties to changing self-energies are given, and, under use of a model for the fireball evolution, nonequilibrium dilepton yields from the decay of {rho} and {omega} mesons are calculated. In a comparison of these yields, those from calculations that assume instantaneous (Markovian) adaption to the changing-medium quantum-mechanical memory effects turn out to be important.

Overview of major hazards. Part 2: Source term; dispersion; combustion; blast, missiles, venting; fire; radiation; runaway reactions; toxic substances; dust explosions

NASA Astrophysics Data System (ADS)

Vilain, J.

Approaches to major hazard assessment and prediction are reviewed. Source term: (phenomenology/modeling of release, influence on early stages of dispersion); dispersion (atmospheric advection, diffusion and deposition, emphasis on dense/cold gases); combustion (flammable clouds and mists covering flash fires, deflagration, transition to detonation; mostly unconfined/partly confined situations); blast formation, propagation, interaction with structures; catastrophic fires (pool fires, torches and fireballs; highly reactive substances) runaway reactions; features of more general interest; toxic substances, excluding toxicology; and dust explosions (phenomenology and protective measures) are discussed.

Chelyabinsk meteoroid entry and airburst damage

NASA Astrophysics Data System (ADS)

Popova, Olga; Emel'yanenko, Vacheslav; Kartashova, Anna; Rybnov, Yurij; Shuvalov, Valery; Jenniskens, Peter; Kharlamov, Vladimir

The Chelyabinsk airburst of 15 February 2013, was exceptional because of the large kinetic energy of the impacting body and the airburst that was generated, which created significant damage on the ground and numerous injuries in a populated area. The meteor and the effects of the airburst were extraordinarily well documented. Other events with comparable or larger energy in the past century or so include the 1963 August 3 bolide over the south Atlantic, for which only an infrasound signal was recorded, and the famous Tunguska impact in 1908. Estimates of the kinetic energy of the Tunguska impact range from 3 to 50 Mt, due to a lack of good observations at the time. The Chelyabinsk event is much better documented than both, and provides a unique opportunity to calibrate the different approaches used to model meteoroid entry and calculate the damaging effects of its airburst. Being able to predict better the potential damage on the ground from an impending small asteroid impact will help future impact hazard mitigation efforts. In order to be able to model the damaging effects of the Chelyabinsk airburst, the initial kinetic energy and approach trajectory needed to be known, how that energy was dissipated in the atmosphere, and what were the properties of the resulting airburst shockwave. Infrasonic waves are an important source of information about the fireball's initial kinetic energy. Further information about the kinetic energy is derived from the fireball's light curve. Analysis of video observations of the fireball and the shadows movements provided a meteor light curve, deceleration curve and trajectory. Video records also provided time of arrivals of the shockwave and much detail about how that shockwave interacted with surface structures. The extent of the glass damage was mapped by visiting over 50 villages in the area. Meteorites were analysed in a consortium study to understand how their material properties may have contributed to the fragmentation process. As a first attempt to understand what happened, numerical models were developed to reproduce the observed bolide light curve and the deceleration profile, which include the effects of ablation and fragmentation. We conclude that meteoroid fragmentation occurred in different forms. Some part of the initial mass broke in fragments well enough separated so that they were efficiently slowed down. A number of numerical simulations were conducted that attempted a realistic release of energy along the trajectory and these results were compared with observations of blast wave arrival times and the extent of the glass damage. The shape of the damaged area could be explained from the fact that the energy was deposited over a range of altitudes.

Near Earth asteroids associated with the Sigma-Capricornids meteoroid stream

NASA Astrophysics Data System (ADS)

Gulchekhra, Kokhirova; Pulat, Babadzhanov; Umed, Khamroev

The Near Earth Asteroids (NEAs) 2008BO16, 2011EC41, and 2013CT36 (http://newton.dm.\\unipi.it/neodys, 2013) have very similar orbits according to the D_{SH} criterion of Southworth, Hawkins (1963). Additionally, their orbits are classed as comet-like by the Tisserand invariant values (Kresak 1982; Kosai 1992). The orbital evolution investigation shows, that during one cycle of variations of the argument of perihelion omega, the asteroids cross the Earth’s orbit four times. Consequently, a developed meteoroid stream, possible associated with them, might produce four meteor showers (Babadzhanov, Obrubov 1992). Theoretical parameters of the predicted showers were calculated and identified with the observable nighttime sigma-Capricornids (Sekanina 1973; Jenniskens 2006) and chi-Sagittarids (Sekanina 1976), and daytime chi-Capricornids (Sekanina 1976) and Capricornids-Sagittarids (Sekanina 1973) meteor showers. The similar and comet-like orbits and association with the meteoroid stream producing four active showers are strong indications that these asteroids have a common cometary origin. Earlier the NEAs (2101) Adonis and 1995CS, which additionally is potentially hazardous asteroid (PHA), were recognized as dormant comets because of their link with the same meteoroid stream (Babadzhanov 2003). So, a conclusion was made, that either the considered NEAs are large sized splinters of the Adonis, or all five objects are fragments of a larger comet that was the parent body of the sigma-Capricornids meteoroid stream, and whose break-up occurred several tens of thousands years ago. During 2010-2011 years three fireballs were photographed by the Tajikistan fireball network (Babadzhanov, Kokhirova 2009), belonging to the sigma-Capricornids meteor shower. Taking into account the observations else six fireballs of this shower in the Canada and USA (Halliday et al. 1996; McCrosky et al. 1978), the mean radiant coordinates, the period of activity, as well as the mean daily radiant drift of the sigma-Capricornids were determined. Further to the PE criterion (Ceplecha, McCrosky 1976), the values of bulk density of the nine fireball producing meteoroids are in the range 0.2-3.5 g cm(-3) that suggests a non-homogeneous compound of the comet-progenitor of the sigma-Capricornids fireball shower. size{ References Babadzhanov, P.B., 2003, A&A,397, 319 Babadzhanov, P.B., Kokhirova, G.I., 2009, Izv. Ak. Nauk Resp. Taj.,2(135),46 Babadzhanov, P.B., Obrubov, Yu.V., 1992, Cel. Mech.& Dyn. Astron., v.54, p.111 Ceplecha, Z., McCrosky, R.E.J., 1976, J. Geophys. Res., 81, 6257 Halliday, I., Griffin, A.A., Blackwell, A.T., 1996, Met.& Planet. Sci., 31, 185 Jenniskens, P., 2006, Meteor showers and their parent comets, New- York: Cambridge Univ. Press, p. 790 Kosai, H., 1992, Cel. Mech. & Dyn. Astron., 54, 237 Kresak, L., 1982, BAC, 33, 104 McCrosky, R.E., Shao, C.Y., Posen, A., 1978, Meteoritika, 37, 44 Sekanina Z., 1973, Icarus, 18, 253 Sekanina Z., 1976, Icarus, 27, 265 Southworth, R.B., Hawkins, G.S., 1963, Smith. Cont. Aph. 7, 261}

Search for high-energy neutrinos from bright GRBs with ANTARES

NASA Astrophysics Data System (ADS)

Albert, A.; André, M.; Anghinolfi, M.; Anton, G.; Ardid, M.; Aubert, J.-J.; Avgitas, T.; Baret, B.; Barrios-Martí, J.; Basa, S.; Bertin, V.; Biagi, S.; Bormuth, R.; Bourret, S.; Bouwhuis, M. C.; Bruijn, R.; Brunner, J.; Busto, J.; Capone, A.; Caramete, L.; Carr, J.; Celli, S.; Chiarusi, T.; Circella, M.; Coelho, J. A. B.; Coleiro, A.; Coniglione, R.; Costantini, H.; Coyle, P.; Creusot, A.; Deschamps, A.; De Bonis, G.; Distefano, C.; di Palma, I.; Donzaud, C.; Dornic, D.; Drouhin, D.; Eberl, T.; El Bojaddaini, I.; Elsässer, D.; Enzenhöfer, A.; Felis, I.; Fusco, L. A.; Galatà, S.; Gay, P.; Geißelsöder, S.; Geyer, K.; Giordano, V.; Gleixner, A.; Glotin, H.; Gregoire, T.; Gracia-Ruiz, R.; Graf, K.; Hallmann, S.; van Haren, H.; Heijboer, A. J.; Hello, Y.; Hernández-Rey, J. J.; Hößl, J.; Hofestädt, J.; Hugon, C.; Illuminati, G.; James, C. W.; de Jong, M.; Jongen, M.; Kadler, M.; Kalekin, O.; Katz, U.; Kießling, D.; Kouchner, A.; Kreter, M.; Kreykenbohm, I.; Kulikovskiy, V.; Lachaud, C.; Lahmann, R.; Lefèvre, D.; Leonora, E.; Lotze, M.; Loucatos, S.; Marcelin, M.; Margiotta, A.; Marinelli, A.; Martínez-Mora, J. A.; Mathieu, A.; Mele, R.; Melis, K.; Michael, T.; Migliozzi, P.; Moussa, A.; Mueller, C.; Nezri, E.; Păvălaş, G. E.; Pellegrino, C.; Perrina, C.; Piattelli, P.; Popa, V.; Pradier, T.; Quinn, L.; Racca, C.; Riccobene, G.; Roensch, K.; Sánchez-Losa, A.; Saldaña, M.; Salvadori, I.; Samtleben, D. F. E.; Sanguineti, M.; Sapienza, P.; Schnabel, J.; Schüssler, F.; Seitz, T.; Sieger, C.; Spurio, M.; Stolarczyk, Th.; Taiuti, M.; Tayalati, Y.; Trovato, A.; Tselengidou, M.; Turpin, D.; Tönnis, C.; Vallage, B.; Vallée, C.; Van Elewyck, V.; Vivolo, D.; Vizzocca, A.; Wagner, S.; Wilms, J.; Zornoza, J. D.; Zúñiga, J.

2017-07-01

Gamma-ray bursts are thought to be sites of hadronic acceleration, thus neutrinos are expected from the decay of charged particles, produced in pγ interactions. The methods and results of a search for muon neutrinos in the data of the ANTARES neutrino telescope from four bright GRBs (GRB 080916C, GRB 110918A, GRB 130427A and GRB 130505A) observed between 2008 and 2013 are presented. Two scenarios of the fireball model have been investigated: the internal shock scenario, leading to the production of neutrinos with energies mainly above 100 TeV, and the photospheric scenario, characterized by a low-energy component in neutrino spectra due to the assumption of neutrino production closer to the central engine. Since no neutrino events have been detected in temporal and spatial coincidence with these bursts, upper limits at 90 per cent confidence level on the expected neutrino fluxes are derived. The non-detection allows for directly constraining the bulk Lorentz factor of the jet Γ and the baryon loading fp.

AMS fireball program, community website, mobile app, and all-sky camera

NASA Astrophysics Data System (ADS)

Hankey, Mike; Perlerin, Vincent

2014-01-01

This short paper describes the content of a video produced by Mike Hankey for the American Meteor Society (AMS) about the technology platform of the organization. This video can be watched on the web.

Infrasonic detection of a near-Earth object impact over Indonesia on 8 October 2009

NASA Astrophysics Data System (ADS)

Silber, Elizabeth A.; Le Pichon, Alexis; Brown, Peter G.

2011-06-01

We present analysis of infrasonic signals produced by a large Earth-impacting fireball, believed to be among the most energetic instrumentally recorded during the last century that occurred on 8 October, 2009 over Indonesia. This extraordinary event, detected by 17 infrasonic stations of the global International Monitoring Network, generated stratospherically ducted infrasound returns at distances up to 17 500 km, the greatest range at which infrasound from a fireball has been detected since the 1908 Tunguska explosion. From these infrasonic records, we find the total source energy for this bolide as 8-67 kilotons of TNT equivalent explosive yield, with the favored best estimate near ˜50 kt. Global impact events of such energy are expected only once per decade and study of their impact effects can provide insight into the impactor threshold levels for ground damage and climate perturbations.

When the Sky Falls NASA's Response to Bright Bolide Events Over Continental USA

NASA Technical Reports Server (NTRS)

Blaauw, R. C.; Cooke, W. J.; Kingery, A. M.; Moser, D. E.

2015-01-01

Being the only U.S. Government entity charged with monitoring the meteor environment, the Meteoroid Environment Office (MEO) has deployed a network of allsky and wide field meteor cameras, along with the appropriate software tools to quickly analyze data from these systems. However, the coverage of this network is still quite limited, forcing the incorporation of data from other cameras posted to the internet in analyzing many of the fireballs reported by the public and media. Information on these bright events often needs to be reported to NASA Headquarters by noon the following day; thus a procedure has been developed that determines the analysis process for a given fireball event based on the types and amount of data available. The differences between these analysis processes are shown by looking at four meteor events that the MEO responded to, all of which were large enough to produce meteorites.

Kinetic Damage from Meteorites

NASA Technical Reports Server (NTRS)

Cooke, William; Brown, Peter; Matney, Mark

2017-01-01

A Near Earth object impacting into Earth's atmosphere may produce damaging effects at the surface due to airblast, thermal pulse, or kinetic impact in the form of meteorites. At large sizes (>many tens of meters), the damage is amplified by the hypersonic impact of these large projectiles moving with cosmic velocity, leaving explosively produced craters. However, much more common is simple "kinetic" damage caused by the impact of smaller meteorites moving at terminal speeds. As of this date a handful of instances are definitively known of people or structures being directly hit and/or damaged by the kinetic impact of meteorites. Meteorites known to have struck humans include the Sylacauga, Alabama fall (1954) and the Mbale meteorite fall (1992). Much more common is kinetic meteorite damage to cars, buildings, and even a post box (Claxton, Georgia - 1984). Historical accounts indicate that direct kinetic damage by meteorites may be more common than recent accounts suggest (Yau et al., 1994). In this talk we will examine the contemporary meteorite flux and estimate the frequency of kinetic damage to various structures, as well as how the meteorite flux might affect the rate of human casualties. This will update an earlier study by Halliday et al (1985), adding variations expected in meteorite flux with latitude (Le Feuvre and Wieczorek, 2008) and validating these model predictions of speed and entry angle with observations from the NASA and SOMN fireball networks. In particular, we explore the physical characteristics of bright meteors which may be used as a diagnostic for estimating which fireballs produce meteorites and hence how early warning of such kinetic damage may be estimated in advance through observations and modelling.

Kinetic Damage from Meteorites

NASA Technical Reports Server (NTRS)

Cooke, William; Brown, Peter; Matney, Mark

2017-01-01

A Near Earth object impacting into Earth's atmosphere may produce damaging effects at the surface due to airblast, thermal pulse, or kinetic impact in the form of meteorites. At large sizes (greater than many tens of meters), the damage is amplified by the hypersonic impact of these large projectiles moving with cosmic velocity, leaving explosively produced craters. However, much more common is simple "kinetic" damage caused by the impact of smaller meteorites moving at terminal speeds. As of this date a handful of instances are definitively known of people or structures being directly hit and/or damaged by the kinetic impact of meteorites. Meteorites known to have struck humans include the Sylacauga, Alabama fall (1954) and the Mbale meteorite fall (1992). Much more common is kinetic meteorite damage to cars, buildings, and even a post box (Claxton, Georgia - 1984). Historical accounts indicate that direct kinetic damage by meteorites may be more common than recent accounts suggest (Yau et al., 1994). In this talk we will examine the contemporary meteorite flux and estimate the frequency of kinetic damage to various structures, as well as how the meteorite flux might affect the rate of human casualties. This will update an earlier study by Halliday et al (1985), adding variations expected in meteorite flux with latitude (Le Feuvre and Wieczorek, 2008) and validating these model predictions of speed and entry angle with observations from the NASA and SOMN fireball networks. In particular, we explore the physical characteristics of bright meteors which may be used as a diagnostic for estimating which fireballs produce meteorites and hence how early warning of such kinetic damage may be estimated in advance through observations and modeling.

Multi-wavelength Observations of GRB 111228A and Implications for the Fireball and its Environment

NASA Astrophysics Data System (ADS)

Xin, Li-Ping; Wang, Yuan-Zhu; Lin, Ting-Ting; Liang, En-Wei; Lü, Hou-Jun; Zhong, Shu-Qing; Urata, Yuji; Zhao, Xiao-Hong; Wu, Chao; Wei, Jian-Yan; Huang, Kui-Yun; Qiu, Yu-Lei; Deng, Jin-Song

2016-02-01

Observations of very early multi-wavelength afterglows are critical to reveal the properties of the radiating fireball and its environment as well as the central engine of gamma-ray bursts (GRBs). We report our optical observations of GRB 111228A from 95 s to about 50 hr after the burst trigger and investigate its properties of the prompt gamma-rays and the ambient medium using our data and the data from the Swift and Fermi missions. Our joint optical and X-ray spectral fits to the afterglow data show that the ambient medium features a low dust-to-gas ratio. Incorporating the energy injection effect, our best fit to the afterglow light curves with the standard afterglow model via the Markov Chain Monte Carlo technique shows that {ɛ }e=(6.9+/- 0.3)× {10}-2, {ɛ }B=(7.73+/- 0.62)× {10}-6,{E}K=(6.32+/- 0.86)× {10}53 {erg}, n=0.100+/- 0.014 cm-3. The low medium density likely implies that the afterglow jet may be in a halo or in a hot ISM. A chromatic shallow decay segment observed in the optical and X-ray bands is well explained with the long-lasting energy injection from the central engine, which would be a magnetar with a period of about 1.92 ms inferred from the data. The Ep of its time-integrated prompt gamma-ray spectrum is ˜26 KeV. Using the initial Lorentz factor ({{{Γ }}}0={476}-237+225) derived from our afterglow model fit, it is found that GRB 111228A satisfies the {L}{{iso}}-{E}p,z-{{{Γ }}}0 relation and bridges the typical GRBs and low luminosity GRBs in this relation.

Adapting a Planetary Science Observational Facility for Space Situational Awareness

NASA Astrophysics Data System (ADS)

Bland, P.; DFN Team

2016-09-01

The Desert Fireball Network (DFN) is designed to track meteoroids entering the atmosphere, determine pre-entry orbits (their origin in the solar system), and pinpoint fall positions for recovery by field teams. Fireball observatories are sited at remote dark-sky sites across Australia - logistics for power, sensor platforms, and data connection are in place. Each observatory is a fully autonomous unit, taking 36MP all-sky images (with fisheye lenses) throughout the night, capable of operating for 12 months in a harsh environment, and storing all imagery collected over that period. They are intelligent imaging systems, using neural network algorithms to recognize and report fireball events. An automated data reduction pipeline delivers orbital data and meteorite fall positions. Currently the DFN stands at 50 observing stations covering 2.5 million km2. A sub-set of the existing stations will be upgraded with a parallel camera package using 50mm prime lenses. Paired stations will allow triangulation. The high resolution array would deliver a Gpixel tiled image of the visible sky every 10 sec, at 20 arcsec resolution, with a limiting magnitude of 13 in a 10 sec snapshot. There are benefits in transient astronomy (optical flashes associated with gamma-ray bursts; flares from sources that generate ultra-high energy cosmic rays), and space situational awareness. The hardware upgrade would extend the resolution of the DFN into the V=11-12 magnitude range for objects in LEO, allowing us to observe significant activity during the terminator period. The result would be a wide field array, capable of triangulation, with a 3500km baseline enabling a larger terminator observing window.

Meteorite Falls and the Fragmentation of Meteorites

NASA Technical Reports Server (NTRS)

Momeni, Daniel

2016-01-01

In order to understand the fragmentation of objects entering the atmosphere and why some produce more fragments than others, I have searched the Meteoritical Society database for meteorites greater than 20 kilograms that fell in the USA, China, and India. I also studied the video and film records of 21 fireballs that produced meteorites. A spreadsheet was prepared that noted smell, fireball, explosion, whistling, rumbling, the number of fragments, light, and impact sounds. Falls with large numbers of fragments were examined to look for common traits. These were: the Norton County aubrite, explosion and a flare greater than 100 fragments; the Forest City H5 chondrite explosion, a flare, a dust trail, 505 specimens; the Richardton H5 chondrite explosion and light, 71 specimens; the Juancheng H5 chondrite explosion, a rumbling, a flare, a dust trail,1000 specimens; the Tagish Lake C2 chondrite explosion, flare, dust trail, 500 specimens. I conclude that fragmentation is governed by the following: (1) Bigger meteors undergo more stress which results in more specimens; (2) Harder meteorites also require more force to break them up which will cause greater fragmentation; (3) Force and pressure are directly proportional during falls. General observations made were; (1) Meteorites produce fireballs sooner due to high friction; (2) Meteors tend to explode as well because of high stress; (3) Softer meteorites tend to cause dust trails; (4) Some falls produce light as they fall at high velocity. I am grateful to NASA Ames for this opportunity and Derek Sears, Katie Bryson, and Dan Ostrowski for discussions.

Fe-57 Mössbauer Study of the Murrili Ordinary Chondrite

NASA Astrophysics Data System (ADS)

Cadogan, J. M.; Bland, P. A.; Benedix, G. K.; Towner, M. C.; Sansom, E. K.; Devillepoix, H.; Howie, R. M.; Paxman, J. P.; Cupak, M.; Cox, M. A.; Jansen-Sturgeon, T.; Stuart, D.; Strangway, D.

2016-08-01

The Murrili meteorite fell in Lake Eyre South, South Australia, after being imaged and located by the Desert Fireball Network. It displays an unusual heterogeneous weathering throughout the stone, here quantified using 57Fe Mössbauer spectroscopy.

NASA's Meteoroid Environments Office's Response to Three Significant Bolide Events Over North America

NASA Technical Reports Server (NTRS)

Blaauw, Rhiannon C.; Cooke, William J.; Kingery, Aaron M.

2015-01-01

Being the only U.S. Government entity charged with monitoring the meteor environment, the Meteoroid Environment Office has deployed a network of all sky and wide field meteor cameras, along with the appropriate software tools to quickly analyze data from these systems. However, the coverage of this network is still quite limited, forcing the incorporation of data from other cameras posted to the internet in analyzing many of the fireballs reported by the public and media. A procedure has been developed that determines the analysis process for a given fireball event based on the types and amount of data available. The differences between these analysis process will be explained and outlined by looking at three bolide events, all of which were large enough to produce meteorites. The first example is an ideal event - a bright meteor that occurred over NASA's All Sky Camera Network on August 2, 2014. With clear video of the event from various angles, a high-accuracy trajectory, beginning and end heights, orbit and approximate brightness/size of the event are able to be found very quickly using custom software. The bolide had the potential to have dropped meteorites, so dark flight analysis and modeling was performed, allowing potential fall locations to be mapped as a function of meteorite mass. The second case study was a bright bolide that occurred November 3, 2014 over West Virginia. This was just north of the NASA southeastern all-sky network, and just south of the Ohio-Pennsylvania network. This case study showcases the MEO's ability to use social media and various internet sources to locate videos of the event from obscure sources (including the Washington Monument) for anything that will permit a determination of a basic trajectory and fireball light curve The third case study will highlight the ability to use doppler weather radar in helping locate meteorites, which enable a definitive classification of the impactor. The input data and analysis steps differ for each case study, but the goals remain the same - a trajectory, orbit, and mass estimate for the bolide within hours of the event, and, for events with a high probability of producing meteorites, a location of the strewn field within a day.

Review of amateur meteor research

NASA Astrophysics Data System (ADS)

Rendtel, Jürgen

2017-09-01

Significant amounts of meteor astronomical data are provided by amateurs worldwide, using various methods. This review concentrates on optical data. Long-term meteor shower analyses based on consistent data are possible over decades (Orionids, Geminids, κ-Cygnids) and allow combination with modelling results. Small and weak structures related to individual stream filaments of cometary dust have been analysed in both major and minor showers (Quadrantids, September ε-Perseids), providing feedback to meteoroid ejection and stream evolution processes. Meteoroid orbit determination from video meteor networks contributes to the improvement of the IAU meteor data base. Professional-amateur cooperation also concerns observations and detailed analysis of fireball data, including meteorite ground searches.

Launch Architecture Impact on Ascent Abort and Crew Survival

NASA Technical Reports Server (NTRS)

Mathias, Donovan L.; Lawrence, Scott L.

2006-01-01

A study was performed to assess the effect of booster configuration on the ascent abort process. A generic abort event sequence was created and booster related risk drivers were identified. Three model boosters were considered in light of the risk drivers: a solid rocket motor configuration, a side mount combination solid and liquid configuration, and a stacked liquid configuration. The primary risk drivers included explosive fireball, overpressure, and fragment effects and booster-crew module re-contact. Risk drivers that were not specifically booster dependent were not addressed. The solid rocket configuration had the most benign influence on an abort while the side mount architecture provided the most challenging abort environment.

Weapon and Sighting System Compatibility Assessment for Prototype Maxillofacial Protection Devices

DTIC Science & Technology

2013-03-01

No Maxillofacial Protection, No Visor (figure 38) ...........................22 7.2 Sighting System Compatibility – Bradley Fighting Vehicle ( BFV ...23 Figure 39. FASTBAC, bracket only ( BFV ...23 Figure 40. FASTBAC bracket and maxillofacial protection ( BFV ). ............................................24 Figure 41. FIREBALL

ScienceCast 156: Perseid Meteors vs the Supermoon

NASA Image and Video Library

2014-07-28

Which is brighter--a flurry of Perseid fireballs or a supermoon? Sky watchers will find out this August when the biggest and brightest full Moon of 2014 arrives just in time for the peak of the annual Perseid meteor shower.

A Comprehensive Study of Chelyabinsk Meteorite: Physical, Mineralogical, Spectral Properties and Solar System Orbit

NASA Astrophysics Data System (ADS)

Gritsevich, Maria; Kohout, T.; Grokhovsky, V.; Yakovlev, G.; Lyytinen, E.; Vinnikov, V.; Haloda, J.; Halodova, P.; Michallik, R.; Penttilä, A.; Muinonen, K.; Peltoniemi, J.; Lupovka, V.; Dmitriev, V.

2013-10-01

On February 15, 2013, at 9:22 am, an exceptionally bright and long duration fireball was observed by many eyewitnesses in the Chelyabinsk region, Russia. A strong shock wave associated with the fireball caused significant damage such as destroyed windows and parts of buildings in Chelyabinsk and the surrounding territories. A number of video records of the event are available and have been used to reconstruct atmospheric trajectory, velocity, deceleration rate, and parent asteroid Apollo-type orbit in the Solar System. Two types of meteorite material are present among recovered fragments of the Chelyabinsk meteorite. These are described as the light-colored and dark-colored lithology. Both types are of LL5 composition with the dark-colored one being an impact-melt shocked to a higher level. Based on the magnetic susceptibility measurements, the Chelyabinsk meteorite is richer in metallic iron as compared to other LL chondrites. The measured bulk and grain densities and the porosity closely resemble other LL chondrites. Shock darkening does not have a significant effect on the material physical properties, but causes a decrease of reflectance and decrease in silicate absorption bands in the reflectance spectra. This is similar to the space weathering effects observed on asteroids. However, no spectral slope change similar to space weathering is observed as a result of shock-darkening. Thus, it is possible that some dark asteroids with invisible silicate absorption bands may be composed of relatively fresh shock darkened chondritic material.

Gamma-ray Bursts May Originate in Star-Forming Regions

NASA Astrophysics Data System (ADS)

2001-04-01

New findings from two X-ray satellites suggest that gamma-ray bursts, some of the most intense blasts in the universe, may be created in the same area where stars are born. Dr. Luigi Piro of the Consiglio Nazionale delle Ricerche (CNR) in Rome, Italy, presented data from NASA's Chandra X-ray Observatory and the Italian-Dutch ASI BeppoSAX observatory today at the Gamma Ray 2001 conference in Baltimore, MD. "We know that when a gamma-ray burst explodes, it produces a blast of material called a fireball, which expands at relativistic speeds like a rapidly inflating bubble," said Piro, who works within CNR's Istituto di Astrofisica Spaziale. "Our team found evidence that the blast wave caused by the fireball brakes against a wall of very dense gas, which we believe is the crowded region where stars form." Several theories exist about what causes gamma-ray bursts. Among more popular theories are that gamma-ray bursts come from various combinations of merging neutron stars and black holes, or, from the explosion of massive stars, called hypernovae. "Because gamma-ray bursts are going off in extremely distant galaxies, it is difficult to 'see' the regions that harbor them," said Piro. "We can only gather circumstantial evidence as to where and how they form." Piro's observations support the hypernova model. Scientists believe that within dense star-forming regions, the massive star required for a hypernova explosion evolves extremely rapidly. On astronomical time scales, the supermassive star would evolve over the course of only about one million years. Thus, the hypernova explosion may occur in the same stellar environment that originally produced the massive star itself, and perhaps may trigger even more star formation. The hint that gamma-ray bursts can occur in dense media came during a Chandra observation of an afterglow that occurred on September 26, 2000. Prof. Gordon Garmire of Pennsylvania State University, University Park, PA, found X-ray emission to be greater than that expected by the standard scenario of a fireball in a low-density medium - an important clue that the explosion occurred in a dense region. Next, on February 22, 2001, Piro said that Chandra observations of the burst's afterglow, one of the brightest bursts ever observed by BeppoSAX, provided evidence of a fireball expanding in a very dense gas. These recent results supported data from four other gamma-ray bursts observed by BeppoSAX and Chandra (GRB970508, GRB990705, GRB991216, and GRB000214). In these bursts, Piro and his team found evidence indicating that the burst had encountered an extremely dense gas. The properties of this gas suggest that it originated from a very massive progenitor before it exploded as a gamma-ray burst. A key element in the success of these observations has been the perfect timing and liaison between the two satellites, Chandra and BeppoSAX, according to Piro. Piro is the Mission Scientist for BeppoSAX, the instrument that first detected X-ray afterglows from gamma-ray bursts. Currently, astronomers are not usually notified about gamma-ray bursts until an hour or so after they occur. These bursts last only for a few milliseconds to about a minute, although their afterglow can linger in X-ray and optical light for days or weeks. The HETE-2 satellite, launched in October 2000, and Swift, scheduled for a 2003 launch, will provide nearly instant notification of bursts in action, providing satellites such as Chandra a better opportunity to study the afterglow phenomenon in depth. The ACIS X-ray camera was developed for NASA by Penn State and the Massachusetts Institute of Technology. The High Energy Transmission Grating Spectrometer was built by MIT. NASA's Marshall Space Flight Center in Huntsville, AL, manages the Chandra program. TRW, Inc., Redondo Beach, California, is the prime contractor for the spacecraft. The Smithsonian's Chandra X-ray Center controls science and flight operations from Cambridge, MA. Images associated with this release are available on the World Wide Web at: http://chandra.harvard.edu AND http://chandra.nasa.gov

Mathematical modeling of ignition of woodlands resulted from accident on the pipeline

NASA Astrophysics Data System (ADS)

Perminov, V. A.; Loboda, E. L.; Reyno, V. V.

2014-11-01

Accidents occurring at the sites of pipelines, accompanied by environmental damage, economic loss, and sometimes loss of life. In this paper we calculated the sizes of the possible ignition zones in emergency situations on pipelines located close to the forest, accompanied by the appearance of fireballs. In this paper, using the method of mathematical modeling calculates the maximum size of the ignition zones of vegetation as a result of accidental releases of flammable substances. The paper suggested in the context of the general mathematical model of forest fires give a new mathematical setting and method of numerical solution of a problem of a forest fire modeling. The boundary-value problem is solved numerically using the method of splitting according to physical processes. The dependences of the size of the forest fuel for different amounts of leaked flammable substances and moisture content of vegetation.

GRB 091127: The Cooling Break Race on Magnetic Fuel

NASA Technical Reports Server (NTRS)

Filgas, R.; Greiner, J.; Schady, P.; Kruhler, T.; Updike, A. C.; Klose, S.; Nardini, M.; Kann, D. A.; Rossi, A.; Sudilovsky, V.;

"Churyumov Unified Network": new tasks for astronomical observatories to protect society

NASA Astrophysics Data System (ADS)

Churyumov, K. I.; Steklov, A. F.; Vidmachenko, A. P.; Dashkiev, G. N.

2016-10-01

As a result of observations in nearly four years the authors have identified a class of twilight bolides. Traces of Twilight bolides are observed from a few minutes to two hours. The paper considers simultaneous observation of the evening twilight fireball in the sky over the Kiev region 08.07.2016. Base distance between the photographing points was 25.8 km. Thermal explosion, flashing and decay of the body invaded into the atmosphere over Kiev region began at altitude of 55-65 km. It flared up and slowly moving along the inclined path disappeared at the height of about 30-33 km.

An Overview of the Chelyabinsk Impact Event (Invited)

NASA Astrophysics Data System (ADS)

Chodas, P. W.; Chesley, S.

2013-12-01

On February 15, 2013, a small asteroid called 2012 DA14 was about to make a much anticipated extremely close flyby of the Earth, when an even smaller asteroid stole the show by impacting into the Earth's atmosphere near Chelyabinsk, Russia, releasing half a megaton of energy and creating a shock wave that reportedly injured more than a thousand people. The passage of a 40-meter asteroid within the ring of geosynchrounous satellites is rare, calculated to be a once-in-40-year event, and yet it was upstaged on the same day by an actual Earth impact of a previously unseen 20-meter asteroid, an event expected to occur only about once per century, on average. Infrasound-based estimates of the released energy from this impact lie in the range of from 450 to 700 kilotons, making the Chelyabinsk fireball the largest impact event since the Tunguska explosion over Siberia in 1908. From the standpoint of acquiring data, it is incredibly fortunate that this impact occurred when and where it did, i.e., near a large city, during the morning commute hours, in a country where continuously operating "dash-cams" are ubiquitous, and in an era when videos can quickly be uploaded and viewed worldwide. There are over 400 videos of the event or its effects catalogued to date, half of them viewing the fireball directly or showing its lightflash. Some of these were available online within an hour of the event, and they enabled a quick scientific assessment of both the size of the fireball and its approximate trajectory. Social media played a key role by providing an early alert to scientists and by calling attention to the online videos. Even a cursory examination of the trajectory of the fireball path revealed that the impactor entered at a very shallow entry angle (later determined to be about 17 deg to the horizontal), and that it entered from the general direction of the Sun. It was clear that the east-to-west trajectory of the Chelyabinsk impactor was very different from the south-to-north path of 2012 DA14. With such clearly different trajectories, we could assure the public with confidence that the two asteroids were unrelated. There have been several detailed analyses of the approach trajectory of the Chelyabinsk impactor, all of them indicating that the asteroid approached the Earth from within 20 degrees of the sunline. Thus, this object could not have been detected on its final approach by any of the asteroid search programs, which optically scan the night sky, well away from direction of the Sun. It is worth noting, however, that the even smaller object 2009 TC3, was discovered by a NASA-funded asteroid survey program on its final plunge to an impact in Sudan in October 2008, but it approached the Earth from the side opposite the Sun. The Chelyabinsk impact event reminds us of the hazard posed by near-Earth asteroids, and validates NASA-funded efforts to find and track as many of these potentially hazardous objects as possible.

Non-LTE model atmosphere analysis of Nova Cygni 1992

NASA Technical Reports Server (NTRS)

Hauschildt, P. H.; Starrfield, S.; Austin, S.; Wagner, R. M.; Shore, S. N.; Sonneborn, G.

1994-01-01

We use spherically symmetric non-local thermodynamic equilibrium (non-LTE), line-blanketed, expanding model atmospheres to analyze the International Ultraviolet Explorer (IUE) and optical spectra of Nova Cygni 1992 during the early phases of its outburst. We find that the first IUE spectrum obtained just after discovery on 1992 February 20, is best reproduced by a model atmosphere with a steep density gradient and homologous expansion, whereas the IUE and optical spectra obtained on February 24 show an extended, optically thick, wind structure. Therefore, we distinguish two phases of the early evolution of the nova photosphere: the initial, rapid, 'fireball' phase and the subsequent, much longer, optically thick 'wind' phase. The importance of line-blanketing in nova spectra is demonstrated. Our preliminary abundance analysis implies that hydrogen is depeleted in the ejecta, corresponding to abundance enhancements of Fe by a factor of approximately 2 and of CNO by more than a factor of 10 when compared to solar abundances. The synthetic spectra reproduce both the observed pseudo-continua as well as most of the observed features from the UV to the optical spectral range and demonstrate the importance of obtaining nearly simultaneous UV and optical spectra for performing accurate analyses of expanding stellar atmospheres (for both novae and supernovae).

An anomalous basaltic meteorite from the innermost main belt.

PubMed

Bland, Philip A; Spurny, Pavel; Towner, Martin C; Bevan, Alex W R; Singleton, Andrew T; Bottke, William F; Greenwood, Richard C; Chesley, Steven R; Shrbeny, Lukas; Borovicka, Jiri; Ceplecha, Zdenek; McClafferty, Terence P; Vaughan, David; Benedix, Gretchen K; Deacon, Geoff; Howard, Kieren T; Franchi, Ian A; Hough, Robert M

2009-09-18

Triangulated observations of fireballs allow us to determine orbits and fall positions for meteorites. The great majority of basaltic meteorites are derived from the asteroid 4 Vesta. We report on a recent fall that has orbital properties and an oxygen isotope composition that suggest a distinct parent body. Although its orbit was almost entirely contained within Earth's orbit, modeling indicates that it originated from the innermost main belt. Because the meteorite parent body would likely be classified as a V-type asteroid, V-type precursors for basaltic meteorites unrelated to Vesta may reside in the inner main belt. This starting location is in agreement with predictions of a planetesimal evolution model that postulates the formation of differentiated asteroids in the terrestrial planet region, with surviving fragments concentrated in the innermost main belt.

Coalescing neutron stars - a step towards physical models. II. Neutrino emission, neutron tori, and gamma-ray bursts.

NASA Astrophysics Data System (ADS)

Ruffert, M.; Janka, H.-T.; Takahashi, K.; Schaefer, G.

1997-03-01

Three-dimensional hydrodynamical, Newtonian calculations of the coalescence of equal-mass binary neutron stars are performed with the "Piecewise Parabolic Method". The properties of neutron star matter are described by the equation of state of Lattimer & Swesty (1991, Nucl. Phys. A535, 331) which allows us to include the emission of neutrinos and to evaluate our models for the νν-annihilation in the vicinity of the merging stars. When the stars have merged into one rapidly spinning massive body, a hot toroidal cloud of gas with a mass of about 0.1-0.2Msun_ forms around the wobbling and pulsating central ~3Msun_ object. At that time the total neutrino luminosity climbs to a maximum value of 1-1.5x10^53^erg/s of which 90-95% originate from the toroidal gas cloud surrounding the very dense core. The mean energies of ν_e_, ν_e_, and heavy-lepton neutrinos ν_x_ are around 12MeV, 20MeV, and 27MeV, respectively. The characteristics of the neutrino emission are very similar to the emission from type-II supernovae, except for the ν_e_ luminosity from the merged neutron stars which is a factor 3-6 higher than the luminosities of the other neutrino species. When the neutrino luminosities are highest, νν-annihilation deposits about 0.2-0.3% of the emitted neutrino energy in the immediate neighborhood of the merger, and the maximum integral energy deposition rate is 3-4x10^50^erg/s. Since the 3Msun_ core of the merged object will most likely collapse into a black hole within milliseconds, the energy that can be pumped into a pair-photon fireball is insufficient by a factor of about 1000 to explain γ-ray bursts at cosmological distances with an energy of the order of 10^51^/(4π) erg/steradian. Analytical estimates show that the additional energy provided by the annihilation of νν pairs emitted from a possible accretion torus of ~0.1Msun_ around the central black hole is still more than a factor of 10 too small, unless focussing of the fireball into a jet-like expansion plays an important role. A few 10^-4^Msun_ of very neutron-rich, low-entropy matter may be dynamically ejected shortly after the neutron stars have merged, and another 10^-4^ up to a few 10^-2^Msun_ of strongly neutronized, high-entropy material could be carried away from the accretion torus in a neutrino-driven wind. The contamination with this baryonic material is a severe threat to a relativistic fireball. Aspects of a possible r-processing in these ejecta are discussed.

The evolution of the X-ray afterglow emission of GW 170817/ GRB 170817A in XMM-Newton observations

NASA Astrophysics Data System (ADS)

D'Avanzo, P.; Campana, S.; Salafia, O. S.; Ghirlanda, G.; Ghisellini, G.; Melandri, A.; Bernardini, M. G.; Branchesi, M.; Chassande-Mottin, E.; Covino, S.; D'Elia, V.; Nava, L.; Salvaterra, R.; Tagliaferri, G.; Vergani, S. D.

2018-05-01

We report our observation of the short gamma-ray burst (GRB) GRB 170817A, associated to the binary neutron star merger gravitational wave (GW) event GW 170817, performed in the X-ray band with XMM-Newton 135 d after the event (on 29 December, 2017). We find evidence for a flattening of the X-ray light curve with respect to the previously observed brightening. This is also supported by a nearly simultaneous optical Hubble Space Telescope observation and successive X-ray Chandra and low-frequency radio observations recently reported in the literature. Since the optical-to-X-ray spectral slope did not change with respect to previous observations, we exclude that the change in the temporal evolution of the light curve is due to the passage of the cooling frequency: its origin must be geometric or dynamical. We interpret all the existing afterglow data with two models: i) a structured jet and ii) a jet-less isotropic fireball with some stratification in its radial velocity structure. Both models fit the data and predict that the radio flux must decrease simultaneously with the optical and X-ray emission, making it difficult to distinguish between them at the present stage. Polarimetric measurements and the rate of short GRB-GW associations in future LIGO/Virgo runs will be key to disentangle these two geometrically different scenarios.

Pre-atmospheric parameters and fragment distribution: Case study for the Kosice meteoroid

NASA Astrophysics Data System (ADS)

Gritsevich, M.; Vinnikov, V.; Kuznetsova, D.; Kohout, T.; Pupyrev, Y.; Peltoniemi, J.; Tóth, J.; Britt, D.; Turchak, L.; Virtanen, J.

2014-07-01

We present results on our investigation on the Košice meteorite --- one of the recent falls with a well-derived trajectory and large number of recovered fragments. A fireball appeared over central-eastern Slovakia on February 28, 2010. The bolide reached an absolute magnitude of at least -18, enabling radiometers of the European Fireball Network to track the fireball despite the cloudy and rainy weather. The landing area was successfully computed on the basis of data from the surveillance cameras operating in Hungary and led to a fast meteorite recovery (Borovička et al. 2013). The first reported fragment of the meteorite was located northwest of the city of Košice in eastern Slovakia (Tóth et al. 2014). 218 fragments of the Košice meteorite, with a total mass of 11.285 kg, have been documented with almost 7 kg belonging to the collection of the Comenius University in Bratislava and Astronomical Institute of Slovak Academy of Sciences (Gritsevich et al. 2014). Based on the statistical investigation of the recovered fragments, bimodal Weibull, bimodal Grady, and bimodal lognormal distributions are found to be the most appropriate distributions for describing the Košice fragmentation process. The most probable scenario suggests that the Košice meteoroid, prior to further extensive fragmentation in the lower atmosphere, was initially represented by two independent pieces with cumulative residual masses of approximately 2 kg and 9 kg respectively (Gritsevich et al. 2014). About 1/3 of the recovered Košice fragments were thoroughly studied, including magnetic susceptibility, bulk and grain density measurements reported by Kohout et al. (2014). This analysis revealed that the Košice meteorites are H5 ordinary chondrites that originated from a homogenous parent meteoroid. To estimate the dynamic mass of the main fragment, we studied the first integral of the drag and mass-loss equations, and the geometrical relation along the meteor trajectory in the atmosphere. By matching these equations to the trajectory data obtained by Borovička et al. (2013), we determine key dimensionless parameters responsible for the meteoroid drag and ablation rate along its visual path in the atmosphere. These parameters allow us to estimate the pre-atmospheric mass, which is in good agreement with the photometric estimate derived by Borovička et al. (2013). Throughout this study, we permit changes in meteoroid shape along the trajectory. Additionally, we estimate the initial shape of the Košice meteoroid based on a statistical analysis (Vinnikov et al. 2014). We also conclude that two to three larger Košice fragments of 500-1000g each should exist, but were either not recovered or not reported by illegal meteorite hunters.

Short Gamma-ray Bursts: Observations and Physics

NASA Astrophysics Data System (ADS)

Janka, H.-Thomas

2007-04-01

The aim of the workshop, which will be held at the scenic Ringberg castle, is supposed to bring together astrophysicists, physicists, and astronomers from different fields in order to discuss recent observational and theoretical discoveries and developments on short gamma-ray bursts. In particular, we plan to address the following topics: * recent short GRB observations * environments and host galaxies of short GRBs * is there a 3rd class of GRBs? * modeling GRB engines and jet outflows * rate and redshift predictions for short GRBs * the fireball model and short GRBs * gravitational-wave signals from short GRBs * neutrino signals from short GRBs * microphysics needed for modeling short GRBs and their engines Scientific and Local organizing committee members: H.-Thomas Janka (Max Planck Institute for Astrophysics, Garching), Miguel Aloy (University of Valencia), Jochen Greiner (Max Planck Institute for Extraterrestrial Physics), Sandra Savaglio (Max Planck Institute for Extraterrestrial Physics), Shri Kulkarni (California Institute of Technology, Pasadena)

Meteorite Falls Observed in U.S. Weather Radar Data in 2015 and 2016 (To Date)

NASA Technical Reports Server (NTRS)

Fries, Marc; Fries, Jeffrey; Hankey, Mike; Matson, Robert

2016-01-01

To date, over twenty meteorite falls have been located in the weather radar imagery of the National Oceanic and Atmospheric Administration (NOAA)'s NEXRAD radar network. We present here the most prominent events recorded since the last Meteoritical Society meeting, covering most of 2015 and early 2016. Meteorite Falls: The following events produced evidence of falling meteorites in radar imagery and resulted in meteorites recovered at the fall site. Creston, CA (24 Oct 2015 0531 UTC): This event generated 218 eyewitness reports submitted to the American Meteor Society (AMS) and is recorded as event #2635 for 2015 on the AMS website. Witnesses reported a bright fireball with fragmentation terminating near the city of Creston, CA, north of Los Angeles. Sonic booms and electrophonic noise were reported in the vicinity of the event. Weather radar imagery records signatures consistent with falling meteorites in data from the KMUX, KVTX, KHNX and KVBX. The Meteoritical Society records the Creston fall as an L6 meteorite with a total recovered mass of 688g. Osceola, FL (24 Jan 2016 1527 UTC): This daytime fireball generated 134 eyewitness reports on AMS report number 266 for 2016, with one credible sonic boom report. The fireball traveled roughly NE to SW with a terminus location north of Lake City, FL in sparsely populated, forested countryside. Radar imagery shows distinct and prominent evidence of a significant meteorite fall with radar signatures seen in data from the KJAX and KVAX radars. Searchers at the fall site found that recoveries were restricted to road sites by the difficult terrain, and yet several meteorites were recovered. Evidence indicates that this was a relatively large meteorite fall where most of the meteorites are unrecoverable due to terrain. Osceola is an L6 meteorite with 991 g total mass recovered to date. Mount Blanco, TX (18 Feb 2016 0343 UTC): This event produced only 39 eyewitness reports and is recorded as AMS event #635 for 2016. No reports of sonic booms or electrophonic noise are recorded in the AMS eyewitness reports, but videos of the event show a relatively long-lasting fireball with fragmentation. Evidence of falling meteorites is seen in radar imagery from the KAMA and KLBB radars defining a roughly WNW to ESE trend with the dominant wind direction. This event featured favorable search ground composed mostly of farmland and ranchland and was extensively searched. Rather surprisingly, only a single L5 chondrite of 36.2g has been recovered to date.

Contribution of Infrasound to IDC Reviewed Event Bulletin

NASA Astrophysics Data System (ADS)

Bittner, Paulina; Polich, Paul; Gore, Jane; Ali, Sherif Mohamed; Medinskaya, Tatiana; Mialle, Pierrick

2016-04-01

Until 2003 two waveform technologies, i.e. seismic and hydroacoustic were used to detect and locate events included in the International Data Centre (IDC) Reviewed Event Bulletin (REB). The first atmospheric event was published in the REB in 2003 but infrasound detections could not be used by the Global Association (GA) Software due to the unmanageable high number of spurious associations. Offline improvements of the automatic processing took place to reduce the number of false detections to a reasonable level. In February 2010 the infrasound technology was reintroduced to the IDC operations and has contributed to both automatic and reviewed IDC bulletins. The primary contribution of infrasound technology is to detect atmospheric events. These events may also be observed at seismic stations, which will significantly improve event location. Examples of REB events, which were detected by the International Monitoring System (IMS) infrasound network were fireballs (e.g. Bangkok fireball, 2015), volcanic eruptions (e.g. Calbuco, Chile 2015) and large surface explosions (e.g. Tjanjin, China 2015). Query blasts and large earthquakes belong to events primarily recorded at seismic stations of the IMS network but often detected at the infrasound stations. Presence of infrasound detection associated to an event from a mining area indicates a surface explosion. Satellite imaging and a database of active mines can be used to confirm the origin of such events. This presentation will summarize the contribution of 6 years of infrasound data to IDC bulletins and provide examples of events recorded at the IMS infrasound network. Results of this study may help to improve location of small events with observations on infrasound stations.

Atmospheric Profile Imprint in Firewall Ablation Coefficient

NASA Technical Reports Server (NTRS)

Ceplecha, Z.; Pecina, P.

1984-01-01

A general formula which expresses the distance along the meteoric fireball trajectory 1 as a function of t is discussed. Differential equations which include the motion and ablation of a single nonfragmenting meteor body are presented. The importance of the atmospheric density profile in the meteor formula is emphasized.

PHOTOCHEMICAL OXIDENTS IN YONKERS, NEW YORK: EFFECTS ON YIELD OF BEAN AND TOMATO

EPA Science Inventory

Field plots of bean (Phaseolus vulgaris cv. Tendergreen) and tomato (Lycopersicon esculentum cv. Fireball 861 VR) were enclosed in chambers and exposed for 43 or 99 days, respectively, to ambient air or to air from which 60 to 70% of the ambient photochemical oxidants were exclud...

Recent meteor observing activities in Japan

NASA Astrophysics Data System (ADS)

Yamamoto, M.

2005-02-01

The meteor train observation (METRO) campaign is described as an example of recent meteor observing activity in Japan. Other topics of meteor observing activities in Japan, including Ham-band radio meteor observation, the ``Japan Fireball Network'', the automatic video-capture software ``UFOCapture'', and the Astro-classroom programme are also briefly introduced.

The "All Sky Camera Network"

ERIC Educational Resources Information Center

Caldwell, Andy

2005-01-01

In 2001, the "All Sky Camera Network" came to life as an outreach program to connect the Denver Museum of Nature and Science (DMNS) exhibit "Space Odyssey" with Colorado schools. The network is comprised of cameras placed strategically at schools throughout Colorado to capture fireballs--rare events that produce meteorites.…

24 CFR Appendix II to Subpart C of... - Development of Standards; Calculation Methods

Code of Federal Regulations, 2012 CFR

2012-04-01

...; Calculation Methods I. Background Information Concerning the Standards (a) Thermal Radiation: (1) Introduction... and structures in the event of fire. The resulting fireball emits thermal radiation which is absorbed... radiation being emitted. The radiation can cause severe burn, injuries and even death to exposed persons...

Pyrotechnic hazards classification and evaluation program. Run-up reaction testing in pyrotechnic dust suspensions

NASA Technical Reports Server (NTRS)

1971-01-01

A preliminary investigation of the parameters included in run-up dust reactions is presented. Two types of tests were conducted: (1) ignition criteria of large bulk pyrotechnic dusts, and (2) optimal run-up conditions of large bulk pyrotechnic dusts. These tests were used to evaluate the order of magnitude and gross scale requirements needed to induce run-up reactions in pyrotechnic dusts and to simulate at reduced scale an accident that occurred in a manufacturing installation. Test results showed that propagation of pyrotechnic dust clouds resulted in a fireball of relatively long duration and large size. In addition, a plane wave front was observed to travel down the length of the gallery.

High baryon densities in heavy ion collisions at energies attainable at the BNL Relativistic Heavy-Ion Collider and the CERN Large Hadron Collider

NASA Astrophysics Data System (ADS)

Li, Ming; Kapusta, Joseph I.

2017-01-01

In very high-energy collisions nuclei are practically transparent to each other but produce very hot nearly baryon-free matter in the so-called central rapidity region. The energy in the central rapidity region comes from the kinetic energy of the colliding nuclei. We calculate the energy and rapidity loss of the nuclei using the color glass condensate model. This model also predicts the excitation energy of the nuclear fragments. Using a space-time picture of the collision we calculate the baryon and energy densities of the receding baryonic fireballs. For central collisions of gold nuclei at the highest energy attainable at the Relativistic Heavy-Ion Collider, for example, we find baryon densities more than ten times that of atomic nuclei over a large volume.

Observations of Twilight Fireballs over Kiev in 2013-2015

NASA Astrophysics Data System (ADS)

Churyumov, Klim; Steklov, Aleksey; Vidmachenko, Anatoliy; Dashkiev, Grigoriy

2016-07-01

The phenomenon of "Chelyabinsk bolide" 15.02.2013, resulted in damage to more than 1000 buildings and injure more than 500 people, after the explosion of fireball's body in the atmosphere over Chelyabinsk. The question about the dangers of such astronomical phenomena for life and health of citizens and for the existence of entire countries, arose with renewed vigor. Normally, bolides leave bright trace from ionized gas and dust. Traces of ionization can be seen particularly well at night. If a meteorite invades at the daytime at the cloudless sky and bright sunshine, the phenomenon of the fireball may not be visible. But if the fireball's track has noticeable angular size, it can be seen even in the daytime. After the flight, bolide remains a noticeable trace of a dust, dark against the light sky. If such a dust trail illuminated by the rays of the Sun, which had just hid behind the horizon (or even in the moonlight), it is visible as bright lanes in the night sky or in twilight. That's why we call it the twilight bolides. Typically, astronomical observations using of meteor patrols, carried out at night after the evening astronomical twilight. But from March 2013 to October 2015, the authors have obtained several thousands of different tracks in the sky over Kiev. Therefore, we have identified a special class of twilight observations of fireballs. We register the traces of invading to atmosphere of meteoroids of natural and artificial origin. At the same time, observe the traces of fireballs at the day-time are also possible. But they are less effective than in the twilight. Night observations of bright meteoric tracks can usually observe some seconds. While traces of the twilight bolides we observed from some minutes up to two hours, before they be scattered by atmospheric currents. It opens the great prospects for low-cost direct experiments probing of these tracks by using, for example, the astronomical aviation. We propose the twilight tracks are classified into the following types: AMT - aero-meteorological tracks, AST - aero-space, ATT - aero-technical, and NST - not yet classified tracks of an unknown nature. In recent years, geostationary satellites often registered flashes in the atmosphere brighter than -17m. The typical initial sizes of the stone bodies have 1-3 meters. If these meteoroids are consist of ice and snow (fragments of cometary nuclei), their size can be increased up to tens of meters. It was a set of fine dust particles with lower average density interconnected by ice of frozen water, carbon dioxide and others. Thus, such a body is actively destroying during the flight through the atmosphere. The mass of Tunguska initial body is estimated at about 2x10^{6} tons. At the speed of entry into the atmosphere 31 km/s, in the way of an explosion, it has passed about 200 km and a lost hundreds of thousands of tons of fine dust. The height of the explosion and flash light, is at a height of maximum braking at altitudes significantly less than the height of the homogeneous atmosphere ( 7.5 km). According to the theory of point explosion in a medium with variable density exponentially if a thermal explosion of the meteoroid will happen at the height of 15 km, the shock wave does not reach the Earth's surface. 06.25.2014 we observed evening twilight bolide in the sky over Kiev. Images were synchronously obtained by Dashkiev G. N. and Steklov A. F. The basic distance between the points of photographing according to GPS data was 8.55 km. A fragment in the atmosphere has moved from the southwest to the northeast. The disintegration of fragment began at a height more of 25 km (it is the highest point of the visible trace, not closed by building and clouds). Traces of disintegration visible at altitudes from 18 to 8.2 km. Therefore, the body is not reached the Earth's surface and disintegrated into finely dispersed particles. Trace was visible for about 20 minutes. Preliminary estimates of the initial mass of this fragment before the atmospheric entry indicates on the mass from 1 to 10 tons. Fragments with a little more mass, formed three bolide phenomena in the sky above the Kyiv 29.03.2013 at 16 hours 22 minutes local time. They arose for about some seconds and been accompanied by flashes, explosions and multiple cascade decays of three fragments, apparently, of the cometary nature, at heights of 35 to 15 km. Thus, we believe that the astronomical studies should be based on a detailed study of the interaction of the planet with the space environment, especially with hazardous meteoroids. During the short period of our observations (from March 2013), was fixed falling at least a dozen fragments of cometary nuclei, at least five of sufficiently large and dozens of smaller fragments of meteoroids. The results of our observations also showed that during the morning and evening twilight over Kiev clearly visible the plume of aerosols of technical nature from the plants, factories and other production facilities.

K*(892)⁰ and K̄*(892)⁰ production in central Pb + Pb, Si + Si, C + C, and inelastic p + p collisions at 158A GeV

DOE PAGES

Anticic, T.; Baatar, B.; Barna, D.; ...

2011-12-13

Production of the K*(892)0 and K̄*(892)⁰ resonances was studied via their K⁺π⁻ and K⁻π⁺ decay modes in central Pb+Pb, Si+Si, C+C, and inelastic p+p collisions at 158A GeV(√( sNN)=17.3 GeV) with the NA49 detector at the CERN SPS. Transverse momentum and rapidity distributions were measured and total yields were estimated. The yield of K* exceeds that of K̄* by about a factor of two in nucleus-nucleus reactions. The total yield ratios ⟨K*⟩/⟨K+⟩ and ⟨K̄*⟩/⟨K-⟩ are strongly suppressed in central Pb+Pb compared to p+p, C+C, and Si+Si collisions, in agreement with the expected attenuation of these short-lived resonance states in themore » hadronic phase of the expanding fireball. The UrQMD model, although incorporating such a scenario, does not provide a quantitative description of the experimental results. The statistical hadron gas model assuming the same freeze-out parameters for stable hadrons and resonances overestimates the ⟨K*⟩/⟨K⟩ ratios in central Pb+Pb collisions by about a factor of 2.5.« less

Will COBE challenge the inflationary paradigm - Cosmic microwave background anisotropies versus large-scale streaming motions revisited

DOE Office of Scientific and Technical Information (OSTI.GOV)

Gorski, K.M.

1991-03-01

The relation between cosmic microwave background (CMB) anisotropies and large-scale galaxy streaming motions is examined within the framework of inflationary cosmology. The minimal Sachs and Wolfe (1967) CMB anisotropies at large angular scales in the models with initial Harrison-Zel'dovich spectrum of inhomogeneity normalized to the local large-scale bulk flow, which are independent of the Hubble constant and specific nature of dark matter, are found to be within the anticipated ultimate sensitivity limits of COBE's Differential Microwave Radiometer experiment. For example, the most likely value of the quadrupole coefficient is predicted to be a2 not less than 7 x 10 tomore » the -6th, where equality applies to the limiting minimal model. If (1) COBE's DMR instruments perform well throughout the two-year period; (2) the anisotropy data are not marred by the systematic errors; (3) the large-scale motions retain their present observational status; (4) there is no statistical conspiracy in a sense of the measured bulk flow being of untypically high and the large-scale anisotropy of untypically low amplitudes; and (5) the low-order multipoles in the all-sky primordial fireball temperature map are not detected, the inflationary paradigm will have to be questioned. 19 refs.« less

Compilation and Preliminary Analysis of Sensitivity Data for Pyrotechnics. Phase 1

DTIC Science & Technology

1975-05-01

700-2, except Green smoke (sulfur based) and match head Mix VI which were tested 6 and 11 times respectively. Optical pyrometer measurements of the...Photographic estimates indicated that an acoustic wave was formed during dust cloud fireball growth. 17 2. 2.3.11.5 Jet Airmix Blending. Bench

Polarization of the prompt gamma-ray emission from the gamma-ray burst of 6 December 2002.

PubMed

Coburn, Wayne; Boggs, Steven E

2003-05-22

Observations of the afterglows of gamma-ray bursts (GRBs) have revealed that they lie at cosmological distances, and so correspond to the release of an enormous amount of energy. The nature of the central engine that powers these events and the prompt gamma-ray emission mechanism itself remain enigmatic because, once a relativistic fireball is created, the physics of the afterglow is insensitive to the nature of the progenitor. Here we report the discovery of linear polarization in the prompt gamma-ray emission from GRB021206, which indicates that it is synchrotron emission from relativistic electrons in a strong magnetic field. The polarization is at the theoretical maximum, which requires a uniform, large-scale magnetic field over the gamma-ray emission region. A large-scale magnetic field constrains possible progenitors to those either having or producing organized fields. We suggest that the large magnetic energy densities in the progenitor environment (comparable to the kinetic energy densities of the fireball), combined with the large-scale structure of the field, indicate that magnetic fields drive the GRB explosion.

Visco-capillarity in Sparkling Fireworks

NASA Astrophysics Data System (ADS)

Inoue, Chihiro; Villermaux, Emmanuel; Utokyo Team; Irphe Team

2015-11-01

A unique toy firework called sparkling fireworks is popular in Japan for 400 years, but the physics behind the beauty remains a hidden mystery. Sparkling fireworks are made by a twisted paper simply wrapping 0.1g of black powder at the lower end. Ignited there, the powder melts in a fireball of molten salts, and streaks of light are ejected. The beautiful fragile streaks are visible from the black body radiation of the hot surface of the ejected droplets. The droplets suddenly fragment up to ten times successively and their light streaks traces are like pine needles. We have already clarified why the droplets are ejected through the bursting of a gas bubble on the mother fireball, leading to successive fragmentations by micro explosions. To quantify phenomenon, we measure the diameter and the ejection velocity of the droplets. It is found that not only inertia and capillarity of the liquid matter, but also its viscosity is important (the Ohnesorge number is about 0.1). The droplets ejection velocity is determined by the liquid surface tension and viscosity, and separate from the mother drop on a visco-capillarity time scale.

SPA Meteor Section Results: 2006

NASA Astrophysics Data System (ADS)

McBeath, Alastair

2010-12-01

A summary of the main analyzed results and other information provided to the SPA Meteor Section from 2006 is presented and discussed. Events covered include: the radio Quadrantid maximum on January 3/4; an impressive fireball seen from parts of England, Belgium and the Netherlands at 22h53m51s UT on July 18, which was imaged from three EFN stations as well; the Southern delta-Aquarid and alpha-Capricornid activity from late July and early August; the radio Perseid maxima on August 12/13; confirmation that the October 5/6 video-meteor outburst was not observed by radio; visual and radio findings from the strong, bright-meteor, Orionid return in October; another impressive UK-observed fireball on November 1/2, with an oil painting of the event as seen from London; the Leonids, which produced a strong visual maximum around 04h-05h UT on November 18/19 that was recorded much less clearly by radio; radio and visual reports from the Geminids, with a note regarding NASA-observed Geminid lunar impact flashes; and the Ursid outburst recorded by various techniques on December 22.

Observations of Ball-Lightning-Like Plasmoids Ejected from Silicon by Localized Microwaves.

PubMed

Meir, Yehuda; Jerby, Eli; Barkay, Zahava; Ashkenazi, Dana; Mitchell, James Brian; Narayanan, Theyencheri; Eliaz, Noam; LeGarrec, Jean-Luc; Sztucki, Michael; Meshcheryakov, Oleg

2013-09-11

This paper presents experimental characterization of plasmoids (fireballs) obtained by directing localized microwave power (<1 kW at 2.45 GHz) onto a silicon-based substrate in a microwave cavity. The plasmoid emerges up from the hotspot created in the solid substrate into the air within the microwave cavity. The experimental diagnostics employed for the fireball characterization in this study include measurements of microwave scattering, optical spectroscopy, small-angle X-ray scattering (SAXS), scanning electron microscopy (SEM) and energy dispersive X-ray spectroscopy (EDS). Various characteristics of these plasmoids as dusty plasma are drawn by a theoretical analysis of the experimental observations. Aggregations of dust particles within the plasmoid are detected at nanometer and micrometer scales by both in - situ SAXS and ex-situ SEM measurements. The resemblance of these plasmoids to the natural ball-lightning (BL) phenomenon is discussed with regard to silicon nano-particle clustering and formation of slowly-oxidized silicon micro-spheres within the BL. Potential applications and practical derivatives of this study (e.g., direct conversion of solids to powders, material identification by breakdown spectroscopy (MIBS), thermite ignition, and combustion) are discussed.

GRB 091127: The cooling break race on magnetic fuel

NASA Astrophysics Data System (ADS)

Filgas, R.; Greiner, J.; Schady, P.; Krühler, T.; Updike, A. C.; Klose, S.; Nardini, M.; Kann, D. A.; Rossi, A.; Sudilovsky, V.; Afonso, P. M. J.; Clemens, C.; Elliott, J.; Nicuesa Guelbenzu, A.; Olivares E., F.; Rau, A.

2011-11-01

Aims: Using high-quality, broad-band afterglow data for GRB 091127, we investigate the validity of the synchrotron fireball model for gamma-ray bursts (GRBs), and infer physical parameters of the ultra-relativistic outflow. Methods: We used multi-wavelength (NIR to X-ray) follow-up observations obtained with GROND simultaneously in the g'r'i'z'JH filters and the XRT onboard the Swift satellite in the 0.3 to 10 keV energy range. The resulting afterglow light curve is of excellent accuracy with relative photometric errors as low as 1%, and the spectral energy distribution (SED) is well-sampled over 5 decades in energy. These data present one of the most comprehensive observing campaigns for a single GRB afterglow and allow us to test several proposed emission models and outflow characteristics in unprecedented detail. Results: Both the multi-color light curve and the broad-band SED of the afterglow of GRB 091127 show evidence of a cooling break moving from high to lower energies. The early light curve is well described by a broken power-law, where the initial decay in the optical/NIR wavelength range is considerably flatter than at X-rays. Detailed fitting of the time-resolved SED shows that the break is very smooth with a sharpness index of 2.2 ± 0.2, and evolves towards lower frequencies as a power-law with index - 1.23 ± 0.06. These are the first accurate and contemporaneous measurements of both the sharpness of the spectral break and its time evolution. Conclusions: The measured evolution of the cooling break (νc ∝ t~-1.2) is not consistent with the predictions of the standard model, wherein νc ∝ t~-0.5 is expected. A possible explanation for the observed behavior is a time dependence of the microphysical parameters, in particular the fraction of the total energy in the magnetic field ɛB. This conclusion provides further evidence that the standard fireball model is too simplistic, and time-dependent micro-physical parameters may be required to model the growing number of well-sampled afterglow light curves. Tables 3 and 4 are only available at the CDS via anonymous ftp to cdsarc.u-strasbg.fr (130.79.128.5) or via http://cdsarc.u-strasbg.fr/viz-bin/qcat?J/A+A/535/A57

Hadronic Resonance production in ALICE

NASA Astrophysics Data System (ADS)

Markert, Christina; ALICE Collaboration

2017-07-01

In heavy ion collisions a fireball of hot and dense matter is created. Short lived hadronic resonances are sensitive to the medium properties, in particular to the temperature, density and system size. Resonance yields and momentum distributions are used to gain insight into the hadronic phase, its expansion velocity and time duration. The multiplicity dependent hadronic resonance production in p-p, p-Pb and Pb-Pb collisions will be discussed within the context of the possible extended hadronic and partonic phase. The experimental results will be compared to EPOS+UrQMD model calculations to discuss the system size dependent interactions of the hadronic medium on various resonances. Small systems such as p-p and p-Pb collisions will be discussed with respect to resonance and strange particle measurements.

Evidence for a link between atmospheric thermonuclear detonations and nitric acid.

PubMed

Holdsworth, G

1986-12-11

Suitably located glacier cores, obtained from high-altitude, low-temperature sites, can reveal detailed information about atmospheric air chemistry at sub-annual resolution 1 . Such data may provide input to climate-change models, the study of acid precipitation patterns and many other phenomena. Here I present data from an ice core which show that during the era of intense atmospheric thermonuclear weapons testing (ATWT) a significant part of the nitrate content in the snow was modulated by the intensity of the nuclear detonations. The fixation of nitrogen by nuclear fireballs leads to NO x gases in the atmosphere 2 and ultimately to nitric acid in precipitation. At certain concentrations, these gases and the associated aerosols may perturb the climate 3,4 .

The remarkable 2011 outburst of the magnetar Swift J1822.3-1606

NASA Astrophysics Data System (ADS)

Chakraborty, Manoneeta; Gogus, Ersin

2016-07-01

Energetic bursts in the X-ray/soft gamma ray band are often observed from magnetars (magnetic field in the range 10^{14} - 10^{15} G). The most energetic of these bursts,- the giant flares, have been observed only from a few sources and exhibit distinct observational characteristics. The 2011 outburst of the relatively low magnetic field magnetar Swift J1822.3-1606 was quite extraordinary due to the interesting timing features observed during this outburst. Periodic modulations at the pulsar spin period were clearly visible, which is a characteristic typical feature seen during the decaying tail of magnetar giant flares. We investigated the temporal variations of the X-ray emission during the early phases of this outburst. The hardness ratio (HR) was found to be strongly anti-correlated X-ray pulse profile intensity much alike that is observed in the case of giant flares. The evolution of the pulse profile morphology also showed a similar behaviour like that for the giant flares but on much longer time scales. The energy released during the entire outburst is comparable to the energy emitted in minutes during the decaying tail of the giant flares. Based on these similarities, we suggest that the same underlying mechanism is probably triggering both the outburst and the giant flares. We propose that the trapped fireball that develops in the magnetosphere at the onset of such energetic events, can radiate away efficiently in minutes in the case of the giant flares, whereas for Swift J1822.3-1606, the efficiency of radiation of the fireball is not as high and, therefore, lasts much longer displaying an outburst. Such a scenario is well supported by the existing theoretical models of magnetars.

Simulation Assisted Risk Assessment Applied to Launch Vehicle Conceptual Design

NASA Technical Reports Server (NTRS)

Mathias, Donovan L.; Go, Susie; Gee, Ken; Lawrence, Scott

2008-01-01

A simulation-based risk assessment approach is presented and is applied to the analysis of abort during the ascent phase of a space exploration mission. The approach utilizes groupings of launch vehicle failures, referred to as failure bins, which are mapped to corresponding failure environments. Physical models are used to characterize the failure environments in terms of the risk due to blast overpressure, resulting debris field, and the thermal radiation due to a fireball. The resulting risk to the crew is dynamically modeled by combining the likelihood of each failure, the severity of the failure environments as a function of initiator and time of the failure, the robustness of the crew module, and the warning time available due to early detection. The approach is shown to support the launch vehicle design process by characterizing the risk drivers and identifying regions where failure detection would significantly reduce the risk to the crew.

Ten per cent polarized optical emission from GRB 090102.

PubMed

Steele, I A; Mundell, C G; Smith, R J; Kobayashi, S; Guidorzi, C

2009-12-10

The nature of the jets and the role of magnetic fields in gamma-ray bursts (GRBs) remains unclear. In a baryon-dominated jet only weak, tangled fields generated in situ through shocks would be present. In an alternative model, jets are threaded with large-scale magnetic fields that originate at the central engine and that accelerate and collimate the material. To distinguish between the models the degree of polarization in early-time emission must be measured; however, previous claims of gamma-ray polarization have been controversial. Here we report that the early optical emission from GRB 090102 was polarized at 10 +/- 1 per cent, indicating the presence of large-scale fields originating in the expanding fireball. If the degree of polarization and its position angle were variable on timescales shorter than our 60-second exposure, then the peak polarization may have been larger than ten per cent.

A Method to Constrain Mass and Spin of GRB Black Holes within the NDAF Model

NASA Astrophysics Data System (ADS)

Liu, Tong; Xue, Li; Zhao, Xiao-Hong; Zhang, Fu-Wen; Zhang, Bing

2016-04-01

Black holes (BHs) hide themselves behind various astronomical phenomena and their properties, I.e., mass and spin, are usually difficult to constrain. One leading candidate for the central engine model of gamma-ray bursts (GRBs) invokes a stellar mass BH and a neutrino-dominated accretion flow (NDAF), with the relativistic jet launched due to neutrino-anti-neutrino annihilations. Such a model gives rise to a matter-dominated fireball, and is suitable to interpret GRBs with a dominant thermal component with a photospheric origin. We propose a method to constrain BH mass and spin within the framework of this model and apply the method to the thermally dominant GRB 101219B, whose initial jet launching radius, r0, is constrained from the data. Using our numerical model of NDAF jets, we estimate the following constraints on the central BH: mass MBH ˜ 5-9 M⊙, spin parameter a* ≳ 0.6, and disk mass 3 M⊙ ≲ Mdisk ≲ 4 M⊙. Our results also suggest that the NDAF model is a competitive candidate for the central engine of GRBs with a strong thermal component.

Ernst F. F. Chladni (1756-1827) and the beginnings of meteoritics

NASA Astrophysics Data System (ADS)

Marvin, U. B.

1994-07-01

Two hundred years ago, in April 1794, Chladni published his small book Uber den Ursprung ... on meteorites and their origins. This bicentennial year seems an appropriate time to examine how Chladni's contemporaries received his book. Would meteoritics have emerged about the turn of the nineteenth century without Chladni's book? Evidence suggests that Chladni's book by itself would have wielded little influence had not several witnessed falls occurred and epoch-making chemical analyses been performed within the next 10 years. Perhaps Chladni narrowly escaped the fate of those scientists who formulate correct hypotheses prematurely. Chladni was the first person to seriously investigate reports of fireballs and masses of stone and iron falling from the sky. He found descriptions to be so consistent from century to century and place to place that he concluded that falling bodies are authentic natural phenomena. After refuting other modes of origin, Chladni proposed that the bodies are small masses of planetary materials from outer space, that produce meteors and fireballs as they plunge through the atmosphere. The Aristotelian dictum that only ether exists between the large bodies of the universe was reaffirmed by Isaac Newton in 1685. Chladnia protested, but his rhetoric and reputation were no match for Newton's. Given the succession of witnessed falls and the chemical work that took place in three countries, meteoritics clearly would have begun flourishing as a new science even if Chladni had not written his book. Nevertheless, as events compelled radical changes of ideas, Chaldni's historical and theoretical treatment of meteorites must have gained the increasing respect of his peers. Today we can admire the clarity of his insights.

iPTF Archival Search for Fast Optical Transients

DOE PAGES

Ho, Anna Y. Q.; Kulkarni, S. R.; Nugent, Peter E.; ...

2018-02-09

There has been speculation about a class of relativistic explosions with an initial Lorentz factor Γ init smaller than that of classical gamma-ray bursts (GRBs). These "dirty fireballs" would lack prompt GRB emission but could be pursued via their optical afterglow, appearing as transients that fade overnight. We report a search for such transients (that fade by 5-σ in magnitude overnight) in four years of archival photometric data from the intermediate Palomar Transient Factory (iPTF). Our search criteria yielded 50 candidates. Of these, two were afterglows to GRBs that had been found in dedicated follow-up observations to triggers from themore » Fermi GRB Monitor. Another (iPTF14yb) was a GRB afterglow discovered serendipitously. Eight were spurious artifacts of reference image subtraction, and one was an asteroid. The remaining 38 candidates have red stellar counterparts in external catalogs. The photometric and spectroscopic properties of the counterparts identify these transients as strong flares from M dwarfs of spectral type M3-M7 at distances of d ≈ 0.15-2.1 kpc; three counterparts were already spectroscopically classified as late-type M stars. With iPTF14yb as the only confirmed relativistic outflow discovered independently of a high-energy trigger, we constrain the all-sky rate of transients that peak at m = 18 and fade by Δm = 2 mag in Δt = 3 hr to be 680 yr -1, with a 68% confidence interval of 1119-2236 yr -1. This implies that the rate of visible dirty fireballs is at most comparable to that of the known population of long-duration GRBs.« less

Sources of Infrasound events listed in IDC Reviewed Event Bulletin

NASA Astrophysics Data System (ADS)

Bittner, Paulina; Polich, Paul; Gore, Jane; Ali, Sherif; Medinskaya, Tatiana; Mialle, Pierrick

2017-04-01

Until 2003 two waveform technologies, i.e. seismic and hydroacoustic were used to detect and locate events included in the International Data Centre (IDC) Reviewed Event Bulletin (REB). The first atmospheric event was published in the REB in 2003, however automatic processing required significant improvements to reduce the number of false events. In the beginning of 2010 the infrasound technology was reintroduced to the IDC operations and has contributed to both automatic and reviewed IDC bulletins. The primary contribution of infrasound technology is to detect atmospheric events. These events may also be observed at seismic stations, which will significantly improve event location. Examples sources of REB events, which were detected by the International Monitoring System (IMS) infrasound network were fireballs (e.g. Bangkok fireball, 2015), volcanic eruptions (e.g. Calbuco, Chile 2015) and large surface explosions (e.g. Tjanjin, China 2015). Query blasts (e.g. Zheleznogorsk) and large earthquakes (e.g. Italy 2016) belong to events primarily recorded at seismic stations of the IMS network but often detected at the infrasound stations. In case of earthquakes analysis of infrasound signals may help to estimate the area affected by ground vibration. Infrasound associations to query blast events may help to obtain better source location. The role of IDC analysts is to verify and improve location of events detected by the automatic system and to add events which were missed in the automatic process. Open source materials may help to identify nature of some events. Well recorded examples may be added to the Reference Infrasound Event Database to help in analysis process. This presentation will provide examples of events generated by different sources which were included in the IDC bulletins.

Characterization of Mason Gully (H5): The second recovered fall from the Desert Fireball Network

NASA Astrophysics Data System (ADS)

Dyl, Kathryn A.; Benedix, Gretchen K.; Bland, Phil A.; Friedrich, Jon M.; Spurný, Pavel; Towner, Martin C.; O'Keefe, Mary Claire; Howard, Kieren; Greenwood, Richard; Macke, Robert J.; Britt, Daniel T.; Halfpenny, Angela; Thostenson, James O.; Rudolph, Rebecca A.; Rivers, Mark L.; Bevan, Alex W. R.

2016-03-01

Mason Gully, the second meteorite recovered using the Desert Fireball Network (DFN), is characterized using petrography, mineralogy, oxygen isotopes, bulk chemistry, and physical properties. Geochemical data are consistent with its classification as an H5 ordinary chondrite. Several properties distinguish it from most other H chondrites. Its 10.7% porosity is predominantly macroscopic, present as intergranular void spaces rather than microscopic cracks. Modal mineralogy (determined via PS-XRD, element mapping via energy dispersive spectroscopy [EDS], and X-ray tomography [for sulfide, metal, and porosity volume fractions]) consistently gives an unusually low olivine/orthopyroxene ratio (0.67-0.76 for Mason Gully versus ~1.3 for typical H5 ordinary chondrites). Widespread "silicate darkening" is observed. In addition, it contains a bright green crystalline object at the surface of the recovered stone (diameter ≈ 1.5 mm), which has a tridymite core with minor α-quartz and a rim of both low- and high-Ca pyroxene. The mineralogy allows the calculation of the temperatures and ƒ(O2) characterizing thermal metamorphism on the parent body using both the two-pyroxene and the olivine-chromite geo-oxybarometers. These indicate that MG experienced a peak metamorphic temperature of ~900 °C and had a similar ƒ(O2) to Kernouvé (H6) that was buffered by the reaction between olivine, metal, and pyroxene. There is no evidence for shock, consistent with the observed porosity structure. Thus, while Mason Gully has some unique properties, its geochemistry indicates a similar thermal evolution to other H chondrites. The presence of tridymite, while rare, is seen in other OCs and likely exogenous; however, the green object itself may result from metamorphism.

Atmospheric behavior and extreme beginning heights of the 13 brightest photographic Leonids from the ground-based expedition to China

NASA Astrophysics Data System (ADS)

Spurný, Pavel; Betlem, Hans; van't Leven, Jaap; Jenniskens, Peter

2000-03-01

Precise atmospheric trajectories including dynamic and photometric data on the 13 of the brightest Leonid fireballs have been determined from the double station photographic observations of Leonids during the ground-based expedition to China in November 1998. The expedition was organized as a collaboration between the Dutch and Chinese Academy of Sciences and was supported by the Leonid MAC program (Jenniskens and Butow, 1999). All data presented here were taken at Xinglong Observatory and at a remote station Lin Ting Kou near Beijing on the night of November 16/17. At Xinglong station photographic cameras were accompanied with an all-sky TV camera equipped with an image intensifier and 15 mm fish-eye objective in order to obtain precise timings for all observed meteors up to magnitude +2. While beginning heights of photographed meteors are all lower than 130 km, those observed by the all-sky TV system are at about 160 km and for three brightest events even above 180 km. Such high beginnings for meteors have never before been observed. We obtained also a precise dynamic single-body solution for the Leonid meteor 98003 including the ablation coefficient, which is an important material and structural quantity (0.16 s2km-2). From this, and from known photometry, we derived a density of this meteoroid of 0.7 g/cm3. Also all PE coefficients indicate that these Leonids belonged to the fireball group IIIB which is typical for the most fragile and weak interplanetary bodies. From a photometric study of the meteor lightcurves we found two typical shapes of light curves for these Leonids.

Time-Dependent Temperature Measurements in Post-Detonation Combustion: Current State-of-the-Art Methods and Emerging Technologies

DTIC Science & Technology

2016-03-01

17 6. SENSOR PARTICLES...explosion also limit measurement options since any sensors employed must be able to withstand the extreme environment, or at least transmit the...in detonations and fireballs. On the other hand, temperature measurements have been less extensive, partly because sensors rugged enough to withstand

Cosmic Inflation

ScienceCinema

Lincoln, Don

2018-01-16

In 1964, scientists discovered a faint radio hiss coming from the heavens and realized that the hiss wasn’t just noise. It was a message from eons ago; specifically the remnants of the primordial fireball, cooled to about 3 degrees above absolute zero. Subsequent research revealed that the radio hiss was the same in every direction. The temperature of the early universe was uniform to at better than a part in a hundred thousand. And this was weird. According to the prevailing theory, the two sides of the universe have never been in contact. So how could two places that had never been in contact be so similar? One possible explanation was proposed in 1979. Called inflation, the theory required that early in the history of the universe, the universe expanded faster than the speed of light. Confused? Watch this video as Fermilab’s Dr. Don Lincoln makes sense of this mind-bending idea.

Cosmic Inflation

DOE Office of Scientific and Technical Information (OSTI.GOV)

Lincoln, Don

In 1964, scientists discovered a faint radio hiss coming from the heavens and realized that the hiss wasn’t just noise. It was a message from eons ago; specifically the remnants of the primordial fireball, cooled to about 3 degrees above absolute zero. Subsequent research revealed that the radio hiss was the same in every direction. The temperature of the early universe was uniform to at better than a part in a hundred thousand. And this was weird. According to the prevailing theory, the two sides of the universe have never been in contact. So how could two places that hadmore » never been in contact be so similar? One possible explanation was proposed in 1979. Called inflation, the theory required that early in the history of the universe, the universe expanded faster than the speed of light. Confused? Watch this video as Fermilab’s Dr. Don Lincoln makes sense of this mind-bending idea.« less

Conditions for the onset of the current filamentation instability in the laboratory

NASA Astrophysics Data System (ADS)

Shukla, N.; Vieira, J.; Muggli, P.; Sarri, G.; Fonseca, R.

2018-06-01

The current filamentation instability (CFI) is capable of generating strong magnetic fields relevant to the explanation of radiation processes in astrophysical objects and leads to the onset of particle acceleration in collisionless shocks. Probing such extreme scenarios in the laboratory is still an open challenge. In this work, we investigate the possibility of using neutral -~e+$ beams to explore the CFI with realistic parameters, by performing two-dimensional particle-in-cell simulations. We show that CFI can occur unless the rate at which the beam expands due to finite beam emittance is larger than the CFI growth rate and as long as the role of the competing electrostatic two-stream instability (TSI) is negligible. We also show that the longitudinal energy spread, typical of plasma-based accelerated electron-positron fireball beams, plays a minor role in the growth of CFI in these scenarios.

Looking for the Phase Transition—Recent NA61/SHINE Results

NASA Astrophysics Data System (ADS)

Turko, Ludwik

2018-03-01

The fixed-target NA61/SHINE experiment (SPS CERN) looks for the critical point of strongly interacting matter and the properties of the onset of deconfinement. It is a two dimensional scan of measurements of particle spectra and fluctuations in proton-proton, proton-nucleus and nucleus-nucleus interactions as a function of collision energy and system size, corresponding to a two dimensional phase diagram (temperature T - baryonic chemical potential $\\mu_B$). New NA61/SHINE results are presented here, such as transverse momentum and multiplicity fluctuations in Ar+Sc collisions compared to NA61/SHINE p+p and Be+Be data, as well as to earlier NA49 A+A results. Recently, a preliminary signature for the new size dependent effect - rapid changes in system size dependence was observed in NA61-SHINE data, labeled as percolation threshold or onset of fireball. This would be closely related to the vicinity of the hadronic phase transition region.

The Chelyabinsk meteor

NASA Astrophysics Data System (ADS)

Popova, O.; Jenniskens, P.; Shuvalov, V.; Emel'yanenko, V.; Rybnov, Y.; Kharlamov, V.; Kartashova, A.; Biryukov, E.; Khaibrakhmanov, S.

2014-07-01

A review is given about what was learned about the 0.5-Mt Chelyabinsk airburst of 15 February 2013 by field studies, the analysis of recovered meteorites, and numerical models of meteoroid fragmentation and airburst propagation. Previous events with comparable or larger energy in recent times include only the 0.5-Mt -sized 3 August 1963 meteor over the south Atlantic, for which only an infrasound signal was recorded, and the famous Tunguska impact of 1908. Estimates of the initial kinetic energy of the Tunguska impact range from 3 to 50 Mt, due to the lack of good observations at the time. The Chelyabinsk event is much better documented than both, and provides a unique opportunity to calibrate the different approaches used to model meteoroid entry and calculate the damaging effects of a shock wave from a large meteoroid impact. A better understanding of what happened might help future impact hazard mitigation efforts by calibrating models of what might happen under somewhat different circumstances. The initial kinetic energy is estimated from infrasonic signals and the fireball's lightcurve, as well as the extent of the glass damage on the ground. Analysis of video observations of the fireball and the shadow movements provided an impact trajectory and a record of the meteor lightcurve, which describes how that energy was deposited in the atmosphere. Ablation and fragmentation scenarios determine the success of attempts to reproduce the observed meteor lightcurve and deceleration profile by numerical modeling. There was almost no deceleration until peak brightness. Meteoroid fragmentation occurred in different forms, some part of the initial mass broke in well separated fragments, the surviving fragments falling on the ground as meteorites. The specific conditions during energy deposition determined the fraction of surviving mass. The extent of the glass damage was mapped by visiting over 50 villages in the area. A number of numerical simulations were conducted that attempted a more realistic release of energy along the trajectory and these results were compared with observations of blast wave arrival times and the extent of the glass damage. The shape of the damaged area could be explained from the fact that the energy was deposited over a range of altitudes. The study of the recovered meteorites provided insight into why the Chelyabinsk meteoroid broke at a relatively high altitude. Its material properties were determined by events that may date back to the Earth-Moon impact event.

Features about pion production in 2.1A and 3.7AGeV 4He-nucleus interactions up to and out of kinematical limit

NASA Astrophysics Data System (ADS)

Abdelsalam, A.; Badawy, B. M.; Amer, H. A.; Osman, W.; El-Ashmawy, M. M.; Abdallah, N.

The shower particle multiplicity characteristics are studied in 2.1A and 3.7A GeV 4He interactions with emulsion nuclei. The dependencies on emission direction, energy, target size, and centrality are examined. The data are compared with the simulation of the modified FRITIOF model. The forward emitted pion multiplicity distributions exhibit KNO scaling. The decay or peaking shaped curves characterize the pion multiplicity distributions. The decay shape is suggested to be due to a single source contribution and the peaking one results from a multisource superposition. The forward emitted pion is created from fireball or hadronic matter. The target nucleus is the origin of the backward one, regarding the nuclear limiting fragmentation hypothesis.

Implications of the pseudo-Dirac scenario for ultra high energy neutrinos from GRBs

DOE Office of Scientific and Technical Information (OSTI.GOV)

Esmaili, Arman; Farzan, Yasaman, E-mail: aesmaili@ifi.unicamp.br, E-mail: yasaman@theory.ipm.ac.ir

2012-12-01

The source of Ultra High Energy Cosmic Rays (UHECR) is still an unresolved mystery. Up until recently, sources of Gamma Ray Bursts (GRBs) had been considered as a suitable source for UHECR. Within the fireball model, the UHECR produced at GRBs should be accompanied with a neutrino flux detectable at the neutrino telescope such as IceCube. Recently, IceCube has set an upper bound on the neutrino flux accompanied by GRBs about 3.7 times below the prediction. We investigate whether this deficit can be explained by the oscillation of the active neutrinos to sterile neutrinos en route from the source tomore » the detectors within the pseudo-Dirac scenario. We then discuss the implication of this scenario for diffuse supernova relic neutrinos.« less

Denning, William Frederick (1848-1931)

NASA Astrophysics Data System (ADS)

Murdin, P.

2000-11-01

Possibly a journalist and certainly an amateur astronomer. Born in Redpost, Somerset, England. The spectacular meteor storm of 1866, and a fireball in 1869, focused his interest on meteor astronomy. In 1877 he demonstrated a steady night by night movement in the Perseid meteor radiant, which proved that meteors came from showers of dust distributed along the path of a comet. Had the distinction t...

Observations of Ball-Lightning-Like Plasmoids Ejected from Silicon by Localized Microwaves

PubMed Central

Meir, Yehuda; Jerby, Eli; Barkay, Zahava; Ashkenazi, Dana; Mitchell, James Brian; Narayanan, Theyencheri; Eliaz, Noam; LeGarrec, Jean-Luc; Sztucki, Michael; Meshcheryakov, Oleg

2013-01-01

This paper presents experimental characterization of plasmoids (fireballs) obtained by directing localized microwave power (<1 kW at 2.45 GHz) onto a silicon-based substrate in a microwave cavity. The plasmoid emerges up from the hotspot created in the solid substrate into the air within the microwave cavity. The experimental diagnostics employed for the fireball characterization in this study include measurements of microwave scattering, optical spectroscopy, small-angle X-ray scattering (SAXS), scanning electron microscopy (SEM) and energy dispersive X-ray spectroscopy (EDS). Various characteristics of these plasmoids as dusty plasma are drawn by a theoretical analysis of the experimental observations. Aggregations of dust particles within the plasmoid are detected at nanometer and micrometer scales by both in-situ SAXS and ex-situ SEM measurements. The resemblance of these plasmoids to the natural ball-lightning (BL) phenomenon is discussed with regard to silicon nano-particle clustering and formation of slowly-oxidized silicon micro-spheres within the BL. Potential applications and practical derivatives of this study (e.g., direct conversion of solids to powders, material identification by breakdown spectroscopy (MIBS), thermite ignition, and combustion) are discussed. PMID:28788315

Can the bump in the composite spectrum of GRB 910503 be an emission line feature of gamma-ray bursts?

NASA Astrophysics Data System (ADS)

Qin, Yi-Ping; Zhang, Fu-Wen

2005-12-01

Appearing in the composite spectral data of BATSE, EGRET and COMPTEL for GRB 910503, there is a bump at around 1600 keV. We perform a statistical analysis on the spectral data, trying to find out if the bump could be accounted for by a blue-shifted and significantly broadened rest frame line due to the Doppler effect of an expanding fireball surface. We made an F-test and adopted previously proposed criteria. The study reveals that the criteria are well satisfied and the feature can be interpreted as the blue shifted 6.4 keV line. From the fit with this line taken into account, we find the Lorentz factor of this source to be Γ = 116+9-9 (at the 68% confident level, triangleχ2 = 1) and the rest frame spectral peak energy to be E0,p = 2.96+0.24-0.18 keV. Although the existence of the emission line feature requires other independent tests to confirm, the analysis suggests that it is feasible to detect emission line features in the high energy range of GRB spectra when taking into account the Doppler effect of fireball expansion.

Measurement of higher harmonic flow coefficients of identified hadrons in Pb-Pb collisions at = 2.76 TeV

NASA Astrophysics Data System (ADS)

Mohammadi, Naghmeh; ALICE Collaboration

2017-01-01

The latest ALICE results on the centrality and transverse momentum dependence of v 2, v 3, v 4 and v 5 for π± , K ± and p() in Pb-Pb collisions at = 2.76 TeV are presented. The flow coefficients exhibit a clear mass ordering for p T < 2.5 GeV/c for all harmonics. For transverse momentum values larger than about 3 GeV/c, mesons exhibit distinctively lower flow values compared to baryons, suggesting that coalescence might be the relevant particle production mechanism in this region. The experimental data for p T < 2.5 GeV/c are described fairly well by the hydrodynamical model iEBE-VISHNU, which models the hydrodynamical expansion of the fireball using a value of η/s = 0.08, coupled to a hadronic cascade model (UrQMD). Finally, A Multi-Phase Transition Model (AMPT) highlights the significant contribution of the hadronic rescattering phase and of coalescence as the dominant particle production mechanism to the mass ordering at low p T and the baryon-meson grouping at intermediate p T, respectively.

The X-Ray Light Curve in GRB 170714A: Evidence for a Quark Star?

NASA Astrophysics Data System (ADS)

Hou, Shu-Jin; Liu, Tong; Xu, Ren-Xin; Mu, Hui-Jun; Song, Cui-Ying; Lin, Da-Bin; Gu, Wei-Min

2018-02-01

Two plateaus and a following bump in the X-ray light curve of GRB 170714A have been detected by the Swift/X-ray Telescope, which could be very significant for the central engine of gamma-ray bursts (GRBs), implying that the origin of this burst might be different from those of other ultra-long GRBs. We propose that merging two neutron stars into a hyper-massive quark star (QS) and then collapsing into a black hole (BH), with a delay time around 104 s, could be responsible for these X-ray components. The hyper-massive QS is initially in a fluid state, being turbulent and differentially rotating, but would solidify and release its latent heat, injecting it into the GRB fireball (lasting about 103 s during the liquid–solid phase transition). A magnetic field as high as ∼1015 G can be created by dynamo action of the newborn liquid QS, and a magnetar-like central engine (after solidification) supplies significant energy for the second plateau. More energy could be released during a fall-back accretion after the post-merger QS collapses to a BH, and the X-ray bump forms. This post-merger QS model could be tested by future observations, with either advanced gravitational wave detectors (e.g., advanced LIGO and VIRGO) or X-ray/optical telescopes.

Closest Gamma Ray Burst Providing Scientists With Crucial Test for Burst Physics

NASA Astrophysics Data System (ADS)

2003-05-01

The closest Gamma Ray Burst (GRB) yet known is providing astronomers with a rare opportunity to gain information vital to understanding these powerful cosmic explosions. Extremely precise radio-telescope observations already have ruled out one proposed mechanism for the bursts. "This is the closest and brightest GRB we've ever seen, and we can use it to decipher the physics of how these bursts work," said Greg Taylor of the National Radio Astronomy Observatory (NRAO) in Socorro, NM. Taylor worked with Dale Frail, also of the NRAO, along with Prof. Shri Kulkarni and graduate student Edo Berger of Caltech in studying a GRB detected on March 29, 2003. The scientists presented their findings to the American Astronomical Society's meeting in Nashville, TN. VLBA image of GRB 030329 VLBA IMAGE of GRB 030329 CREDIT: NRAO/AUI/NSF (Click on Image for Larger Version) Taylor and Frail used the National Science Foundation's (NSF) Very Long Baseline Array (VLBA) and other radio telescopes to study the burst, known as GRB 030329. In a series of observations from April 1 to May 19, they determined the size of the expanding "fireball" from the burst and measured its position in the sky with great precision. At a distance of about 2.6 billion light-years, GRB 030329 is hardly next door. However, compared to other GRBs at typical distances of 8-10 billion light-years, it presents an easier target for study. "We only expect to see one burst per decade this close," said Frail. The precise measurement of the object's position allowed the scientists to show that one theoretical model for GRBs can be ruled out. This model, proposed in 2000, says that the radio-wave energy emitted by the GRB comes from "cannonballs" of material shot from the explosion at extremely high speeds. "The 'cannonball model' predicted that we should see the radio-emitting object move across the sky by a specific amount. We have not seen that motion," Taylor said. The currently standard "fireball model" of GRBs says that the radio emission comes from a rapidly-expanding shock wave. This model was first proposed by Peter Meszaros, Bohdan Paczynski and Sir Martin Rees, who won the American Astronomical Society's Bruno Rossi Prize in 2000 for their work. In this standard model, as the shock wave expands outward, the emission becomes fainter, but the center of the observed emission does not change position. The cannonball model, however, proposes that the emission arises from distinct concentrations of matter shot outward from the burst. As they move farther from the burst, their motion should be detected as a change in their position in the sky. On April 3, proponents of the cannonball model predicted a specific amount of motion for GRB 030329 and suggested that the VLBA's sharp radio "vision" could detect the motion and confirm their prediction. Instead, "our observations are consistent with no motion at all," Taylor said. "This is at odds with the cannonball model -- they made a specific prediction based on their model and the observations do not bear them out," he added. The scientists' direct measurement of the size of the GRB fireball also will provide new insights into the physics behind the burst. "By directly measuring the size and the expansion rate, we can start putting some real limits on the physics involved," Taylor said. First, he said, "We already can confirm that the fireball is expanding at nearly the speed of light, as the standard model predicts. Next, once our May observations are fully analyzed, we can put limits on the energy of the burst and provide a test of the standard model." Taylor and Frail observed GRB 030329 with the VLBA on April 1 and April 6. On April 22, they used the 100-meter radio telescope in Effelsberg, Germany in addition to the VLBA. On May 19, they used the VLBA, the Very Large Array (VLA) in New Mexico, the NSF's Robert C. Byrd Green Bank Telescope in West Virginia, and the Effelsberg telescope. In addition to gamma-ray and X-ray observations, visible light from GRB 030329 was observed by 65 telescopes around the world. At its brightest, the visible light from this burst was detectable with moderate-sized amateur telescopes. Gamma Ray Bursts were first detected in 1967 by a satellite monitoring compliance with the 1963 atmospheric nuclear test-ban treaty. For three decades thereafter, astronomers were unable to determine their distances from Earth, and thus were unable to begin understanding the physics underlying the explosions. In 1997, the first distance measurements were made to GRBs, and the NSF's Very Large Array (VLA) detected the first radio emission from a GRB afterglow. Once scientists determined that GRBs originate in distant galaxies and that they probably occur in regions of those galaxies where stars are actively forming, some 200 proposed models for what causes GRBs were reduced to a handful of viable models. Most scientists now believe that GRBs arise from a violent explosion that ends the life of a star much more massive than the Sun. Whereas such an explosion as a typical supernova leaves a dense neutron star, a GRB explosion leaves a black hole, a concentration of mass with gravitational pull so strong that not even light can escape it. The VLBA is a continent-wide system of ten radio- telescope antennas, ranging from Hawaii in the west to the U.S. Virgin Islands in the east, providing the greatest resolving power, or ability to see fine detail, in astronomy. Dedicated in 1993, the VLBA is operated from the NRAO's Array Operations Center in Socorro, New Mexico. The National Radio Astronomy Observatory is a facility of the National Science Foundation, operated under cooperative agreement by Associated Universities, Inc.

Earth's Minimoons: Opportunities for Science and Technology.

NASA Astrophysics Data System (ADS)

Jedicke, Robert; Bolin, Bryce T.; Bottke, William F.; Chyba, Monique; Fedorets, Grigori; Granvik, Mikael; Jones, Lynne; Urrutxua, Hodei

2018-05-01

Twelve years ago the Catalina Sky Survey discovered Earth's first known natural geocentric object other than the Moon, a few-meter diameter asteroid designated \\RH. Despite significant improvements in ground-based asteroid surveying technology in the past decade they have not discovered another temporarily-captured orbiter (TCO; colloquially known as minimoons) but the all-sky fireball system operated in the Czech Republic as part of the European Fireball Network detected a bright natural meteor that was almost certainly in a geocentric orbit before it struck Earth's atmosphere. Within a few years the Large Synoptic Survey Telescope (LSST) will either begin to regularly detect TCOs or force a re-analysis of the creation and dynamical evolution of small asteroids in the inner solar system. The first studies of the provenance, properties, and dynamics of Earth's minimoons suggested that there should be a steady state population with about one 1- to 2-meter diameter captured objects at any time, with the number of captured meteoroids increasing exponentially for smaller sizes. That model was then improved and extended to include the population of temporarily-captured flybys (TCFs), objects that fail to make an entire revolution around Earth while energetically bound to the Earth-Moon system. Several different techniques for discovering TCOs have been considered but their small diameters, proximity, and rapid motion make them challenging targets for existing ground-based optical, meteor, and radar surveys. However, the LSST's tremendous light gathering power and short exposure times could allow it to detect and discover many minimoons. We expect that if the TCO population is confirmed, and new objects are frequently discovered, they can provide new opportunities for 1) studying the dynamics of the Earth-Moon system, 2) testing models of the production and dynamical evolution of small asteroids from the asteroid belt, 3) rapid and frequent low delta-v missions to multiple minimoons, and 4) evaluating in-situ resource utilization techniques on asteroidal material. Here we review the past decade of minimoon studies in preparation for capitalizing on the scientific and commercial opportunities of TCOs in the first decade of LSST operations.

Multidimensional Analysis of Nuclear Detonations

DTIC Science & Technology

2015-09-17

Features on the nuclear weapons testing films because of the expanding and emissive nature of the nuclear fireball. The use of these techniques to produce...Treaty (New Start Treaty) have reduced the acceptable margins of error. Multidimensional analysis provides the modern approach to nuclear weapon ...scientific community access to the information necessary to expand upon the knowledge of nuclear weapon effects. This data set has the potential to provide

Neutron star mergers and gamma-ray bursts

NASA Technical Reports Server (NTRS)

Narayan, Ramesh

1993-01-01

Under the support of grant NAG 5-1904, we have carried out research on several topics related to gamma-ray bursts (GRB's). In our proposal, we stated that we would study three topics: (1) fireball evolution; (2) neutron star mergers; and (3) statistics of bursts. We have completed a significant amount of work in each of these areas. Resulting papers from this work are presented.

ARC-1994-AC94-0353-3

NASA Image and Video Library

1994-07-01

Photo by Peter McGregor Comet Shoemaker-Levy 9 impacting Jupiter; impact of Fragment G of Comet Shoemaker-Levy on Jupiter. The fireball is seen 12 minutes after impact at 2.34 microns. The impact A site is seen on the oposite limb of the planet. Image at 2.34 microns with CASPIR by Peter McGregor ANU 2.3m telescope at Siding Spring. (JPL Ref; P-44419)

Heavy flavours production in quark-gluon plasma formed in high energy nuclear reactions

NASA Technical Reports Server (NTRS)

Kloskinski, J.

1985-01-01

Results on compression and temperatures of nuclear fireballs and on relative yield of strange and charmed hadrons are given . The results show that temperatures above 300 MeV and large compressions are unlikely achieved in average heavy ion collision. In consequence, thermal production of charm is low. Strange particle production is, however, substantial and indicates clear temperature - threshold behavior.

K*(892) and ϕ(1020) production and their decay into the hadronic medium at the Large Hadron Collider

NASA Astrophysics Data System (ADS)

Shapoval, V. M.; Braun-Munzinger, P.; Sinyukov, Yu. M.

2017-12-01

The production of the K* (892) strange resonance in Pb +Pb collisions at √{sNN} = 2.76 TeV LHC energy is analyzed within the integrated hydrokinetic model (iHKM) at different equations of state of superdense matter. The similar analysis is done also for the RHIC top energy √{sNN} = 200 GeV for comparison purposes. A modification of experimental K* (892)-identification is studied for different centralities in view of possible re-scattering of the decay products at the afterburner stage of the fireball evolution. We see quite intensive rescattering of the decay products as well as recombination processes for K* (892). In addition, the production of the much longer-long-lived ϕ (1020) resonance with hidden strange quark content is investigated.

Global Modeling of Uranium Molecular Species Formation Using Laser-Ablated Plasmas

NASA Astrophysics Data System (ADS)

Curreli, Davide; Finko, Mikhail; Azer, Magdi; Armstrong, Mike; Crowhurst, Jonathan; Radousky, Harry; Rose, Timothy; Stavrou, Elissaios; Weisz, David; Zaug, Joseph

2016-10-01

Uranium is chemically fractionated from other refractory elements in post-detonation nuclear debris but the mechanism is poorly understood. Fractionation alters the chemistry of the nuclear debris so that it no longer reflects the chemistry of the source weapon. The conditions of a condensing fireball can be simulated by a low-temperature plasma formed by vaporizing a uranium sample via laser heating. We have developed a global plasma kinetic model in order to model the chemical evolution of U/UOx species within an ablated plasma plume. The model allows to track the time evolution of the density and energy of an uranium plasma plume moving through an oxygen atmosphere of given fugacity, as well as other relevant quantities such as average electron and gas temperature. Comparison of model predictions with absorption spectroscopy of uranium-ablated plasmas provide preliminary insights on the key chemical species and evolution pathways involved during the fractionation process. This project was sponsored by the DoD, Defense Threat Reduction Agency, Grant HDTRA1-16-1-0020. This work was performed in part under the auspices of the U.S. DoE by Lawrence Livermore National Laboratory under Contract DE-AC52-07NA27344.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Liu, Tong; Xue, Li; Zhao, Xiao-Hong

Black holes (BHs) hide themselves behind various astronomical phenomena and their properties, i.e., mass and spin, are usually difficult to constrain. One leading candidate for the central engine model of gamma-ray bursts (GRBs) invokes a stellar mass BH and a neutrino-dominated accretion flow (NDAF), with the relativistic jet launched due to neutrino-anti-neutrino annihilations. Such a model gives rise to a matter-dominated fireball, and is suitable to interpret GRBs with a dominant thermal component with a photospheric origin. We propose a method to constrain BH mass and spin within the framework of this model and apply the method to the thermallymore » dominant GRB 101219B, whose initial jet launching radius, r {sub 0}, is constrained from the data. Using our numerical model of NDAF jets, we estimate the following constraints on the central BH: mass M {sub BH} ∼ 5–9 M {sub ⊙}, spin parameter a {sub *} ≳ 0.6, and disk mass 3 M {sub ⊙} ≲ M {sub disk} ≲ 4 M {sub ⊙}. Our results also suggest that the NDAF model is a competitive candidate for the central engine of GRBs with a strong thermal component.« less

Measurement of Apparent Temperature in Post-Detonation Fireballs Using Atomic Emission Spectroscopy

DTIC Science & Technology

2009-05-01

have been studied analogously by seeding thermometric species into burners.3,12 Interestingly, Wilkin- son et al.6 have recently observed Al atomic...effects of self-absorption. Additionally, candidate thermometric species must produce several strong emission lines in the spectrum that originate from...different upper energy levels in order to allow the populations of the associated states to be determined. Barium nitrate was chosen as a thermometric

Low-energy Spectra of Gamma-Ray Bursts from Cooling Electrons

NASA Astrophysics Data System (ADS)

Geng, Jin-Jun; Huang, Yong-Feng; Wu, Xue-Feng; Zhang, Bing; Zong, Hong-Shi

2018-01-01

The low-energy spectra of gamma-ray bursts’ (GRBs) prompt emission are closely related to the energy distribution of electrons, which is further regulated by their cooling processes. We develop a numerical code to calculate the evolution of the electron distribution with given initial parameters, in which three cooling processes (i.e., adiabatic, synchrotron, and inverse Compton cooling) and the effect of a decaying magnetic field are coherently considered. A sequence of results is presented by exploring the plausible parameter space for both the fireball and the Poynting flux–dominated regime. Different cooling patterns for the electrons can be identified, and they are featured by a specific dominant cooling mechanism. Our results show that the hardening of the low-energy spectra can be attributed to the dominance of synchrotron self-Compton cooling within the internal shock model or to decaying synchrotron cooling within the Poynting flux–dominated jet scenario. These two mechanisms can be distinguished by observing the hard low-energy spectra of isolated short pulses in some GRBs. The dominance of adiabatic cooling can also lead to hard low-energy spectra when the ejecta is moving at an extreme relativistic speed. The information from the time-resolved low-energy spectra can help to probe the physical characteristics of the GRB ejecta via our numerical results.

Jet simulations and gamma-ray burst afterglow jet breaks

NASA Astrophysics Data System (ADS)

van Eerten, H. J.; Meliani, Z.; Wijers, R. A. M. J.; Keppens, R.

2011-01-01

The conventional derivation of the gamma-ray burst afterglow jet break time uses only the blast wave fluid Lorentz factor and therefore leads to an achromatic break. We show that in general gamma-ray burst afterglow jet breaks are chromatic across the self-absorption break. Depending on circumstances, the radio jet break may be postponed significantly. Using high-accuracy adaptive mesh fluid simulations in one dimension, coupled to a detailed synchrotron radiation code, we demonstrate that this is true even for the standard fireball model and hard-edged jets. We confirm these effects with a simulation in two dimensions. The frequency dependence of the jet break is a result of the angle dependence of the emission, the changing optical depth in the self-absorbed regime and the shape of the synchrotron spectrum in general. In the optically thin case the conventional analysis systematically overestimates the jet break time, leading to inferred opening angles that are underestimated by a factor of ˜1.3 and explosion energies that are underestimated by a factor of ˜1.7, for explosions in a homogeneous environment. The methods presented in this paper can be applied to adaptive mesh simulations of arbitrary relativistic fluid flows. All analysis presented here makes the usual assumption of an on-axis observer.

The microwave background anisotropies: Observations

PubMed Central

Wilkinson, David

1998-01-01

Most cosmologists now believe that we live in an evolving universe that has been expanding and cooling since its origin about 15 billion years ago. Strong evidence for this standard cosmological model comes from studies of the cosmic microwave background radiation (CMBR), the remnant heat from the initial fireball. The CMBR spectrum is blackbody, as predicted from the hot Big Bang model before the discovery of the remnant radiation in 1964. In 1992 the cosmic background explorer (COBE) satellite finally detected the anisotropy of the radiation—fingerprints left by tiny temperature fluctuations in the initial bang. Careful design of the COBE satellite, and a bit of luck, allowed the 30 μK fluctuations in the CMBR temperature (2.73 K) to be pulled out of instrument noise and spurious foreground emissions. Further advances in detector technology and experiment design are allowing current CMBR experiments to search for predicted features in the anisotropy power spectrum at angular scales of 1° and smaller. If they exist, these features were formed at an important epoch in the evolution of the universe—the decoupling of matter and radiation at a temperature of about 4,000 K and a time about 300,000 years after the bang. CMBR anisotropy measurements probe directly some detailed physics of the early universe. Also, parameters of the cosmological model can be measured because the anisotropy power spectrum depends on constituent densities and the horizon scale at a known cosmological epoch. As sophisticated experiments on the ground and on balloons pursue these measurements, two CMBR anisotropy satellite missions are being prepared for launch early in the next century. PMID:9419320

Proceedings of the DICE THROW Symposium 21-23 June 1977. Volume 1

DTIC Science & Technology

1977-07-01

different scaled ANFO events to insure yield scalability. Phase 1 of the program consisted of a series of one-pound events to examine cratering and...characterization of a 500-ton-equivalent event. A large number of agencies were involved in different facets of the development program. Probably most...charge geometry observed in the 1000-pound series, supported the observations from the Phase 1 program. Differences were observed in the fireball

Nuclear Weapons Effects Mitigation Techniques

DTIC Science & Technology

1982-06-01

ELF ) into the ultra-high (UHF) frequeniese, with much of Its energy concentrated In frequenrv ranges (high frequency (IF) into UHF) employed by Army...tactical Communications equipment. It Is of concern because the damage and upset it causes can occur Rt distances from the burst far beyond where...radiation is scattered from all directions, most of’ it comes from direct line-of-sight to the fireball. Therefore, the flat earth cover of an underground

Narrative Report on the Hazard to Civilization Due to Fireballs and Comets

DTIC Science & Technology

1996-01-01

active during the last one ( Hoyle 1981; Clube, Hoyle , Napier & Wickramasinghe, 1996). This ’ice haze’ formation process may be simulated using zonally...historical record may now be seriously contemplated (cf Clube & Napier 1990, Cohn 1993, Hoyle 1993). The future implications for government and...clearly recognised by (cometary) astronomers (eg Fred Whipple in the US and Ernst Opik in the UK), it was chiefly a catastrophist geologist (Eugene

Measurement of Apparent Temperature in Post-Detonation Fireballs Using Atomic Emission Spectroscopy

DTIC Science & Technology

2011-02-01

thermometric species into burners.3,12 Interestingly, Wilkin- son et al.6 have recently observed Al atomic emission lines in the spectrum of aluminum...candidate thermometric species must produce several strong emission lines in the spectrum that originate from different upper energy levels in order to...allow the populations of the associated states to be determined. Barium nitrate was chosen as a thermometric impurity for the current work since Ba

The Nature of Airbursts and their Contribution to the Impact Hazard (Invited)

NASA Astrophysics Data System (ADS)

Boslough, M. B.

2009-12-01

Ongoing simulations of low-altitude airbursts from hypervelocity asteroid impacts have led to a re-evaluation of the impact hazard that accounts for the enhanced damage potential relative to the standard point-source approximations. Computational models demonstrate that the altitude of maximum energy deposition is not a good estimate of the equivalent height of a point explosion, because the center of mass of an exploding projectile maintains a significant fraction of its initial momentum and is transported downward in the form of a high-temperature jet of expanding gas. This “fireball” descends to a depth well beneath the burst altitude before its velocity becomes subsonic. The time scale of this descent is similar to the time scale of the explosion itself, so the jet simultaneously couples both its translational and its radial kinetic energy to the atmosphere. Because of this downward flow, larger blast waves and stronger thermal radiation pulses are experienced at the surface than would be predicted for a nuclear explosion of the same yield at the same burst height. For impacts with a kinetic energy below some threshold value, the hot jet of vaporized projectile loses its momentum before it can make contact with the Earth's surface. The 1908 Tunguska explosion is the largest observed example of this first type of airburst. For impacts above the threshold, the fireball descends all the way to the ground, where it expands radially, driving supersonic winds and radiating thermal energy at temperatures that can melt silicate surface materials. The Libyan Desert Glass event, 29 million years ago, may be an example of this second, larger, and more destructive type of airburst. The kinetic energy threshold that demarcates these two airburst types depends on asteroid velocity, density, strength, and impact angle. There is no evidence that the Tunguska fireball descended all the way to the surface, suggesting that its yield was about 5 megatons or lower. Better understanding of airbursts, combined with the diminishing number of undiscovered large asteroids, leads to the conclusion that airbursts represent a large and growing fraction of the total impact threat. Sandia is a multiprogram laboratory operated by Sandia Corp, a Lockheed Martin Company, for the US DOE under Contract DE-AC04-94AL85000. At altitude of maximum energy deposition (9 km) for a 15-megaton stony asteroid, its mass continues to descend at 9 km/s (60% of initial velocity).

Meteor Shower Forecast Improvements from a Survey of All-Sky Network Observations

NASA Technical Reports Server (NTRS)

Moorhead, Althea V.; Sugar, Glenn; Brown, Peter G.; Cooke, William J.

2015-01-01

Meteoroid impacts are capable of damaging spacecraft and potentially ending missions. In order to help spacecraft programs mitigate these risks, NASA's Meteoroid Environment Office (MEO) monitors and predicts meteoroid activity. Temporal variations in near-Earth space are described by the MEO's annual meteor shower forecast, which is based on both past shower activity and model predictions. The MEO and the University of Western Ontario operate sister networks of all-sky meteor cameras. These networks have been in operation for more than 7 years and have computed more than 20,000 meteor orbits. Using these data, we conduct a survey of meteor shower activity in the "fireball" size regime using DBSCAN. For each shower detected in our survey, we compute the date of peak activity and characterize the growth and decay of the shower's activity before and after the peak. These parameters are then incorporated into the annual forecast for an improved treatment of annual activity.

Measurements of Transverse Energy Distributions in Au+Au Collisions at {radical}s{sub NN} = 200 GeV

DOE Office of Scientific and Technical Information (OSTI.GOV)

Adams, J.; Aggarwal, M.M.; Ahammed, Z.

2004-07-02

Transverse energy (E{sub T}) distributions have been measured for Au+Au collisions at {radical}s{sub NN} = 200 GeV by the STAR collaboration at RHIC. E{sub T} is constructed from its hadronic and electromagnetic components, which have been measured separately. E{sub T} production for the most central collisions is well described by several theoretical models whose common feature is large energy density achieved early in the fireball evolution. The magnitude and centrality dependence of E{sub T} per charged particle agrees well with measurements at lower collision energy, indicating that the growth in E{sub T} for larger collision energy results from the growthmore » in particle production. The electromagnetic fraction of the total E{sub T} is consistent with a final state dominated by mesons and independent of centrality.« less

An absence of neutrinos associated with cosmic-ray acceleration in γ-ray bursts

NASA Astrophysics Data System (ADS)

Abbasi, R.; Abdou, Y.; Abu-Zayyad, T.; Ackermann, M.; Adams, J.; Aguilar, J. A.; Ahlers, M.; Altmann, D.; Andeen, K.; Auffenberg, J.; Bai, X.; Baker, M.; Barwick, S. W.; Bay, R.; Bazo Alba, J. L.; Beattie, K.; Beatty, J. J.; Bechet, S.; Becker, J. K.; Becker, K.-H.; Bell, M.; Benabderrahmane, M. L.; Benzvi, S.; Berdermann, J.; Berghaus, P.; Berley, D.; Bernardini, E.; Bertrand, D.; Besson, D. Z.; Bindig, D.; Bissok, M.; Blaufuss, E.; Blumenthal, J.; Boersma, D. J.; Bohm, C.; Bose, D.; Böser, S.; Botner, O.; Brayeur, L.; Brown, A. M.; Buitink, S.; Caballero-Mora, K. S.; Carson, M.; Casier, M.; Chirkin, D.; Christy, B.; Clevermann, F.; Cohen, S.; Colnard, C.; Cowen, D. F.; Cruz Silva, A. H.; D'Agostino, M. V.; Danninger, M.; Daughhetee, J.; Davis, J. C.; de Clercq, C.; Degner, T.; Descamps, F.; Desiati, P.; de Vries-Uiterweerd, G.; Deyoung, T.; Díaz-Vélez, J. C.; Dierckxsens, M.; Dreyer, J.; Dumm, J. P.; Dunkman, M.; Eisch, J.; Ellsworth, R. W.; Engdegård, O.; Euler, S.; Evenson, P. A.; Fadiran, O.; Fazely, A. R.; Fedynitch, A.; Feintzeig, J.; Feusels, T.; Filimonov, K.; Finley, C.; Fischer-Wasels, T.; Flis, S.; Franckowiak, A.; Franke, R.; Gaisser, T. K.; Gallagher, J.; Gerhardt, L.; Gladstone, L.; Glüsenkamp, T.; Goldschmidt, A.; Goodman, J. A.; Góra, D.; Grant, D.; Griesel, T.; Groß, A.; Grullon, S.; Gurtner, M.; Ha, C.; Haj Ismail, A.; Hallgren, A.; Halzen, F.; Han, K.; Hanson, K.; Heereman, D.; Heinen, D.; Helbing, K.; Hellauer, R.; Hickford, S.; Hill, G. C.; Hoffman, K. D.; Hoffmann, B.; Homeier, A.; Hoshina, K.; Huelsnitz, W.; Hülβ, J.-P.; Hulth, P. O.; Hultqvist, K.; Hussain, S.; Ishihara, A.; Jacobi, E.; Jacobsen, J.; Japaridze, G. S.; Johansson, H.; Kappes, A.; Karg, T.; Karle, A.; Kiryluk, J.; Kislat, F.; Klein, S. R.; Köhne, J.-H.; Kohnen, G.; Kolanoski, H.; Köpke, L.; Kopper, S.; Koskinen, D. J.; Kowalski, M.; Kowarik, T.; Krasberg, M.; Kroll, G.; Kunnen, J.; Kurahashi, N.; Kuwabara, T.; Labare, M.; Laihem, K.; Landsman, H.; Larson, M. J.; Lauer, R.; Lünemann, J.; Madsen, J.; Marotta, A.; Maruyama, R.; Mase, K.; Matis, H. S.; Meagher, K.; Merck, M.; Mészáros, P.; Meures, T.; Miarecki, S.; Middell, E.; Milke, N.; Miller, J.; Montaruli, T.; Morse, R.; Movit, S. M.; Nahnhauer, R.; Nam, J. W.; Naumann, U.; Nowicki, S. C.; Nygren, D. R.; Odrowski, S.; Olivas, A.; Olivo, M.; O'Murchadha, A.; Panknin, S.; Paul, L.; Pérez de Los Heros, C.; Piegsa, A.; Pieloth, D.; Posselt, J.; Price, P. B.; Przybylski, G. T.; Rawlins, K.; Redl, P.; Resconi, E.; Rhode, W.; Ribordy, M.; Richman, M.; Riedel, B.; Rizzo, A.; Rodrigues, J. P.; Rothmaier, F.; Rott, C.; Ruhe, T.; Rutledge, D.; Ruzybayev, B.; Ryckbosch, D.; Sander, H.-G.; Santander, M.; Sarkar, S.; Schatto, K.; Schmidt, T.; Schöneberg, S.; Schönwald, A.; Schukraft, A.; Schulte, L.; Schultes, A.; Schulz, O.; Schunck, M.; Seckel, D.; Semburg, B.; Seo, S. H.; Sestayo, Y.; Seunarine, S.; Silvestri, A.; Smith, M. W. E.; Spiczak, G. M.; Spiering, C.; Stamatikos, M.; Stanev, T.; Stezelberger, T.; Stokstad, R. G.; Stößl, A.; Strahler, E. A.; Ström, R.; Stüer, M.; Sullivan, G. W.; Taavola, H.; Taboada, I.; Tamburro, A.; Ter-Antonyan, S.; Tilav, S.; Toale, P. A.; Toscano, S.; Tosi, D.; van Eijndhoven, N.; van Overloop, A.; van Santen, J.; Vehring, M.; Voge, M.; Walck, C.; Waldenmaier, T.; Wallraff, M.; Walter, M.; Wasserman, R.; Weaver, Ch.; Wendt, C.; Westerhoff, S.; Whitehorn, N.; Wiebe, K.; Wiebusch, C. H.; Williams, D. R.; Wischnewski, R.; Wissing, H.; Wolf, M.; Wood, T. R.; Woschnagg, K.; Xu, C.; Xu, D. L.; Xu, X. W.; Yanez, J. P.; Yodh, G.; Yoshida, S.; Zarzhitsky, P.; Zoll, M.; IceCube Collaboration

2012-04-01

Very energetic astrophysical events are required to accelerate cosmic rays to above 1018electronvolts. GRBs (γ-ray bursts) have been proposed as possible candidate sources. In the GRB `fireball' model, cosmic-ray acceleration should be accompanied by neutrinos produced in the decay of charged pions created in interactions between the high-energy cosmic-ray protons and γ-rays. Previous searches for such neutrinos found none, but the constraints were weak because the sensitivity was at best approximately equal to the predicted flux. Here we report an upper limit on the flux of energetic neutrinos associated with GRBs that is at least a factor of 3.7 below the predictions. This implies either that GRBs are not the only sources of cosmic rays with energies exceeding 1018electronvolts or that the efficiency of neutrino production is much lower than has been predicted.

Search for High-Energy Muon Neutrinos from the "Naked-Eye" GRB 080319B with the IceCube Neutrino Telescope

NASA Astrophysics Data System (ADS)

Abbasi, R.; Abdou, Y.; Abu-Zayyad, T.; Adams, J.; Aguilar, J. A.; Ahlers, M.; Andeen, K.; Auffenberg, J.; Bai, X.; Baker, M.; Barwick, S. W.; Bay, R.; Bazo Alba, J. L.; Beattie, K.; Beatty, J. J.; Bechet, S.; Becker, J. K.; Becker, K.-H.; Benabderrahmane, M. L.; Berdermann, J.; Berghaus, P.; Berley, D.; Bernardini, E.; Bertrand, D.; Besson, D. Z.; Bissok, M.; Blaufuss, E.; Boersma, D. J.; Bohm, C.; Bolmont, J.; Botner, O.; Bradley, L.; Braun, J.; Breder, D.; Castermans, T.; Chirkin, D.; Christy, B.; Clem, J.; Cohen, S.; Cowen, D. F.; D'Agostino, M. V.; Danninger, M.; Day, C. T.; De Clercq, C.; Demirörs, L.; Depaepe, O.; Descamps, F.; Desiati, P.; de Vries-Uiterweerd, G.; DeYoung, T.; Diaz-Velez, J. C.; Dreyer, J.; Dumm, J. P.; Duvoort, M. R.; Edwards, W. R.; Ehrlich, R.; Eisch, J.; Ellsworth, R. W.; Engdegård, O.; Euler, S.; Evenson, P. A.; Fadiran, O.; Fazely, A. R.; Feusels, T.; Filimonov, K.; Finley, C.; Foerster, M. M.; Fox, B. D.; Franckowiak, A.; Franke, R.; Gaisser, T. K.; Gallagher, J.; Ganugapati, R.; Gerhardt, L.; Gladstone, L.; Goldschmidt, A.; Goodman, J. A.; Gozzini, R.; Grant, D.; Griesel, T.; Groß, A.; Grullon, S.; Gunasingha, R. M.; Gurtner, M.; Ha, C.; Hallgren, A.; Halzen, F.; Han, K.; Hanson, K.; Hasegawa, Y.; Heise, J.; Helbing, K.; Herquet, P.; Hickford, S.; Hill, G. C.; Hoffman, K. D.; Hoshina, K.; Hubert, D.; Huelsnitz, W.; Hülß, J.-P.; Hulth, P. O.; Hultqvist, K.; Hussain, S.; Imlay, R. L.; Inaba, M.; Ishihara, A.; Jacobsen, J.; Japaridze, G. S.; Johansson, H.; Joseph, J. M.; Kampert, K.-H.; Kappes, A.; Karg, T.; Karle, A.; Kelley, J. L.; Kenny, P.; Kiryluk, J.; Kislat, F.; Klein, S. R.; Knops, S.; Kohnen, G.; Kolanoski, H.; Köpke, L.; Kowalski, M.; Kowarik, T.; Krasberg, M.; Kuehn, K.; Kuwabara, T.; Labare, M.; Lafebre, S.; Laihem, K.; Landsman, H.; Lauer, R.; Lennarz, D.; Lucke, A.; Lundberg, J.; Lünemann, J.; Madsen, J.; Majumdar, P.; Maruyama, R.; Mase, K.; Matis, H. S.; McParland, C. P.; Meagher, K.; Merck, M.; Mészáros, P.; Middell, E.; Milke, N.; Miyamoto, H.; Mohr, A.; Montaruli, T.; Morse, R.; Movit, S. M.; Münich, K.; Nahnhauer, R.; Nam, J. W.; Nießen, P.; Nygren, D. R.; Odrowski, S.; Olivas, A.; Olivo, M.; Ono, M.; Panknin, S.; Patton, S.; Pérez de los Heros, C.; Petrovic, J.; Piegsa, A.; Pieloth, D.; Pohl, A. C.; Porrata, R.; Potthoff, N.; Price, P. B.; Prikockis, M.; Przybylski, G. T.; Rawlins, K.; Redl, P.; Resconi, E.; Rhode, W.; Ribordy, M.; Rizzo, A.; Rodrigues, J. P.; Roth, P.; Rothmaier, F.; Rott, C.; Roucelle, C.; Rutledge, D.; Ryckbosch, D.; Sander, H.-G.; Sarkar, S.; Schlenstedt, S.; Schmidt, T.; Schneider, D.; Schukraft, A.; Schulz, O.; Schunck, M.; Seckel, D.; Semburg, B.; Seo, S. H.; Sestayo, Y.; Seunarine, S.; Silvestri, A.; Slipak, A.; Spiczak, G. M.; Spiering, C.; Stamatikos, M.; Stanev, T.; Stephens, G.; Stezelberger, T.; Stokstad, R. G.; Stoufer, M. C.; Stoyanov, S.; Strahler, E. A.; Straszheim, T.; Sulanke, K.-H.; Sullivan, G. W.; Swillens, Q.; Taboada, I.; Tamburro, A.; Tarasova, O.; Tepe, A.; Ter-Antonyan, S.; Terranova, C.; Tilav, S.; Toale, P. A.; Tosi, D.; Turčan, D.; van Eijndhoven, N.; Vandenbroucke, J.; Van Overloop, A.; Voigt, B.; Walck, C.; Waldenmaier, T.; Walter, M.; Wendt, C.; Westerhoff, S.; Whitehorn, N.; Wiebusch, C. H.; Wiedemann, A.; Wikström, G.; Williams, D. R.; Wischnewski, R.; Wissing, H.; Woschnagg, K.; Xu, X. W.; Yodh, G.; Yoshida, S.; IceCube Collaboration

2009-08-01

We report on a search with the IceCube detector for high-energy muon neutrinos from GRB 080319B, one of the brightest gamma-ray bursts (GRBs) ever observed. The fireball model predicts that a mean of 0.1 events should be detected by IceCube for a bulk Lorentz boost of the jet of 300. In both the direct on-time window of 66 s and an extended window of about 300 s around the GRB, no excess was found above background. The 90% CL upper limit on the number of track-like events from the GRB is 2.7, corresponding to a muon neutrino fluence limit of 9.5 × 10-3 erg cm-2 in the energy range between 120 TeV and 2.2 PeV, which contains 90% of the expected events.

A Correlated Optical and Gamma Emission from GRB 081126A

DOE Office of Scientific and Technical Information (OSTI.GOV)

Gendre, B.; Klotz, A.; CESR, Observatoire Midi-Pyrenees, CNRS, Universite de Toulouse, BP 4346, F-31028-Toulouse Cedex 04

2010-10-15

We present an analysis of time-resolved optical emissions observed from the gamma-ray burst GRB 081126 during the prompt phase. The analysis employed time-resolved photometry using optical data obtained by the TAROT telescope, BAT data from the Swift spacecraft and time-resolved spectroscopy at high energies from the GBM instrument onboard the Fermi spacecraft. The optical emission of GRB 081126 is found to be compatible with the second gamma emission pulse shifted by a positive time-lag of 8.4{+-}3.9 sec. This is the first well resolved observation of a time lag between optical and gamma emissions during a gamma-ray burst. Our observations couldmore » potentially provide new constraints on the fireball model for gamma ray burst early emissions. Furthermore, observations of time-lags between optical and gamma ray photons provides an exciting opportunity to constrain quantum gravity theories.« less

Relativistic MHD simulations of collision-induced magnetic dissipation in Poynting-flux-dominated jets/outflows

DOE Office of Scientific and Technical Information (OSTI.GOV)

Deng, Wei

2015-07-21

The question of the energy composition of the jets/outflows in high-energy astrophysical systems, e.g. GRBs, AGNs, is taken up first: Matter-flux-dominated (MFD), σ < 1, and/or Poynting-flux-dominated (PFD), σ >1? The standard fireball IS model and dissipative photosphere model are MFD, while the ICMART (Internal-Collision-induced MAgnetic Reconnection and Turbulence) model is PFD. Motivated by ICMART model and other relevant problems, such as “jets in a jet” model of AGNs, the author investigates the models from the EMF energy dissipation efficiency, relativistic outflow generation, and σ evolution points of view, and simulates collisions between high-σ blobs to mimic the situation ofmore » the interactions inside the PFD jets/outflows by using a 3D SRMHD code which solves the conservative form of the ideal MHD equations. σ b,f is calculated from the simulation results (threshold = 1). The efficiency obtained from this hybrid method is similar to the efficiency got from the energy evolution of the simulations (35.2%). Efficiency is nearly σ independent, which is also confirmed by the hybrid method. σ b,i - σ b,f provides an interesting linear relationship. Results of several parameter studies of EMF energy dissipation efficiency are shown.« less

On the high fidelity simulation of chemical explosions and their interaction with solid particle clouds

NASA Astrophysics Data System (ADS)

Balakrishnan, Kaushik

The flow field behind chemical explosions in multiphase environments is investigated using a robust, state-of-the-art simulation strategy that accounts for the thermodynamics, gas dynamics and fluid mechanics of relevance to the problem. Focus is laid on the investigation of blast wave propagation, growth of hydrodynamic instabilities behind explosive blasts, the mixing aspects behind explosions, the effects of afterburn and its quantification, and the role played by solid particles in these phenomena. In particular, the confluence and interplay of these different physical phenomena are explored from a fundamental perspective, and applied to the problem of chemical explosions. A solid phase solver suited for the study of high-speed, two-phase flows has been developed and validated. This solver accounts for the inter-phase mass, momentum and energy transfer through empirical laws, and ensures two-way coupling between the two phases, viz. solid particles and gas. For dense flow fields, i.e., when the solid volume fraction becomes non-negligible (˜60%), the finite volume method with a Godunov type shock-capturing scheme requires modifications to account for volume fraction gradients during the computation of cell interface gas fluxes. To this end, the simulation methodology is extended with the formulation of an Eulerian gas, Lagrangian solid approach, thereby ensuring that the so developed two-phase simulation strategy can be applied for both flow conditions, dilute and dense alike. Moreover, under dense loading conditions the solid particles inevitably collide, which is accounted for in the current research effort with the use of an empirical collision/contact model from literature. Furthermore, the post-detonation flow field consists of gases under extreme temperature and pressure conditions, necessitating the use of real gas equations of state in the multiphase model. This overall simulation strategy is then extended to the investigation of chemical explosions in multiphase environments, with emphasis on the study of hydrodynamic instability growth, mixing, afterburn effects ensuing from the process, particle ignition and combustion (if reactive), dispersion, and their interaction with the vortices in the mixing layer. The post-detonation behavior of heterogeneous explosives is addressed by using three parts to the investigation. In the first part, only one-dimensional effects are considered, with the goal to assess the presently developed dense two-phase formulation. The total deliverable impulsive loading from heterogeneous explosive charges containing inert steel particles is estimated for a suite of operating parameters and compared, and it is demonstrated that heterogeneous explosive charges deliver a higher near-field impulse than homogeneous explosive charges containing the same mass of the high explosive. In the second part, three-dimensional effects such as hydrodynamic instabilities are accounted for, with the focus on characterizing the mixing layer ensuing from the detonation of heterogeneous explosive charges containing inert steel particles. It is shown that particles introduce significant amounts of hydrodynamic instabilities in the mixing layer, resulting in additional physical phenomena that play a prominent role in the flow features. In particular, the fluctuation intensities, fireball size and growth rates are augmented for heterogeneous explosions vis-a-vis homogeneous explosions, thereby demonstrating that solid particles enhance the perturbation intensities in the flow. In the third part of the investigation of heterogeneous explosions, dense, aluminized explosions are considered, and the particles are observed to burn in two phases, with an initial quenching due to the rarefaction wave, and a final quenching outside the fireball. Due to faster response time scales, smaller particles are observed to heat and accelerate more during early times, and also cool and decelerate more at late times, compared to counterpart larger particle sizes. Furthermore, the average particle velocities at late times are observed to be independent of the initial solid volume fraction in the explosive charge, as the particles eventually reach an equilibrium with the local gas. These studies have provided some crucial insights to the flow physics of dense, aluminized explosives. (Abstract shortened by UMI.)

Meteorites, Bolides and Comets: A Tale of Inconsistency

NASA Astrophysics Data System (ADS)

Jakes, P.; Padevet, V.

1992-07-01

Inhomogeneity of cometary nuclei has been established through the observed disruptions of comets [1] and through the determination of dust particle composition during the encounter of the Vega and Giotto satellites with comet Halley [2,3,4]. The raisin bread model of cometary nuclei [5,6] assumes the presence of solid (rock) and dust particle material set in the volatile rich, ice- cemented material. Rock material may contribute to the formation of dust particles. Gombosi and Houpis [5] argued that only the composition of dust particles derived from the icy, volatile component of the comet were analyzed and implied thus that the third cometary component present (raisins/rocks) has not been examined. The compositions of the cometary (Halley) dust and the interplanetary dust particles (IDPs) are "chondritic" (Blanford et al., 1988). It is difficult, therefore to estimate the proportion of cometary to asteroid-derived dust in near Earth space, e.g., among the IDPs [7] unless other criteria are available. Bolide multistation photographic tracking allows the determination of the orbital preencounter parameters of solid bodies (0.01-100,000 kg in mass) with the Earth, and allows us to classify them according to their ablation coefficient (tau), penetration depth into the atmosphere (PE), theoretical densities (sigma), and terminal velocities (V(sub)E). Four groups are recognized (Table 1). Three of the type I bolides were recovered as ordinary chondrites (Pribram, Lost City, and Innisfree). Ceplecha [8] has shown that 38% of bolides (fireballs) come from cometary orbits (11% from highly eccentric orbits typical of new comets), but most of the bolides (62%) originate at asteroidal orbits. Seven of the 14 known meteoric showers could be attributed to known comets: N,S Taurids to 1970 P/Encke, Lyrids to 1861 I Thatcher-Beaker, Perseids to 1862 III Swift-Tuttle- Simons, Orionids to 1835 III P/Halley, Draconids to 1946 V P/Giacobini-Zinner, Leonids to 1966 I Tempel-Tuttle, and Leo Minorids to 1739 Zanotti. Geminids were related to asteroid 3200 Phaeton, considered to be an "extinct comet." Spurny [9], using ablation coefficient and penetration depth criteria, found that Geminids (frequently) and Taurids (rarely) contain bolides of types I and II. This may indicate that meteoric showers from "comets" on AAA orbits contain some portion of "rocky" material comparable to chondrites. These observations revive Opik's (1963) idea that comets may be captured in the asteroid belt on AAA orbits and may contain (and supply) chondritic meteorites to the Earth [10]. If the relationship among large solid particles "native to the asteroid belt" and those from the outer solar system can be established, they can be scaled and applied to IDPs. We have studied the records of 292 bolides (Prairie and European networks) with measured terminal velocities. We attempt to use the terminal velocity, calculated density, estimated terminal mass, and mechanical strength to correlate features with the meteorite features. We compare the meteorite fall frequency [11] with the bolide features. Two extreme hypotheses (Table 1) are examined: (A) bolides of types IIIa and IIIb do not have equivalents among the meteorites and (B) all four bolide types have meteoritic equivalents, and only IDPs do not produce bolides (fireballs). If the entry parameters of meteoroids are similar, bodies with lower density should reach terminal velocity at higher altitudes than those with higher density. If it is assumed that fragmentation is the same for dense (I and II) and less dense bodies (IIIa and IIIb), the calculated terminal altitudes show that among the bolides exist materials with lower densities than those of recovered meteorites and that model A of the correlation between meteorite falls and bolide observations is likely [12]. If, however, the less dense bodies were more easily fragmented than denser bodies, the correlation is better for hypothesis B. Table 1, which in the hard copy appears here, shows fireball observations. Using the value of terminal velocities and the average value of ablation coefficients the terminal (residual) masses (m(sub)E) can be calculated. Among the bodies studied, 99 were heavier than 0.1 kg and 153 heavier than 0.01 kg. The parameter (m(sub)E) indicates the end of ablation in the atmosphere, but it cannot distinguish between meteoroids that were totally disintegrated and those genuinely decelerated. Similarly the calculated terminal altitudes and mechanical strength values do not provide a unequivocal interpretation. Correlation of bolide properties with meteorite falls could well be accommodated by the hypothesis B in which each bolide type has a meteorite equivalent. This has, however, some "outrageous" implications: comets may carry chondrites, icy dust balls do not produce fireballs; the extremely primitive carbon-rich particles represented by the IDPs do not form larger discrete bodies (fireballs) of "asteroidal" size; and the asteroid belt is a mixture of "native fractionated old bodies" together with the captured comets. Hypothesis B therefore contradicts the "established" scheme of the asteroid belt in which the non-differentiated meteorites (CI, CM, and CV) form the outer part of the asteroid belt, whereas the fractionated metamorphosed and igneous meteorites characterize the inner asteroids. References: [1] Whipple F. L., 1987, Phil. Trans. R. Soc. Lond., A 323, 339. [2] Dikov Yu. P. et al., 1991, Geochemistry International, 29, 33-38. [3] Kissel J., et al., 1986, Nature, 321, 326. [4] Solc M., et al., 1987, Publ. Astr. Inst. Czechosl., 67, 47. [5] Gombosi T. I. and Houpis H. L. F., 1986, Nature, 324, 43. [6] Delsemme A. H., 1977, Comets, asteroids, meteorites, Univ. of Toledo Press. [7] Gibson E. K., 1992, J. Geophys. Res., 97, E3 3865. [8] Ceplecha Z., 1988, Bull. Astr. Inst. Czech., 39, 221. [9] Spurny P., 1991, doc. diss., Astr. Inst. Czechosl. [10] Opik E. J., 1963, Adv. Astr. Astrophys., 2, 219. [11] Hutchinson R., et al., 1977, Appendix to Catalogue of Meteorites, British Museum, London. [12] Ceplecha Z. and McCrosky R. E., 1976, J. Geophys. Res., 81, 6257.

Experimental Characterization of Soot Formation in Diffusion Flames and Explosive Fireballs

DTIC Science & Technology

2012-04-01

49 Figure 48. A side view of the elevated pressure-opposed flow rig on the test stand. The IR cutoff filter is shown in front of the...turbulent flows of mixed gasses in excited states. To perform this measurement, we have built and characterized a sensitive, selective infrared ( IR ...tool for TDLAS (Kosterev and Tittel, 2002). The QCL operates near room temperature and provides a powerful (~10 mW), stable, single-mode, mid- IR

WESCOM. A Fortran Code for Evaluation of Nuclear Weapon Effects on Satellite Communications. Volume 2. Code Structure

DTIC Science & Technology

1981-01-31

quantities for h i ;.;h-:t It i 1 ndc hurst s 1BMI.I Determines t ime-independent fireball quantities for low-altitude bursts 10 Table 1...of reference Oval of Cassini (km) LAFBP - vortex longitudinal radius (km) LAFBP - vortex transverse radius (km) Power law exponent Inner scale...Maximum slant range of ionization from transmitter (km) Power law exponent Frequency (Hz) Striation velocity flag Propagation path index Radius

Emission Spectroscopy of the Interior of Optically Dense Post-Detonation Fireballs

DTIC Science & Technology

2013-03-01

sample. Light from the fiber optics was sent to spectrograph located in a shielded observation room several meters away from the explosive charge. The...spectrograph was constructed from a 1/8 m spectrometer (Oriel) interfaced to a 4096 pixel line-scan camera (Basler Sprint ) with a data collection rate... 400 ) 45 4000 (200) … FIG. 3. Time-resolved emission spectra obtained from detonation of 20 g charges of RDX containing 20 wt. % aluminum nanoparticles

Comparing Eyewitness-Derived Trajectories of Bright Meteors to Ground Truth Data

NASA Technical Reports Server (NTRS)

Moser, D. E.

2016-01-01

The NASA Meteoroid Environment Office (MEO) is the only US government agency tasked with analyzing meteors of public interest. When queried about a meteor observed over the United States, the MEO must respond with a characterization of the trajectory, orbit, and size within a few hours. Using observations from meteor networks like the NASA All Sky Fireball Network or the Southern Ontario Meteor Network, such a characterization is often easy. If found, casual recordings from the public and stationary web cameras can be used to roughly analyze a meteor if the camera's location can be identified and its imagery calibrated. This technique was used with great success in the analysis of the Chelyabinsk meteorite fall. But if the event is outside meteor network coverage, if an insufficient number of videos are found, or if the imagery cannot be geolocated or calibrated, a timely assessment can be difficult if not impossible. In this situation, visual reports made by eyewitnesses may be the only resource available. This has led to the development of a tool to quickly calculate crude meteor trajectories from eyewitness reports made to the American Meteor Society. The output is illustrated in Figure 1. A description of the tool, example case studies, and a comparison to ground truth data observed by the NASA All Sky Fireball Network will be presented.

Experimental investigation of spontaneous ignition and flame propagation at pressurized hydrogen release through tubes with varying cross-section.

PubMed

Duan, Qiangling; Xiao, Huahua; Gao, Wei; Gong, Liang; Sun, Jinhua

2016-12-15

An experimental investigation of spontaneous ignition and flame propagation at high-pressure hydrogen release via cylindrical tubes with varying cross-section is presented. Tubes with different transverse cross-sections are considered in the experiments: (1) local contraction, (2) local enlargement, (3) abrupt contraction, and (4) abrupt enlargement. The results show that the presence of the varying cross-section geometries can significantly promote the occurrence of spontaneous ignition. Compared to the tube with constant cross-section, the minimum pressure release needed for spontaneous ignition for the varying cross-sections tubes is considerably lower. Moreover, the initial ignition location is closer to the disk in the presence of varying cross-section geometries in comparison with straight channel. As the flame emerges from the outlet of the tube, the velocity of the flame front in the vicinity of the nozzle increases sharply. Then, a deflagration develops across the mixing zone of hydrogen/air mixture. The maximum deflagration overpressure increases linearly with the release pressure. Subsequently, a hydrogen jet flame is produced and evolves different shapes at different release stages. A fireball is formed after the jet flame spouts in the open air. Later, the fireball develops into a jet flame which shifts upward and continues to burn in the vertical direction. Copyright © 2016 Elsevier B.V. All rights reserved.

On the Pre-impact Orbital Evolution of 2018 LA, Parent Body of the Bright Fireball Observed Over Botswana on 2018 June 2

NASA Astrophysics Data System (ADS)

de la Fuente Marcos, Carlos; de la Fuente Marcos, Raúl

2018-06-01

On 2018 June 2, meteoroid 2018 LA became the third natural body ever to be observed before entering our atmosphere ---small asteroids 2014 AA and 2008 TC3 had stricken the Earth on 2014 January 2 and 2008 October 7, respectively. Here, we explore the pre-impact orbital evolution of 2018 LA and investigate the possible presence of known NEOs moving in similar orbits using N-body simulations and the D-criteria. We identify several objects moving in orbits similar to that of 2018 LA and focus on three of them: (454100) 2013 BO73, which is the largest of the group and a PHA, 2016 LR, and 2018 BA5, which follows a path very close to that of 2018 LA in terms of semimajor axis, eccentricity, and inclination. All these objects could be part of a dynamical grouping and their orbital evolution is rather chaotic, experiencing close encounters with Venus, the Earth-Moon system, and Mars. NEO encounters take place at the node and, on the short-term, the relative positions of our planet in its orbit around the Sun repeat every year. Besides the bright fireball observed over Botswana on 2018 June 2, three other bolides were observed early in June in recent years: Crete on 2002 June 6, Washington State on 2004 June 3, and Reisadalen on 2007 June 7.

Testing gamma-ray burst models with the afterglow of GRB 090102

NASA Astrophysics Data System (ADS)

Gendre, B.; Klotz, A.; Palazzi, E.; Krühler, T.; Covino, S.; Afonso, P.; Antonelli, L. A.; Atteia, J. L.; D'Avanzo, P.; Boër, M.; Greiner, J.; Klose, S.

2010-07-01

We present the observations of the afterglow of gamma-ray burst GRB 090102. Optical data taken by the Telescope a Action Rapide pour les Objets Transitoires (TAROT), Rapid Eye Mount (REM), Gamma-Ray burst Optical/Near-Infrared Detector (GROND), together with publicly available data from Palomar, Instituto de Astrofísica de Canarias (IAC) and Nordic Optical Telescope (NOT) telescopes, and X-ray data taken by the XRT instrument on board the Swift spacecraft were used. This event features an unusual light curve. In X-rays, it presents a constant decrease with no hint of temporal break from 0.005 to 6d after the burst. In the optical, the light curve presents a flattening after 1ks. Before this break, the optical light curve is steeper than that of the X-ray. In the optical, no further break is observed up to 10d after the burst. We failed to explain these observations in light of the standard fireball model. Several other models, including the cannonball model were investigated. The explanation of the broad-band data by any model requires some fine-tuning when taking into account both optical and X-ray bands. Based on observations obtained with TAROT, REM, GROND. E-mail: bruce.gendre@asdc.asi.it ‡ Present address: ASDC, Via Galileo Galilei, 00044 Frascati, Italy.

Assessment of an explosive LPG release accident: a case study.

PubMed

Bubbico, Roberto; Marchini, Mauro

2008-07-15

In the present paper, an accident occurred during a liquefied petroleum gas (LPG) tank filling activity has been taken into consideration. During the transfer of LPG from the source road tank car to the receiving fixed storage vessel, an accidental release of LPG gave rise to different final consequences ranging from a pool fire, to a fireball and to the catastrophic rupture of the tank with successive explosion of its contents. The sequence of events has been investigated by using some of the consequence calculation models most commonly adopted in risk analysis and accident investigation. On one hand, this allows to better understand the link between the various events of the accident. On the other hand, a comparison between the results of the calculations and the damages actually observed after the accident, allows to check the accuracy of the prediction models and to critically assess their validity. In particular, it was shown that the largest uncertainty is associated with the calculation of the energy involved in the physical expansion of the fluid (both liquid and vapor) after the catastrophic rupture of the tank.

High Fidelity Modeling of Turbulent Mixing and Chemical Kinetics Interactions in a Post-Detonation Flow Field

NASA Astrophysics Data System (ADS)

Sinha, Neeraj; Zambon, Andrea; Ott, James; Demagistris, Michael

2015-06-01

Driven by the continuing rapid advances in high-performance computing, multi-dimensional high-fidelity modeling is an increasingly reliable predictive tool capable of providing valuable physical insight into complex post-detonation reacting flow fields. Utilizing a series of test cases featuring blast waves interacting with combustible dispersed clouds in a small-scale test setup under well-controlled conditions, the predictive capabilities of a state-of-the-art code are demonstrated and validated. Leveraging physics-based, first principle models and solving large system of equations on highly-resolved grids, the combined effects of finite-rate/multi-phase chemical processes (including thermal ignition), turbulent mixing and shock interactions are captured across the spectrum of relevant time-scales and length scales. Since many scales of motion are generated in a post-detonation environment, even if the initial ambient conditions are quiescent, turbulent mixing plays a major role in the fireball afterburning as well as in dispersion, mixing, ignition and burn-out of combustible clouds in its vicinity. Validating these capabilities at the small scale is critical to establish a reliable predictive tool applicable to more complex and large-scale geometries of practical interest.

A meteorite crater on Earth formed on September 15, 2007: The Carancas hypervelocity impact

NASA Astrophysics Data System (ADS)

Tancredi, G.; Ishitsuka, J.; Schultz, P. H.; Harris, R. S.; Brown, P.; Revelle, D. O.; Antier, K.; Le Pichon, A.; Rosales, D.; Vidal, E.; Varela, M. E.; Sánchez, L.; Benavente, S.; Bojorquez, J.; Cabezas, D.; Dalmau, A.

2009-01-01

On September 15, 2007, a bright fireball was observed and a big explosion was heard by many inhabitants near the southern shore of Lake Titicaca. In the community of Carancas (Peru), a 13.5 m crater and several fragments of a stony meteorite were found close to the site of the impact. The Carancas event is the first impact crater whose formation was directly observed by several witnesses as well as the first unambiguous seismic recording of a crater-forming meteorite impact on Earth. We present several lines of evidence that suggest that the Carancas crater was a hypervelocity impact. An event like this should have not occurred according to the accepted picture of stony meteoroids ablating in the Earth’s atmosphere, therefore it challenges our present models of entry dynamics. We discuss alternatives to explain this particular event. This emphasizes the weakness in the pervasive use of “average” parameters (such as tensile strength, fragmentation behavior and ablation behavior) in current modeling efforts. This underscores the need to examine a full range of possible values for these parameters when drawing general conclusions from models about impact processes.

Ideological principles of Neo-Byurakan Cosmogony

NASA Astrophysics Data System (ADS)

Poghosyan, Samvel

2015-07-01

There exists an insurmountable antagonism between the Classical and the Byurakan approaches on the origins of celestial bodies. The Classical approach states that celestial bodies arise from the condensation of gases, gravitational compression; and according to the Byurakan conception, they come into existence due to the explosions, differentiation of compact, superdense bodies. Rejecting each other, the supporters of these two polarized views do not accept that those two trends, differentiation and integration, dispersion and unity are interconnected and mutually conditioned processes: there are always cases of dispersion and differentiation in integration and unity and vice versa. Neo-Byurakan theory distinguishes two types of physical symmetries: substantial and relational symmetries. The types of substantial symmetry are: Symmetry of positive and negative gravitational charges (masses), Symmetry of particles and antiparticles (matter and antimatter). The types of relational symmetry are: Symmetry of differentiation and integration, Symmetry of homogeneity and inhomogeneity, Symmetry of statics (or stationarity) and dynamics, Symmetry of great unity, of strong and electroweak forces and interactions, Symmetry of electroweak unity, of weak and electromagnetic forces. As the above mentioned examples show, substantial symmetries are related to the basic types of matter; and relational symmetries to the interactions of these types. Both types can be explicit and implicit. Neo-Byurakan cosmogony puts forward a range of new ideas: 1.Being a part of Gc?? Cosmology, it differentiates and identifies the concepts of "Eternal Universe", "our Universe" and "Metagalaxy". Viewing Metagalaxy as a subsystem of our universe, as a unity of all galaxies and their clusters, it defines the basic equations which express the basic physical parameters of Metagalaxy, describes its structure, giving a physical explanation to the homogeneity of the large-scale structure of Metagalaxy, mentioning the laws and peculiarities of its origination and evolution. 2.Admitting the fact of its expansion, Neo-Byurakan theory considers that during evolution all physical parameters of Metagalaxy change, including not only the volume and average density but also the mass of Metagalaxy. And it means that the Friedman-Gamow theory of Fireball cannot be ascribed to Metagalaxy, especially to our Universe. A hypothesis is put forward, according to which the concept of Fireball or Big Bang refers to and accurately describes the differentiation and evaluation of compact, superdense superclusters of galaxies through explosion. The immediate components of the large-scale homogeneity of Metagalaxy are superclusters of galaxies. They are similar physical systems belonging to the same class, which have similar structures, and though they arise at different times, they undergo similar phases of evolution.

R{sub AA} of J/psi near midrapidity in heavy ion collisions at sq root(s{sub NN})=200 GeV

DOE Office of Scientific and Technical Information (OSTI.GOV)

Song, Taesoo; Park, Woosung; Lee, Su Houng

2010-03-15

We build up a model to reproduce the experimentally measured R{sub AA} of J/psi near midrapidty in an Au+Au collision at sq root(s{sub NN})=200 GeV. The model takes into account the J/psi suppression from the quark-gluon plasma and hadron gas as well as the nuclear absorption of primordial charmonia and the regeneration effects at the hadronization stage and hence is a generalization of the two-component model introduced by Grandchamp and Rapp. The improvements in this work are twofold; the addition of the initial local temperature profile and a consistent use of QCD next-to-leading order (NLO) formula for both the dissociationmore » cross section in the hadron gas and the thermal decay widths in the quark-gluon plasma for the charmonium states. The initial local temperature profile is determined from the assumption that the local entropy density is proportional to a formula involving the number densities of the number of participants and of the binary collisions that reproduces the multiplicities of charged particles at chemical freeze-out. The initial local temperature profile brings about a kink in the R{sub AA} curve due to the initial melting of J/psi. The initially formed fireball, composed of weakly interacting quarks and gluons with thermal masses that are extracted from lattice QCD, follows an isentropic expansion with cylindrical symmetry. The fit reproduces well the Au+Au as well as the Cu+Cu data. The same method is applied to predict the R{sub AA} expected from the Pb+Pb collision at Large Hadron Collider (LHC) energy.« less

The Meteor and Fireball Network of the Sociedad Malagueña de Astronomía

NASA Astrophysics Data System (ADS)

Aznar, J. C.; Castellón, A.; Gálvez, F.; Martínez, E.; Troughton, B.; Núñez, J. M.; Villalba, F.

2016-12-01

One of the most active fields in which has been dedicated the Málaga Astronomical Society (SMA) is the meteors and meteor showers. Since 2006 the SMA refers parts of visual observations and photographic detections from El Pinillo station (Torremolinos, Spain). In 2013 it was decided to give an extra boost to get a camera network that allowed the calculation of the atmospheric trajectory of a meteoroid and, where possible, obtaining the orbital elements.

Meteor detections at the Metsähovi Fundamental Geodetic Research Station (Finland)

NASA Astrophysics Data System (ADS)

Raja-Halli, A.; Gritsevich, M.; Näränen, J.; Moreno-Ibáñez, M.; Lyytinen, E.; Virtanen, J.; Zubko, N.; Peltoniemi, J.; Poutanen, M.

2016-01-01

We provide an overview and present some spectacular examples of the recent meteor observations at the Metsähovi Geodetic Research Station. In conjunction with the Finnish Fireball Network the all-sky images are used to reconstruct atmospheric trajectories and to calculate the pre-impact meteor orbits in the Solar System. In addition, intensive collaborative work is pursued with the meteor research groups worldwide. We foresee great potential of this activity also for educational and outreach purposes.

A study of the origin, nature, and behavior of particulate matter and metallic atoms in the mesosphere, lower thermosphere, and at the mesopause. [using lidar data

NASA Technical Reports Server (NTRS)

Poultney, S. K.

1973-01-01

In a study of particulate matter and metallic atoms in the vicinity of the mesopause, three areas have received the most effort. These areas are: the significance of cometary dust influxes to the earth's atmosphere; the relation of nightglows to atmospheric motions and aerosols; and the feasibility of using an airborne resonant scatter lidar to study polar noctilucent clouds, the sodium layer, and fireball dust.

A New Search Paradigm for Correlated Neutrino Emission from Discrete GRBs using Antarctic Cherenkov Telescopes in the Swift Era

DOE Office of Scientific and Technical Information (OSTI.GOV)

Stamatikos, Michael; Band, David L.; JCA/UMBC, Baltimore, MD 21250

2006-05-19

We describe the theoretical modeling and analysis techniques associated with a preliminary search for correlated neutrino emission from GRB980703a, which triggered the Burst and Transient Source Experiment (BATSE GRB trigger 6891), using archived data from the Antarctic Muon and Neutrino Detector Array (AMANDA-B10). Under the assumption of associated hadronic acceleration, the expected observed neutrino energy flux is directly derived, based upon confronting the fireball phenomenology with the discrete set of observed electromagnetic parameters of GRB980703a, gleaned from ground-based and satellite observations, for four models, corrected for oscillations. Models 1 and 2, based upon spectral analysis featuring a prompt photon energymore » fit to the Band function, utilize an observed spectroscopic redshift, for isotropic and anisotropic emission geometry, respectively. Model 3 is based upon averaged burst parameters, assuming isotropic emission. Model 4 based upon a Band fit, features an estimated redshift from the lag-luminosity relation, with isotropic emission. Consistent with our AMANDA-II analysis of GRB030329, which resulted in a flux upper limit of {approx} 0.150GeV /cm2/s for model 1, we find differences in excess of an order of magnitude in the response of AMANDA-B10, among the various models for GRB980703a. Implications for future searches in the era of Swift and IceCube are discussed.« less

VLA Observations Confirm Origin of Gamma Ray Bursts in Short-Lived Stars

NASA Astrophysics Data System (ADS)

1998-06-01

Radio telescope studies of the fiery afterglow of a Gamma Ray Burst have provided astronomers with the best clues yet about the origins of these tremendous cosmic cataclysms since their discovery more than 30 years ago. Observations with the National Science Foundation's (NSF) Very Large Array (VLA) radio telescope confirm that a blast seen to occur on March 29 had its origin in a star-forming region in a distant galaxy. "There are two leading theories for the causes of Gamma Ray Bursts," said Dale Frail of the NSF National Radio Astronomy Observatory (NRAO) in Socorro, NM. "According to one theory, the blasts occur in the death throes of pairs of old stars. The other requires them to arise from exploding, massive, short-lived stars that still reside within the star-forming gas and dust from which they formed. The VLA studies of the burst show that at least this one almost certainly occurred within a star-forming region. This result also explains why half of the Gamma Ray Burst afterglows are not detected by optical telescopes." Frail heads a VLA observing team including Greg Taylor, also of NRAO, and Shri Kulkarni of Caltech, that reported its findings to the American Astronomical Society meeting in San Diego, CA. The March 29 burst was seen clearly by radio telescopes (the accompanying image is GRB 980329 as seen by the VLA) but only very faintly with optical instruments. "That is extremely important," said Taylor. "This burst was very faint at visible wavelengths, brighter at infrared wavelengths and brighter still at radio wavelengths. This is a clear indication that the exploding object was surrounded by dust. Dust is most commonly found in star-forming regions." This strongly favors one of the two leading theories about Gamma Ray Bursts over the other. One explanation for these tremendously energetic fireballs is that a pair of superdense neutron stars collides. The other is that a single, very massive star explodes in a "hypernova," more powerful than a supernova, at the end of its normal life. The hypernova explosion, scientists believe, would come only a few million years after the giant star was formed, while it is still within the cloud of gas and dust from which it formed. Neutron stars, on the other hand, are formed by supernova explosions that give a "kick" to the resulting neutron star, propelling it at high speeds. An orbiting pair of neutron stars, astronomers think, would collide only after hundreds of millions of years of orbital decay, by which time they would be far away from the gas and dust of their birthplace. "The observations already have provided crucial insight; we intend to continue observing the relic of the March 29 burst with the VLA, and in the coming months, we will gain new information that will help further refine our ideas about these fireballs," Frail said. "We're going to learn about the size and expansion rate of the fireball and test predictions made by the models." "These observations indicate the extraordinary importance of radio astronomy for providing information that can be gained in no other way about one of the major frontier areas of astrophysics," said Hugh Van Horn, Director of the NSF's Division of Astronomical Sciences. The March 29 burst (GRB 980329) was the second such blast to have its afterglow detected at radio wavelengths. Last year, the VLA made the first radio detection of a GRB afterglow, finding radio emission coming from the location of a Gamma Ray Burst on May 8, 1997 (GRB 970508). "Of the world's radio telescopes, only the VLA has the sensitivity and resolving power to quickly detect these radio afterglows of Gamma Ray Bursts and study them in detail over extended periods of time," Taylor said. "Even so, we only see the brightest one-third of them. With upgraded capabilities at the VLA, as planned by NRAO, we will see them all." The National Radio Astronomy Observatory is a facility of the National Science Foundation, operated under cooperative agreement by Associated Universities, Inc.

Orbits and emission spectra from the 2014 Camelopardalids

NASA Astrophysics Data System (ADS)

Madiedo, José M.; Trigo-Rodríguez, Josep M.; Zamorano, Jaime; Izquierdo, Jaime; de Miguel, Alejandro Sánchez; Ocaña, Francisco; Ortiz, José L.; Espartero, Francisco; Morillas, Lorenzo G.; Cardeñosa, David; Moreno-Ibáñez, Manuel; Urzáiz, Marta

2014-12-01

We have analysed the meteor activity associated with meteoroids of fresh dust trails of Comet 209P/LINEAR, which produced an outburst of the Camelopardalid meteor shower (IAU code #451, CAM) in 2014 May. With this aim, we have employed an array of high-sensitivity CCD video devices and spectrographs deployed at 10 meteor observing stations in Spain in the framework of the Spanish Meteor Network. Additional meteoroid flux data were obtained by means of two forward-scatter radio systems. The observed peak zenithal hourly rate was much lower than expected, of around 20 meteors h-1. Despite of the small meteor flux in the optical range, we have obtained precise atmospheric trajectory, radiant and orbital information for 11 meteor and fireball events associated with this stream. The ablation behaviour and low tensile strength calculated for these particles reveal that Camelopardalid meteoroids are very fragile, mostly pristine aggregates with strength similar to that of the Orionids and the Leonids. The mineral grains seem to be glued together by a volatile phase. We also present and discuss two unique emission spectra produced by two Camelopardalid bright meteors. These suggest a non-chondritic nature for these particles, which exhibit Fe depletion in their composition.

The Kosice meteorite

NASA Astrophysics Data System (ADS)

Toth, J.; Svoren, J.

2012-01-01

The glare of the bolide on the night of February 28, 2010, illuminated streets and interiors of apartments at some location in eastern Slovakia and northern Hungary. In addition, cannon-like bursts or series of low frequency blasts were heard. Due to bad weather, cloudy skies, and scattered showers, the Central European Fireball Network (operated by Dr. Pavel Spurny of the Czech Academy of Sciences) did not take direct optical records of the bolide and the Slovak Video Meteor Network (operated by the first author) was not operational that night. So, at first sight, it seemed that there were no scientific records of this event. Fortunately, fast photoelectric sensors on seven automated fireball stations in the Czech Republic (6) and Austria (1) detected the illumination of the sky caused by the bolide, which made it possible to determine exact time and duration of the bolide and estimate its brightness. The bolide reached its maximum brightness of at least magnitude -18 in one huge flare. Later on, several surveillance camera data were published showing the moment when the night turned into day for a second, but only two videos from Hungary (Orkeny village, Fazzi Daniella and Vass Gabor; Telki village, contact persons Sarneczky Krisztian, and Kiss Laszlo) actually captured the fireball itself. Thanks to calibration of videos by several members of the Hungarian Astronomical Association (MCSE, http://www.mcse.hu) contributing (in particular, Antal Igaz) and a trajectory analysis by Dr. Jiri Borovicka of the Czech Academy of Sciences gave the hope that significant numbers of meteorite fragments reached the surface. He also calculated the impact area, near the town of Kosice in eastern Slovakia. The data from the Local Seismic Network of Eastern Slovakia (project led by Professor Moczo of Comenius University) confirmed the atmospheric trajectory as well. The expedition consisting of scientists and graduate students of the Astronomical Institute of the Slovak Academy of Sciences (under the leadership of the second author), Comenius University in Bratislava (under the leadership of the first author), and the Czech Academy of Sciences (under the leadership of Pavel Spurny) started to sweep meadows and forests at the calculated area. The first meteorite was discovered by Juraj Toth on March 20th. By October 6th, 77 meteorite fragments were found. The heaviest fragment weighs 2.17 kg and was found by Tereza Krejcova; the smallest pieces were only about 0.5 g (finder Julius Koza). The total mass recovered is 4.3 kg. There were 28 finders: Juraj Toth, Diana Buzova, Marek Husarik, Tereza Krejcova, Jan Svoren, Julius Koza, David Capek, Pavel Spurny, Stanislav Kaniansky, Eva Schunova, Marcel Skreka, Dusan Tomko, Pavol Zigo, Miroslav Seben, Jiri Silha, Leonard Kornos, Marcela Bodnarova, Peter Veres, Jozef Nedoroscik, Zuzana Mimovicova, Zuzana Krisandova, Jaromir Petrzala, Stefan Gajdos, Tomas Dobrovodsky, Peter Delincak, Zdenko Bartos, Ales Kucera, and Jozef Vilagi. Preliminary as well as complex mineralogic analysis implies that the recovered meteorite is classified as an ordinary H5 chondrite (Dr. J. Haloda, Czech Geological Survey, D. Ozdin, and P. Uher, Comenius University in Bratislava). The authors are grateful to all collaborators mentioned above. More details about the meteorite will be published in the near future.

Colliding neutron stars. Gravitational waves, neutrino emission, and gamma-ray bursts

NASA Astrophysics Data System (ADS)

Ruffert, M.; Janka, H.-Th.

1998-10-01

Three-dimensional hydrodynamical simulations are presented for the direct head-on or off-center collision of two neutron stars, employing a basically Newtonian PPM code but including the emission of gravitational waves and their back-reaction on the hydrodynamical flow. A physical nuclear equation of state is used that allows us to follow the thermodynamical evolution of the stellar matter and to compute the emission of neutrinos. Predicted gravitational wave signals, luminosities and waveforms, are presented. The models are evaluated for their implications for gamma-ray burst scenarios. We find an extremely luminous outburst of neutrinos with a peak luminosity of more than 4* 10(54) erg/s for several milliseconds. This leads to an efficiency of about 1% for the annihilation of neutrinos with antineutrinos, corresponding to an average energy deposition rate of more than 10(52) erg/s and a total energy of about 10(50) erg deposited in electron-positron pairs around the collision site within 10 ms. Although these numbers seem very favorable for gamma-ray burst scenarios, the pollution of the e(+/-) pair-plasma cloud with nearly 10(-1} M_{sun) of dynamically ejected baryons is 5 orders of magnitude too large. Therefore the formation of a relativistically expanding fireball that leads to a gamma-ray burst powered by neutrino emission from colliding neutron stars is definitely ruled out.

Photometric evolution of seven recent novae and the double-component characterizing the light curve of those emitting in gamma rays

NASA Astrophysics Data System (ADS)

Munari, U.; Hambsch, F.-J.; Frigo, A.

2017-08-01

The BVI light curves of seven recent novae (I.e. V1534 Sco, V1535 Sco, V2949 Oph, V3661 Oph, MASTER OT J010603.18-744715.8, TCP J1734475-240942 and ASASSN-16ma) have been extensively mapped with daily robotic observations from Atacama (Chile): five belong to the Galactic bulge, one to the Small Magellanic Cloud and another is a Galactic disc object. The two programme novae detected in γ-rays by Fermi-LAT (I.e. TCP J1734475-240942 and ASASSN-16ma) are bulge objects with unevolved companions. They distinguish themselves by showing a double-component optical light curve. The first component to develop is the fireball from freely expanding, ballistic-launched ejecta, with a time of passage through maximum that is strongly dependent on wavelength (˜1 d delay between the B and I bands). The second component, emerging simultaneously with the nova detection in γ-rays, evolves at a slower pace, its optical brightness being proportional to the γ-ray flux, and its passage through maximum not dependent on wavelength. The fact that γ-rays are detected at a flux level that differs by four times from novae at the distance of the bulge seems to suggest that γ-ray emission is not a widespread property of normal novae. We discuss the advantages offered by high-quality photometric observations collected with only one telescope (as opposed to data provided by a number of different instruments). We also observe the effects of the wavelength dependence of fireball expansion, the recombination in the flashed wind of a giant companion, the subtle presence of hiccups and plateaus, and the super-soft X-ray emission and its switch-off. Four programme novae (V2949 Oph, V3661 Oph, TCP J18102829-2729590 and ASASSN-16ma) have normal dwarf companions: V1534 Sco contains an M3 III giant, V1535 Sco a K-type giant and MASTER OT J010603.18-744715.8 a subgiant. We also comment briefly on the maximum absolute magnitude relation with decline time (MMRD).

DOE Office of Scientific and Technical Information (OSTI.GOV)

Aartsen, M. G.; Ackermann, M.; Adams, J.

We present an all-sky search for muon neutrinos produced during the prompt γ -ray emission of 1172 gamma-ray bursts (GRBs) with the IceCube Neutrino Observatory. The detection of these neutrinos would constitute evidence for ultra-high-energy cosmic-ray (UHECR) production in GRBs, as interactions between accelerated protons and the prompt γ -ray field would yield charged pions, which decay to neutrinos. A previously reported search for muon neutrino tracks from northern hemisphere GRBs has been extended to include three additional years of IceCube data. A search for such tracks from southern hemisphere GRBs in five years of IceCube data has been introducedmore » to enhance our sensitivity to the highest energy neutrinos. No significant correlation between neutrino events and observed GRBs is seen in the new data. Combining this result with previous muon neutrino track searches and a search for cascade signature events from all neutrino flavors, we obtain new constraints for single-zone fireball models of GRB neutrino and UHECR production.« less

Comets: Dirty snowballs or icy dirtballs

NASA Astrophysics Data System (ADS)

Keller, H. U.

1989-12-01

The observations of comet Halley show that the non-volatile (dust) component of the cometary nucleus has become more dominant if compared to the perception based on the icy conglomerate nucleus. The in-situ observations on the Giotto spacecraft revealed an excess of large dust particles that dominate the mass distribution. Even larger particles were derived from the attitude changes of the spacecraft bridging the gap to the cloud of particles observed by radar techniques. A dust to gas ratio larger than one was derived for comet Halley. The importance of dust for the structure of the nucleus is corroborated by the amount of particles and their lifetime in meteor streams. Fireballs show that large (meter size) objects separate from the nucleus and are stable enough to survive hundreds of orbital periods. From the various lines of evidence it is concluded that the structure of cometary nuclei is determined by the non-volatile component rather than by ice or snow. Laboratory models based on icy agglomerations do not seem realistic as nucleus analogs.

Photoacoustic Sounds from Meteors.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Spalding, Richard E.; Tencer, John; Sweatt, William C.

2015-03-01

High-speed photometric observations of meteor fireballs have shown that they often produce high-amplitude light oscillations with frequency components in the kHz range, and in some cases exhibit strong millisecond flares. We built a light source with similar characteristics and illuminated various materials in the laboratory, generating audible sounds. Models suggest that light oscillations and pulses can radiatively heat dielectric materials, which in turn conductively heats the surrounding air on millisecond timescales. The sound waves can be heard if the illuminated material is sufficiently close to the observer’s ears. The mechanism described herein may explain many reports of meteors that appearmore » to be audible while they are concurrently visible in the sky and too far away for sound to have propagated to the observer. This photoacoustic (PA) explanation provides an alternative to electrophonic (EP) sounds hypothesized to arise from electromagnetic coupling of plasma oscillation in the meteor wake to natural antennas in the vicinity of an observer.« less

Extending the Search for Muon Neutrinos Coincident with Gamma-Ray Bursts in IceCube Data

NASA Astrophysics Data System (ADS)

Aartsen, M. G.; Ackermann, M.; Adams, J.; Aguilar, J. A.; Ahlers, M.; Ahrens, M.; Samarai, I. Al; Altmann, D.; Andeen, K.; Anderson, T.; Ansseau, I.; Anton, G.; Archinger, M.; Argüelles, C.; Auffenberg, J.; Axani, S.; Bai, X.; Barwick, S. W.; Baum, V.; Bay, R.; Beatty, J. J.; Becker Tjus, J.; Becker, K.-H.; BenZvi, S.; Berley, D.; Bernardini, E.; Besson, D. Z.; Binder, G.; Bindig, D.; Blaufuss, E.; Blot, S.; Bohm, C.; Börner, M.; Bos, F.; Bose, D.; Böser, S.; Botner, O.; Braun, J.; Brayeur, L.; Bretz, H.-P.; Bron, S.; Burgman, A.; Carver, T.; Casier, M.; Cheung, E.; Chirkin, D.; Christov, A.; Clark, K.; Classen, L.; Coenders, S.; Collin, G. H.; Conrad, J. M.; Cowen, D. F.; Cross, R.; Day, M.; de André, J. P. A. M.; De Clercq, C.; del Pino Rosendo, E.; Dembinski, H.; De Ridder, S.; Desiati, P.; de Vries, K. D.; de Wasseige, G.; de With, M.; DeYoung, T.; Díaz-Vélez, J. C.; di Lorenzo, V.; Dujmovic, H.; Dumm, J. P.; Dunkman, M.; Eberhardt, B.; Ehrhardt, T.; Eichmann, B.; Eller, P.; Euler, S.; Evenson, P. A.; Fahey, S.; Fazely, A. R.; Feintzeig, J.; Felde, J.; Filimonov, K.; Finley, C.; Flis, S.; Fösig, C.-C.; Franckowiak, A.; Friedman, E.; Fuchs, T.; Gaisser, T. K.; Gallagher, J.; Gerhardt, L.; Ghorbani, K.; Giang, W.; Gladstone, L.; Glauch, T.; Glüsenkamp, T.; Goldschmidt, A.; Gonzalez, J. G.; Grant, D.; Griffith, Z.; Haack, C.; Hallgren, A.; Halzen, F.; Hansen, E.; Hansmann, T.; Hanson, K.; Hebecker, D.; Heereman, D.; Helbing, K.; Hellauer, R.; Hickford, S.; Hignight, J.; Hill, G. C.; Hoffman, K. D.; Hoffmann, R.; Hoshina, K.; Huang, F.; Huber, M.; Hultqvist, K.; In, S.; Ishihara, A.; Jacobi, E.; Japaridze, G. S.; Jeong, M.; Jero, K.; Jones, B. J. P.; Kang, W.; Kappes, A.; Karg, T.; Karle, A.; Katz, U.; Kauer, M.; Keivani, A.; Kelley, J. L.; Kheirandish, A.; Kim, J.; Kim, M.; Kintscher, T.; Kiryluk, J.; Kittler, T.; Klein, S. R.; Kohnen, G.; Koirala, R.; Kolanoski, H.; Konietz, R.; Köpke, L.; Kopper, C.; Kopper, S.; Koskinen, D. J.; Kowalski, M.; Krings, K.; Kroll, M.; Krückl, G.; Krüger, C.; Kunnen, J.; Kunwar, S.; Kurahashi, N.; Kuwabara, T.; Kyriacou, A.; Labare, M.; Lanfranchi, J. L.; Larson, M. J.; Lauber, F.; Lennarz, D.; Lesiak-Bzdak, M.; Leuermann, M.; Lu, L.; Lünemann, J.; Madsen, J.; Maggi, G.; Mahn, K. B. M.; Mancina, S.; Mandelartz, M.; Maruyama, R.; Mase, K.; Maunu, R.; McNally, F.; Meagher, K.; Medici, M.; Meier, M.; Menne, T.; Merino, G.; Meures, T.; Miarecki, S.; Micallef, J.; Momenté, G.; Montaruli, T.; Moulai, M.; Nahnhauer, R.; Naumann, U.; Neer, G.; Niederhausen, H.; Nowicki, S. C.; Nygren, D. R.; Obertacke Pollmann, A.; Olivas, A.; O'Murchadha, A.; Palczewski, T.; Pandya, H.; Pankova, D. V.; Peiffer, P.; Penek, Ö.; Pepper, J. A.; Pérez de los Heros, C.; Pieloth, D.; Pinat, E.; Price, P. B.; Przybylski, G. T.; Quinnan, M.; Raab, C.; Rädel, L.; Rameez, M.; Rawlins, K.; Reimann, R.; Relethford, B.; Relich, M.; Resconi, E.; Rhode, W.; Richman, M.; Riedel, B.; Robertson, S.; Rongen, M.; Rott, C.; Ruhe, T.; Ryckbosch, D.; Rysewyk, D.; Sabbatini, L.; Sanchez Herrera, S. E.; Sandrock, A.; Sandroos, J.; Sarkar, S.; Satalecka, K.; Schlunder, P.; Schmidt, T.; Schoenen, S.; Schöneberg, S.; Schumacher, L.; Seckel, D.; Seunarine, S.; Soldin, D.; Song, M.; Spiczak, G. M.; Spiering, C.; Stachurska, J.; Stanev, T.; Stasik, A.; Stettner, J.; Steuer, A.; Stezelberger, T.; Stokstad, R. G.; Stößl, A.; Ström, R.; Strotjohann, N. L.; Sullivan, G. W.; Sutherland, M.; Taavola, H.; Taboada, I.; Tatar, J.; Tenholt, F.; Ter-Antonyan, S.; Terliuk, A.; Tešić, G.; Tilav, S.; Toale, P. A.; Tobin, M. N.; Toscano, S.; Tosi, D.; Tselengidou, M.; Tung, C. F.; Turcati, A.; Unger, E.; Usner, M.; Vandenbroucke, J.; van Eijndhoven, N.; Vanheule, S.; van Rossem, M.; van Santen, J.; Vehring, M.; Voge, M.; Vogel, E.; Vraeghe, M.; Walck, C.; Wallace, A.; Wallraff, M.; Wandkowsky, N.; Waza, A.; Weaver, Ch.; Weiss, M. J.; Wendt, C.; Westerhoff, S.; Whelan, B. J.; Wickmann, S.; Wiebe, K.; Wiebusch, C. H.; Wille, L.; Williams, D. R.; Wills, L.; Wolf, M.; Wood, T. R.; Woolsey, E.; Woschnagg, K.; Xu, D. L.; Xu, X. W.; Xu, Y.; Yanez, J. P.; Yodh, G.; Yoshida, S.; Zoll, M.; IceCube Collaboration

2017-07-01

We present an all-sky search for muon neutrinos produced during the prompt γ-ray emission of 1172 gamma-ray bursts (GRBs) with the IceCube Neutrino Observatory. The detection of these neutrinos would constitute evidence for ultra-high-energy cosmic-ray (UHECR) production in GRBs, as interactions between accelerated protons and the prompt γ-ray field would yield charged pions, which decay to neutrinos. A previously reported search for muon neutrino tracks from northern hemisphere GRBs has been extended to include three additional years of IceCube data. A search for such tracks from southern hemisphere GRBs in five years of IceCube data has been introduced to enhance our sensitivity to the highest energy neutrinos. No significant correlation between neutrino events and observed GRBs is seen in the new data. Combining this result with previous muon neutrino track searches and a search for cascade signature events from all neutrino flavors, we obtain new constraints for single-zone fireball models of GRB neutrino and UHECR production.

Effect of the oxygen balance on ignition and detonation properties of liquid explosive mixtures

NASA Astrophysics Data System (ADS)

Genetier, M.; Osmont, A.; Baudin, G.

2014-05-01

The objective is to compare the ignition and detonation properties of various liquid high explosives having negative up to positive oxygen balance (OB): nitromethane (OB < 0), saccharose and hydrogen peroxide based mixture (quasi nil OB), hydrogen peroxide with more than 90% purity (OB > 0). The decomposition kinetic rates and the equations of state (EOS) for the liquid mixtures and detonation products (DP) are the input data for a detonation model. EOS are theoretically determined using the Woolfolk et al. universal liquid polar shock law and thermochemical computations for DP. The decomposition kinetic rate laws are determined to reproduce the shock to detonation transition for the mixtures submitted to planar plate impacts. Such a model is not sufficient to compute open field explosions. The aerial overpressure is well reproduced in the first few microseconds, however, after it becomes worse at large expansion of the fireball and the impulse is underestimated. The problem of the DP EOS alone is that it takes only the detonation into account, the secondary combustion DP - air is not considered. To solve this problem a secondary combustion model has been developed to take the OB effect into account. The detonation model has been validated on planar plate impact experiments. The secondary combustion parameters were deduced from thermochemical computations. The whole model has been used to predict the effects of the oxygen balance on open air blast effects of spherical charges.

Effect of the oxygen balance on ignition and detonation properties of liquid explosive mixtures

NASA Astrophysics Data System (ADS)

Genetier, Marc; Osmont, Antoine; Baudin, Gerard

2013-06-01

The objective is to compare ignition and detonation properties of various liquid high explosives having negative up to positive oxygen balance (OB): nitromethane (OB < 0), saccharose and hydrogen peroxide based mixture (quasi nil OB), hydrogen peroxide with more than 90% purity (OB > 0). The decomposition kinetic rates and the equations of state (EOS) for the liquid mixtures and detonation products (DP) are the input data for a detonation model. EOS are theoretically determined using the Woolfolk et al universal liquid polar shock law and thermochemical computations for DP. The decomposition kinetic rate laws are determined to reproduce the shock to detonation transition for the mixtures submitted to planar plate impacts. Such a model is not sufficient to compute open field explosions. The aerial overpressure is well reproduced in the first microseconds, however, after it becomes worse at large expansion of the fireball and the impulse is underestimated. The problem of the DP EOS alone is that it takes into account only the detonation, the secondary combustion DP - air being not considered. To solve this problem a secondary combustion model has been developed to take into account the OB effect. The detonation model has been validated on planar plate impact experiments. The secondary combustion parameters were deduced from thermochemical computations. The whole model has been used to predict the effects of the oxygen balance on open air blast effects of spherical charges.

Mid-Infrared Study of Samples from Several Stones from the Sutter's Mill Meteorite

NASA Technical Reports Server (NTRS)

Sandford, Scott; Nuevo, Michel; Flynn, George J.; Wirick, Sue

2013-01-01

On April 22, 2012, a fireball was observed over California and Nevada, and the falling fragments of the meteorite were detected by weather radar near small townships in the El Dorado County, California. Some of these stones were collected at Sutter s Mill, in the historic site where the California gold rush was initiated, giving the name to this meteorite. Thus far, 77 pieces of the meteorite have been collected, for a total mass of 943 g, with the biggest stone weighing 205 g [1].

No Expanding Fireball: Resolving the Recurrent Nova RS Ophiuchi with Infrared Interferometry

NASA Astrophysics Data System (ADS)

Monnier, J. D.; Barry, R. K.; Traub, W. A.; Lane, B. F.; Akeson, R. L.; Ragland, S.; Schuller, P. A.; Le Coroller, H.; Berger, J.-P.; Millan-Gabet, R.; Pedretti, E.; Schloerb, F. P.; Koresko, C.; Carleton, N. P.; Lacasse, M. G.; Kern, P.; Malbet, F.; Perraut, K.; Kuchner, M. J.; Muterspaugh, M. W.

2006-08-01

Following the recent outburst of the recurrent nova RS Oph on 2006 February 12, we measured its near-infrared size using the IOTA, Keck, and PTI Interferometers at multiple epochs. The characteristic size of ~3 mas hardly changed over the first 60 days of the outburst, ruling out currently popular models whereby the near-infrared emission arises from hot gas in the expanding shock. The emission was also found to be significantly asymmetric, evidenced by nonzero closure phases detected by IOTA. The physical interpretation of these data depends strongly on the adopted distance to RS Oph. Our data can be interpreted as the first direct detection of the underlying RS Oph binary, lending support to the recent ``reborn red giant'' models of Hachisu & Kato. However, this result hinges on an RS Oph distance of <~540 pc, in strong disagreement with the widely adopted distance of ~1.6 kpc. At the farther distance, our observations imply instead the existence of a nonexpanding, dense, and ionized circumbinary gaseous disk or reservoir responsible for the bulk of the near-infrared emission. Longer baseline infrared interferometry is uniquely suited to distinguish between these models and to ultimately determine the distance, binary orbit, and component masses for RS Oph, one of the closest known (candidate) Type 1a supernova progenitor systems.

QCD with Chiral Imbalance: models vs. lattice

NASA Astrophysics Data System (ADS)

Andrianov, Alexander; Andrianov, Vladimir; Espriu, Domenec

2017-03-01

In heavy ion collisions (HIC) at high energies there may appear new phases of matter which must be described by QCD. These phases may have different color and flavour symmetries associated with the constituents involved in collisions as well as various space-time symmetries of hadron matter. Properties of the QCD medium in such a matter can be approximately described, in particular, by a number of right-handed (RH) and left-handed (LH) light quarks. The chiral imbalance (ChI) is characterized by the difference between the numbers of RH and LH quarks and supposedly occurs in the fireball after HIC. Accordingly we have to introduce a quark chiral (axial) chemical potential which simulates a ChI emerging in such a phase. In this report we discuss the possibility of a phase with Local spatial Parity Breaking (LPB) in such an environment and outline conceivable signatures for the registration of LPB as well as the appearance of new states in the spectra of scalar, pseudoscalar and vector particles as a consequence of local ChI. The comparison of the results obtained in the effective QCD- motivated models with lattice data is also performed.

Consequence analysis in LPG installation using an integrated computer package.

PubMed

Ditali, S; Colombi, M; Moreschini, G; Senni, S

2000-01-07

This paper presents the prototype of the computer code, Atlantide, developed to assess the consequences associated with accidental events that can occur in a LPG storage plant. The characteristic of Atlantide is to be simple enough but at the same time adequate to cope with consequence analysis as required by Italian legislation in fulfilling the Seveso Directive. The application of Atlantide is appropriate for LPG storage/transferring installations. The models and correlations implemented in the code are relevant to flashing liquid releases, heavy gas dispersion and other typical phenomena such as BLEVE/Fireball. The computer code allows, on the basis of the operating/design characteristics, the study of the relevant accidental events from the evaluation of the release rate (liquid, gaseous and two-phase) in the unit involved, to the analysis of the subsequent evaporation and dispersion, up to the assessment of the final phenomena of fire and explosion. This is done taking as reference simplified Event Trees which describe the evolution of accidental scenarios, taking into account the most likely meteorological conditions, the different release situations and other features typical of a LPG installation. The limited input data required and the automatic linking between the single models, that are activated in a defined sequence, depending on the accidental event selected, minimize both the time required for the risk analysis and the possibility of errors. Models and equations implemented in Atlantide have been selected from public literature or in-house developed software and tailored with the aim to be easy to use and fast to run but, nevertheless, able to provide realistic simulation of the accidental event as well as reliable results, in terms of physical effects and hazardous areas. The results have been compared with those of other internationally recognized codes and with the criteria adopted by Italian authorities to verify the Safety Reports for LPG installations. A brief of the theoretical basis of each model implemented in Atlantide and an example of application are included in the paper.

FIREBall, CHaS, and the diffuse universe

NASA Astrophysics Data System (ADS)

Hamden, Erika Tobiason

The diffuse universe, consisting of baryons that have not yet collapsed into structures such as stars, galaxies, etc., has not been well studied. While the intergalactic and circumgalactic mediums (IGM & CGM) may contain 30-40% of the baryons in the universe, this low density gas is difficult to observe. Yet it is likely a key driver of the evolution of galaxies and star formation through cosmic time. The IGM provides a reservoir of gas that can be used for star formation, if it is able to accrete onto a galaxy. The CGM bridges the IGM and the galaxy itself, as a region of both inflows from the IGM and outflows from galactic star formation and feedback. The diffuse interstellar medium (ISM) gas and dust in the galaxy itself may also be affected by the CGM of the galaxy. Careful observations of the ISM of our own Galaxy may provide evidence of interaction with the CGM. These three regions of low density, the IGM, CGM, and ISM, are arbitrary divisions of a continuous flow of low density material into and out of galaxies. My thesis focuses on observations of this low density material using existing telescopes as well as on the development of technology and instruments that will increase the sensitivity of future missions. I used data from the Galaxy Evolution Explorer (GALEX) to create an all sky map of the diffuse Galactic far ultraviolet (FUV) background, probing the ISM of our own galaxy and comparing to other Galactic all sky maps. The FUV background is primarily due to dust scattered starlight from bright stars in the Galactic plane, and the changing intensity across the sky can be used to characterize dust scattering asymmetry and albedo. We measure a consistent low level non-scattered isotropic component to the diffuse FUV, which may be due in small part to an extragalactic component. There are also several regions of unusually high FUV intensity given other Galactic quantities. Such regions may be the location of interactions between Galactic super-bubbles and the CGM. Other ways of probing the CGM including direct detection via emission lines. I built a proto-type of the Circumgalactic Halpha Spectrograph (CHalphaS), a wide-field, low-cost, narrow-band integral field unit (IFU) that is designed to observe Halpha emission from the CGM of nearby, low-z galaxies. This proto-type has had two recent science runs, with preliminary data on several nearby galaxies. Additional probes of the CGM are emission lines in the rest ultra-violet. These include OVI, Lyalpha, CIV, SiIII, CIII, CII, FeII, and MgII. Such lines are accessible for low redshift galaxies in the space UV, historically a difficult wavelength range in which to work due in part to low efficiency of the available detectors. I have worked with NASA's Jet Propulsion Laboratory to develop advanced anti-reflection (AR) coatings for use on thinned, delta-doped charge coupled device (CCD) detectors. These detectors have achieved world record quantum efficiency (QE) at UV wavelengths (>50% between 130 nm and 300nm), with the potential for even greater QE with a more complex coating. One of these AR coated detectors will be used on the Faint Intergalactic Redshifted Emission Balloon (FIREBall-2), a balloon-born UV spectrograph designed to observe the CGM at 205 nm via redshifted Lyalpha (at z=0.7), CIV (at z=0.3), and OVI (at z=1.0). FIREBall-2 will launch in the fall of 2015.

The Fall and Recovery of the Tagish Lake Meteorite

DOE Office of Scientific and Technical Information (OSTI.GOV)

Hildebrand, Alan R.; McCausland, Phil J.; Brown, Peter G.

2006-03-01

The Tagish Lake C2 (ungrouped) carbonaceous chondrite fall of January 18, 2000 delivered >10 kg of one of the most primitive and physically weak meteorites yet studied. In this paper we report the detailed circumstances of the fall and the recovery of all documented Tagish Lake fragments. We also provide measurements of bulk physical properties (mass, grain and bulk density), bulk triple oxygen-isotope ratios, and short-lived cosmogenic radionuclides counts for several fragments. Ground eyewitnesses and recorded observations of the Tagish Lake fireball event provide a refined estimate of the fireball trajectory, and hence, its pre-atmospheric orbit. From its calculated orbitmore » and its similarity to the remotely-sensed properties of the D and P-class asteroids, the Tagish Lake carbonaceous chondrite represents these outer belt asteroids, and is not of cometary origin. The bulk oxygen-isotope compositions reported here are among the highest known for meteorites. These data plot just below the Terrestrial Fractionation Line, following a trend similar to the CM meteorite mixing line. The bulk density of the Tagish Lake material (1.66 ±0.02 g/cm3) is the same, within error, as the total bulk densities of many C-class and especially D- and P-class asteroids. The high microporosity of Tagish Lake samples (~40%) provides an obvious candidate material for the composition of low bulk density primitive asteroids such as Phobos, Deimos and the P-class binary 87 Sylvia, without requiring a substantial contribution from macroporosity in the form of ice, thick regolith or “rubble pile” assemblages with large interior voids.« less

An Extraordinary Outburst of the Magnetar Swift J1822.3-1606

NASA Astrophysics Data System (ADS)

Chakraborty, Manoneeta; Göğüş, Ersin

2015-08-01

The 2011 outburst of Swift J1822.3-1606 was extraordinary; periodic modulations at the spin period of the underlying neutron star were clearly visible, remarkably similar to what is observed during the decaying tail of magnetar giant flares. We investigated the temporal characteristics of X-ray emission during the early phases of the outburst. We performed a periodicity search with the spectral hardness ratio (HR) and found a coherent signal near the spin period of the neutron star, but with a lag of about 3 radians. Therefore, the HR is strongly anti-correlated with the X-ray intensity, which is also seen in the giant flares. We studied the time evolution of the pulse profile and found that it evolves from a complex morphology to a much simpler shape within about a month. Pulse profile simplification also takes place during the giant flares, but on a much shorter timescale of about a few minutes. We found that the amount of energy emitted during the first 25 days of the outburst is comparable to what was detected in minutes during the decaying tail of giant flares. Based on these similarities, we suggest that the triggering mechanisms of the giant flares and the magnetar outbursts are likely the same. We propose that the trapped fireball that develops in the magnetosphere at the onset of the outburst radiates away efficiently in minutes in magnetars exhibiting giant flares, while in other magnetars, such as Swift J1822.3-1606, the efficiency of radiation of the fireball is not as high and, therefore, lasts much longer.

An Empirical Fitting Method to Type Ia Supernova Light Curves. III. A Three-parameter Relationship: Peak Magnitude, Rise Time, and Photospheric Velocity

NASA Astrophysics Data System (ADS)

Zheng, WeiKang; Kelly, Patrick L.; Filippenko, Alexei V.

2018-05-01

We examine the relationship between three parameters of Type Ia supernovae (SNe Ia): peak magnitude, rise time, and photospheric velocity at the time of peak brightness. The peak magnitude is corrected for extinction using an estimate determined from MLCS2k2 fitting. The rise time is measured from the well-observed B-band light curve with the first detection at least 1 mag fainter than the peak magnitude, and the photospheric velocity is measured from the strong absorption feature of Si II λ6355 at the time of peak brightness. We model the relationship among these three parameters using an expanding fireball with two assumptions: (a) the optical emission is approximately that of a blackbody, and (b) the photospheric temperatures of all SNe Ia are the same at the time of peak brightness. We compare the precision of the distance residuals inferred using this physically motivated model against those from the empirical Phillips relation and the MLCS2k2 method for 47 low-redshift SNe Ia (0.005 < z < 0.04) and find comparable scatter. However, SNe Ia in our sample with higher velocities are inferred to be intrinsically fainter. Eliminating the high-velocity SNe and applying a more stringent extinction cut to obtain a “low-v golden sample” of 22 SNe, we obtain significantly reduced scatter of 0.108 ± 0.018 mag in the new relation, better than those of the Phillips relation and the MLCS2k2 method. For 250 km s‑1 of residual peculiar motions, we find 68% and 95% upper limits on the intrinsic scatter of 0.07 and 0.10 mag, respectively.

Cooling Timescales and Temporal Structure of Gamma-Ray Bursts

NASA Astrophysics Data System (ADS)

Sari, Re'em; Narayan, Ramesh; Piran, Tsvi

1996-12-01

A leading mechanism for producing cosmological gamma-ray bursts (GRBs) is via ultrarelativistic particles in an expanding fireball. The kinetic energy of the particles is converted into thermal energy in two shocks, a forward shock and a reverse shock, when the outward flowing particles encounter the interstellar medium. The thermal energy is then radiated via synchrotron emission and Comptonization. We estimate the synchrotron cooling timescale of the shocked material in the forward and reverse shocks for electrons of various Lorentz factors, focusing in particular on those electrons whose radiation falls within the energy detection range of the BATSE detectors. We find that in order to produce the rapid variability observed in most bursts, the energy density of the magnetic field in the shocked material must be greater than about 1% of the thermal energy density. In addition, the electrons must be nearly in equipartition with the protons, since otherwise we do not have reasonable radiative efficiencies of GRBs. Inverse Compton scattering can increase the cooling rate of the relevant electrons, but the Comptonized emission itself is never within the BATSE range. These arguments allow us to pinpoint the conditions within the radiating regions in GRBs and to determine the important radiation processes. In addition, they provide a plausible explanation for several observations. The model predicts that the duty cycle of intensity variations in GRB light curves should be nearly independent of burst duration and should scale inversely as the square root of the observed photon energy. Both correlations are in agreement with observations. The model also provides a plausible explanation for the bimodal distribution of burst durations. There is no explanation, however, for the presence of a characteristic break energy in GRB spectra.

Low-energy Electrons in Gamma-Ray Burst Afterglow Models

NASA Astrophysics Data System (ADS)

Jóhannesson, Guđlaugur; Björnsson, Gunnlaugur

2018-05-01

Observations of gamma-ray burst (GRB) afterglows have long provided the most detailed information about the origin of this spectacular phenomenon. The model that is most commonly used to extract physical properties of the event from the observations is the relativistic fireball model, where ejected material moving at relativistic speeds creates a shock wave when it interacts with the surrounding medium. Electrons are accelerated in the shock wave, generating the observed synchrotron emission through interactions with the magnetic field in the downstream medium. It is usually assumed that the accelerated electrons follow a simple power-law distribution in energy between specific energy boundaries, and that no electron exists outside these boundaries. This Letter explores the consequences of adding a low-energy power-law segment to the electron distribution with energy that contributes insignificantly to the total energy budget of the distribution. The low-energy electrons have a significant impact on the radio emission, providing synchrotron absorption and emission at these long wavelengths. Shorter wavelengths are affected through the normalization of the distribution. The new model is used to analyze the light curves of GRB 990510, and the resulting parameters are compared to a model without the extra electrons. The quality of the fit and the best-fit parameters are significantly affected by the additional model component. The new component is in one case found to strongly affect the X-ray light curves, showing how changes to the model at radio frequencies can affect light curves at other frequencies through changes in best-fit model parameters.

Experimental Overview of the Search for Chiral Effects at RHIC

NASA Astrophysics Data System (ADS)

Wang, Gang

2017-01-01

In high-energy heavy-ion collisions, various novel transport phenomena in local chiral domains result from the interplay of quantum anomalies with magnetic field and vorticity, and could survive the expansion of the fireball and be detected in experiments. Among these phenomena are the chiral magnetic effect, the chiral vortical effect and the chiral magnetic wave, the experimental searches for which have aroused extensive interest. This review will describe the current status of experimental studies at Relativistic Heavy Ion Collider at BNL, and outline the future work in experiment needed to eliminate the existing uncertainties in the interpretation of the data.

Extremely Bright GRB 160625B with Multiple Emission Episodes: Evidence for Long-term Ejecta Evolution

DOE Office of Scientific and Technical Information (OSTI.GOV)

Lü, Hou-Jun; Lü, Jing; Zhong, Shu-Qing

GRB 160625B is an extremely bright GRB with three distinct emission episodes. By analyzing its data observed with the Gamma-Ray Burst Monitor (GBM) and Large Area Telescope (LAT) on board the Fermi mission, we find that a multicolor blackbody (mBB) model can be used to fit very well the spectra of the initial short episode (Episode I) within the hypothesis of photosphere emission of a fireball model. The time-resolved spectra of its main episode (Episode II), which was detected with both GBM and LAT after a long quiescent stage (∼180 s) following the initial episode, can be fitted with amore » model comprising an mBB component plus a cutoff power-law (CPL) component. This GRB was detected again in the GBM and LAT bands with a long extended emission (Episode III) after a quiescent period of ∼300 s. The spectrum of Episode III is adequately fitted with CPL plus single power-law models, and no mBB component is required. These features may imply that the emission of the three episodes are dominated by distinct physics processes, i.e., Episode I is possible from the cocoon emission surrounding the relativistic jet, Episode II may be from photosphere emission and internal shock of the relativistic jet, and Episode III is contributed by internal and external shocks of the relativistic jet. On the other hand, both X-ray and optical afterglows are consistent with the standard external shocks model.« less

Extremely Bright GRB 160625B with Multiple Emission Episodes: Evidence for Long-term Ejecta Evolution

NASA Astrophysics Data System (ADS)

Lü, Hou-Jun; Lü, Jing; Zhong, Shu-Qing; Huang, Xiao-Li; Zhang, Hai-Ming; Lan, Lin; Xie, Wei; Lu, Rui-Jing; Liang, En-Wei

2017-11-01

GRB 160625B is an extremely bright GRB with three distinct emission episodes. By analyzing its data observed with the Gamma-Ray Burst Monitor (GBM) and Large Area Telescope (LAT) on board the Fermi mission, we find that a multicolor blackbody (mBB) model can be used to fit very well the spectra of the initial short episode (Episode I) within the hypothesis of photosphere emission of a fireball model. The time-resolved spectra of its main episode (Episode II), which was detected with both GBM and LAT after a long quiescent stage (˜180 s) following the initial episode, can be fitted with a model comprising an mBB component plus a cutoff power-law (CPL) component. This GRB was detected again in the GBM and LAT bands with a long extended emission (Episode III) after a quiescent period of ˜300 s. The spectrum of Episode III is adequately fitted with CPL plus single power-law models, and no mBB component is required. These features may imply that the emission of the three episodes are dominated by distinct physics processes, I.e., Episode I is possible from the cocoon emission surrounding the relativistic jet, Episode II may be from photosphere emission and internal shock of the relativistic jet, and Episode III is contributed by internal and external shocks of the relativistic jet. On the other hand, both X-ray and optical afterglows are consistent with the standard external shocks model.

Storage Rings in the Sky: Gamma Ray Bursts and Galactic Gravitational Collapse Stored Energy

NASA Astrophysics Data System (ADS)

Greyber, H. D.

2004-05-01

The recent discovery of almost 100% polarization of the prompt gamma ray emission from GRB021206, (1), confirms my 44 year old ``Strong" Magnetic Field" model (SMF) for galactic dynamics. In SMF, Storage Ring particles were accelerated long ago during the original gravitational collapse of the pregalactic/prequasar plasma cloud that is permeated by an almost uniform primordial magnetic field (2,3) The enormous, intense, slender, relativistic, stable, completely coherent Storage Ring stores a very small fraction of the huge galactic gravitational collapse energy in an almost radiationless state, unless disturbed. The concept of an Astrophysical Storage Ring was introduced by me in l961. At first it was to explain galactic structure, but soon it proved useful to explain active galactic nuclei (AGN) and the dynamics of quasar/AGN jets. AGN and galactic morphology, energetics and dynamics vary as the ratio of magnetic energy to rotational energy in the particular object. Gamma ray bursts (GRB) are due simply to a ``rock". i.e. a white dwarf, ordinary star, neutron sstar, asteroid, planet, etc. falling rapidly through the Storage Ring and being almost instantly vaporized into a hot plasma fireball, causing an electromagnetic shower (2) Then the fireball speeds into the huge organized magnetic field surrounding the current ring, thus generating very highly polarized prompt gamma ray emission (as seen in GRB021206) from the synchrotron radiation process. The timing fits the GRB observations nicely. For instance, a ``rock" racing at 1000 kilometers per second across a 20,000 km. path in the beam would produce a twenty second burst. Other times, a target might track across a short chord for a short burst. Space missions have shown that often typical currents in space plasmas are made up of slender filaments. Thus the puzzling less than one millisecond spikes observed in some GRB are simply describing the structure of that particular ring current at that particular time. 1. W. Coburn and S.E. Boggs, Nature, 423, 415, (2003) 2. H. D. Greyber in a book, After the Dark Ages: When Galaxies Were Young, eds. S.S. Holt and E. P. Smith, AIP Conference Proceedings 470, 388-396. (1998) 3. H. D. Greyber in a Space Telescope Science Institute Report: Poster Papers from their 2001 Spring Symposium, ``The Dark Universe: Matter, Energy and Gravity," ed. Mario Livio, published March 2003, (34-39)

Earth Impact Effects Program: Estimating the Regional Environmental Consequences of Impacts On Earth

NASA Astrophysics Data System (ADS)

Collins, G. S.; Melosh, H. J.; Marcus, R. A.

2009-12-01

The Earth Impact Effects Program (www.lpl.arizona.edu/impacteffects) is a popular web-based calculator for estimating the regional environmental consequences of a comet or asteroid impact on Earth. It is widely used, both by inquisitive members of the public as an educational device and by scientists as a simple research tool. It applies a variety of scaling laws, based on theory, nuclear explosion test data, observations from terrestrial and extraterrestrial craters and the results of small-scale impact experiments and numerical modelling, to quantify the principal hazards that might affect the people, buildings and landscape in the vicinity of an impact. The program requires six inputs: impactor diameter, impactor density, impact velocity prior to atmospheric entry, impact angle, and the target type (sedimentary rock, crystalline rock, or a water layer above rock), as well as the distance from the impact at which the environmental effects are to be calculated. The program includes simple algorithms for estimating the fate of the impactor during atmospheric traverse, the thermal radiation emitted by the impact plume (fireball) and the intensity of seismic shaking. The program also approximates various dimensions of the impact crater and ejecta deposit, as well as estimating the severity of the air blast in both crater-forming and airburst impacts. We illustrate the strengths and limitations of the program by comparing its predictions (where possible) against known impacts, such as Carancas, Peru (2007); Tunguska, Siberia (1908); Barringer (Meteor) crater, Arizona (ca 49 ka). These tests demonstrate that, while adequate for large impactors, the simple approximation of atmospheric entry in the original program does not properly account for the disruption and dispersal of small impactors as they traverse Earth's atmosphere. We describe recent improvements to the calculator to better describe atmospheric entry of small meteors; the consequences of oceanic impacts; and the recurrance interval between impacts of a given size. In addition, we assess the potential regional hazard of hypothetical impact scenarios of different scales. Our simple calculator suggests that the most wide-reaching regional hazard is seismic shaking: both ejecta-deposit thickness and airblast pressure decay much more rapidly with distance than seismic ground motion. Close to the impact site the most severe hazard is from thermal radiation; however, the curvature of the Earth implies that distant localities are shielded from direct thermal radiation because the fireball is below the horizon.

Constraints on the explosion mechanism and progenitors of Type Ia supernovae

NASA Astrophysics Data System (ADS)

Dessart, Luc; Blondin, Stéphane; Hillier, D. John; Khokhlov, Alexei

2014-06-01

Observations of SN 2011fe at early times reveal an evolution analogous to a fireball model of constant colour. In contrast, our unmixed delayed detonations of Chandrasekhar-mass white dwarfs (DDC series) exhibit a faster brightening concomitant with a shift in colour to the blue. In this paper, we study the origin of these discrepancies. We find that strong chemical mixing largely resolves the photometric mismatch at early times, but it leads to an enhanced line broadening that contrasts, for example, with the markedly narrow Si II 6355 Å line of SN 2011fe. We also explore an alternative configuration with pulsational-delayed detonations (PDDEL model series). Because of the pulsation, PDDEL models retain more unburnt carbon, have little mass at high velocity, and have a much hotter outer ejecta after the explosion. The pulsation does not influence the inner ejecta, so PDDEL and DDC models exhibit similar radiative properties beyond maximum. However, at early times, PDDEL models show bluer optical colours and a higher luminosity, even for weak mixing. Their early-time radiation is derived primarily from the initial shock-deposited energy in the outer ejecta rather than radioactive-decay heating. Furthermore, PDDEL models show short-lived C II lines, reminiscent of SN 2013dy. They typically exhibit lines that are weaker, narrower, and of near-constant width, reminiscent of SN 2011fe. In addition to multidimensional effects, varying configurations for such `pulsations' offer a source of spectral diversity amongst Type Ia supernovae (SNe Ia). PDDEL and DDC models also provide one explanation for low- and high-velocity-gradient SNe Ia.

A sputnik IV saga

NASA Astrophysics Data System (ADS)

Lundquist, Charles A.

2009-12-01

The Sputnik IV launch occurred on May 15, 1960. On May 19, an attempt to deorbit a 'space cabin' failed and the cabin went into a higher orbit. The orbit of the cabin was monitored and Moonwatch volunteer satellite tracking teams were alerted to watch for the vehicle demise. On September 5, 1962, several team members from Milwaukee, Wisconsin made observations starting at 4:49 a.m. of a fireball following the predicted orbit of Sputnik IV. Requests went out to report any objects found under the fireball path. An early morning police patrol in Manitowoc had noticed a metal object on a street and had moved it to the curb. Later the officers recovered the object and had it dropped off at the Milwaukee Journal. The Moonwarch team got the object and reported the situation to Moonwatch Headquarters at the Smithsonian Astrophysical Observatory. A team member flew to Cambridge with the object. It was a solid, 9.49 kg piece of steel with a slag-like layer attached to it. Subsequent analyses showed that it contained radioactive nuclei produced by cosmic ray exposure in space. The scientists at the Observatory quickly recognized that measurements of its induced radioactivity could serve as a calibration for similar measurements of recently fallen nickel-iron meteorites. Concurrently, the Observatory directorate informed government agencies that a fragment from Sputnik IV had been recovered. Coincidently, a debate in the UN Committee on Peaceful Uses of Outer Space involved the issue of liability for damage caused by falling satellite fragments. On September 12, the Observatory delivered the bulk of the fragment to the US Delegation to the UN. Two days later, the fragment was used by US Ambassador Francis Plimpton as an exhibit that the time had come to agree on liability for damage from satellite debris. He offered the Sputnik IV fragment to USSR Ambassador P.D. Morozov, who refused the offer. On October 23, Drs. Alla Massevitch and E.K. Federov of the USSR visited the Observatory. They were shown the Sputnik IV fragment. Measurements on the fragment were reported at the American Geophysical Union meeting on December 28, 1962. Early in January, 1963, the Soviet Embassy told the State Department that the USSR wished to accept the remaining fragment. On January 5, 1963 it was picked up by the Soviet Embassy. This four-month saga dramatically illustrated the need for international agreements on satellite debris issues.

A time-dependent search for high-energy neutrinos from bright GRBs with ANTARES

NASA Astrophysics Data System (ADS)

Celli, Silvia

2017-03-01

Astrophysical point-like neutrino sources, like Gamma-Ray Bursts (GRBs), are one of the main targets for neutrino telescopes, since they are among the best candidates for Ultra-High-Energy Cosmic Ray (UHECR) acceleration. From the interaction between the accelerated protons and the intense radiation fields of the source jet, charged mesons are produced, which then decay into neutrinos. The methods and the results of a search for high-energy neutrinos in spatial and temporal correlation with the detected gamma-ray emission are presented for four bright GRBs observed between 2008 and 2013: a time-dependent analysis, optimised for each flare of the selected bursts, is performed to predict detailed neutrino spectra. The internal shock scenario of the fireball model is investigated, relying on the neutrino spectra computed through the numerical code NeuCosmA. The analysis is optimized on a per burst basis, through the maximization of the signal discovery probability. Since no events in ANTARES data passed the optimised cuts, 90% C.L. upper limits are derived on the expected neutrino fluences.

A link between prompt optical and prompt gamma-ray emission in gamma-ray bursts.

PubMed

Vestrand, W T; Wozniak, P R; Wren, J A; Fenimore, E E; Sakamoto, T; White, R R; Casperson, D; Davis, H; Evans, S; Galassi, M; McGowan, K E; Schier, J A; Asa, J W; Barthelmy, S D; Cummings, J R; Gehrels, N; Hullinger, D; Krimm, H A; Markwardt, C B; McLean, K; Palmer, D; Parsons, A; Tueller, J

2005-05-12

The prompt optical emission that arrives with the gamma-rays from a cosmic gamma-ray burst (GRB) is a signature of the engine powering the burst, the properties of the ultra-relativistic ejecta of the explosion, and the ejecta's interactions with the surroundings. Until now, only GRB 990123 had been detected at optical wavelengths during the burst phase. Its prompt optical emission was variable and uncorrelated with the prompt gamma-ray emission, suggesting that the optical emission was generated by a reverse shock arising from the ejecta's collision with surrounding material. Here we report prompt optical emission from GRB 041219a. It is variable and correlated with the prompt gamma-rays, indicating a common origin for the optical light and the gamma-rays. Within the context of the standard fireball model of GRBs, we attribute this new optical component to internal shocks driven into the burst ejecta by variations of the inner engine. The correlated optical emission is a direct probe of the jet isolated from the medium. The timing of the uncorrelated optical emission is strongly dependent on the nature of the medium.

AN EXTRAORDINARY OUTBURST OF THE MAGNETAR SWIFT J1822.3–1606

DOE Office of Scientific and Technical Information (OSTI.GOV)

Chakraborty, Manoneeta; Göğüş, Ersin

2015-08-20

The 2011 outburst of Swift J1822.3–1606 was extraordinary; periodic modulations at the spin period of the underlying neutron star were clearly visible, remarkably similar to what is observed during the decaying tail of magnetar giant flares. We investigated the temporal characteristics of X-ray emission during the early phases of the outburst. We performed a periodicity search with the spectral hardness ratio (HR) and found a coherent signal near the spin period of the neutron star, but with a lag of about 3 radians. Therefore, the HR is strongly anti-correlated with the X-ray intensity, which is also seen in the giantmore » flares. We studied the time evolution of the pulse profile and found that it evolves from a complex morphology to a much simpler shape within about a month. Pulse profile simplification also takes place during the giant flares, but on a much shorter timescale of about a few minutes. We found that the amount of energy emitted during the first 25 days of the outburst is comparable to what was detected in minutes during the decaying tail of giant flares. Based on these similarities, we suggest that the triggering mechanisms of the giant flares and the magnetar outbursts are likely the same. We propose that the trapped fireball that develops in the magnetosphere at the onset of the outburst radiates away efficiently in minutes in magnetars exhibiting giant flares, while in other magnetars, such as Swift J1822.3–1606, the efficiency of radiation of the fireball is not as high and, therefore, lasts much longer.« less

The σ-Capricornids complex of near-Earth objects

NASA Astrophysics Data System (ADS)

Babadzhanov, P. B.; Kokhirova, G. I.; Khamroev, U. Kh.

2015-04-01

The Earth-crossing asteroids 2008BO16, 2011EC41, and 2013CT36 have very similar orbits according to the Southworth and Hawkins DSH criterion. Their orbits are additionally classified as comet-like based on using the Tisserand parameter which is a standard tool used to distinction between asteroids and comets. The orbital evolution research shows that they cross the Earth's orbit four times over one cycle of the perihelion argument variations. Consequently, a meteoroid stream, possibly associated with them, may produce four meteor showers. Theoretic parameters of the predicted showers were calculated and identified with the observable nighttime σ-Capricornids and χ-Sagittariids, and daytime χ-Capricornids and Capricornids-Sagittariids meteor showers. The similar comet-like orbits and the linkage with the same meteoroid stream producing four active showers provide strong evidence that these asteroids have a common cometary origin. Earlier, it was demonstrated that the Earth-crossing asteroids (2101) Adonis and 1995CS, being a potentially hazardous asteroid (PHA), were recognized as dormant comets because of their linkage with the σ-Capricornids meteoroid stream. Thus, a conclusion was made, that either the considered objects are large pieces of the Adonis, or all five objects are extinct or dormant fragments of a larger comet that was the parent body of the σ-Capricornids meteoroid stream, and whose break-up occurred several tens of thousands years ago. During 2010-2011, three σ-Capricornids fireballs were captured by the Tajikistan fireball network. Taking into account the observations in Canada and the USA, the dynamic and physical properties of the σ-Capricornid meteoroids were identified. According to the estimated meteoroids bulk density a non-homogeneous compound of the σ-Capricornids shower comet-progenitor was suggested.

GRB 060605: multi-wavelength analysis of the first GRB observed using integral field spectroscopy

NASA Astrophysics Data System (ADS)

Ferrero, P.; Klose, S.; Kann, D. A.; Savaglio, S.; Schulze, S.; Palazzi, E.; Maiorano, E.; Böhm, P.; Grupe, D.; Oates, S. R.; Sánchez, S. F.; Amati, L.; Greiner, J.; Hjorth, J.; Malesani, D.; Barthelmy, S. D.; Gorosabel, J.; Masetti, N.; Roth, M. M.

2009-04-01

The long and relatively faint gamma-ray burst GRB 060605 detected by Swift/BAT lasted about 20 s. Its afterglow could be observed with Swift/XRT for nearly 1 day, while Swift/UVOT could detect the afterglow during the first 6 h after the event. Here, we report on integral field spectroscopy of its afterglow performed with PMAS/PPak mounted at the Calar Alto 3.5 m telescope. In addition, we report on a detailed analysis of XRT and UVOT data and on the results of deep late-time VLT observations that reveal the GRB host galaxy. We find that the burst occurred at a redshift of z = 3.773, possibly associated with a faint, RC = 26.4 ± 0.3 host. Based on the optical and X-ray data, we deduce information on the SED of the afterglow, the position of the cooling frequency in the SED, the nature of the circumburst environment, its collimation factor, and its energetics. We find that the GRB fireball was expanding into a constant-density medium and that the explosion was collimated with a narrow half-opening angle of about 2.4 degrees. The initial Lorentz factor of the fireball was about 250; however, its beaming-corrected energy release in the gamma-ray band was comparably low. The optical, X-ray afterglow, on the other hand, was rather luminous. Finally, we find that the data are consistent within the error bars with an achromatic evolution of the afterglow during the suspected jet break time at about 0.27 days after the burst. Based on observations collected at the German-Spanish Calar Alto Observatory in Spain (Programme F06-3.5-055) and at the European Southern Observatory, La Silla and Paranal, Chile (ESO Programme 177.D-0591).

Transformation of a Virgo Cluster dwarf irregular galaxy by ram pressure stripping: IC3418 and its fireballs

DOE Office of Scientific and Technical Information (OSTI.GOV)

Kenney, Jeffrey D. P.; Geha, Marla; Jáchym, Pavel

We present optical imaging and spectroscopy and H I imaging of the Virgo Cluster galaxy IC 3418, which is likely a 'smoking gun' example of the transformation of a dwarf irregular into a dwarf elliptical galaxy by ram pressure stripping. IC 3418 has a spectacular 17 kpc length UV-bright tail comprised of knots, head-tail, and linear stellar features. The only Hα emission arises from a few H II regions in the tail, the brightest of which are at the heads of head-tail UV sources whose tails point toward the galaxy ('fireballs'). Several of the elongated tail sources have Hα peaksmore » outwardly offset by ∼80-150 pc from the UV peaks, suggesting that gas clumps continue to accelerate through ram pressure, leaving behind streams of newly formed stars which have decoupled from the gas. Absorption line strengths, measured from Keck DEIMOS spectra, together with UV colors, show star formation stopped 300 ± 100 Myr ago in the main body, and a strong starburst occurred prior to quenching. While neither Hα nor H I emission are detected in the main body of the galaxy, we have detected 4 × 10{sup 7} M {sub ☉} of H I from the tail with the Very Large Array. The velocities of tail H II regions, measured from Keck LRIS spectra, extend only a small fraction of the way to the cluster velocity, suggesting that star formation does not happen in more distant parts of the tail. Stars in the outer tail have velocities exceeding the escape speed, but some in the inner tail should fall back into the galaxy, forming halo streams.« less

Shock Initiated Reactions of Reactive Multiphase Blast Explosives

NASA Astrophysics Data System (ADS)

Wilson, Dennis; Granier, John; Johnson, Richard; Littrell, Donald

2015-06-01

This paper describes a new class of reactive multiphase blast explosives (RMBX) and characterization of their blast characteristics. These RMBXs are non-ideal explosive compositions of perfluoropolyether (PFPE), nano aluminum, and a micron-size high-density reactive metal - Tantalum, Zirconium, or Zinc in mass loadings of 66 to 83 percent. Unlike high explosives, these PFPE-metal compositions release energy via a fast self-oxidized combustion wave (rather than a true self-sustaining detonation) that is shock dependent, and can be overdriven to control energy release rate. The term ``reactive multiphase blast'' refers to the post-dispersion blast behavior: multiphase in that there are a gas phase that imparts pressure and a solid (particulate) phase that imparts momentum; and reactive in that the hot metal particles react with atmospheric oxygen and the explosive gas products to give an extended pressure pulse. The RMBX formulations were tested in two spherical core-shell geometries - an RMBX shell exploded by a high explosive core, and an RMBX core imploded by a high explosive shell. The fireball and blast characteristics were compared to a C-4 baseline charge.

Shock initiated reactions of reactive multi-phase blast explosives

NASA Astrophysics Data System (ADS)

Wilson, Dennis; Granier, John; Johnson, Richard; Littrell, Donald

2017-01-01

This paper describes a new class of non-ideal explosive compositions made of perfluoropolyether (PFPE), nanoaluminum, and a micron-size, high mass density, reactive metal. Unlike high explosives, these compositions release energy via a fast self-oxidized combustion wave rather than a true self-sustaining detonation. Their reaction rates are shock dependent and they can be overdriven to change their energy release rate. These compositions are fuel rich and have an extended aerobic energy release phase. The term "reactive multiphase blast" refers to the post-dispersion blast behavior: multiphase in that there are a gas phase that imparts pressure and a solid (particulate) phase that imparts energy and momentum [1]; and reactive in that the hot metal particles react with atmospheric oxygen and the explosive gas products to give an extended pressure pulse. Tantalum-based RMBX formulations were tested in two spherical core-shell configurations - an RMBX shell exploded by a high explosive core, and an RMBX core imploded by a high explosive shell. The fireball and blast characteristics were compared to a C-4 baseline charge.

Near-Earth object 2012XJ112 as a source of bright bolides of achondritic nature

NASA Astrophysics Data System (ADS)

Madiedo, José M.; Trigo-Rodríguez, Josep M.; Williams, Iwan P.; Konovalova, Natalia; Ortiz, José L.; Castro-Tirado, Alberto J.; Pastor, Sensi; de los Reyes, José A.; Cabrera-Caño, Jesús

2014-04-01

We analyse the likely link between the recently discovered near-Earth object 2012XJ112 and a bright fireball observed over the south of Spain on 2012 December 27. The bolide, with an absolute magnitude of -9 ± 1, was simultaneously imaged during the morning twilight from two meteor stations operated by the SPanish Meteor Network (SPMN). It was also observed by several casual witnesses. The emission spectrum produced during the ablation of the meteoroid in the atmosphere was also recorded. From its analysis, the chemical nature of this particle was inferred. Although our orbital association software identified several potential parent bodies for this meteoroid, the analysis of the evolution of the orbital elements performed with the MERCURY 6 symplectic integrator supports the idea that NEO 2012XJ112 is the source of this meteoroid. The implications of this potential association are discussed here. In particular, the meteoroid bulk chemistry is consistent with a basaltic achondrite, and this emphasizes the importance to deduce from future Earth approaches the reflectance spectrum and taxonomic nature of 2012XJ112.

Cosmic dust in the atmosphere and in the interplanetary space at 1 AU today and in the early solar system

NASA Technical Reports Server (NTRS)

Fechtig, H.

1973-01-01

A description of techniques used in recent experiments to detect and analyze cosmic dust and micrometeorites is given and the results both from the study of lunar crater statistics and from in situ measurements are reviewed. The results from lunar crater statistics show an agreement with the results obtained from in situ measurements in interplanetary space and derived from zodiacal light measurements. The near earth results show an enhancement in the flux numbers. This can be caused either by secondary lunar debris or by disintegration of low density fireballs in the outer atmosphere.

Dynamical evolution of spectator systems produced in ultrarelativistic heavy-ion collisions

NASA Astrophysics Data System (ADS)

Mazurek, K.; Szczurek, A.; Schmitt, C.; Nadtochy, P. N.

2018-02-01

In peripheral heavy-ion collisions at ultrarelativistic energies, usually only parts of the colliding nuclei effectively interact with each other. In the overlapping zone, a fireball or quark-gluon plasma is produced. The excitation energy of the heavy remnant can range from a few tens to several hundreds of MeV, depending on the impact parameter. The decay of these excited spectators is investigated in this work for the first time within a dynamical approach based on the multidimensional stochastic Langevin equation. The potential of this exploratory work to understand the connection between electromagnetic fields generated by the heavy spectators and measured pion distributions is discussed.

The secret of the Soviet hydrogen bomb

NASA Astrophysics Data System (ADS)

Wellerstein, Alex; Geist, Edward

2017-11-01

Was the first Soviet thermonuclear device really a step in the wrong direction? No bomb design has been as much maligned or otherwise disparaged as the first Soviet thermonuclear weapon. Detonated in August 1953, the bomb, officially tested under the name RDS-6s but usually known as Sloika or "layer cake" (the name Andrei Sakharov coined for it), was nothing to sneeze at. Shown in Figure 1 and able to be dropped from aircraft, it released the explosive equivalent, or yield, of almost half a megaton of TNT. The result was a blazing fireball with 20 times the power of the bomb that leveled Nagasaki, Japan.

Fluctuations and QCD phase structure

NASA Astrophysics Data System (ADS)

Kitazawa, Masakiyo

2014-11-01

Fluctuation observables are invaluable tools in relativistic heavy ion collisions to investigate primordial thermodynamics of fireballs. Active experimental measurements have been performed at RHIC and LHC. In particular, interesting experimental results were recently reported on the electric charge fluctuation at ALICE and on the higher order cumulants at STAR, which show nontrivial behaviors reflecting non-hadronic and/or non-thermal physics. We argue that more detailed understanding on these observables are needed to use them effectively in the analysis of QCD phase structure. We suggest that the measurement of various cumulants of conserved charges including baryon number and their rapidity window dependence will provide important information needed for making progress in this subject.

The Tunguska comet or the great Siberian mystery explosion of 1908

USGS Publications Warehouse

Spall, H.

1986-01-01

The boat disintegrates, hurling men and animals into the freezing river. The farmer's shirt is scorched off his back; the tramp is blown off his feet, his ports and pans scattering like shrapnel. One of the trappers standing in the doorway of the trading post is knocked unconscious, overcome by the searing heat; the tents of the nomads are torn loose, the men and dogs inside being rolled over the ground like leaves in a gale. All that remain of the reindeer are charred carcasses. The forest has been turning into a crackling inferno, and a black fireball rises into the air. 

KSC-99padig002

NASA Image and Video Library

1999-06-24

KENNEDY SPACE CENTER, FLA. -- A fireball erupts under the Boeing Delta II rocket, amid clouds of smoke and steam, as it lifts off from Launch Pad 17A, Cape Canaveral Air Station, at 11:44 a.m. EDT. The shadow of a photographer (right) is caught watching the perfect launch. The rocket carries NASA's Far Ultraviolet Spectroscopic Explorer (FUSE) satellite, which was developed to investigate the origin and evolution of the lightest elements in the universe hydrogen and deuterium. In addition, the FUSE satellite will examine the forces and process involved in the evolution of the galaxies, stars and planetary systems by investigating light in the far ultraviolet portion of the electromagnetic spectrum

On meteor-generated infrasound. [propagation characteristics during entry into earth atmosphere

NASA Technical Reports Server (NTRS)

Revelle, D. O.

1976-01-01

The characteristics of generation and propagation of infrasonic pressure waves excited during meteor entry into the earth's atmosphere are studied. Existing line source blast wave theory is applied to infrasonic airwave data from four bright fire-balls. It is shown that the strong shock behavior of the blast wave is confined to a cylinderical region with a radius proportional to the product of the meteor Mach number and its diameter. A description of the wave form far from the source is provided. Infrasonic data reported elsewhere are analyzed. All the results should be considered as preliminary, and additional work is under way to refine the estimates obtained.

VARIATION OF SPECTRAL AND TIMING PROPERTIES IN THE EXTENDED BURST TAILS FROM THE MAGNETAR 4U 0142+61

DOE Office of Scientific and Technical Information (OSTI.GOV)

Chakraborty, Manoneeta; Göğüş, Ersin; Muş, Sinem Şaşmaz

2016-03-10

Extended emission episodes with an intensity above the preburst level are observed following magnetar bursts from a number of soft gamma repeaters and anomalous X-ray pulsars (AXPs). Such extended tail emissions were observed following two events detected from AXP 4U 0142+61. We investigated in detail the evolution of spectral and temporal properties during these two tail segments using Rossi X-ray Timing Explorer/Proportional Counter Array observations, and report distinct variations in the spectral and temporal behavior throughout the tails. In particular, in both cases we observed a sudden enhancement of the pulsation amplitude in conjunction with bursts and a smooth declinemore » of X-ray emission (cooling) during the tail. We suggest that an inefficiently radiating trapped fireball formed during the burst, which can heat up the stellar surface, is able to explain the tail properties and its energetics. We also present the episodic detection of absorption and emission features during tails. One possible mechanism that has been proposed to give rise to such spectral lines is the proton/ion cyclotron resonance process, which has been suggested as offering a valuable tool in probing the complex magnetic field of magnetars.« less

BEAM ON TARGET MODEL Produces All Gamma Ray Burst Phenomena Including Afterglow

NASA Astrophysics Data System (ADS)

Greyber, H.

2000-12-01

While one must applaud the splendid research by L. Piro et al and L. Amati et al reported in SCIENCE recently, one must question, as M. Rees and S. Woolsey have done, their conclusion that a ``supranova model" is the only explanation for these new X-ray observations. In fact L. Piro was quoted as saying, ``Our data helps rule out the scenario where two neutron stars or black holes collide. We think GRBs result from something similar to a supernova explosion, but much more powerful." A relatively unknown physical model for GRBs, Greyber's Beam On Target model (BOT), dating back to the first CGRO observations, can plausibly explain the iron emission lines observed for GRB991216, and also the mass of the dense medium within a light-day of the GRB being roughly equivalent to at least one-tenth solar mass, as well as the initial shedding of material followed by the GRB event. When a galaxy forms under gravitational collapse in the presence of a primordial magnetic field, Mestel and Strittmatter demonstrated that, for finite Ohmic diffusion, a growing equatorial current loop is formed. Even if this stable ``Storage Ring" has only 10exp-9 of the total energy released during a typical galaxy's formation, the relativistic beam can possess 10exp58 ergs. The GRB ``fireball" occurs when a target star races across the powerful beam, blowing off target material as a hot, rapidly expanding plasma cloud, simulating an explosion. Since currents in space are known to be sometimes filamentary, sharp millisecond spikes can be expected in some GRBs. Proton and alpha particle nuclear reactions produce a gamma ray beam. Beam particles impinging on denser cloud material create an electromagnetic shower, producing X-ray, optical and radio radiation. Since the Storage Ring has an intense magnetic field around it, synchrotron radiation is expected. The beam, striking a highly evolved massive target star, produces the iron emission lines. H. D. Greyber, in ``After the Dark Ages:When Galaxies Were Young", A.I.P. Confer. Proc. no.470, 388, (1999) L. Mestel & P. Strittmatter, Mon. Not. Royal Astron. Society, 137, 95, (1967)

Asteroid families spin and shape models to be supported by the ProjectSoft robotic observatory

NASA Astrophysics Data System (ADS)

Brož, M.; Ďurech, J.; Hanuš, J.; Lehký, M.

2014-07-01

In our recent work (Hanuš et al. 2013), we studied dynamics of asteroid families constrained by the distribution of pole latitudes vs semimajor axis. The model contained the following ingredients: (i) the Yarkovsky semimajor-axis drift; (ii) secular spin evolution due to the YORP effect; (iii) collisional re-orientations; (iv) a simple treatment of spin-orbit resonances; and (v) of mass shedding. We suggest to use a different complementary approach, based on distribution functions of shape parameters. Based on ˜1000 old and new convex-hull shape models, we construct the distributions of suitable quantities (ellipticity, normalized facet areas, etc.) and we discuss a significance of differences among asteroid populations. We check for outlier points which may then serve as a possible identification of (large) interlopers among ''real'' family members. This has also implications for SPH models of asteroid disruptions which can be possibly further constrained by the shape models of resulting fragments. Up to now, the observed size-frequency distribution and velocity field were used as constraints, sometimes allowing for a removal of interlopers (Michel et al. 2011). We also outline an ongoing construction of the ProjectSoft robotic observatory called ''Blue Eye 600'', which will support our efforts to complete the sample of shapes for a substantial fraction of (large) family members. Dense photometry will be targeted in such a way to maximize a possibility to derive a new pole/shape model. Other possible applications of the observatory include: (i) fast resolved observations of fireballs (thanks to a fast-motion capability, tens of degrees per second); or, (ii) an automatic survey of a particular population of objects (main-belt and near-Earth asteroids, variable stars, novae etc.)

The Meteoritical Quincentennial: The Stone of Ensisheim 1492-1992

NASA Astrophysics Data System (ADS)

Marvin, U. B.

1992-07-01

This year marks the 500th anniversary of the fall of a meteorite at Ensisheim in Alsace. In at least two respects this event is unique in the history of meteoritics. First, this was the earliest witnessed meteorite fall in the West from which pieces are preserved. Second, it is the only meteorite of which a continuous five-century public record exists in manuscripts and books. Beginning with newsheets printed in 1492, writings about this event illuminate the evolution of ideas from a 15th century belief that stones from the sky were of miraculous origin, to an 18th century conviction that stones do not fall from the sky, to our present view that they fall in abundance, originating in interplanetary space (Marvin, 1992). This paper will highlight certain previously unexamined aspects of the story and address problems inherent in historical analysis. Unusable Maps. The fall of the stone was heralded by an explosion which, according to Sebastian Brant (1492), was heard along the valleys of the Danube, Neckar, Aare, Ill, and Rhine and in the alpine cantons of Schwyz and Uri. Contemporary maps, such as that published in The Nuremberg Chronicle of 1493, so distorted the regional geography that a fireball trajectory cannot be reconstructed on them. On modern maps, however, the areas Brant listed stretch about 150 km to the southeast of Ensisheim, a distance well within the range of sounds reported from other exploding fireballs. Newton (1891) and Marvin (1992) worked out possible trajectories that could account for the sound being heard in all named localities. This suggests that, far from exaggerating distances for dramatic effect, Brant's description may well have been accurate. If so, he compiled his information from word-of-mouth reports without reference to the rudimentary maps available in his time. The Language of Wonder. A document mounted beside the stone in the Ensisheim church stated that learned men did not know what it was: it must be supernatural, a wonder of God, because never before had such a thing been heard, or seen, or written about. Von der Muhll (1961) and others have asked how such statements could be made when Pliny the Elder wrote of fallen stones as early as the 1st century A.D., and Heynlin de Lapide, at nearby Basel, was translating Pliny's works at the time of the fall. However, expressions such as "never before heard, seen, or written about," spiced the reports of Medieval travelers struggling to describe the marvels of far-off lands. In this instance, the phrases described a marvel that burst upon the people of the upper Rhineland in the course of their daily routines. In truth, nothing ever written could have prepared them for the incandescent fireball, resounding explosion, and the black stone that plunged to Earth at Ensisheim. Unimaginative Eyewitnesses. A boy saw the stone fall and a crowd dug it out of a wheat field. In 1800, the chemist, Charles Barthold, rejected the eyewitness story and concluded that the stone was a common type of rock that could have washed down from a mountainside. In 1803, after meteorites, including the Ensisheim stone, had become accepted as authentic natural phenomena, Joseph Izarn wrote that the boy's testimony should be believed because ignorant persons like him have no imagination and could not possible invent tales about stones from the sky. Izarn's opinion was not eccentric; numerous writings show that it reflected a centuries-old tradition of placing special value on observations by unschooled witnesses. References: Brant S. (1492) Flugblatt, J. von Ople, Basel, 1 p. Izarn J. (1803) Lithologie Atmospherique, Delalain Fils, Paris, 422 pp. Marvin U. B. (1992) Meteoritics 27, 28-72. Newton H. A. (1891) Comptes Rendus Acad. Sci. 113, 234. Muhll Th. von der (1975) Donnerstein von Ensisheim, Birkhauser Verlag, Basel, 42 pp. Schedel H. (1493) Nuremberg Chronicle, A. Korberger, Nuremberg, 299 pp.

The Innisfree meteorite: Dynamical history of the orbit - Possible family of meteor bodies

NASA Astrophysics Data System (ADS)

Galibina, I. V.; Terent'eva, A. K.

1987-09-01

Evolution of the Innisfree meteorite orbit caused by secular perturbations is studied over the time interval of 500000 yrs (from the current epoch backwards). Calculations are made by the Gauss-Halphen-Gorjatschew method taking into account perturbations from the four outer planets - Jupiter, Saturn, Uranus and Neptune. In the above mentioned time interval the meteorite orbit has undergone no essential transformations. The Innisfree orbit intersected in 91 cases the Earth orbit and in 94 - the Mars orbit. A system of small and large meteor bodies (producing ordinary meteors and fireballs) which may be genetically related to the Innisfree meteorite has been found, i.e. there probably exists an Innisfree family of meteor bodies.

Propylene Glycol Poisoning From Excess Whiskey Ingestion: A Case of High Osmolal Gap Metabolic Acidosis.

PubMed

Cunningham, Courtney A; Ku, Kevin; Sue, Gloria R

2015-01-01

In this report, we describe a case of high anion gap metabolic acidosis with a significant osmolal gap attributed to the ingestion of liquor containing propylene glycol. Recently, several reports have characterized severe lactic acidosis occurring in the setting of iatrogenic unintentional overdosing of medications that use propylene glycol as a diluent, including lorazepam and diazepam. To date, no studies have explored potential effects of excess propylene glycol in the setting of alcohol intoxication. Our patient endorsed drinking large volumes of cinnamon flavored whiskey, which was likely Fireball Cinnamon Whisky. To our knowledge, this is the first case of propylene glycol toxicity from an intentional ingestion of liquor containing propylene glycol.

Propylene Glycol Poisoning From Excess Whiskey Ingestion

PubMed Central

Ku, Kevin; Sue, Gloria R.

2015-01-01

In this report, we describe a case of high anion gap metabolic acidosis with a significant osmolal gap attributed to the ingestion of liquor containing propylene glycol. Recently, several reports have characterized severe lactic acidosis occurring in the setting of iatrogenic unintentional overdosing of medications that use propylene glycol as a diluent, including lorazepam and diazepam. To date, no studies have explored potential effects of excess propylene glycol in the setting of alcohol intoxication. Our patient endorsed drinking large volumes of cinnamon flavored whiskey, which was likely Fireball Cinnamon Whisky. To our knowledge, this is the first case of propylene glycol toxicity from an intentional ingestion of liquor containing propylene glycol. PMID:26904700

Experimental results on chiral magnetic and vortical effects

DOE PAGES

Wang, Gang; Wen, Liwen

2017-01-12

Various novel transport phenomena in chiral systems result from the interplay of quantum anomalies with magnetic field and vorticity in high-energy heavy-ion collisions and could survive the expansion of the fireball and be detected in experiments. Among them are the chiral magnetic effect, the chiral vortical effect, and the chiral magnetic wave, the experimental searches for which have aroused extensive interest. As a result, the goal of this review is to describe the current status of experimental studies at Relativistic Heavy-Ion Collider at BNL and the Large Hadron Collider at CERN and to outline the future work in experiment neededmore » to eliminate the existing uncertainties in the interpretation of the data.« less

Photographic fireball networks

NASA Technical Reports Server (NTRS)

Ceplecha, Z.

1987-01-01

Long term radar observations of any meteor shower yield good data for a study of the features of its cross section structure in detail. The hourly rates of meteor echoes represent usually the basic data from which shower characteristics are derived. Unfortunately, the hourly rate does not depend only on the activity of the shower in question but also on the position of the shower radiant, on the mutual radiant antenna position, and on the parameters of the radar system. It is known that the knowledge of the response function of the radar is necessary for good interpretation of the hourly echo counts. A method of long term radar shower data analysis is discussed along with preliminary results.

FreeTure: A Free software to capTure meteors for FRIPON

NASA Astrophysics Data System (ADS)

Audureau, Yoan; Marmo, Chiara; Bouley, Sylvain; Kwon, Min-Kyung; Colas, François; Vaubaillon, Jérémie; Birlan, Mirel; Zanda, Brigitte; Vernazza, Pierre; Caminade, Stephane; Gattecceca, Jérôme

2014-02-01

The Fireball Recovery and Interplanetary Observation Network (FRIPON) is a French project started in 2014 which will monitor the sky, using 100 all-sky cameras to detect meteors and to retrieve related meteorites on the ground. There are several detection software all around. Some of them are proprietary. Also, some of them are hardware dependent. We present here the open source software for meteor detection to be installed on the FRIPON network's stations. The software will run on Linux with gigabit Ethernet cameras and we plan to make it cross platform. This paper is focused on the meteor detection method used for the pipeline development and the present capabilities.

Time-resolved photometry of Io and Europa in the course of impacts of A and Q secondary nuclei of D/comet Shoemaker-Levy 9.

NASA Astrophysics Data System (ADS)

Churyumov, K. I.; Kleshchonok, V. V.

Observations of the Jupiter satellites within the program for investigation of the comet D/SL-9 Jupiter collision were held with the electrophotometer installed on the AZT-14 (D = 0.48 m) telescope at the Lisnyki Station of the Kiev University Astronomical Observatory. Circumstances for observations did not reveal changes in the satellite brightnesses which could be linked with the reflection of light of a fireball in the Jupiter atmosphere, with the exception of the A and Q2 nucleus fall down. Here, three events that can be tied with the outburst during the nuclei fall down were found out.

Detection of the Phoenicids meteor shower in 2014

NASA Astrophysics Data System (ADS)

Sato, Mikiya; Watanabe, Jun-ichi; Tsuchiya, Chie; Moorhead, Althea V.; Moser, Danielle E.; Brown, Peter G.; Cooke, William J.

2017-09-01

An appearance of the Phoenicids meteor shower was predicted in 2014 by using a dust trail simulation of an outburst of 1956. We detected Phoenicids meteors on December 2 through multiple observation methods. The NASA All Sky Fireball Network and the Southern Ontario Meteor Network detected five meteors of Phoenicids via video observation. The Canadian Meteor Orbit Radar (CMOR) found fourteen candidate meteors, eight of which were confirmed as Phoenicids. The observed radiant point is consistent with that of our model predictions. In addition to the above observations, a visual observation was carried out by the Japanese team near the Observatorio del Roque de los Muchachos (ORM) of Instituto de Astrofisica de Canarias (IAC) in La Palma Island. The obtained zenithal hourly rate (ZHR) was 16.4±4.9. The maximum ZHR was roughly estimated to be between 20 and 30, which indicates that the cometary activity of parent object 289P/Blanpain in the early 20th century was only about one fifth or one eighth as high as its activity in the late 18th and early 19th century. Accordingly, it seems to be the case that 289P/Blanpain is gradually transforming from a comet to a dormant object.

The spatial distribution patterns of condensed phase post-blast explosive residues formed during detonation.

PubMed

Abdul-Karim, Nadia; Blackman, Christopher S; Gill, Philip P; Karu, Kersti

2016-10-05

The continued usage of explosive devices, as well as the ever growing threat of 'dirty' bombs necessitates a comprehensive understanding of particle dispersal during detonation events in order to develop effectual methods for targeting explosive and/or additive remediation efforts. Herein, the distribution of explosive analytes from controlled detonations of aluminised ammonium nitrate and an RDX-based explosive composition were established by systematically sampling sites positioned around each firing. This is the first experimental study to produce evidence that the post-blast residue mass can distribute according to an approximate inverse-square law model, while also demonstrating for the first time that distribution trends can vary depending on individual analytes. Furthermore, by incorporating blast-wave overpressure measurements, high-speed imaging for fireball volume recordings, and monitoring of environmental conditions, it was determined that the principle factor affecting all analyte dispersals was the wind direction, with other factors affecting specific analytes to varying degrees. The dispersal mechanism for explosive residue is primarily the smoke cloud, a finding which in itself has wider impacts on the environment and fundamental detonation theory. Copyright © 2016 The Authors. Published by Elsevier B.V. All rights reserved.

Tying Extinction Events to Comet Impacts Large Enough to Cause an Extinction in Themselves.

NASA Astrophysics Data System (ADS)

Burgener, J. A.

2017-12-01

Comets over 35 km in size impacting Earth will create vast fireballs, and will boil large parts of the oceans, causing extinction events in themselves. They will likely provide enough energy to shatter the crust and eject large masses of molten rock from the mantle, forming traps. Traps are clearly associated with extinction events, but are not expected to cause extinctions. While Chicxulub is recognized to have occurred at the time of the K/Pg boundary layer, it is recognized as being too small in itself to cause an extinction. Are large comet impacts likely? The Kuiper belt has more than 100,000 objects over 100 km in diameter and millions over 10 km. Typically their orbits are less stable than asteroid orbits due to large bodies such as Pluto moving through the belt. The asteroid belt has only 10,000 objects over 10 km diameter. Comet impacts should be more common than asteroid impacts, yet none of the recognized craters are expected to be due to comets. There are many features on Earth that are poorly explained by Plate Tectonics that would be well explained if they were considered to be comet impact craters. A consideration of the Black Sea and the Tarim Basin will show that impact interpretations are a better fit than the present Plate Tectonics' explanations. Both basins are in the midst of mountain building from plate collisions, but are themselves not being disturbed by the plate collisions. Both are ellipses angled at 23.4 degrees to the equator, matching the angle expected for a low angle impact from a comet traveling in the ecliptic. Both are too deep at 15 km depths to be standard oceans (typically 5 km deep). Both are filled with horizontal layers of sediments, undisturbed by the mountain building occurring at the edges. Both have thin crusts and high Moho boundaries. Both have thin lithosphere. Yet both show GPS movement of the land around them moving away from them, as though they were much thicker and stronger than the surrounding land. The Tarim Basin is 1000 km X 380 km, and the Black Sea is in two sections each 600 km X 350 km. They would require impactors in the range of 35 - 40 km diameter, hitting at impact angles of 20 - 30 degrees. The fireballs from such impacts would cover nearly half the planet, which would be large enough in themselves to cause extinctions.

Meteorite Sterlitamak -- A New Crater Forming Fall

NASA Astrophysics Data System (ADS)

Petaev, M. I.

1992-07-01

The Sterlitamak meteorite fell on May 17, 1990 at 23h20m local time (17h20m GMT) and formed a crater in a field 20 km westward of the town of Sterlitamak (Petaev et al., 1991). Many witnesses in South Bashkiria saw a very bright fireball (up to -5 magnitude) moving from south to north at a ~45 degree angle to the horizon. Witnesses located ~2 km from the crater observed the fireball glowing right up to the time of impact, after which several explosions were heard. The crater was found on May 19. From witnesses' reports, the fresh crater was 4.5-5 m in depth and had sheer walls ~3 m in height below which was a conical talus surface with a hole in the center. The crater itself was surrounded by a continuous rim 60-70 cm in thickness and by radial ejecta. Our field team arrived at the crater on May 23, six days after its formation. We found the crater in rather good condition except for partial collapse of the rim, material from which had filled in the crater up to ~3 m from the surface. The western wall of the crater was composed of well-preserved brown loam with shale- like parting dipping 25-30 degrees away from the crater center. A large slip block of autogenic breccia was observed along the eastern crater wall. An allogenic breccia composed of a mixture of brown loam and black soil was traced to the depth of ~5 m from the surface. Outside the rim, the crater ejecta formed an asymmetric continuous blanket and distinct radial rays. The southern rays were shorter and thicker than the northern and eastern rays. About 2 dozen meteorite fragments, from several grams to several hundred grams in weight, were recovered in the crater vicinity. A search for other meteorite fragments or individuals at distances up to 1 km southward from the crater was unsuccessful. Two partly encrusted fragments (3 and 6 kg) with clear Widmanstatten pattern on a broken surface were found at a depth of ~8 m during crater excavation. In May of 1991 a 315-kg partly fragmented individual was recovered at a depth of ~12 m. This sample is a 50 x 45 x 28 cm block with front, rear and two adjoining lateral surfaces covered by regmaglypts and thick (~0.5 mm) fusion crust. The other two surfaces are very rough, contain no regmaglypts, and have a thinner fusion crust. The preimpact shape of the meteorite may be approximately modeled as a slab ~100 x 100 x 28 cm. An estimate of the projectile mass was made based on the crater dimensions. From the relationships between crater diameter and projectile mass determined for the Sikhote-Alin craters, the impact mass of the Sterlitamak meteorite is estimated at ~1 ton (Petaev, 1992). A separate estimate, based on cratering energy, yields a total mass of ~1.5 tons (Ivanov, Petaev, 1992). A comparison of the estimated projectile mass and the weight and morphology of the individual recovered suggests a fragmentation of the projectile in the atmosphere and the formation of the crater by the impact of an agglomeration of individuals. The other fragments of the projectile are still in the crater. REFERENCES Ivanov B.A., Petaev M.I. (1992) Lunar Planet. Sci. (abstract), 23, 573-574. Petaev M.I. (1992) Astron. Vestnik, #4, in press (in Russian) (English translation is named Solar System Research). Petaev M.I., Kisarev Yu.L., Mustafin Sh.A., Shakurov R.K., Pavlov A.V., Ivanov B.A. (1991) Lunar Planet. Sci. (abstract), 22, 1059-1060

The afterglow and elliptical host galaxy of the short gamma-ray burst GRB 050724.

PubMed

Berger, E; Price, P A; Cenko, S B; Gal-Yam, A; Soderberg, A M; Kasliwal, M; Leonard, D C; Cameron, P B; Frail, D A; Kulkarni, S R; Murphy, D C; Krzeminski, W; Piran, T; Lee, B L; Roth, K C; Moon, D-S; Fox, D B; Harrison, F A; Persson, S E; Schmidt, B P; Penprase, B E; Rich, J; Peterson, B A; Cowie, L L

2005-12-15

Despite a rich phenomenology, gamma-ray bursts (GRBs) are divided into two classes based on their duration and spectral hardness--the long-soft and the short-hard bursts. The discovery of afterglow emission from long GRBs was a watershed event, pinpointing their origin to star-forming galaxies, and hence the death of massive stars, and indicating an energy release of about 10(51) erg. While theoretical arguments suggest that short GRBs are produced in the coalescence of binary compact objects (neutron stars or black holes), the progenitors, energetics and environments of these events remain elusive despite recent localizations. Here we report the discovery of the first radio afterglow from the short burst GRB 050724, which unambiguously associates it with an elliptical galaxy at a redshift z = 0.257. We show that the burst is powered by the same relativistic fireball mechanism as long GRBs, with the ejecta possibly collimated in jets, but that the total energy release is 10-1,000 times smaller. More importantly, the nature of the host galaxy demonstrates that short GRBs arise from an old (> 1 Gyr) stellar population, strengthening earlier suggestions and providing support for coalescing compact object binaries as the progenitors.

TWA Flight 800, explosion airblast unexplained

NASA Astrophysics Data System (ADS)

Reed, Jack W.

2003-10-01

TWA Flight 800 disintegrated off Long Island, NY, on 16 July 1996. Immediate reports from other flyers described what appeared as attacking missiles. Search for terrorists began quickly, with over 1000 FBI agents to collect debris, interview eyewitnesses, and analyze sightings to give a missile launch point. They found no evidence of criminal attack, and turned investigations over to the NTSB to find some accidental cause. The ``empty'' central fuel tank was determined to be the likely explosion source. On the other hand, early witnesses reported a ``loud'' bang after seeing a great fireball fall from the sky, but at 15 km or greater range, they saw and heard two different events. This acoustic discrepancy has not been adequately investigated. When finally released, FBI reports from more than 200 ``ear-witnesses'' give similar observations. Their loudness reports confirm that at least a ton of TNT equivalent explosion had occurred. NASA acousticians engaged by NTSB, however, through spectral analysis techniques for sonic booms, concluded that a 10-kg TNT explosion, from detonating fuel tank vapors, could be heard on Long Island. Evidence for a much larger yield is presented here, but its form remains a mystery.

Spatial Characterization of Polycyclic Aromatic Hydrocarbons in 2008 TC3 Samples

NASA Astrophysics Data System (ADS)

Sabbah, Hassan; Morrow, A.; Zare, R. N.; Jenniskens, P.

2009-09-01

Hassan Sabbah1, Amy L. Morrow1, Richard N. Zare1 and Petrus Jenniskens2 1Stanford University, Stanford, California 94305, 2 SETI Institute, Carl Sagan Center, 515 North Whisman Road, Mountain View, California 94043, USA. In October 2006 a small asteroid (2-3 meters) was observed in outer space. On October 7, 2008, it entered the Earth's atmosphere creating a fireball over Northern Sudan. Some 280 meteorites were collected by the University of Khartoum. In order to explore the existence of organic materials, specifically polycyclic aromatic hydrocarbons (PAHs), we applied two-step laser desorption laser ionization mass spectrometry (L2MS) to some selected fragments. This technique consists of desorbing with a pulsed infrared laser beam the solid materials into a gaseous phase with no fragmentation followed by resonance enhanced multiphoton ionization to analyze the PAH content. L2MS was already applied to an array of extraterrestrial objects including interplanetary dust particles IDPs, carbonaceous chondrites and comet coma particles. Moreover, spatial resolution of PAHs in 2008 TC3 samples was achieved to explore the heterogeneity within individual fragments. The results of these studies and their contribution to understanding the formation of this asteroid will be discussed.

Distributions of spin/shape parameters of asteroid families and targeted photometry by ProjectSoft robotic observatory

NASA Astrophysics Data System (ADS)

Broz, Miroslav; Durech, Josef; Hanus, Josef; Lehky, Martin

2014-11-01

In our recent work (Hanus et al. 2013) we studied dynamics of asteroid families constrained by the distribution of pole latitudes vs semimajor axis. The model contained the following ingredients: (i) the Yarkovsky semimajor-axis drift, (ii) secular spin evolution due to the YORP effect, (iii) collisional reorientations, (iv) a simple treatment of spin-orbit resonances and (v) of mass shedding.We suggest to use a different complementary approach, based on distribution functions of shape parameters. Based on ~1000 old and new convex-hull shape models, we construct the distributions of suitable quantities (ellipticity, normalized facet areas, etc.) and we discuss differences among asteroid populations. We also check for outlier points which may then serve as a possible identification of (large) interlopers among "real" family members.This has also implications for SPH models of asteroid disruptions which can be possibly further constrained by the shape models of resulting fragments. Up to now, the observed size-frequency distribution and velocity field were used as constraints, sometimes allowing for a removal of interlopers (Michel et al. 2011).We also describe ongoing observations by the ProjectSoft robotic observatory called "Blue Eye 600", which supports our efforts to complete the sample of shapes for a substantial fraction of (large) family members. Dense photometry is targeted in such a way to maximize a possibility to derive a new pole/shape model.Other possible applications of the observatory include: (i) fast resolved observations of fireballs (thanks to a fast-motion capability, up to 90 degrees/second), or (ii) an automatic survey of a particular population of objects (MBAs, NEAs, variable stars, novae etc.)Acknowledgements: This work was supported by the Technology Agency of the Czech Republic (grant no. TA03011171) and Czech Science Foundation (grant no. 13-01308S).

OT1_mhuang01_1: GRB Afterglow Photometry with Herschel Infrared Cameras

NASA Astrophysics Data System (ADS)

Huang, M.

2010-07-01

GRB Afterglow Photometry with Herschel Infrared Cameras (GRAPHICS) Gamma-ray bursts (GRBs) are the most luminous explosions in the universe. It has been difficult to obtain a full spectral picture of the phenomena in the short period when GRBs become ``alive'', i.e. when they generate bursts in Gamma-ray and produce afterglows in other wavelengths. Between NIR (12micron) and submillimeter (850micron) there lies nearly two orders of magnitude of spectral range where GRB afterglows have never been detected. Herschel is unique in its cutting edge sensitivity, efficiency, and readiness in FIR observations, and is capable of detecting GRB afterglows. Observing GRB afterglows with Herschel would greatly enrich our understanding of GRB physics and conditions of the Universe in early epochs. We propose Target of Opportunity studies using the SPIRE and PACS instruments of Herschel to observe 3 bright GRB afterglows, each within a few hours to a few tens of days after burst. We will make follow-up observations after the initial one to photometrically measure GRB light curves and IR SEDs. We will make ground optical observations to compliment Herschel data, and have the the GRB community informed. Observing the forward shock peak in the FIR light curve and compare it (both the flux and time) with those in the optical and radio bands would give a unambiguous test to the fireball model, and offer a direct measurement of the density profile of the circumburst material. Catching the short-lived reverse shock emission and measure its magnitude would lead to constraints on some important parameters of the GRB ejecta and address the unknown composition of GRBs, baryonic vs. magnetic.

The January 7, 2015, superbolide over Romania and structural diversity of meter-sized asteroids

NASA Astrophysics Data System (ADS)

Borovička, Jiří; Spurný, Pavel; Grigore, Valentin I.; Svoreň, Ján

2017-09-01

Superbolides, i.e. extremely bright meteors produced by entries of meter-sized bodies into terrestrial atmosphere, are rare events. We present here detailed analysis of a superbolide, which occurred over Romania on January 7, 2015. The trajectory, velocity, and orbit were determined using two all-sky photographs from a station of the European Fireball Network (EN) in Slovakia and five casual video records from Romania, which were carefully calibrated. Bolide light curve was measured by EN radiometers. We found that the entry speed was 27.76±0.19 km s-1, significantly lower than reported by US Government sensors. The orbit was asteroidal with low inclination and aphelion inside Jupiter's orbit. The atmospheric behavior was, however, not typical for an asteroidal body. The peak brightness of absolute magnitude of -21 was reached at a quite large height of 42.8 km and the brightness then decreased quickly. The bolide almost disappeared at a height of 38.7 km, leaving just a stationary luminous trail visible for several seconds. Only one small fragment continued until the height of 36 km. Brief meteorite searches were unsuccessful. The modeling of the light curve revealed that the body of initial mass of about 4500 kg remained almost intact until the dynamic pressure reached 0.9 MPa but it was then quickly disintegrated into many tiny fragments and dust under 1-3 MPa. A comparison was made with three other superbolides for which we have radiometric light curves: ordinary chondrite fall Košice, carbonaceous chondrite fall Maribo, and cometary Taurid bolide of October 31, 2015. The Romanian superbolide was not similar to any of these and represents probably a new type of material with intrinsic strength of about 1 MPa.

The Remarkable Afterglow of GRB 061007: Implications for Optical Flashes and GRB Fireballs

NASA Astrophysics Data System (ADS)

Mundell, C. G.; Melandri, A.; Guidorzi, C.; Kobayashi, S.; Steele, I. A.; Malesani, D.; Amati, L.; D'Avanzo, P.; Bersier, D. F.; Gomboc, A.; Rol, E.; Bode, M. F.; Carter, D.; Mottram, C. J.; Monfardini, A.; Smith, R. J.; Malhotra, S.; Wang, J.; Bannister, N.; O'Brien, P. T.; Tanvir, N. R.

2007-05-01

We present a multiwavelength analysis of Swift GRB 061007. The 2 m robotic Faulkes Telescope South began observing 137 s after the onset of the γ-ray emission, when the optical counterpart was already decaying from R~10.3 mag, and continued observing for the next 5.5 hr. These observations begin during the final γ-ray flare and continue through and beyond a long, soft tail of γ-ray emission whose flux shows an underlying simple power-law decay identical to that seen at optical and X-ray wavelengths, with temporal slope α~1.7 (F~t-α). This remarkably simple decay in all of these bands is rare for Swift bursts, which often show much more complex light curves. We suggest the afterglow emission begins as early as 30-100 s and is contemporaneous with the ongoing variable prompt emission from the central engine, but originates from a physically distinct region dominated by the forward shock. The observed multiwavelength evolution of GRB 061007 is explained by an expanding fireball whose optical, X-ray, and late-time γ-ray emission is dominated by emission from a forward shock with typical synchrotron frequency, νm, that is already below the optical band as early as t=137 s and a cooling frequency, νc, above the X-ray band to at least t=105 s. In contrast, the typical frequency of the reverse shock lies in the radio band at early time. We suggest that the unexpected lack of bright optical flashes from the majority of Swift GRBs may be explained with a low νm originating from small microphysics parameters, ɛe and ɛB. Finally, the optical light curves imply a minimum jet opening angle θ=4.7deg, and no X-ray jet break before t~106 s makes GRB 061007 a secure outlier to spectral energy correlations.

Vigie-Ciel : a french citizen network to study meteors and meteorites

NASA Astrophysics Data System (ADS)

Bouley, S.; Zanda, B.; Colas, F.; Vaubaillon, J.; Marmo, C.; Vernazza, P.; Gattacceca, J.

2013-12-01

Vigie Ciel is a french citizen network supported by the Muséum National d'Histoire Naturelle (MNHN) and the Université Paris-Sud (UPsud). It is based on the scientific FRIPON program developed by Paris Observatory (Fireball Recovery and Planetary Inter Observation Network) which has for main goal to (i) determine the source region(s) of the various meteorite classes, (ii) collect both fresh and rare meteorite types and (iii) perform scientific outreach. This will be achieved by building the densest camera network in the world, based on state of the art technologies and associated with a participative network for meteorite recovery. We propose to install a network of 100 digital cameras covering the entire French territory to compute impact locations with accuracy of the order of one kilometer. Considering that there are 5 to 25 falls over France per year (~15 on average), during the same time, we will observe ~50 falls out of which we realistically expect to find 10 meteorites. Our project is original in several ways. (i) It is inter-disciplinary, involving experts in meteoritics, asteroidal science as well as fireball observation and dynamics. It will thus create new synergies between prominent institutions and/or laboratories, namely between MNHN, Paris Observatory and Université Paris-Sud in the Parisian region; and between CEREGE and LAM in the Provence region. Overall, scientists from over 25 laboratories will be involved, covering a mix of scientific disciplines and all the regions of France. (ii) It will generate a large body of data, feeding databases of interest to several disciplines (e.g. bird migration, variations of the luminosity of the brightest stars, observation of space debris, meteorology...). (iii) It will for the first time involve the general public (including schools) in the search for the meteorite falls, thus boosting the interest in meteorite and asteroid related science.

Probing the use of spectroscopy to determine the meteoritic analogues of meteors

NASA Astrophysics Data System (ADS)

Drouard, A.; Vernazza, P.; Loehle, S.; Gattacceca, J.; Vaubaillon, J.; Zanda, B.; Birlan, M.; Bouley, S.; Colas, F.; Eberhart, M.; Hermann, T.; Jorda, L.; Marmo, C.; Meindl, A.; Oefele, R.; Zamkotsian, F.; Zander, F.

2018-05-01

Context. Determining the source regions of meteorites is one of the major goals of current research in planetary science. Whereas asteroid observations are currently unable to pinpoint the source regions of most meteorite classes, observations of meteors with camera networks and the subsequent recovery of the meteorite may help make progress on this question. The main caveat of such an approach, however, is that the recovery rate of meteorite falls is low (<20%), implying that the meteoritic analogues of at least 80% of the observed falls remain unknown. Aims: Spectroscopic observations of incoming bolides may have the potential to mitigate this problem by classifying the incoming meteoritic material. Methods: To probe the use of spectroscopy to determine the meteoritic analogues of incoming bolides, we collected emission spectra in the visible range (320-880 nm) of five meteorite types (H, L, LL, CM, and eucrite) acquired in atmospheric entry-like conditions in a plasma wind tunnel at the Institute of Space Systems (IRS) at the University of Stuttgart (Germany). A detailed spectral analysis including a systematic line identification and mass ratio determinations (Mg/Fe, Na/Fe) was subsequently performed on all spectra. Results: It appears that spectroscopy, via a simple line identification, allows us to distinguish the three main meteorite classes (chondrites, achondrites and irons) but it does not have the potential to distinguish for example an H chondrite from a CM chondrite. Conclusions: The source location within the main belt of the different meteorite classes (H, L, LL, CM, CI, etc.) should continue to be investigated via fireball observation networks. Spectroscopy of incoming bolides only marginally helps precisely classify the incoming material (iron meteorites only). To reach a statistically significant sample of recovered meteorites along with accurate orbits (>100) within a reasonable time frame (10-20 years), the optimal solution may be the spatial extension of existing fireball observation networks. The movie associated to this article is available at http://www.aanda.org

IYL Blog: Astronomers travel in time and space with light

NASA Technical Reports Server (NTRS)

Mather, John C.

2015-01-01

As an astronomer, I use light to travel through the universe, and to look back in time to when the universe was young. So do you! All of us see things as they were when the light was emitted, not as they are now. The farthest thing you can easily see without a telescope is the Andromeda Nebula, which is a galaxy like the Milky Way, about 2.5 million light years away. You see it as it was 2.5 million years ago, and we really don't know what it looks like today; the disk will have rotated a bit, new stars will have been born, there could have been all kinds of exploding stars, and the black hole in the middle could be lighting up. People may be skeptical of the Big Bang theory, even though we have a TV show named for it, but we (I should say Penzias and Wilson) measured its heat radiation 51 years ago at Bell Telephone Labs in New Jersey. Their discovery marks the beginning of the era of cosmology as a measurement science rather than speculation. Penzias and Wilson received the Nobel Prize in 1978 for their finding, which had been predicted in 1948 by Alpher and Herman. By the way, heat radiation is just another form of light - we call it radiation because we can't see it, but it's exactly the same phenomenon of electromagnetic waves, and the only difference is the wavelength. In the old days of analog television, if you tuned your TV in between channels, about 1% of the snow that you could see came from the Big Bang. So when we look at the heat radiation of the early universe, we really are gazing right at what seems to us a cosmic fireball, which surrounds us completely. It's a bit of an illusion; if you can imagine what astronomers in other galaxies would see, they would also feel surrounded by the fireball, and they would also think they were in the middle. So from a mathematical version of imagination, we conclude that there is no observable center and no edge of our universe, and that the heat of the fireball fills the entire universe uniformly. Astronomers are also using light to find out whether we are alone in the universe. The Kepler observatory showed that thousands of stars blink a little when their orbiting planets pass between us and them, and other observatories use light to measure the wobble of stars as their planets pull on them. Eventually, we will find out whether planets like Earth have atmospheres like Earth's too - with water, carbon dioxide, oxygen, methane, and other gases that would be evidence of photosynthetic life. I think in a few decades we will have evidence that some planets do have life, and it will be done using light for remote chemical analysis. Also, astronomers at the SETI project are using light (long wavelength light we can pick up with radio telescopes) to look for signals from intelligent civilizations. That's a harder project because we don't know what to look for. But if we wanted to send signals all the way across the Milky Way, we could do it with laser beams, and if somebody over there knew what to look for, he or she could decode the message. On with the search! Dr. John C. Mather is a Senior Astrophysicist and is the Senior Project Scientist for the James Webb Space Telescope at NASA's Goddard Space Flight Center in Greenbelt, MD. His research centers on infrared astronomy and cosmology. With the Cosmic Background Explorer (COBE) team, he showed that the cosmic microwave background radiation has a blackbody spectrum within 50 parts per million, confirming the expanding universe model (aka the Big Bang Theory) to extraordinary accuracy, and initiating the study of cosmology as a precision science. The COBE team also made the first map of the hot and cold spots in the background radiation. The COBE maps have been confirmed and improved by two succeeding space missions, the Wilkinson Microwave Anisotropy Probe (WMAP, built by GSFC with Princeton University), and the Planck mission built by ESA. Based on these maps, astronomers have now developed a "standard model" of cosmology and have built detailed numerical simulations that begin to match Hubble observations, and require the existence of both "dark matter" and "dark energy", neither of which has been detected or deduced in laboratory experiments. Dr. Mather is the recipient of numerous awards, including the Nobel Prize in Physics (2006) with George Smoot, for the COBE work, and the NASA Distinguished Service Medal (2007). He is a member of many professional societies including the National Academy of Sciences and the American Academy of Arts and Sciences. Dr. Mather is now working with teams and committees to develop plans for a future great telescope capable of observing signs of life on planets orbiting other stars.

CID Post-impact fireball

NASA Technical Reports Server (NTRS)

1984-01-01

Following its controlled impact on posts imbedded in the lakebed, the B-720 is sliding sideways and almost enveloped in the large fireball with only the aircraft's nose and right wing-tip exposed. In a typical aircraft crash, fuel spilled from ruptured fuel tanks forms a fine mist that can be ignited by a number of sources at the crash site. In 1984 the NASA Dryden Flight Research Facility (after 1994 a full-fledged Center again) and the Federal Aviation Administration (FAA) teamed-up in a unique flight experiment called the Controlled Impact Demonstration (CID), to test crash a Boeing 720 aircraft using standard fuel with an additive designed to supress fire. The additive, FM-9, a high-molecular-weight long-chain polymer, when blended with Jet-A fuel had demonstrated the capability to inhibit ignition and flame propagation of the released fuel in simulated crash tests. This anti-misting kerosene (AMK) cannot be introduced directly into a gas turbine engine due to several possible problems such as clogging of filters. The AMK must be restored to almost Jet-A before being introduced into the engine for burning. This restoration is called 'degradation' and was accomplished on the B-720 using a device called a 'degrader.' Each of the four Pratt & Whitney JT3C-7 engines had a 'degrader' built and installed by General Electric (GE) to break down and return the AMK to near Jet-A quality. In addition to the AMK research the NASA Langley Research Center was involved in a structural loads measurement experiment, which included having instrumented dummies filling the seats in the passenger compartment. Before the final flight on December 1, 1984, more than four years of effort passed trying to set-up final impact conditions considered survivable by the FAA. During those years while 14 flights with crews were flown the following major efforts were underway: NASA Dryden developed the remote piloting techniques necessary for the B-720 to fly as a drone aircraft; General Electric installed and tested four degraders (one on each engine); and the FAA refined AMK (blending, testing, and fueling a full-size aircraft). The 15 flights had 15 takeoffs, 14 landings and a larger number of approaches to about 150 feet above the prepared crash site under remote control. These flight were used to introduce AMK one step at a time into some of the fuel tanks and engines while monitoring the performance of the engines. On the final flight (No. 15) with no crew, all fuel tanks were filled with a total of 76,000 pounds of AMK and the remotely-piloted aircraft landed on Rogers Dry Lakebed in an area prepared with posts to test the effectiveness of the AMK in a controlled impact. The CID, which some wags called the Crash in the Desert, was spectacular with a large fireball enveloping and burning the B-720 aircraft. From the standpoint of AMK the test was a major set-back, but for NASA Langley, the data collected on crashworthiness was deemed successful and just as important.

CID Post-impact fireball

NASA Technical Reports Server (NTRS)

1984-01-01

The B-720 after impact and sliding through the wing openers is becoming enveloped in a fireball. The right wing appears to be folding over as the aircraft continues to slide. In a typical aircraft crash, fuel spilled from ruptured fuel tanks forms a fine mist that can be ignited by a number of sources at the crash site. In 1984 the NASA Dryden Flight Research Facility (after 1994 a full-fledged Center again) and the Federal Aviation Administration (FAA) teamed-up in a unique flight experiment called the Controlled Impact Demonstration (CID), to test crash a Boeing 720 aircraft using standard fuel with an additive designed to supress fire. The additive, FM-9, a high-molecular-weight long-chain polymer, when blended with Jet-A fuel had demonstrated the capability to inhibit ignition and flame propagation of the released fuel in simulated crash tests. This anti-misting kerosene (AMK) cannot be introduced directly into a gas turbine engine due to several possible problems such as clogging of filters. The AMK must be restored to almost Jet-A before being introduced into the engine for burning. This restoration is called 'degradation' and was accomplished on the B-720 using a device called a 'degrader.' Each of the four Pratt & Whitney JT3C-7 engines had a 'degrader' built and installed by General Electric (GE) to break down and return the AMK to near Jet-A quality. In addition to the AMK research the NASA Langley Research Center was involved in a structural loads measurement experiment, which included having instrumented dummies filling the seats in the passenger compartment. Before the final flight on December 1, 1984, more than four years of effort passed trying to set-up final impact conditions considered survivable by the FAA. During those years while 14 flights with crews were flown the following major efforts were underway: NASA Dryden developed the remote piloting techniques necessary for the B-720 to fly as a drone aircraft; General Electric installed and tested four degraders (one on each engine); and the FAA refined AMK (blending, testing, and fueling a full-size aircraft). The 15 flights had 15 takeoffs, 14 landings and a larger number of approaches to about 150 feet above the prepared crash site under remote control. These flight were used to introduce AMK one step at a time into some of the fuel tanks and engines while monitoring the performance of the engines. On the final flight (No. 15) with no crew, all fuel tanks were filled with a total of 76,000 pounds of AMK and the remotely-piloted aircraft landed on Rogers Dry Lakebed in an area prepared with posts to test the effectiveness of the AMK in a controlled impact. The CID, which some wags called the Crash in the Desert, was spectacular with a large fireball enveloping and burning the B-720 aircraft. From the standpoint of AMK the test was a major set-back, but for NASA Langley, the data collected on crashworthiness was deemed successful and just as important.

Ernst Florens Friedrich Chladni (1756-1827) and the origins of modern meteorite research

NASA Astrophysics Data System (ADS)

Marvin, Ursula B.

1996-09-01

In 1794, Ernst F. F. Chladni published a 63-page book Über den Ursprung der von Pallas gefundenen und anderer ihr änlicher Eisenmassen und über einige damit in Verbindung stehende Naturerscheinungen in which he proposed that meteor-stones and iron masses enter the atmosphere from cosmic space and form fireballs as they plunge to Earth. These ideas violated two strongly held contemporary beliefs: (1) fragments of rock and metal do not fall from the sky, and (2) no small bodies exist in space beyond the Moon. From the beginning, Chladni was severely criticised for basing his hypotheses on historical eyewitness reports of falls which others regarded as folk tales and for taking gross liberties with the laws of physics. Eight years later, the study of fallen stones and irons was established as a valid field of investigation. Today, some scholars credit Chladni with founding meteoritics as a science; others regard his contributions as scarcely worthy of mention. Writings by his contemporaries suggest that Chladni's book alone would not have led to changes of prevailing theories; thus, he narrowly escaped the fate of those scientists who propose valid hypotheses prematurely. However between 1794 and 1798, four falls of stones were witnessed and widely publicized. There followed a series of epoch-making analyses of fallen stones and "native irons" by the chemist Edward C. Howard and the mineralogist Jacques-Louis de Bournon. They showed that all the stones were much alike in texture and composition but significantly different from the Earth's known crustal rocks. Of primary importance was Howard's discovery of nickel in the irons and the metal grains of the stones. This linked the two as belonging to the same natural phenomenon. The chemical results, published in 1802 February, persuaded leading scientists in England, France, and Germany that bodies fall from the sky. Within a few months, chemists in France reported similar results and a new field of study was inaugurated internationally—although opposition lingered on until 1803 April, when nearly 3,000 stones fell at L'Aigle in Normandy and transformed the last skeptics into believers. Chladni immediately received full credit for his hypothesis of falls, but decades passed before his linking of falling bodies with fireballs received general acceptance. His hypothesis of their origin met with strong resistance from those who argued that stones formed within the Earth's atmosphere or were ejected by lunar volcanoes. After 1860, when both of these hypotheses were abandoned, there followed a century of debate between proponents of an interstellar vs. a planetary origin. Not until the 1950s did conclusive evidence of their elliptical orbits establish meteorite parent bodies as members of the solar system. Thus, nearly 200 years passed before the questions of origin that Chladni raised finally were resolved.

Production of e+e- from U+U collisions at √{sNN } = 193 GeV and Au+Au collisions at √{sNN } = 19.6 , 27 , 39 , 62.4, and 200 GeV as measured by STAR

NASA Astrophysics Data System (ADS)

Butterworth, Joey; STAR Collaboration

2017-08-01

We present STAR's measurement of the e+e- continuum as a function of centrality, invariant mass, and transverse momentum for U+U collisions at √{sNN } = 193 GeV. Also reported are the acceptance-corrected e+e- invariant mass spectra for minimum-bias Au+Au collisions at √{sNN } = 27 , 39, and 62.4 GeV and U+U collisions at √{sNN } = 193 GeV. The connection between the integrated e+e- excess yields normalized by charge particle multiplicity (dNch / dy) at mid-rapidity and the lifetime of the fireball is discussed.

1997 Leonid Shower From Space

NASA Technical Reports Server (NTRS)

Jenniskens, Peter; Nugent, David; Murthy, Jayant; Tedesco, Ed; DeVincenzi, Donal L. (Technical Monitor)

2000-01-01

In November 1997, the Midcourse Space Experiment satellite (MSX) was deployed to observe the Leonid shower from space. The shower lived up to expectations, with abundant bright fireballs. Twenty-nine meteors were detected by a wide-angle, visible wavelength, camera near the limb of the Earth in a 48-minute interval, and three meteors by the narrow field camera. This amounts to a meteoroid influx of 5.5 +/- 0.6 10(exp -5)/sq km hr for masses greater than 0.3 gram. The limiting magnitude for limb observations of Leonid meteors was measured at M(sub v) = -1.5 magn The Leonid shower magnitude population index was 1.6 +/- 0.2 down to M(sub v) = -7 magn., with no sign of an upper mass cut-off.

Inclusive reconstruction of hadron resonances in elementary and heavy-ion collisions with HADES

NASA Astrophysics Data System (ADS)

Kornakov, Georgy

2016-11-01

The unambiguous identification of hadron modifications in hot and dense QCD matter is one of the important goals in nuclear physics. In the regime of 1 - 2 GeV kinetic energy per nucleon, HADES has measured rare and penetrating probes in elementary and heavy-ion collisions. The main creation mechanism of mesons is the excitation and decay of baryonic resonances throughout the fireball evolution. The reconstruction of shortlived (≈ 1 fm/c) resonance states through their decay products is notoriously difficult. We have developed a new iterative algorithm, which builds the best hypothesis of signal and background by distortion of individual particle properties. This allows to extract signals with signal-to-background ratios of <1%.

Early-time VLA Observations and Broadband Afterglow Analysis of the Fermi/LAT Detected GRB 130907A

NASA Astrophysics Data System (ADS)

Veres, Péter; Corsi, Alessandra; Frail, Dale A.; Cenko, S. Bradley; Perley, Daniel A.

2015-09-01

We present multi-wavelength observations of the hyper-energetic gamma-ray burst (GRB) 130907A, a Swift-discovered burst with early radio observations starting at ≈4 hr after the γ-ray trigger. GRB 130907A was also detected by the Fermi/LAT instrument and at late times showed a strong spectral evolution in X-rays. We focus on the early-time radio observations, especially at >10 GHz, to attempt to identify reverse shock signatures. While our radio follow-up of GRB 130907A ranks among the earliest observations of a GRB with the Karl G. Jansky Very Large Array, we did not see an unambiguous signature of a reverse shock. While a model with both reverse and forward shock can correctly describe the observations, the data is not constraining enough to decide upon the presence of the reverse-shock component. We model the broadband data using a simple forward-shock synchrotron scenario with a transition from a wind environment to a constant density interstellar medium (ISM) in order to account for the observed features. Within the confines of this model, we also derive the underlying physical parameters of the fireball, which are within typical ranges except for the wind density parameter (A*), which is higher than those for bursts with wind-ISM transition, but typical for the general population of bursts. We note the importance of early-time radio observations of the afterglow (and of well-sampled light curves) for unambiguously identifying the potential contribution of the reverse shock.

Higher harmonic flow coefficients of identified hadrons in Pb-Pb collisions at √{s_{NN}}=2.76 TeV

NASA Astrophysics Data System (ADS)

Adam, J.; Adamová, D.; Aggarwal, M. M.; Aglieri Rinella, G.; Agnello, M.; Agrawal, N.; Ahammed, Z.; Ahmad, S.; Ahn, S. U.; Aiola, S.; Akindinov, A.; Alam, S. N.; Albuquerque, D. S. D.; Aleksandrov, D.; Alessandro, B.; Alexandre, D.; Alfaro Molina, R.; Alici, A.; Alkin, A.; Alme, J.; Alt, T.; Altinpinar, S.; Altsybeev, I.; Alves Garcia Prado, C.; An, M.; Andrei, C.; Andrews, H. A.; Andronic, A.; Anguelov, V.; Antičić, T.; Antinori, F.; Antonioli, P.; Aphecetche, L.; Appelshäuser, H.; Arcelli, S.; Arnaldi, R.; Arnold, O. W.; Arsene, I. C.; Arslandok, M.; Audurier, B.; Augustinus, A.; Averbeck, R.; Azmi, M. D.; Badalà, A.; Baek, Y. W.; Bagnasco, S.; Bailhache, R.; Bala, R.; Balasubramanian, S.; Baldisseri, A.; Baral, R. C.; Barbano, A. M.; Barbera, R.; Barile, F.; Barnaföldi, G. G.; Barnby, L. S.; Barret, V.; Bartalini, P.; Barth, K.; Bartke, J.; Bartsch, E.; Basile, M.; Bastid, N.; Basu, S.; Bathen, B.; Batigne, G.; Batista Camejo, A.; Batyunya, B.; Batzing, P. C.; Bearden, I. G.; Beck, H.; Bedda, C.; Behera, N. K.; Belikov, I.; Bellini, F.; Bello Martinez, H.; Bellwied, R.; Belmont, R.; Belmont-Moreno, E.; Beltran, L. G. E.; Belyaev, V.; Bencedi, G.; Beole, S.; Berceanu, I.; Bercuci, A.; Berdnikov, Y.; Berenyi, D.; Bertens, R. A.; Berzano, D.; Betev, L.; Bhasin, A.; Bhat, I. R.; Bhati, A. K.; Bhattacharjee, B.; Bhom, J.; Bianchi, L.; Bianchi, N.; Bianchin, C.; Bielčík, J.; Bielčíková, J.; Bilandzic, A.; Biro, G.; Biswas, R.; Biswas, S.; Bjelogrlic, S.; Blair, J. T.; Blau, D.; Blume, C.; Bock, F.; Bogdanov, A.; Bøggild, H.; Boldizsár, L.; Bombara, M.; Bonora, M.; Book, J.; Borel, H.; Borissov, A.; Borri, M.; Bossú, F.; Botta, E.; Bourjau, C.; Braun-Munzinger, P.; Bregant, M.; Breitner, T.; Broker, T. A.; Browning, T. A.; Broz, M.; Brucken, E. J.; Bruna, E.; Bruno, G. E.; Budnikov, D.; Buesching, H.; Bufalino, S.; Buncic, P.; Busch, O.; Buthelezi, Z.; Butt, J. B.; Buxton, J. T.; Cabala, J.; Caffarri, D.; Cai, X.; Caines, H.; Calero Diaz, L.; Caliva, A.; Calvo Villar, E.; Camerini, P.; Carena, F.; Carena, W.; Carnesecchi, F.; Castillo Castellanos, J.; Castro, A. J.; Casula, E. A. R.; Ceballos Sanchez, C.; Cepila, J.; Cerello, P.; Cerkala, J.; Chang, B.; Chapeland, S.; Chartier, M.; Charvet, J. L.; Chattopadhyay, S.; Chattopadhyay, S.; Chauvin, A.; Chelnokov, V.; Cherney, M.; Cheshkov, C.; Cheynis, B.; Chibante Barroso, V.; Chinellato, D. D.; Cho, S.; Chochula, P.; Choi, K.; Chojnacki, M.; Choudhury, S.; Christakoglou, P.; Christensen, C. H.; Christiansen, P.; Chujo, T.; Chung, S. U.; Cicalo, C.; Cifarelli, L.; Cindolo, F.; Cleymans, J.; Colamaria, F.; Colella, D.; Collu, A.; Colocci, M.; Conesa Balbastre, G.; Conesa del Valle, Z.; Connors, M. E.; Contreras, J. G.; Cormier, T. M.; Corrales Morales, Y.; Cortés Maldonado, I.; Cortese, P.; Cosentino, M. R.; Costa, F.; Crkovska, J.; Crochet, P.; Cruz Albino, R.; Cuautle, E.; Cunqueiro, L.; Dahms, T.; Dainese, A.; Danisch, M. C.; Danu, A.; Das, D.; Das, I.; Das, S.; Dash, A.; Dash, S.; De, S.; De Caro, A.; de Cataldo, G.; de Conti, C.; de Cuveland, J.; De Falco, A.; De Gruttola, D.; De Marco, N.; De Pasquale, S.; De Souza, R. D.; Deisting, A.; Deloff, A.; Dénes, E.; Deplano, C.; Dhankher, P.; Di Bari, D.; Di Mauro, A.; Di Nezza, P.; Di Ruzza, B.; Diaz Corchero, M. A.; Dietel, T.; Dillenseger, P.; Divià, R.; Djuvsland, Ø.; Dobrin, A.; Domenicis Gimenez, D.; Dönigus, B.; Dordic, O.; Drozhzhova, T.; Dubey, A. K.; Dubla, A.; Ducroux, L.; Dupieux, P.; Ehlers, R. J.; Elia, D.; Endress, E.; Engel, H.; Epple, E.; Erazmus, B.; Erdemir, I.; Erhardt, F.; Espagnon, B.; Estienne, M.; Esumi, S.; Eulisse, G.; Eum, J.; Evans, D.; Evdokimov, S.; Eyyubova, G.; Fabbietti, L.; Fabris, D.; Faivre, J.; Fantoni, A.; Fasel, M.; Feldkamp, L.; Feliciello, A.; Feofilov, G.; Ferencei, J.; Fernández Téllez, A.; Ferreiro, E. G.; Ferretti, A.; Festanti, A.; Feuillard, V. J. G.; Figiel, J.; Figueredo, M. A. S.; Filchagin, S.; Finogeev, D.; Fionda, F. M.; Fiore, E. M.; Floris, M.; Foertsch, S.; Foka, P.; Fokin, S.; Fragiacomo, E.; Francescon, A.; Francisco, A.; Frankenfeld, U.; Fronze, G. G.; Fuchs, U.; Furget, C.; Furs, A.; Fusco Girard, M.; Gaardhøje, J. J.; Gagliardi, M.; Gago, A. M.; Gajdosova, K.; Gallio, M.; Galvan, C. D.; Gangadharan, D. R.; Ganoti, P.; Gao, C.; Garabatos, C.; Garcia-Solis, E.; Garg, K.; Gargiulo, C.; Gasik, P.; Gauger, E. F.; Germain, M.; Gheata, M.; Ghosh, P.; Ghosh, S. K.; Gianotti, P.; Giubellino, P.; Giubilato, P.; Gladysz-Dziadus, E.; Glässel, P.; Goméz Coral, D. M.; Gomez Ramirez, A.; Gonzalez, A. S.; Gonzalez, V.; González-Zamora, P.; Gorbunov, S.; Görlich, L.; Gotovac, S.; Grabski, V.; Grachov, O. A.; Graczykowski, L. K.; Graham, K. L.; Grelli, A.; Grigoras, A.; Grigoras, C.; Grigoriev, V.; Grigoryan, A.; Grigoryan, S.; Grinyov, B.; Grion, N.; Gronefeld, J. M.; Grosse-Oetringhaus, J. F.; Grosso, R.; Gruber, L.; Guber, F.; Guernane, R.; Guerzoni, B.; Gulbrandsen, K.; Gunji, T.; Gupta, A.; Gupta, R.; Guzman, I. B.; Haake, R.; Hadjidakis, C.; Haiduc, M.; Hamagaki, H.; Hamar, G.; Hamon, J. C.; Harris, J. W.; Harton, A.; Hatzifotiadou, D.; Hayashi, S.; Heckel, S. T.; Hellbär, E.; Helstrup, H.; Herghelegiu, A.; Herrera Corral, G.; Herrmann, F.; Hess, B. A.; Hetland, K. F.; Hillemanns, H.; Hippolyte, B.; Horak, D.; Hosokawa, R.; Hristov, P.; Hughes, C.; Humanic, T. J.; Hussain, N.; Hussain, T.; Hutter, D.; Hwang, D. S.; Ilkaev, R.; Inaba, M.; Incani, E.; Ippolitov, M.; Irfan, M.; Isakov, V.; Ivanov, M.; Ivanov, V.; Izucheev, V.; Jacak, B.; Jacazio, N.; Jacobs, P. M.; Jadhav, M. B.; Jadlovska, S.; Jadlovsky, J.; Jahnke, C.; Jakubowska, M. J.; Janik, M. A.; Jayarathna, P. H. S. Y.; Jena, C.; Jena, S.; Jimenez Bustamante, R. T.; Jones, P. G.; Jusko, A.; Kalinak, P.; Kalweit, A.; Kang, J. H.; Kaplin, V.; Kar, S.; Karasu Uysal, A.; Karavichev, O.; Karavicheva, T.; Karayan, L.; Karpechev, E.; Kebschull, U.; Keidel, R.; Keijdener, D. L. D.; Keil, M.; Mohisin Khan, M.; Khan, P.; Khan, S. A.; Khanzadeev, A.; Kharlov, Y.; Khatun, A.; Kileng, B.; Kim, D. W.; Kim, D. J.; Kim, D.; Kim, H.; Kim, J. S.; Kim, J.; Kim, M.; Kim, S.; Kim, T.; Kirsch, S.; Kisel, I.; Kiselev, S.; Kisiel, A.; Kiss, G.; Klay, J. L.; Klein, C.; Klein, J.; Klein-Bösing, C.; Klewin, S.; Kluge, A.; Knichel, M. L.; Knospe, A. G.; Kobdaj, C.; Kofarago, M.; Kollegger, T.; Kolojvari, A.; Kondratiev, V.; Kondratyeva, N.; Kondratyuk, E.; Konevskikh, A.; Kopcik, M.; Kour, M.; Kouzinopoulos, C.; Kovalenko, O.; Kovalenko, V.; Kowalski, M.; Koyithatta Meethaleveedu, G.; Králik, I.; Kravčáková, A.; Krivda, M.; Krizek, F.; Kryshen, E.; Krzewicki, M.; Kubera, A. M.; Kučera, V.; Kuhn, C.; Kuijer, P. G.; Kumar, A.; Kumar, J.; Kumar, L.; Kumar, S.; Kurashvili, P.; Kurepin, A.; Kurepin, A. B.; Kuryakin, A.; Kweon, M. J.; Kwon, Y.; La Pointe, S. L.; La Rocca, P.; Ladron de Guevara, P.; Lagana Fernandes, C.; Lakomov, I.; Langoy, R.; Lapidus, K.; Lara, C.; Lardeux, A.; Lattuca, A.; Laudi, E.; Lea, R.; Leardini, L.; Lee, S.; Lehas, F.; Lehner, S.; Lemmon, R. C.; Lenti, V.; Leogrande, E.; León Monzón, I.; León Vargas, H.; Leoncino, M.; Lévai, P.; Li, S.; Li, X.; Lien, J.; Lietava, R.; Lindal, S.; Lindenstruth, V.; Lippmann, C.; Lisa, M. A.; Ljunggren, H. M.; Lodato, D. F.; Loenne, P. I.; Loginov, V.; Loizides, C.; Lopez, X.; López Torres, E.; Lowe, A.; Luettig, P.; Lunardon, M.; Luparello, G.; Lupi, M.; Lutz, T. H.; Maevskaya, A.; Mager, M.; Mahajan, S.; Mahmood, S. M.; Maire, A.; Majka, R. D.; Malaev, M.; Maldonado Cervantes, I.; Malinina, L.; Mal'Kevich, D.; Malzacher, P.; Mamonov, A.; Manko, V.; Manso, F.; Manzari, V.; Mao, Y.; Marchisone, M.; Mareš, J.; Margagliotti, G. V.; Margotti, A.; Margutti, J.; Marín, A.; Markert, C.; Marquard, M.; Martin, N. A.; Martinengo, P.; Martínez, M. I.; Martínez García, G.; Martinez Pedreira, M.; Mas, A.; Masciocchi, S.; Masera, M.; Masoni, A.; Mastroserio, A.; Matyja, A.; Mayer, C.; Mazer, J.; Mazzilli, M.; Mazzoni, M. A.; Meddi, F.; Melikyan, Y.; Menchaca-Rocha, A.; Meninno, E.; Mercado Pérez, J.; Meres, M.; Mhlanga, S.; Miake, Y.; Mieskolainen, M. M.; Mikhaylov, K.; Milano, L.; Milosevic, J.; Mischke, A.; Mishra, A. N.; Mishra, T.; Miskowiec, D.; Mitra, J.; Mitu, C. M.; Mohammadi, N.; Mohanty, B.; Molnar, L.; Montaño Zetina, L.; Montes, E.; Moreira De Godoy, D. A.; Moreno, L. A. P.; Moretto, S.; Morreale, A.; Morsch, A.; Muccifora, V.; Mudnic, E.; Mühlheim, D.; Muhuri, S.; Mukherjee, M.; Mulligan, J. D.; Munhoz, M. G.; Münning, K.; Munzer, R. H.; Murakami, H.; Murray, S.; Musa, L.; Musinsky, J.; Naik, B.; Nair, R.; Nandi, B. K.; Nania, R.; Nappi, E.; Naru, M. U.; Natal da Luz, H.; Nattrass, C.; Navarro, S. R.; Nayak, K.; Nayak, R.; Nayak, T. K.; Nazarenko, S.; Nedosekin, A.; Negrao De Oliveira, R. A.; Nellen, L.; Ng, F.; Nicassio, M.; Niculescu, M.; Niedziela, J.; Nielsen, B. S.; Nikolaev, S.; Nikulin, S.; Nikulin, V.; Noferini, F.; Nomokonov, P.; Nooren, G.; Noris, J. C. C.; Norman, J.; Nyanin, A.; Nystrand, J.; Oeschler, H.; Oh, S.; Oh, S. K.; Ohlson, A.; Okatan, A.; Okubo, T.; Oleniacz, J.; Oliveira Da Silva, A. C.; Oliver, M. H.; Onderwaater, J.; Oppedisano, C.; Orava, R.; Oravec, M.; Ortiz Velasquez, A.; Oskarsson, A.; Otwinowski, J.; Oyama, K.; Ozdemir, M.; Pachmayer, Y.; Pagano, D.; Pagano, P.; Paić, G.; Pal, S. K.; Palni, P.; Pan, J.; Pandey, A. K.; Papikyan, V.; Pappalardo, G. S.; Pareek, P.; Park, W. J.; Parmar, S.; Passfeld, A.; Paticchio, V.; Patra, R. N.; Paul, B.; Pei, H.; Peitzmann, T.; Peng, X.; Pereira Da Costa, H.; Peresunko, D.; Perez Lezama, E.; Peskov, V.; Pestov, Y.; Petráček, V.; Petrov, V.; Petrovici, M.; Petta, C.; Piano, S.; Pikna, M.; Pillot, P.; Pimentel, L. O. D. L.; Pinazza, O.; Pinsky, L.; Piyarathna, D. B.; Ploskon, M.; Planinic, M.; Pluta, J.; Pochybova, S.; Podesta-Lerma, P. L. M.; Poghosyan, M. G.; Polichtchouk, B.; Poljak, N.; Poonsawat, W.; Pop, A.; Poppenborg, H.; Porteboeuf-Houssais, S.; Porter, J.; Pospisil, J.; Prasad, S. K.; Preghenella, R.; Prino, F.; Pruneau, C. A.; Pshenichnov, I.; Puccio, M.; Puddu, G.; Pujahari, P.; Punin, V.; Putschke, J.; Qvigstad, H.; Rachevski, A.; Raha, S.; Rajput, S.; Rak, J.; Rakotozafindrabe, A.; Ramello, L.; Rami, F.; Raniwala, R.; Raniwala, S.; Räsänen, S. S.; Rascanu, B. T.; Rathee, D.; Ravasenga, I.; Read, K. F.; Redlich, K.; Reed, R. J.; Rehman, A.; Reichelt, P.; Reidt, F.; Ren, X.; Renfordt, R.; Reolon, A. R.; Reshetin, A.; Reygers, K.; Riabov, V.; Ricci, R. A.; Richert, T.; Richter, M.; Riedler, P.; Riegler, W.; Riggi, F.; Ristea, C.; Rodríguez Cahuantzi, M.; Rodriguez Manso, A.; Røed, K.; Rogochaya, E.; Rohr, D.; Röhrich, D.; Ronchetti, F.; Ronflette, L.; Rosnet, P.; Rossi, A.; Roukoutakis, F.; Roy, A.; Roy, C.; Roy, P.; Rubio Montero, A. J.; Rui, R.; Russo, R.; Ryabinkin, E.; Ryabov, Y.; Rybicki, A.; Saarinen, S.; Sadhu, S.; Sadovsky, S.; Šafařík, K.; Sahlmuller, B.; Sahoo, P.; Sahoo, R.; Sahoo, S.; Sahu, P. K.; Saini, J.; Sakai, S.; Saleh, M. A.; Salzwedel, J.; Sambyal, S.; Samsonov, V.; Šándor, L.; Sandoval, A.; Sano, M.; Sarkar, D.; Sarkar, N.; Sarma, P.; Scapparone, E.; Scarlassara, F.; Schiaua, C.; Schicker, R.; Schmidt, C.; Schmidt, H. R.; Schmidt, M.; Schuchmann, S.; Schukraft, J.; Schutz, Y.; Schwarz, K.; Schweda, K.; Scioli, G.; Scomparin, E.; Scott, R.; Šefčík, M.; Seger, J. E.; Sekiguchi, Y.; Sekihata, D.; Selyuzhenkov, I.; Senosi, K.; Senyukov, S.; Serradilla, E.; Sevcenco, A.; Shabanov, A.; Shabetai, A.; Shadura, O.; Shahoyan, R.; Shangaraev, A.; Sharma, A.; Sharma, M.; Sharma, M.; Sharma, N.; Sheikh, A. I.; Shigaki, K.; Shou, Q.; Shtejer, K.; Sibiriak, Y.; Siddhanta, S.; Sielewicz, K. M.; Siemiarczuk, T.; Silvermyr, D.; Silvestre, C.; Simatovic, G.; Simonetti, G.; Singaraju, R.; Singh, R.; Singhal, V.; Sinha, T.; Sitar, B.; Sitta, M.; Skaali, T. B.; Slupecki, M.; Smirnov, N.; Snellings, R. J. M.; Snellman, T. W.; Song, J.; Song, M.; Song, Z.; Soramel, F.; Sorensen, S.; Sozzi, F.; Spiriti, E.; Sputowska, I.; Spyropoulou-Stassinaki, M.; Stachel, J.; Stan, I.; Stankus, P.; Stenlund, E.; Steyn, G.; Stiller, J. H.; Stocco, D.; Strmen, P.; Suaide, A. A. P.; Sugitate, T.; Suire, C.; Suleymanov, M.; Suljic, M.; Sultanov, R.; Šumbera, M.; Sumowidagdo, S.; Swain, S.; Szabo, A.; Szarka, I.; Szczepankiewicz, A.; Szymanski, M.; Tabassam, U.; Takahashi, J.; Tambave, G. J.; Tanaka, N.; Tarhini, M.; Tariq, M.; Tarzila, M. G.; Tauro, A.; Tejeda Muñoz, G.; Telesca, A.; Terasaki, K.; Terrevoli, C.; Teyssier, B.; Thäder, J.; Thakur, D.; Thomas, D.; Tieulent, R.; Tikhonov, A.; Timmins, A. R.; Toia, A.; Trogolo, S.; Trombetta, G.; Trubnikov, V.; Trzaska, W. H.; Tsuji, T.; Tumkin, A.; Turrisi, R.; Tveter, T. S.; Ullaland, K.; Uras, A.; Usai, G. L.; Utrobicic, A.; Vala, M.; Valencia Palomo, L.; Van Der Maarel, J.; Van Hoorne, J. W.; van Leeuwen, M.; Vanat, T.; Vande Vyvre, P.; Varga, D.; Vargas, A.; Vargyas, M.; Varma, R.; Vasileiou, M.; Vasiliev, A.; Vauthier, A.; Vázquez Doce, O.; Vechernin, V.; Veen, A. M.; Velure, A.; Vercellin, E.; Vergara Limón, S.; Vernet, R.; Vickovic, L.; Viinikainen, J.; Vilakazi, Z.; Villalobos Baillie, O.; Villatoro Tello, A.; Vinogradov, A.; Vinogradov, L.; Virgili, T.; Vislavicius, V.; Viyogi, Y. P.; Vodopyanov, A.; Völkl, M. A.; Voloshin, K.; Voloshin, S. A.; Volpe, G.; von Haller, B.; Vorobyev, I.; Vranic, D.; Vrláková, J.; Vulpescu, B.; Wagner, B.; Wagner, J.; Wang, H.; Wang, M.; Watanabe, D.; Watanabe, Y.; Weber, M.; Weber, S. G.; Weiser, D. F.; Wessels, J. P.; Westerhoff, U.; Whitehead, A. M.; Wiechula, J.; Wikne, J.; Wilk, G.; Wilkinson, J.; Willems, G. A.; Williams, M. C. S.; Windelband, B.; Winn, M.; Yalcin, S.; Yang, P.; Yano, S.; Yin, Z.; Yokoyama, H.; Yoo, I.-K.; Yoon, J. H.; Yurchenko, V.; Zaborowska, A.; Zaccolo, V.; Zaman, A.; Zampolli, C.; Zanoli, H. J. C.; Zaporozhets, S.; Zardoshti, N.; Zarochentsev, A.; Závada, P.; Zaviyalov, N.; Zbroszczyk, H.; Zgura, I. S.; Zhalov, M.; Zhang, H.; Zhang, X.; Zhang, Y.; Zhang, C.; Zhang, Z.; Zhao, C.; Zhigareva, N.; Zhou, D.; Zhou, Y.; Zhou, Z.; Zhu, H.; Zhu, J.; Zichichi, A.; Zimmermann, A.; Zimmermann, M. B.; Zinovjev, G.; Zyzak, M.

2016-09-01

The elliptic, triangular, quadrangular and pentagonal anisotropic flow coefficients for π±, K± and p+overline{p} in Pb-Pb collisions at √{s_{NN}}=2.76 TeV were measured with the ALICE detector at the Large Hadron Collider. The results were obtained with the Scalar Product method, correlating the identified hadrons with reference particles from a different pseudorapidity region. Effects not related to the common event symmetry planes (non-flow) were estimated using correlations in pp collisions and were subtracted from the measurement. The obtained flow coefficients exhibit a clear mass ordering for transverse momentum ( p T) values below ≈ 3 GeV/ c. In the intermediate p T region (3 < p T < 6 GeV/ c), particles group at an approximate level according to the number of constituent quarks, suggesting that coalescence might be the relevant particle production mechanism in this region. The results for p T < 3 GeV/ c are described fairly well by a hydrodynamical model (iEBE-VISHNU) that uses initial conditions generated by A Multi-Phase Transport model (AMPT) and describes the expansion of the fireball using a value of 0.08 for the ratio of shear viscosity to entropy density ( η/s), coupled to a hadronic cascade model (UrQMD). Finally, expectations from AMPT alone fail to quantitatively describe the measurements for all harmonics throughout the measured transverse momentum region. However, the comparison to the AMPT model highlights the importance of the late hadronic rescattering stage to the development of the observed mass ordering at low values of p T and of coalescence as a particle production mechanism for the particle type grouping at intermediate values of p T for all harmonics. [Figure not available: see fulltext.

Higher harmonic flow coefficients of identified hadrons in Pb-Pb collisions at $$\\sqrt{s_{\\mathrm{NN}}}=2.76 $$ TeV

DOE PAGES

Adam, J.; Adamová, D.; Aggarwal, M. M.; ...

2016-09-28

The elliptic, triangular, quadrangular and pentagonal anisotropic flow coefficients for π ± , K ± and p +more » $$\\bar{p}$$ in Pb-Pb collisions at √s NN=2.76 TeV were measured with the ALICE detector at the Large Hadron Collider. The results were obtained with the Scalar Product method, correlating the identified hadrons with reference particles from a different pseudorapidity region. Effects not related to the common event symmetry planes (non-flow) were estimated using correlations in pp collisions and were subtracted from the measurement. The obtained flow coefficients exhibit a clear mass ordering for transverse momentum (p T ) values below ≈ 3 GeV/c. In the intermediate p T region (3 < p T < 6 GeV/c), particles group at an approximate level according to the number of constituent quarks, suggesting that coalescence might be the relevant particle production mechanism in this region. The results for p T < 3 GeV/c are described fairly well by a hydrodynamical model (iEBE-VISHNU) that uses initial conditions generated by A Multi-Phase Transport model (AMPT) and describes the expansion of the fireball using a value of 0.08 for the ratio of shear viscosity to entropy density (η/s), coupled to a hadronic cascade model (UrQMD). Finally, expectations from AMPT alone fail to quantitatively describe the measurements for all harmonics throughout the measured transverse momentum region. However, the comparison to the AMPT model highlights the importance of the late hadronic rescattering stage to the development of the observed mass ordering at low values of p T and of coalescence as a particle production mechanism for the particle type grouping at intermediate values of p T for all harmonics.« less

Pion emission in α-particle interactions with various targets of nuclear emulsion detector

NASA Astrophysics Data System (ADS)

Abdelsalam, A.; Abou-Moussa, Z.; Rashed, N.; M. Badawy, B.; A. Amer, H.; Osman, W.; M. El-Ashmawy, M.; Abdallah, N.

2015-09-01

The behavior of relativistic hadron multiplicity for 4He-nucleus interactions is investigated. The experiment is carried out at 2.1 A and 3.7 A GeV (Dubna energy) to search for the incident energy effect on the interactions inside different emulsion target nuclei. Data are presented in terms of the number of emitted relativistic hadrons in both forward and backward angular zones. The dependence on the target size is presented. For this purpose the statistical events are discriminated into groups according to the interactions with H, CNO, Em, and AgBr target nuclei. The separation of events, into the mentioned groups, is executed based on Glauber's multiple scattering theory approach. Features suggestive of a decay mechanism seem to be a characteristic of the backward emission of relativistic hadrons. The results strongly support the assumption that the relativistic hadrons may already be emitted during the de-excitation of the excited target nucleus, in a behavior like that of compound-nucleus disintegration. Regarding the limiting fragmentation hypothesis beyond 1 A GeV, the target size is the main parameter affecting the backward production of the relativistic hadron. The incident energy is a principal factor responsible for the forward relativistic hadron production, implying that this system of particle production is a creation system. However, the target size is an effective parameter as well as the projectile size considering the geometrical concept regarded in the nuclear fireball model. The data are analyzed in the framework of the FRITIOF model.

Park Forest (L5) and the asteroidal source of shocked L chondrites

NASA Astrophysics Data System (ADS)

Meier, Matthias M. M.; Welten, Kees C.; Riebe, My E. I.; Caffee, Marc W.; Gritsevich, Maria; Maden, Colin; Busemann, Henner

2017-08-01

The Park Forest (L5) meteorite fell in a suburb of Chicago, Illinois (USA) on March 26, 2003. It is one of the currently 25 meteorites for which photographic documentation of the fireball enabled the reconstruction of the meteoroid orbit. The combination of orbits with pre-atmospheric sizes, cosmic-ray exposure (CRE), and radiogenic gas retention ages ("cosmic histories") is significant because they can be used to constrain the meteoroid's "birth region," and test models of meteoroid delivery. Using He, Ne, Ar, 10Be, and 26Al, as well as a dynamical model, we show that the Park Forest meteoroid had a pre-atmospheric size close to 180 g cm-2, 0-40% porosity, and a pre-atmospheric mass range of 2-6 tons. It has a CRE age of 14 ± 2 Ma, and (U, Th)-He and K-Ar ages of 430 ± 90 and 490 ± 70 Ma, respectively. Of the meteorites with photographic orbits, Park Forest is the second (after Novato) that was shocked during the L chondrite parent body (LCPB) break-up event approximately 470 Ma ago. The suggested association of this event with the formation of the Gefion family of asteroids has recently been challenged and we suggest the Ino family as a potential alternative source for the shocked L chondrites. The location of the LCPB break-up event close to the 5:2 resonance also allows us to put some constraints on the possible orbital migration paths of the Park Forest meteoroid.

Simulation of the airwave caused by the Chelyabinsk superbolide

NASA Astrophysics Data System (ADS)

Avramenko, Mikhail I.; Glazyrin, Igor V.; Ionov, Gennady V.; Karpeev, Artem V.

2014-06-01

Numerical simulations were carried out to model the propagation of an airwave from the fireball that passed over Chelyabinsk (Russia) on 15 February 2013. The airburst of the Chelyabinsk meteoroid occurred due to its catastrophic fragmentation in the atmosphere. Simulations of the space-time distribution of energy deposition during the airburst were done using a novel fragmentation model based on dimensionality considerations and analogy to the fission chain reaction in fissile materials. To get an estimate of the airburst energy, observed values of the airwave arrival times to different populated localities were retrieved from video records available on the Internet. The calculated arrival times agree well with the observed values for all the localities. Energy deposition in the atmosphere obtained from observations of the airwave arrival times was found to be 460 ± 60 kt in trinitrotoluene (TNT) equivalent. We also obtained an independent estimate for the deposited energy, 450-160+200 kt TNT from detecting the air increment velocity due to the wave passage in Chelyabinsk. Assuming that the energy of about 90 kt TNT was irradiated in the form of visible light and infrared radiation, as registered with optical sensors [Yeomans and Chodas, 2013], one can value the total energy release to be about 550 kt TNT which is in agreement with previous estimates from infrasound registration and from optical sensors data. The overpressure amplitude and its positive phase duration in the airwave that reached the city of Chelyabinsk were calculated to be about 2 kPa and 10 s accordingly.

Matter Under Extreme Conditions: The Early Years

NASA Astrophysics Data System (ADS)

Keeler, R. Norris; Gibson, Carl H.

2012-03-01

Extreme conditions in natural flows are examined, starting with a turbulent big bang. A hydro-gravitational-dynamics cosmology model is adopted. Planck-Kerr turbulence instability causes Planck-particle turbulent combustion. Inertial-vortex forces induce a non-turbulent ki- netic energy cascade to Planck-Kolmogorov scales where vorticity is produced, overcoming 10113 Pa Planck-Fortov pressures. The spinning, expanding fireball has a slight deficit of Planck antiparticles. Space and mass-energy powered by gluon viscous stresses expand exponentially at speeds >1025 c. Turbulent temperature and spin fluctuations fossilize at scales larger than ct, where c is light speed and t is time. Because "dark-energy" antigravity forces vanish when infla- tion ceases, and because turbulence produces entropy, the universe is closed and will collapse and rebound. Density and spin fossils of big bang turbulent mixing trigger structure formation in the plasma epoch. Fragmenting protosuperclustervoids and protoclustervoids produce weak tur- bulence until the plasma-gas transition give chains of protogalaxies with the morphology of tur- bulence. Chain galaxy clusters observed at large redshifts ~8.6 support this interpretation. Pro- togalaxies fragment into clumps, each with a trillion Earth-mass H-He gas planets. These make stars, supernovae, the first chemicals, the first oceans and the first life soon after the cosmologi- cal event.

UNCOVERING THE INTRINSIC VARIABILITY OF GAMMA-RAY BURSTS

NASA Astrophysics Data System (ADS)

Golkhou, V. Zach; Butler, Nathaniel R

2014-08-01

We develop a robust technique to determine the minimum variability timescale for gamma-ray burst (GRB) light curves, utilizing Haar wavelets. Our approach averages over the data for a given GRB, providing an aggregate measure of signal variation while also retaining sensitivity to narrow pulses within complicated time series. In contrast to previous studies using wavelets, which simply define the minimum timescale in reference to the measurement noise floor, our approach identifies the signature of temporally smooth features in the wavelet scaleogram and then additionally identifies a break in the scaleogram on longer timescales as a signature of a true, temporally unsmooth light curve feature or features. We apply our technique to the large sample of Swift GRB gamma-ray light curves and for the first time—due to the presence of a large number of GRBs with measured redshift—determine the distribution of minimum variability timescales in the source frame. We find a median minimum timescale for long-duration GRBs in the source frame of Δtmin = 0.5 s, with the shortest timescale found being on the order of 10 ms. This short timescale suggests a compact central engine (3000 km). We discuss further implications for the GRB fireball model and present a tantalizing correlation between the minimum timescale and redshift, which may in part be due to cosmological time dilation.

Assembly and analysis of fragmentation data for liquid propellant vessels

NASA Technical Reports Server (NTRS)

Baker, W. E.; Parr, V. B.; Bessey, R. L.; Cox, P. A.

1974-01-01

Fragmentation data was assembled and analyzed for exploding liquid propellant vessels. These data were to be retrieved from reports of tests and accidents, including measurements or estimates of blast yield, etc. A significant amount of data was retrieved from a series of tests conducted for measurement of blast and fireball effects of liquid propellant explosions (Project PYRO), a few well-documented accident reports, and a series of tests to determine auto-ignition properties of mixing liquid propellants. The data were reduced and fitted to various statistical functions. Comparisons were made with methods of prediction for blast yield, initial fragment velocities, and fragment range. Reasonably good correlation was achieved. Methods presented in the report allow prediction of fragment patterns, given type and quantity of propellant, type of accident, and time of propellant mixing.

September epsilon Perseid cluster as a result of orbital fragmentation

NASA Astrophysics Data System (ADS)

Koten, P.; Čapek, D.; Spurný, P.; Vaubaillon, J.; Popek, M.; Shrbený, L.

2017-04-01

Context. A bright fireball was observed above the Czech Republic on September 9, 2016, at 23:06:59 UT. Moreover, the video cameras at two different stations recorded eight fainter meteors flying on parallel atmospheric trajectories within less than 2 s. All the meteors belong to the September epsilon Perseid meteor shower. The measured proximity of all meteors during a very low activity meteor shower suggests that a cluster of meteors was observed. Aims: The goal of the paper is first to determine whether this event was a random occurrence or a real meteor cluster and second, if it was a cluster, to determine the epoch and at what distance from the Earth the separation of the particles occurred. Methods: The atmospheric trajectories of the observed meteors, masses, and relative distances of individual particles were determined using a double-station observation. According to the distances and masses of the particles, the most probable distance and time of fragmentation is determined. Results: The observed group of meteors is interpreted as the result of the orbital fragmentation of a bigger meteoroid. The fragmentation happened no earlier than 2 or 3 days before the encounter with the Earth at a distance smaller than 0.08 AU from the Earth.

Angular power spectrum in publically released ALICE events

NASA Astrophysics Data System (ADS)

Llanes-Estrada, Felipe J.; Muñoz Martinez, Jose L.

2018-02-01

We study the particles emitted in the fireball following a Relativistic Heavy Ion Collision with the traditional angular analysis employed in cosmology and earth sciences, producing Mollweide plots of the number and pt distribution of a few actual, publically released ALICE-collaboration events and calculating their angular power spectrum. We also examine the angular spectrum of a simple two-particle correlation. While this may not be the optimal way of analyzing heavy ion data, our intention is to provide a one to one comparison to analysis in cosmology. With the limited statistics at hand, we do not find evidence for acoustic peaks but a decrease of Cl that is reminiscent of viscous attenuation, but subject to a strong effect from the rapidity acceptance which probably dominates (so we also subtract the m = 0 component). As an exercise, we still extract a characteristic Silk damping length (proportional to the square root of the viscosity over entropy density ratio) to illustrate the method. The absence of acoustic-like peaks is also compatible with a crossover from the QGP to the hadron gas (because a surface tension at domain boundaries would effect a restoring force that could have driven acoustic oscillations). Presently we do not understand a depression of the l = 6 multipole strength; perhaps ALICE could reexamine it with full statistics.

Directed flow of charged particles at midrapidity relative to the spectator plane in Pb-Pb collisions at √(s(NN))=2.76 TeV.

PubMed

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Jha, D M; Jimenez Bustamante, R T; Jones, P G; Jung, H; Jusko, A; Kaidalov, A B; Kalcher, S; Kaliňák, P; Kalliokoski, T; Kalweit, A; Kang, J H; Kaplin, V; Kar, S; Karasu Uysal, A; Karavichev, O; Karavicheva, T; Karpechev, E; Kazantsev, A; Kebschull, U; Keidel, R; Ketzer, B; Khan, M M; Khan, P; Khan, K H; Khan, S A; Khanzadeev, A; Kharlov, Y; Kileng, B; Kim, J S; Kim, B; Kim, T; Kim, D J; Kim, S; Kim, M; Kim, D W; Kim, J H; Kim, M; Kirsch, S; Kisel, I; Kiselev, S; Kisiel, A; Kiss, G; Klay, J L; Klein, J; Klein-Bösing, C; Kliemant, M; Kluge, A; Knichel, M L; Knospe, A G; Köhler, M K; Kollegger, T; Kolojvari, A; Kompaniets, M; Kondratiev, V; Kondratyeva, N; Konevskikh, A; Kovalenko, V; Kowalski, M; Kox, S; Koyithatta Meethaleveedu, G; Kral, J; Králik, I; Kramer, F; Kravčáková, A; Krelina, M; Kretz, M; Krivda, M; Krizek, F; Krus, M; Kryshen, E; Krzewicki, M; Kucera, V; Kucheriaev, Y; Kugathasan, T; Kuhn, C; Kuijer, P G; Kulakov, I; Kumar, J; Kurashvili, P; Kurepin, A; Kurepin, A B; Kuryakin, A; 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Martínez, M I; Martínez García, G; Martynov, Y; Mas, A; Masciocchi, S; Masera, M; Masoni, A; Massacrier, L; Mastroserio, A; Matyja, A; Mayer, C; Mazer, J; Mazumder, R; Mazzoni, M A; Meddi, F; Menchaca-Rocha, A; Mercado Pérez, J; Meres, M; Miake, Y; Mikhaylov, K; Milano, L; Milosevic, J; Mischke, A; Mishra, A N; Miśkowiec, D; Mitu, C; Mlynarz, J; Mohanty, B; Molnar, L; Montaño Zetina, L; Monteno, M; Montes, E; Moon, T; Morando, M; Moreira De Godoy, D A; Moretto, S; Morreale, A; Morsch, A; Muccifora, V; Mudnic, E; Muhuri, S; Mukherjee, M; Müller, H; Munhoz, M G; Murray, S; Musa, L; Musinsky, J; Nandi, B K; Nania, R; Nappi, E; Nasar, M; Nattrass, C; Nayak, T K; Nazarenko, S; Nedosekin, A; Nicassio, M; Niculescu, M; Nielsen, B S; Nikolaev, S; Nikolic, V; Nikulin, V; Nikulin, S; Nilsen, B S; Nilsson, M S; Noferini, F; Nomokonov, P; Nooren, G; Nyanin, A; Nyatha, A; Nygaard, C; Nystrand, J; Ochirov, A; Oeschler, H; Oh, S K; Oh, S; Olah, L; Oleniacz, J; Oliveira Da Silva, A C; Onderwaater, J; Oppedisano, C; Ortiz Velasquez, A; Oskarsson, A; Ostrowski, P; Otwinowski, J; Oyama, K; Ozawa, K; Pachmayer, Y; Pachr, M; Padilla, F; Pagano, P; Paić, G; Painke, F; Pajares, C; Pal, S K; Palaha, A; Palmeri, A; Papikyan, V; Pappalardo, G S; Park, W J; Passfeld, A; Patalakha, D I; Paticchio, V; Paul, B; Pavlinov, A; Pawlak, T; Peitzmann, T; Pereira Da Costa, H; Pereira De Oliveira Filho, E; Peresunko, D; Pérez Lara, C E; Perrino, D; Peryt, W; Pesci, A; Pestov, Y; Petráček, V; Petran, M; Petris, M; Petrov, P; Petrovici, M; Petta, C; Piano, S; Pikna, M; Pillot, P; Pinazza, O; Pinsky, L; Pitz, N; Piyarathna, D B; Planinic, M; Płoskoń, M; Pluta, J; Pocheptsov, T; Pochybova, S; Podesta-Lerma, P L M; Poghosyan, M G; Polák, K; Polichtchouk, B; Poljak, N; Pop, A; Porteboeuf-Houssais, S; Pospíšil, V; Potukuchi, B; Prasad, S K; Preghenella, R; Prino, F; Pruneau, C A; Pshenichnov, I; Puddu, G; Punin, V; Putschke, J; Qvigstad, H; Rachevski, A; Rademakers, A; Rak, J; Rakotozafindrabe, A; Ramello, L; Raniwala, S; Raniwala, R; Räsänen, S S; Rascanu, B T; Rathee, D; Rauch, W; Rauf, A W; Razazi, V; Read, K F; Real, J S; Redlich, K; Reed, R J; Rehman, A; Reichelt, P; Reicher, M; Reidt, F; Renfordt, R; Reolon, A R; Reshetin, A; Rettig, F; Revol, J-P; Reygers, K; Riccati, L; Ricci, R A; Richert, T; Richter, M; Riedler, P; Riegler, W; Riggi, F; Rivetti, A; Rodríguez Cahuantzi, M; Rodriguez Manso, A; Røed, K; Rogochaya, E; Rohr, D; Röhrich, D; Romita, R; Ronchetti, F; Rosnet, P; Rossegger, S; Rossi, A; Roy, P; Roy, C; Rubio Montero, A J; Rui, R; Russo, R; Ryabinkin, E; Rybicki, A; Sadovsky, S; Safařík, K; Sahoo, R; Sahu, P K; Saini, J; Sakaguchi, H; Sakai, S; Sakata, D; Salgado, C A; Salzwedel, J; Sambyal, S; Samsonov, V; Sanchez Castro, X; Sándor, L; Sandoval, A; Sano, M; Santagati, G; Santoro, R; Sarkar, D; Scapparone, E; Scarlassara, F; Scharenberg, R P; Schiaua, C; Schicker, R; Schmidt, C; Schmidt, H R; Schuchmann, S; Schukraft, J; Schulc, M; Schuster, T; Schutz, Y; Schwarz, K; Schweda, K; Scioli, G; Scomparin, E; Scott, P A; Scott, R; Segato, G; Selyuzhenkov, I; Senyukov, S; Seo, J; Serci, S; Serradilla, E; Sevcenco, A; Shabetai, A; Shabratova, G; Shahoyan, R; Sharma, N; Sharma, S; Rohni, S; Shigaki, K; Shtejer, K; Sibiriak, Y; Siddhanta, S; Siemiarczuk, T; Silvermyr, D; Silvestre, C; Simatovic, G; Simonetti, G; Singaraju, R; Singh, R; Singha, S; Singhal, V; Sinha, T; Sinha, B C; Sitar, B; Sitta, M; Skaali, T B; Skjerdal, K; Smakal, R; Smirnov, N; Snellings, R J M; Søgaard, C; Soltz, R; Song, J; Song, M; Soos, C; Soramel, F; Spacek, M; Sputowska, I; Spyropoulou-Stassinaki, M; Srivastava, B K; Stachel, J; Stan, I; Stefanek, G; Steinpreis, M; Stenlund, E; Steyn, G; Stiller, J H; Stocco, D; Stolpovskiy, M; Strmen, P; Suaide, A A P; Subieta Vásquez, M A; Sugitate, T; Suire, C; Suleymanov, M; Sultanov, R; Sumbera, M; Susa, T; Symons, T J M; Szanto de Toledo, A; Szarka, I; Szczepankiewicz, A; Szymański, M; Takahashi, J; Tangaro, M A; Tapia Takaki, J D; Tarantola Peloni, A; Tarazona Martinez, A; Tauro, A; Tejeda Muñoz, G; Telesca, A; Ter Minasyan, A; Terrevoli, C; Thäder, J; Thomas, D; Tieulent, R; Timmins, A R; Tlusty, D; Toia, A; Torii, H; Toscano, L; Trubnikov, V; Truesdale, D; Trzaska, W H; Tsuji, T; Tumkin, A; Turrisi, R; Tveter, T S; Ulery, J; Ullaland, K; Ulrich, J; Uras, A; Urciuoli, G M; Usai, G L; Vajzer, M; Vala, M; Valencia Palomo, L; Vallero, S; Vande Vyvre, P; Van Hoorne, J W; van Leeuwen, M; Vannucci, L; Vargas, A; Varma, R; Vasileiou, M; Vasiliev, A; Vechernin, V; Veldhoen, M; Venaruzzo, M; Vercellin, E; Vergara, S; Vernet, R; Verweij, M; Vickovic, L; Viesti, G; Viinikainen, J; Vilakazi, Z; Villalobos Baillie, O; Vinogradov, Y; Vinogradov, A; Vinogradov, L; Virgili, T; Viyogi, Y P; Vodopyanov, A; Völkl, M A; Voloshin, K; Voloshin, S; Volpe, G; von Haller, B; Vorobyev, I; Vranic, D; Vrláková, J; Vulpescu, B; Vyushin, A; Wagner, B; Wagner, V; Wagner, J; Wang, Y; Wang, M; Wang, Y; Watanabe, D; Watanabe, K; Weber, M; Wessels, J P; Westerhoff, U; Wiechula, J; Wielanek, D; Wikne, J; Wilde, M; Wilk, G; Wilkinson, J; Williams, M C S; Winn, M; Windelband, B; Xiang, C; Yaldo, C G; Yamaguchi, Y; Yang, H; Yang, S; Yang, P; Yano, S; Yasnopolskiy, S; Yi, J; Yin, Z; Yoo, I-K; Yoon, J; Yushmanov, I; Zaccolo, V; Zach, C; Zampolli, C; Zaporozhets, S; Zarochentsev, A; Závada, P; Zaviyalov, N; Zbroszczyk, H; Zelnicek, P; Zgura, I S; Zhalov, M; Zhang, Y; Zhang, X; Zhang, F; Zhang, H; Zhou, Y; Zhou, F; Zhou, D; Zhu, H; Zhu, X; Zhu, J; Zhu, J; Zichichi, A; Zimmermann, A; Zinovjev, G; Zoccarato, Y; Zynovyev, M; Zyzak, M

2013-12-06

The directed flow of charged particles at midrapidity is measured in Pb-Pb collisions at √(s(NN))=2.76 TeV relative to the collision symmetry plane defined by the spectator nucleons. A negative slope of the rapidity-odd directed flow component with approximately 3 times smaller magnitude than found at the highest RHIC energy is observed. This suggests a smaller longitudinal tilt of the initial system and disfavors the strong fireball rotation predicted for the LHC energies. The rapidity-even directed flow component is measured for the first time with spectators and found to be independent of pseudorapidity with a sign change at transverse momenta p(T) between 1.2 and 1.7  GeV/c. Combined with the observation of a vanishing rapidity-even p(T) shift along the spectator deflection this is strong evidence for dipolelike initial density fluctuations in the overlap zone of the nuclei. Similar trends in the rapidity-even directed flow and the estimate from two-particle correlations at midrapidity, which is larger by about a factor of 40, indicate a weak correlation between fluctuating participant and spectator symmetry planes. These observations open new possibilities for investigation of the initial conditions in heavy-ion collisions with spectator nucleons.

Atmospheric trajectory and heliocentric orbit of the Ejby meteorite fall in Denmark on February 6, 2016

NASA Astrophysics Data System (ADS)

Spurný, P.; Borovička, J.; Baumgarten, G.; Haack, H.; Heinlein, D.; Sørensen, A. N.

2017-09-01

A very bright bolide illuminated the sky over Denmark and neighboring countries on February 6th, 2016 at 21:07:18-23UT. It terminated by a multiple meteorite fall in the heavily populated area of the western outskirts of Copenhagen. Several meteorites classified as the H5/6 ordinary chondrites have been found shortly after the fall and total recovered mass reached almost 9 kg (Haack, 2016). Although this spectacular bolide has been reported by many casual witnesses, the instrumental records are very scarce, mainly due to bad weather over Denmark and neighboring countries. Despite it we were able to collect five instrumental records taken from different locations which were useful for the analysis of this event. We used three high resolution digital photographic images taken in Germany, one high resolution radiometric light curve taken by the northernmost Czech automated fireball observatory and one video record taken by a surveillance camera on the Danish west coast where a part of the fireball trajectory was recorded. It allowed us to reliably determine basic parameters defining the luminous trajectory of the bolide in the atmosphere and also heliocentric orbit of the initial meteoroid causing this spectacular meteorite fall. We found that this event was caused by a relatively fragile 50 cm meteoroid with initial mass about 250 kg. It entered the atmosphere with velocity of 14.5 km s-1 and quite steep entry angle of 62°. Its luminous flight started at 85.5 km and after 76 km long trajectory it terminated at 18.3 km. The heliocentric orbit of this meteoroid was of Apollo type with low inclination of 1° and perihelion distance just inside the Earth's orbit. It had a relatively large semimajor axis of 2.8 AU and aphelion distance 4.64 AU. It is the second largest aphelion distance among all meteorites with known orbits and the orbit had the same character as that of the Košice meteorite (H5 ordinary chondrite), which fell on February 28, 2010 (Borovička et al., 2013).

GRO: Black hole models for gamma-ray bursts

NASA Technical Reports Server (NTRS)

Ruderman, Malvin

1995-01-01

The Burst and Transient Source Experiment (BATSE) on board the Compton Gamma Ray Observatory (CGRO) has established that the distribution of gamma-ray bursts (GRB's) is isotropic but is bound radially. This finding suggests that the bursts are either cosmological or they originate from an extended Galactic halo. The implied luminosities and the observed variability of the GRB's on time scales as short as one millisecond suggest that they originate from compact objects. We are presently studying black hole models for GRB's. Any such model must produce a non-thermal photon spectrum to agree with the observed properties. For a wide range of burst parameters the assumed bursting source consists of a non-thermal electron-positron-photon plasma of very high density. It seems possible to produce such a plasma in accretion onto black holes. In our on-going work, we are developing the kinetic theory for a non-equilibrium pair plasma. The main new features of our work are as follows: (1) We do not assume the presence of a thermal electron bath. (2) Non-thermal, high-energy pairs are allowed to have an arbitrary concentration and energy distribution. (3) There is no soft photon source in our model; initially all the photons in the plasma are either energetic X-rays or gamma-rays. (4) The initial energy distribution of the pairs as well as photons is arbitrary. (5) We collect the analytical expressions for the kinetic kernels for all relevant processes. And (6) we present a different approach to finding the time-evolution of pair and photon spectra, which is a combination of the kinetic-theory and the non-linear Monte-Carlo schemes. We have developed many Monte-Carlo programs to model various process, to take into account the time evolution, and to incorporate various physical effects which are unique to non-thermal plasmas. The hydrodynamics of fireballs in GRB's was studied before. Applying results from kinetic theory will improve our understanding of these systems.

Comparing Eyewitness-Derived Trajectories of Bright Meteors to Ground Truth Data

NASA Technical Reports Server (NTRS)

Moser, D. E.

2016-01-01

The NASA Meteoroid Environment Office is a US government agency tasked with analyzing meteors of public interest. When queried about a meteor observed over the United States, the MEO must respond with a characterization of the trajectory, orbit, and size within a few hours. If the event is outside meteor network coverage and there is no imagery recorded by the public, a timely assessment can be difficult if not impossible. In this situation, visual reports made by eyewitnesses may be the only resource available. This has led to the development of a tool to quickly calculate crude meteor trajectories from eyewitness reports made to the American Meteor Society. A description of the tool, example case studies, and a comparison to ground truth data observed by the NASA All Sky Fireball Network are presented.

Shock waves raised by explosions in space as sources of ultra-high-energy cosmic rays

NASA Astrophysics Data System (ADS)

Kichigin, Gennadiy

2015-03-01

The paper discusses the possibility of particle acceleration up to ultrahigh energies in the relativistic waves generated by various explosive processes in the interstellar medium. We propose to use the surfatron mechanism of acceleration (surfing) of charged particles trapped in the front of relativistic waves as a generator of high-energy cosmic rays (CRs). Conditions under which surfing in these waves can be made are studied thoroughly. Ultra-high-energy CRs (up to 10^20 eV) are shown to be obtained due to the surfing in the relativistic plane and spherical waves. Surfing is supposed to take place in nonlinear Langmuir waves excited by powerful electromagnetic radiation or relativistic beams of charged particles, as well as in strong shock waves generated by relativistic jets or spherical formations that expand fast (fireballs).

The Small Acceptance Vertex Detector of NA61/SHINE

NASA Astrophysics Data System (ADS)

Deveaux, M.; Aduszkiewicz, A.; Ali, Y.; Baszczyk, M.; Brylinski, W.; Dorosz, P.; Di Luise, S.; Feofilov, G.; Gazdzicki, M.; Igolkin, S.; Jablonski, M.; Kovalenko, V.; Koziel, M.; Kucewicz, W.; Larsen, D.; Lazareva, T.; Martinengo, P.; Merzlaya, A.; Mik, L.; Planeta, R.; Snoch, A.; Vechernin, V.; Tefelski, D.; Suljic, M.; Staszel, P.

2018-02-01

Charmonium production in heavy ion collisions is considered as an important diagnostic probe for studying the phase diagram of strongly interacting matter for potential phase transitions. The interpretation of existing data from the CERN SPS is hampered by a lack of knowledge on the properties of open charm particle production in the fireball. Moreover, open charm production in heavy ion collisions by itself is poorly understood. To overcome this obstacle, the NA61/SHINE was equipped with a Small Acceptance Vertex Detector (SAVD), which is predicted to make the experiment sensitive to open charm mesons produced in A-A collisions at the SPS top energy. This paper will introduce the concept and the hardware of the SAVD. Moreover, first running experience as obtained in a commissioning run with a 150 AGeV/c Pb+Pb collision system will be reported.

Magnetospheric Effects as a New Aspect of the Asteroid Impact Problem: Necessity and Possibilities of Laboratory Simulation Experiments

NASA Astrophysics Data System (ADS)

Zakharov, Yuri P.; Nikitin, Sergei A.; Ponomarenko, Arnold G.; Minami, Shigeyuki

1997-05-01

This paper discusses the possible consequences to the Earth's magnetosphere, when due to too short an advanced warning, attempts at mitigation of a near-Earth object (NEO) must be made in close proximity to the Earth. The energy Eo, and explosive plasma release during impact may be compared with the kinetic energy Ek of the NEO and with the energy, Ee (Ee approximately Ek), needed for NEO deflection by a strong (protective force) explosive, at distances close to the scale of the magnetosphere. If the energy, Em, of the Earth's dipole field latter is relatively small (Em is less than Eo for a NEO size approximately 1 km), global or even catastrophic disturbances could occur. These ecologically important magnetospheric aspects of the NEO impact problem have been discussed recently; particularly in the context of the comet SL-9/Jupiter impact. In the latter case, the effect on Jupiter's magnetosphere of the 'NEO' explosions was very small (x equals Eo/Em approximately 0.001, where Em is the 'outer' magnetic energy of the planetary dipole field) and the corresponding model of its 'fireball' development could be simulated numerically in 'zero' approximation, with the assumption of an undisturbed magnetospheric media as a whole. However, in general, and, in the rather probable case of NEO impacts with values x approximately 1, the development of such 3D, nonstationary MHD or PIC-models at this time. Such information can be obtained from new kinds of simulation experiments with the laboratory magnetosphere, the so-called 'terrella'.

Optical Meteor Systems Used by the NASA Meteoroid Environment Office

NASA Technical Reports Server (NTRS)

Kingery, A. M.; Blaauw, R. C.; Cooke, W. J.; Moser, D. E.

2015-01-01

The NASA Meteoroid Environment Office (MEO) uses two main meteor camera networks to characterize the meteoroid environment: an all sky system and a wide field system to study cm and mm size meteors respectively. The NASA All Sky Fireball Network consists of fifteen meteor video cameras in the United States, with plans to expand to eighteen cameras by the end of 2015. The camera design and All-Sky Guided and Real-time Detection (ASGARD) meteor detection software [1, 2] were adopted from the University of Western Ontario's Southern Ontario Meteor Network (SOMN). After seven years of operation, the network has detected over 12,000 multi-station meteors, including meteors from at least 53 different meteor showers. The network is used for speed distribution determination, characterization of meteor showers and sporadic sources, and for informing the public on bright meteor events. The NASA Wide Field Meteor Network was established in December of 2012 with two cameras and expanded to eight cameras in December of 2014. The two camera configuration saw 5470 meteors over two years of operation with two cameras, and has detected 3423 meteors in the first five months of operation (Dec 12, 2014 - May 12, 2015) with eight cameras. We expect to see over 10,000 meteors per year with the expanded system. The cameras have a 20 degree field of view and an approximate limiting meteor magnitude of +5. The network's primary goal is determining the nightly shower and sporadic meteor fluxes. Both camera networks function almost fully autonomously with little human interaction required for upkeep and analysis. The cameras send their data to a central server for storage and automatic analysis. Every morning the servers automatically generates an e-mail and web page containing an analysis of the previous night's events. The current status of the networks will be described, alongside with preliminary results. In addition, future projects, CCD photometry and broadband meteor color camera system, will be discussed.

PHOTOSPHERE EMISSION FROM A HYBRID RELATIVISTIC OUTFLOW WITH ARBITRARY DIMENSIONLESS ENTROPY AND MAGNETIZATION IN GRBs

DOE Office of Scientific and Technical Information (OSTI.GOV)

Gao, He; Zhang, Bing, E-mail: gaohe@physics.unlv.edu, E-mail: zhang@physics.unlv.edu, E-mail: hug18@psu.edu

2015-03-10

In view of the recent Fermi observations of gamma-ray burst (GRB) prompt emission spectra, we develop a theory of photosphere emission of a hybrid relativistic outflow with a hot fireball component (defined by dimensionless entropy η) and a cold Poynting-flux component (defined by magnetization σ{sub 0} at the central engine). We consider the scenarios both without and with sub-photospheric magnetic dissipations. Based on a simplified toy model of jet dynamics, we develop two approaches: a 'bottom-up' approach to predict the temperature (for a non-dissipative photosphere) and luminosity of the photosphere emission and its relative brightness for a given pair ofmore » (η, σ{sub 0}); and a 'top-down' approach to diagnose central engine parameters (η and σ{sub 0}) based on the observed quasi-thermal photosphere emission properties. We show that a variety of observed GRB prompt emission spectra with different degrees of photosphere thermal emission can be reproduced by varying η and σ{sub 0} within the non-dissipative photosphere scenario. In order to reproduce the observed spectra, the outflows of most GRBs need to have a significant σ, both at the central engine and at the photosphere. The σ value at 10{sup 15} cm from the central engine (a possible non-thermal emission site) is usually also greater than unity, so that internal-collision-induced magnetic reconnection and turbulence (ICMART) may be the mechanism to power the non-thermal emission. We apply our top-down approach to GRB 110721A and find that the temporal evolution behavior of its blackbody component can be well interpreted with a time-varying (η, σ{sub 0}) at the central engine, instead of invoking a varying engine base size r {sub 0} as proposed by previous authors.« less

Gamma-Ray Burst Afterglows as Probes of Environment and Blastwave Physics II: The Distribution of p and Structure of the Circumburst Medium

NASA Technical Reports Server (NTRS)

Starling, R. L. C.; vanderHorst, A. J.; Rol, E.; Wijers, R. A. M. J.; Kouveliotou, C.; Wiersema, K.; Curran, P. A.; Weltevrede, P.

2007-01-01

We constrain blastwave parameters and the circumburst media of a subsample of BeppoSAX Gamma-Ray Bursts. For this sample we derive the values of the injected electron energy distribution index, p, and the density structure index of the circumburst medium, k, from simultaneous spectral fits to their X-ray, optical and nIR afterglow data. The spectral fits have been done in count space and include the effects of metallicity, and are compared with the previously reported optical and X-ray temporal behaviour. Assuming the fireball model, we can find a mean value of p for the sample as a whole of 2.035. A statistical analysis Of the distribution demonstrates that the p values in this sample are inconsistent with a single universal value for p at the 3sigma level or greater. This approach provides us with a measured distribution of circumburst density structures rather than considering only the cases of k = 0 (homogeneous) and k = 2 (wind-like). We find five GRBs for which k can be well constrained, and in four of these cases the circumburst medium is clearly wind-like. The fifth source has a value of 0 less than or equal to k less than or equal to 1, consistent with a homogeneous circumburst medium.

C-H Hot Bands in the Near-IR Emission Spectra of Leonids

NASA Technical Reports Server (NTRS)

Freund, F. T.; Scoville, J.; Holm, R.; Seelemann, R.; Freund, M. M.

2002-01-01

The reported infrared (IR) emission spectra from 1999 Leonid fireballs show a 3.4 micron C-H emission band and unidentified bands at longer wavelengths. Upon atmospheric entry, the Leonid meteorites were flash-heated to temperatures around 2400K, which would destroy any organics on the surface of the meteorite grains. We propose that the nu(sub )CH emission band in the Leonid emission spectra arises from matrix-embedded C(sub n)-H-O entities that are protected from instant pyrolysis. Our model is based on IR absorption nu(sub )CH bands, which we observed in laboratory-grown MgO and natural olivine single crystals, where they arise from C(sub n)-H-O units imbedded in the mineral matrix, indicative of aliphatic -CH2- and -CH3 organics. Instead of being pyrolyzed, the C(sub n)-H-O entities in the Leonid trails become vibrationally excited to higher levels n = 1, 2, 3 etc. During de-excitation they emit at 3.4 microns, due to the (0 => 1) transition, and at longer wavelengths, due to hot bands. As a first step toward verifying this hypothesis we measured the C-H vibrational manifold of hexane (C6H14). The calculated positions of the (2 => l ) , (3 => 2), and possibly (4 => 3) hot bands agree with the Leonid emission bands at 3.5, 3.8 and 4.l microns.

Signatures of α clustering in ultrarelativistic collisions with light nuclei

NASA Astrophysics Data System (ADS)

Rybczyński, Maciej; Piotrowska, Milena; Broniowski, Wojciech

2018-03-01

We explore possible observable signatures of α clustering of light nuclei in ultrarelativistic nuclear collisions involving Be,97, 12C, and 16O. The clustering leads to specific spatial correlations of the nucleon distributions in the ground state, which are manifest in the earliest stage of the ultrahigh energy reaction. The formed initial state of the fireball is sensitive to these correlations, and the effect influences, after the collective evolution of the system, the hadron production in the final stage. Specifically, we study effects on the harmonic flow in collisions of light clustered nuclei with a heavy target (208Pb), showing that measures of the elliptic flow are sensitive to clusterization in Be,97, whereas triangular flow is sensitive to clusterization in 12C and 16O. Specific predictions are made for model collisions at energies available at the CERN Super Proton Synchrotron. In another exploratory development we also examine proton-beryllium collisions, where the 3 /2- ground state of Be,97 nuclei is polarized by an external magnetic field. Clusterization leads to multiplicity distributions of participant nucleons which depend on the orientation of the polarization with respect to the collision axis, as well as on the magnetic number of the state. The obtained effects on multiplicities reach a factor of a few for collisions with a large number of participant nucleons.

From RHIC to LHC: Lessons on the QGP

NASA Astrophysics Data System (ADS)

Heinz, Ulrich

2011-10-01

Recent data from heavy-ion collisions at RHIC and LHC, together with significant advances in theory, have allowed us to make significant first steps in proceeding from a qualitative understanding of high energy collision dynamics to a quantitative characterization of the transport properties of the hot and dense QCD matter created in these collisions. The almost perfectly liquid nature of the Quark-Gluon Plasma (QGP) created at RHIC has recently also been confirmed at the much higher LHC energies, and we can now constrain the specific QGP shear viscosity (η / s) QGP to within a factor of 2.5 of its conjectured lower quantum bound. Viscous hydrodynamics, coupled to a microscopic hadron cascade at late times, has proven to be an extremely successful and highly predictive model for the QGP evolution at RHIC and LHC. The experimental discovery of higher order harmonic flow coefficients and their theoretically predicted differential sensitivity to shear viscosity promises additional gains in precision by about a factor 5 in (η / s) QGP for the very near future. The observed modification of jets and suppression of high-pT hadrons confirms the picture of the QGP as a strongly coupled colored liquid, and recent LHC data yield strong constraints on parton energy loss models, putting significant strain on some theoretical approaches, tuned to RHIC data, that are based on leading-order perturbative QCD. Thermal photon radiation provides important cross-checks on the early stages of dynamical evolution models and constrains the initial QGP temperature, but the recently measured strong photon elliptic flow challenges our present understanding of photon emission rates in the hadronic phase. Recent progress in developing a complete theoretical model for all stages of the QGP fireball expansion, from strong fluctuating gluon fields at its beginning to final hadronic freeze-out, and remaining challenges will be discussed. Work supported by DOE (grants DE-SC0004286 and DE-SC0004104 (JET Collaboration)).

Field validation of sound mitigation models and air pollutant emission testing in support of missile motor disposal activities.

PubMed

McFarland, Michael J; Palmer, Glenn R; Kordich, Micheal M; Pollet, Dean A; Jensen, James A; Lindsay, Mitchell H

2005-08-01

The U.S. Department of Defense approved activities conducted at the Utah Test and Training Range (UTTR) include both operational readiness test firing of intercontinental ballistic missile motors as well as the destruction of obsolete or otherwise unusable intercontinental ballistic missile motors through open burn/open detonation (OB/ OD). Within the Utah Division of Air Quality, these activities have been identified as having the potential to generate unacceptable noise levels, as well as significant amounts of hazardous air pollutants. Hill Air Force Base, UT, has completed a series of field tests at the UTTR in which sound-monitoring surveillance of OB/OD activities was conducted to validate the Sound Intensity Prediction System (SIPS) model. Using results generated by the SIPS model to support the decision to detonate, the UTTR successfully disposed of missile motors having an aggregate net explosive weight (NEW) of 56,500 lbs without generating adverse noise levels within populated areas. These results suggest that, under appropriate conditions, missile motors of even larger NEW may be detonated without exceeding regulatory noise limits. In conjunction with collecting noise monitoring data, air quality data was collected to support the development of air emission factors for both static missile motor firings and OB/OD activities. Through the installation of 15 ground-based air samplers, the generation of combustion fixed gases, hazardous air pollutants, and chlorides were monitored during the 56,500-lb NEW detonation event. Comparison of field measurements to predictions generated from the U.S. Navy's energetic combustion pollutant formation model, POLU4WN, indicated that, as the detonation fireball expanded from ground zero, organic compounds as well as carbon monoxide continued to oxidize as the hot gases reacted with ambient air. Hazardous air pollutant analysis of air samplers confirmed the presence of chloromethane, benzene, toluene, 1,2-propadiene, and 2-methyl-l-propene, whereas the absence of hydrogen chloride gas suggested that free chlorine is not generated during the combustion process.

First Earth-Based Detection of a Superbolide on Jupiter

NASA Technical Reports Server (NTRS)

Hueso, R.; Wesley, A.; Go, C.; Perez-Hoyos, S.; Wong, M. H.; Fletcher, L. N.; Sanchez-Lavega, A.; Boslough, M. B.; DePater, I.; Orton, G. S.;

Generation of Vorticity by Slow Conductive Cooling Flows.

NASA Astrophysics Data System (ADS)

Meerson, Baruch; Glasner, Ami; Livne, Eli

1996-11-01

Rapid energy release in a gas produces a ``hot channel" or ``fireball", depending on the energy release geometry. During its relaxation, the ``hot channel" develops significant vorticity and turbulence(J.M. Picone, J.P. Boris, J.R. Greig, M. Raleigh, and R.F. Fernsler, J. Atmos. Sci. 38), 2056 (1981). that strongly enhance its cooling. Picone and Boris(J.M. Picone and J.P. Boris, Phys. Fluids 26), 365 (1983). attributed the effect to an earlier, plasma-expansion-related stage of the process. We show that vorticity can also be produced on a longer time scale. After a few acoustic times, the plasma pressure becomes very close to the ambient pressure. As the temperature is still high, slow (subacoustic) conductive cooling flow (CCF) develops that cools the cavity and fills it with gas from the periphery(B. Meerson, Phys. Fluids A 1), 887 (1989); D. Kaganovich, B. Meerson, A. Zigler, C. Cohen, and J. Levin, Phys. Plasmas 3, 631 (1996).. Due to asymmetries, this flow develops significant vorticity on the heat-conduction time scale. We present a simplified theory for this effect that employs, as a zero-order solution, a novel two-dimensional (2d) similarity solution for an irrotational isobaric CCF. We also report on gas-dynamic simulations in 2d (with the heat transfer taken into account) which show vorticity generation by the slow CCF.

SU(2) x U(1) vacuum and the Centauro events

NASA Technical Reports Server (NTRS)

Kazanas, D.; Balasubrahmanyan, V. K.; Streitmatter, R. E.

1985-01-01

It is proposed that the fireballs invoked to explain the Centauro events are bubbles of a metastable superdense state of nuclear matter, created in high energy (E approximately 10 to the 15th power eV) cosmic ray collisions at the top of the atmosphere. If these bubbles are created with a Lorentz factor gamma approximately equals 10 at their CM frame, the objections against the origin of these events in cosmic ray interactions are overcome. A relationship then between their lifetime, tau, and the threshold energy for bubble formation, E sub th, appears to be insensitive to the value of tau and always close to E sub th approximately 10 to 15th power eV. Finally it is speculated that these bubbles might be manifestations of the SU(2) x U(1) false vacuum excited in these collisions. The absence of in the Centauro events is then explained by the decay modes of these excitations.

Relativistic-microwave theory of ball lightning.

PubMed

Wu, H-C

2016-06-22

Ball lightning, a fireball sometimes observed during lightnings, has remained unexplained. Here we present a comprehensive theory for the phenomenon: At the tip of a lightning stroke reaching the ground, a relativistic electron bunch can be produced, which in turn excites intense microwave radiation. The latter ionizes the local air and the radiation pressure evacuates the resulting plasma, forming a spherical plasma bubble that stably traps the radiation. This mechanism is verified by particle simulations. The many known properties of ball lightning, such as the occurrence site, relation to the lightning channels, appearance in aircraft, its shape, size, sound, spark, spectrum, motion, as well as the resulting injuries and damages, are also explained. Our theory suggests that ball lighting can be created in the laboratory or triggered during thunderstorms. Our results should be useful for lightning protection and aviation safety, as well as stimulate research interest in the relativistic regime of microwave physics.

Magnetized hypermassive neutron-star collapse: a central engine for short gamma-ray bursts.

PubMed

Shibata, Masaru; Duez, Matthew D; Liu, Yuk Tung; Shapiro, Stuart L; Stephens, Branson C

2006-01-27

A hypermassive neutron star (HMNS) is a possible transient formed after the merger of a neutron-star binary. In the latest axisymmetric magnetohydrodynamic simulations in full general relativity, we find that a magnetized HMNS undergoes "delayed" collapse to a rotating black hole (BH) as a result of angular momentum transport via magnetic braking and the magnetorotational instability. The outcome is a BH surrounded by a massive, hot torus with a collimated magnetic field. The torus accretes onto the BH at a quasisteady accretion rate [FORMULA: SEE TEXT]; the lifetime of the torus is approximately 10 ms. The torus has a temperature [FORMULA: SEE TEXT], leading to copious ([FORMULA: SEE TEXT]) thermal radiation that could trigger a fireball. Therefore, the collapse of a HMNS is a promising scenario for generating short-duration gamma-ray bursts and an accompanying burst of gravitational waves and neutrinos.

Exotic meson decays in the environment with chiral imbalance

NASA Astrophysics Data System (ADS)

Andrianov, A. A.; Andrianov, V. A.; Espriu, D.; Iakubovich, A. V.; Putilova, A. E.

2017-10-01

An emergence of Local Parity Breaking (LPB) in central heavy-ion collisions (HIC) at high energies is discussed. LPB in the fireball can be produced by a difference between the number densities of right- and left-handed chiral fermions (Chiral Imbalance) which is implemented by a chiral (axial) chemical potential. The effective meson lagrangian induced by QCD is extended to the medium with Chiral Imbalance and the properties of light scalar and pseudoscalar mesons (π, α0) are analyzed. It is shown that exotic decays of scalar mesons arise as a result of mixing of π and α0 vacuum states in the presence of chiral imbalance. The pion electromagnetic formfactor obtains an unusual parity-odd supplement which generates a photon polarization asymmetry in pion polarizability. We hope that the above pointed indications of LPB can be identified in experiments on LHC, RHIC, CBM FAIR and NICA accelerators.

Relativistic-microwave theory of ball lightning

NASA Astrophysics Data System (ADS)

Wu, H.-C.

2016-06-01

Ball lightning, a fireball sometimes observed during lightnings, has remained unexplained. Here we present a comprehensive theory for the phenomenon: At the tip of a lightning stroke reaching the ground, a relativistic electron bunch can be produced, which in turn excites intense microwave radiation. The latter ionizes the local air and the radiation pressure evacuates the resulting plasma, forming a spherical plasma bubble that stably traps the radiation. This mechanism is verified by particle simulations. The many known properties of ball lightning, such as the occurrence site, relation to the lightning channels, appearance in aircraft, its shape, size, sound, spark, spectrum, motion, as well as the resulting injuries and damages, are also explained. Our theory suggests that ball lighting can be created in the laboratory or triggered during thunderstorms. Our results should be useful for lightning protection and aviation safety, as well as stimulate research interest in the relativistic regime of microwave physics.

Relativistic-microwave theory of ball lightning

PubMed Central

Wu, H.-C.

2016-01-01

Ball lightning, a fireball sometimes observed during lightnings, has remained unexplained. Here we present a comprehensive theory for the phenomenon: At the tip of a lightning stroke reaching the ground, a relativistic electron bunch can be produced, which in turn excites intense microwave radiation. The latter ionizes the local air and the radiation pressure evacuates the resulting plasma, forming a spherical plasma bubble that stably traps the radiation. This mechanism is verified by particle simulations. The many known properties of ball lightning, such as the occurrence site, relation to the lightning channels, appearance in aircraft, its shape, size, sound, spark, spectrum, motion, as well as the resulting injuries and damages, are also explained. Our theory suggests that ball lighting can be created in the laboratory or triggered during thunderstorms. Our results should be useful for lightning protection and aviation safety, as well as stimulate research interest in the relativistic regime of microwave physics. PMID:27328835

Development and flight testing of UV optimized Photon Counting CCDs

NASA Astrophysics Data System (ADS)

Hamden, Erika T.

2018-06-01

I will discuss the latest results from the Hamden UV/Vis Detector Lab and our ongoing work using a UV optimized EMCCD in flight. Our lab is currently testing efficiency and performance of delta-doped, anti-reflection coated EMCCDs, in collaboration with JPL. The lab has been set-up to test quantum efficiency, dark current, clock-induced-charge, and read noise. I will describe our improvements to our circuit boards for lower noise, updates from a new, more flexible NUVU controller, and the integration of an EMCCD in the FIREBall-2 UV spectrograph. I will also briefly describe future plans to conduct radiation testing on delta-doped EMCCDs (both warm, unbiased and cold, biased configurations) thus summer and longer term plans for testing newer photon counting CCDs as I move the HUVD Lab to the University of Arizona in the Fall of 2018.

The CBM RICH detector

NASA Astrophysics Data System (ADS)

Adamczewski-Musch, J.; Akishin, P.; Becker, K.-H.; Belogurov, S.; Bendarouach, J.; Boldyreva, N.; Chernogorov, A.; Deveaux, C.; Dobyrn, V.; Dürr, M.; Eschke, J.; Förtsch, J.; Heep, J.; Höohne, C.; Kampert, K.-H.; Kochenda, L.; Kopfer, J.; Kravtsov, P.; Kres, I.; Lebedev, S.; Lebedeva, E.; Leonova, E.; Linev, S.; Mahmoud, T.; Michel, J.; Miftakhov, N.; Niebur, W.; Ovcharenko, E.; Pauly, C.; Pfeifer, D.; Querchfeld, S.; Rautenberg, J.; Reinecke, S.; Riabov, Y.; Roshchin, E.; Samsonov, V.; Tarasenkova, O.; Traxler, M.; Ugur, C.; Vznuzdaev, E.; Vznuzdaev, M.

2016-05-01

The CBM RICH detector will use CO2 as radiator gas, focussing glass mirrors with Al+MgF2 reflective and protective coating and Hamamatsu H12700 MAPMTs as photon detectors. The detector will serve for electron to pion separation up to momenta of 8 GeV/c and thus enable in CBM the measurement of electromagnetic radiation from the early and dense fireball in A+A collisions at SIS 100. In this article, the current status of the CBM RICH development will be presented including new measurements of the radiation hardness of the H12700 MAPMT and WLS coatings with p-terphenyl, the new concept for the readout electronics, and optimizations ongoing with respect to the mirror mount structure and overall geometry. Prior to the usage in CBM, part of the already ordered MAPMTs will be used to upgrade the HADES RICH detector for a new measurement campaign at SIS 18 from 2018-2020.

Understanding overpressure in the FAA aerosol can test by C3H2F3Br (2-BTP)✩

PubMed Central

Linteris, Gregory Thomas; Babushok, Valeri Ivan; Pagliaro, John Leonard; Burgess, Donald Raymond; Manion, Jeffrey Alan; Takahashi, Fumiaki; Katta, Viswanath Reddy; Baker, Patrick Thomas

2018-01-01

Thermodynamic equilibrium calculations, as well as perfectly-stirred reactor (PSR) simulations with detailed reaction kinetics, are performed for a potential halon replacement, C3H2F3Br (2-BTP, C3H2F3Br, 2-Bromo-3,3,3-trifluoropropene), to understand the reasons for the unexpected enhanced combustion rather than suppression in a mandated FAA test. The high pressure rise with added agent is shown to depend on the amount of agent, and is well-predicted by an equilibrium model corresponding to stoichiometric reaction of fuel, oxygen, and agent. A kinetic model for the reaction of C3H2F3Br in hydrocarbon-air flames has been applied to understand differences in the chemical suppression behavior of C3H2F3Br vs. CF3Br in the FAA test. Stirred-reactor simulations predict that in the conditions of the FAA test, the inhibition effectiveness of C3H2F3Br at high agent loadings is relatively insensitive to the overall stoichiometry (for fuel-lean conditions), and the marginal inhibitory effect of the agent is greatly reduced, so that the mixture remains flammable over a wide range of conditions. Most important, the flammability of the agent-air mixtures themselves (when compressively preheated), can support low-strain flames which are much more difficult to extinguish than the easy-to extinguish, high-strain primary fireball from the impulsively released fuel mixture. Hence, the exothermic reaction of halogenated hydrocarbons in air should be considered in other situations with strong ignition sources and low strain flows, especially at preheated conditions. PMID:29628525

Chelyabinsk fireball and Dyatlov pass tragedy

NASA Astrophysics Data System (ADS)

Kochemasov, G. G.

2013-09-01

The Chelyabinsk bolide as well as the Kunashak meteorite in 1949 (Fig. 3, black square) hit ground in ectonically peculiar place in the Ural Mountains. The main explosion was followed by a series of weaker bangs. The long Uralian fold belt (Pz) separates two subsectors (1 & 2, Fig. 1) of the Eurasian sector (1+2) of the Eastern hemisphere sectoral structure (Fig. 1). At the Pamirs-Hindukush massif (the "Pamirs' cross") meet four tectonic sectors of this structure: two opposite differently uplifted (Africa-Mediterranean ++ and Asian +) and separating them two opposite differently subsided (Eurasian - and Indooceanic - -). Tectonic bisectors divide the sectors into two differently tectonically elevated subsectors. The Ural Mountains is one of these bisectors dividing the somewhat risen East-European subsector and the relatively fallen West-Siberian one. Even more important is the sharp tectonic boundary between subsided Eurasian sector and uplifted Asian one (between 2 and 3, Fig. 1). Fig. 3 shows distribution of electrophonic bolides over USSR [1]. Observations numbers are in circles. The total of 343 observations is distributed at relevant districts; accompanied meteorites were found only in 23-24 cases; in the chart are excluded background values of 1-2 observations per district. Two areas are obviously anomalous. These of the Urals, and the Eurasia-Asia sectoral contact (Novosibirsk - Yenisei R. - Tunguska). A location in the long Uralian belt is determined by its intersection with the Timan fold belt coming from the northwest (Fig. 3). The catastrophic Dyatlov pass where nine people mysteriously died at once occurs there (triangle in Fig. 3). Mancy aborigines know this place as deadly where killing white shining spheres appear. Moreover this belt intersection is well known among hunters for UFO as the Permian triangle (Fig. 2). They meet there to observe unusual atmospheric shining and other anomalous phenomena. In the Yenisei-Tunguska-Baikal region lightning balls appear regularly causing broken trees [2]. In conclusion, these two tectonically distinctive regions are famous by anomalously often appearance of bolides part of which is accompanied by meteorite falls. Out of 343 observations meteorites accompanied less than 10 %. Unclear remains a strange attraction of bolides by very pronounced tectonic features.

Path to the stars: the evolution of the species in the hunting to the GRBs

NASA Astrophysics Data System (ADS)

Vitali, Fabrizio; Chincarini, Guido; Zannoni, Mario; Covino, Stefano; Molinari, Emilio; Benetti, Stefano; Bonoli, Carlotta; Bortoletto, Favio; Cascone, Enrico; Cosentino, Rosario; D'Alessio, Francesco; D'Avanzo, Paolo; de Caprio, Vincenzo; Della Valle, Massimo; Fernandez-Soto, Alberto; Fugazza, Dino; Giro, Enrico; Magrin, Demetrio; Malaspina, Giuseppe; Mankiewicz, Lech; Margutti, Raffaella; Mazzoleni, Ruben; Nicastro, Luciano; Riva, Alberto; Riva, Marco; Salvaterra, Ruben; Spanò, Paolo; Sperandio, Monica; Stefanon, Mauro; Tosti, Gino; Testa, Vincenzo

2010-07-01

During the last years, a number of telescopes and instruments have been dedicated to the follow-up of GRBs: recent studies of the prompt emission (see for instance GRB080319B) and of their afterglows, evidenced a series of phenomena that do not fit very well within the standard fireball model. In those cases, optical observations were fundamental to distinguish among different emission mechanisms and models. In particular, simultaneous observation in various optical filters became essential to understand the physics, and we discovered the need to have a detailed high time resolution follow up. Finally, recent observations of the polarization in GRB 090102 clearly indicate the presence of an ordered magnetic field favoring the electromagnetic outflows models. This is, however, only one case and, in order to detail properly the model, we need a bit of statistics. But, after the Swift launch, the average observed intensity of GRB afterglows showed to be lower than thought before. Robotic telescopes, as demonstrated by REM, ROTSE, TAROT, etc. (but see also the GROND set up) is clearly the winning strategy. Indeed, as we will also briefly discuss later on, the understanding of the prompt emission mechanism depends on the observations covering the first few hundreds seconds since the beginning of the event with high temporal resolution. To tackle these problems and track down a realistic model, we started the conceptual design and phase A study of a 4 meter class, fast-pointing telescope (40 sec on target), equipped with multichannel imagers, from Visible to Near Infrared (Codevisir/Pathos). In the study we explored all the different parts of the project, from the telescope to the instrumental suite to data managing and analysis, to the dome and site issue. Contacts with industry have been fruitful in understanding the actual feasibility of building such a complex machine and no show stoppers have been identified, even if some critical points should be better addressed in the Phase B study. In this paper, we present the main results of the feasibility study we performed.

Operational Planetary Space Weather Services for the Europlanet 2020 Research Infrastructure

NASA Astrophysics Data System (ADS)

André, Nicolas; Grande, Manuel

2017-04-01

Under Horizon 2020, the Europlanet 2020 Research Infrastructure (EPN2020-RI, http://www.europlanet-2020-ri.eu) includes an entirely new Virtual Access Service, "Planetary Space Weather Services" (PSWS) that will extend the concepts of space weather and space situational awareness to other planets in our Solar System and in particular to spacecraft that voyage through it. PSWS will provide at the end of 2017 12 services distributed over 4 different service domains - 1) Prediction, 2) Detection, 3) Modelling, 4) Alerts. These services include 1.1) A 1D MHD solar wind prediction tool, 1.2) Extensions of a Propagation Tool, 1.3) A meteor showers prediction tool, 1.4) A cometary tail crossing prediction tool, 2.1) Detection of lunar impacts, 2.2) Detection of giant planet fireballs, 2.3) Detection of cometary tail events, 3.1) A Transplanet model of magnetosphere-ionosphere coupling, 3.2) A model of the Mars radiation environment, 3.3.) A model of giant planet magnetodisc, 3.4) A model of Jupiter's thermosphere, 4) A VO-event based alert system. We will detail in the present paper some of these services with a particular emphasis on those already operational at the time of the presentation (1.1, 1.2, 1.3, 2.2, 3.1, 4). The proposed Planetary Space Weather Services will be accessible to the research community, amateur astronomers as well as to industrial partners planning for space missions dedicated in particular to the following key planetary environments: Mars, in support of ESA's ExoMars missions; comets, building on the success of the ESA Rosetta mission; and outer planets, in preparation for the ESA JUpiter ICy moon Explorer (JUICE). These services will also be augmented by the future Solar Orbiter and BepiColombo observations. This new facility will not only have an impact on planetary space missions but will also allow the hardness of spacecraft and their components to be evaluated under variety of known conditions, particularly radiation conditions, extending their knownflight-worthiness for terrestrial applications. Europlanet 2020 RI has received funding from the European Union's Horizon 2020 research and innovation programme under grant agreement No 654208.

Near-infrared instrumentation for rapid-response astronomy

NASA Astrophysics Data System (ADS)

Capone, John Isaac

gamma-ray bursts (GRBs) are the Universe's most luminous transient events. Since the discovery of GRBs was announced in 1973, efforts have been ongoing to obtain data over a broader range of the electromagnetic spectrum at the earliest possible times following the initial detection. The discovery of the theorized "afterglow'' emission in radio through X-ray bands in the late 1990s confirmed the cosmological nature of these events. At present, GRB afterglows are among the best probes of the early Universe (z ≥ 9). In addition to informing theories about GRBs themselves, observations of afterglows probe the circum-burst medium (CBM), properties of the host galaxies and the progress of cosmic reionization. To explore the early-time variability of afterglows, I have developed a generalized analysis framework which models near-infrared (NIR), optical, ultra-violet (UV) and X-ray light curves without assuming an underlying model. These fits are then used to construct the spectral energy distribution (SED) of afterglows at arbitrary times within the observed window. Physical models are then used to explore the evolution of the SED parameter space with time. I demonstrate that this framework produces evidence of the photodestruction of dust in the CBM of GRB 120119A, similar to the findings from a previous study of this afterglow. The framework is additionally applied to the afterglows of GRB 140419A and GRB 080607. In these cases the evolution of the SEDs appears consistent with the standard fireball model. Having introduced the scientific motivations for early-time observations, I introduce the Rapid Infrared Imager-Spectrometer (RIMAS). Once commissioned on the 4.3 meter Discovery Channel Telescope (DCT), RIMAS will be used to study the afterglows of GRBs through photometric and spectroscopic observations beginning within minutes of the initial burst. The instrument will operate in the NIR, from 0.97 microm to 2.37 microm, permitting the detection of very high redshift (z ≥ 7) afterglows which are attenuated at shorter wavelengths by Lyman-alpha absorption in the intergalactic medium (IGM). A majority of my graduate work has been spent designing and aligning RIMAS's cryogenic ( 80 K) optical systems. Design efforts have included an original camera used to image the field surrounding spectroscopic slits, tolerancing and optimizing all of the instrument's optics, thermal modeling of optomechanical systems, and modeling the diffraction efficiencies for some of the dispersive elements. To align the cryogenic optics, I developed a procedure that was successfully used for a majority of the instrument's sub-assemblies. My work on this cryogenic instrument has necessitated experimental and computational projects to design and validate designs of several subsystems. Two of these projects describe simple and effective measurements of optomechanical components in vacuum and at cryogenic temperatures using an 8-bit CCD camera. Models of heat transfer via electrical harnesses used to provide current to motors located within the cryostat are also presented.

Spectra and physical properties of Taurid meteoroids

NASA Astrophysics Data System (ADS)

Matlovič, Pavol; Tóth, Juraj; Rudawska, Regina; Kornoš, Leonard

2017-09-01

Taurids are an extensive stream of particles produced by comet 2P/Encke, which can be observed mainly in October and November as a series of meteor showers rich in bright fireballs. Several near-Earth asteroids have also been linked with the meteoroid complex, and recently the orbits of two carbonaceous meteorites were proposed to be related to the stream, raising interesting questions about the origin of the complex and the composition of 2P/Encke. Our aim is to investigate the nature and diversity of Taurid meteoroids by studying their spectral, orbital, and physical properties determined from video meteor observations. Here we analyze 33 Taurid meteor spectra captured during the predicted outburst in November 2015 by stations in Slovakia and Chile, including 14 multi-station observations for which the orbital elements, material strength parameters, dynamic pressures, and mineralogical densities were determined. It was found that while orbits of the 2015 Taurids show similarities with several associated asteroids, the obtained spectral and physical characteristics point towards cometary origin with highly heterogeneous content. Observed spectra exhibited large dispersion of iron content and significant Na intensity in all cases. The determined material strengths are typically cometary in the KB classification, while PE criterion is on average close to values characteristic for carbonaceous bodies. The studied meteoroids were found to break up under low dynamic pressures of 0.02-0.10 MPa, and were characterized by low mineralogical densities of 1.3-2.5 g cm-3. The widest spectral classification of Taurid meteors to date is presented.

Quantitative Risk Mapping of Urban Gas Pipeline Networks Using GIS

NASA Astrophysics Data System (ADS)

Azari, P.; Karimi, M.

2017-09-01

Natural gas is considered an important source of energy in the world. By increasing growth of urbanization, urban gas pipelines which transmit natural gas from transmission pipelines to consumers, will become a dense network. The increase in the density of urban pipelines will influence probability of occurring bad accidents in urban areas. These accidents have a catastrophic effect on people and their property. Within the next few years, risk mapping will become an important component in urban planning and management of large cities in order to decrease the probability of accident and to control them. Therefore, it is important to assess risk values and determine their location on urban map using an appropriate method. In the history of risk analysis of urban natural gas pipeline networks, the pipelines has always been considered one by one and their density in urban area has not been considered. The aim of this study is to determine the effect of several pipelines on the risk value of a specific grid point. This paper outlines a quantitative risk assessment method for analysing the risk of urban natural gas pipeline networks. It consists of two main parts: failure rate calculation where the EGIG historical data are used and fatal length calculation that involves calculation of gas release and fatality rate of consequences. We consider jet fire, fireball and explosion for investigating the consequences of gas pipeline failure. The outcome of this method is an individual risk and is shown as a risk map.

Constraining Gamma-ray Burst Initial Lorentz Factor with the Afterglow Onset Feature and Discovery of a Tight Γ0-E γ,iso Correlation

NASA Astrophysics Data System (ADS)

Liang, En-Wei; Yi, Shuang-Xi; Zhang, Jin; Lü, Hou-Jun; Zhang, Bin-Bin; Zhang, Bing

2010-12-01

The onset of gamma-ray burst (GRB) afterglow is characterized by a smooth bump in the early afterglow light curve as the GRB fireball is decelerated by the circumburst medium. We extensively search for GRBs with such an onset feature in their optical and X-ray light curves from the literature and from the catalog established with the Swift/XRT. Twenty optically selected GRBs and 12 X-ray-selected GRBs are obtained, among which 17 optically selected and 2 X-ray-selected GRBs have redshift measurements. We fit these light curves with a smooth broken power law and measure the width (w), rising timescale (t r), and decaying timescale (t d) at full width at half-maximum. Strong mutual correlations among these timescales and with the peak time (t p) are found. The ratio t r/t d is almost universal among bursts, but the ratio t r/t p varies from 0.3 to ~1. The optical peak luminosity in the R band (L R,p) is anti-correlated with t p and w in the burst frame, indicating a dimmer and broader bump peaking at a later time. The isotropic prompt gamma-ray energy (E γ,iso) is also tightly correlated with L R,p and t p in the burst frame. Assuming that the bumps signal the deceleration of the GRB fireballs in a constant density medium, we calculate the initial Lorentz factor (Γ0) and the deceleration radius (R d) of the GRBs with redshift measurements. The derived Γ0 is typically a few hundreds, and the deceleration radius is R dec ~ 2 × 1017 cm. More intriguingly, a tight correlation between Γ0 and E γ,iso is found, namely Γ0 ~= 182(E γ,iso/1052 erg)0.25. This correlation also applies to the small sample of GRBs which show the signature of the afterglow onset in their X-ray afterglow, and to two bursts (GRBs 990123 and 080319B) whose early optical emission is dominated by a reverse shock. The lower limits of Γ0 derived from a sample of optical afterglow light curves showing a decaying feature from the beginning of the observation are also generally consistent with such a correlation. The tight lower limits of Γ0 of GRBs 080916C and 090902B derived from the opacity constraints with Fermi/LAT observations are also consistent with the correlation at the 2σ confidence level, but the short GRB 090510 is a clear outlier of this relation. This correlation may give insight to GRB physics and could serve as an indicator of Γ0 for long GRBs without early afterglow detections. A comparison of the early X-ray and optical afterglow light curves shows that the early bright X-ray emission is usually dominated by a non-forward-shock component, but occasionally (for one case) the forward shock emission is observable, and an achromatic deceleration feature is observed. The superposition of the internal and external components in X-rays causes the diversity of the observed X-ray light curves.

Climate Impact of a Regional Nuclear Weapons Exchange: An Improved Assessment Based On Detailed Source Calculations

NASA Astrophysics Data System (ADS)

Reisner, Jon; D'Angelo, Gennaro; Koo, Eunmo; Even, Wesley; Hecht, Matthew; Hunke, Elizabeth; Comeau, Darin; Bos, Randall; Cooley, James

2018-03-01

We present a multiscale study examining the impact of a regional exchange of nuclear weapons on global climate. Our models investigate multiple phases of the effects of nuclear weapons usage, including growth and rise of the nuclear fireball, ignition and spread of the induced firestorm, and comprehensive Earth system modeling of the oceans, land, ice, and atmosphere. This study follows from the scenario originally envisioned by Robock, Oman, Stenchikov, et al. (2007, https://doi.org/10.5194/acp-7-2003-2007), based on the analysis of Toon et al. (2007, https://doi.org/10.5194/acp-7-1973-2007), which assumes a regional exchange between India and Pakistan of fifty 15 kt weapons detonated by each side. We expand this scenario by modeling the processes that lead to production of black carbon, in order to refine the black carbon forcing estimates of these previous studies. When the Earth system model is initiated with 5 × 109 kg of black carbon in the upper troposphere (approximately from 9 to 13 km), the impact on climate variables such as global temperature and precipitation in our simulations is similar to that predicted by previously published work. However, while our thorough simulations of the firestorm produce about 3.7 × 109 kg of black carbon, we find that the vast majority of the black carbon never reaches an altitude above weather systems (approximately 12 km). Therefore, our Earth system model simulations conducted with model-informed atmospheric distributions of black carbon produce significantly lower global climatic impacts than assessed in prior studies, as the carbon at lower altitudes is more quickly removed from the atmosphere. In addition, our model ensembles indicate that statistically significant effects on global surface temperatures are limited to the first 5 years and are much smaller in magnitude than those shown in earlier works. None of the simulations produced a nuclear winter effect. We find that the effects on global surface temperatures are not uniform and are concentrated primarily around the highest arctic latitudes, dramatically reducing the global impact on human health and agriculture compared with that reported by earlier studies. Our analysis demonstrates that the probability of significant global cooling from a limited exchange scenario as envisioned in previous studies is highly unlikely, a conclusion supported by examination of natural analogs, such as large forest fires and volcanic eruptions.

Climate impact of a regional nuclear weapons exchange: An improved assessment based on detailed source calculations

DOE PAGES

Reisner, Jon Michael; D'Angelo, Gennaro; Koo, Eunmo; ...

2018-02-13

In this paper, we present a multi-scale study examining the impact of a regional exchange of nuclear weapons on global climate. Our models investigate multiple phases of the effects of nuclear weapons usage, including growth and rise of the nuclear fireball, ignition and spread of the induced firestorm, and comprehensive Earth system modeling of the oceans, land, ice, and atmosphere. This study follows from the scenario originally envisioned by Robock et al. (2007a), based on the analysis of Toon et al. (2007), which assumes a regional exchange between India and Pakistan of fifty 15-kiloton weapons detonated by each side. Wemore » expand this scenario by modeling the processes that lead to production of black carbon, in order to refine the black carbon forcing estimates of these previous studies. When the Earth system model is initiated with 5 × 10 9 kg of black carbon in the upper troposphere (approximately 9 to 13 km), the impact on climate variables such as global temperature and precipitation in our simulations is similar to that predicted by previously published work. However, while our thorough simulations of the firestorm produce about 3.7 × 10 9 kg of black carbon, we find that the vast majority of the black carbon never reaches an altitude above weather systems (approximately 12 km). Therefore, our Earth system model simulations conducted with model-informed atmospheric distributions of black carbon produce significantly lower global climatic impacts than assessed in prior studies, as the carbon at lower altitudes is more quickly removed from the atmosphere. In addition, our model ensembles indicate that statistically significant effects on global surface temperatures are limited to the first 5 years and are much smaller in magnitude than those shown in earlier works. None of the simulations produced a nuclear winter effect. We find that the effects on global surface temperatures are not uniform and are concentrated primarily around the highest arctic latitudes, dramatically reducing the global impact on human health and agriculture compared with that reported by earlier studies. Lastly, our analysis demonstrates that the probability of significant global cooling from a limited exchange scenario as envisioned in the previous studies is highly unlikely, a conclusion supported by examination of natural analogs, such as large forest fires and volcanic eruptions.« less

Climate impact of a regional nuclear weapons exchange: An improved assessment based on detailed source calculations

DOE Office of Scientific and Technical Information (OSTI.GOV)

Reisner, Jon Michael; D'Angelo, Gennaro; Koo, Eunmo

In this paper, we present a multi-scale study examining the impact of a regional exchange of nuclear weapons on global climate. Our models investigate multiple phases of the effects of nuclear weapons usage, including growth and rise of the nuclear fireball, ignition and spread of the induced firestorm, and comprehensive Earth system modeling of the oceans, land, ice, and atmosphere. This study follows from the scenario originally envisioned by Robock et al. (2007a), based on the analysis of Toon et al. (2007), which assumes a regional exchange between India and Pakistan of fifty 15-kiloton weapons detonated by each side. Wemore » expand this scenario by modeling the processes that lead to production of black carbon, in order to refine the black carbon forcing estimates of these previous studies. When the Earth system model is initiated with 5 × 10 9 kg of black carbon in the upper troposphere (approximately 9 to 13 km), the impact on climate variables such as global temperature and precipitation in our simulations is similar to that predicted by previously published work. However, while our thorough simulations of the firestorm produce about 3.7 × 10 9 kg of black carbon, we find that the vast majority of the black carbon never reaches an altitude above weather systems (approximately 12 km). Therefore, our Earth system model simulations conducted with model-informed atmospheric distributions of black carbon produce significantly lower global climatic impacts than assessed in prior studies, as the carbon at lower altitudes is more quickly removed from the atmosphere. In addition, our model ensembles indicate that statistically significant effects on global surface temperatures are limited to the first 5 years and are much smaller in magnitude than those shown in earlier works. None of the simulations produced a nuclear winter effect. We find that the effects on global surface temperatures are not uniform and are concentrated primarily around the highest arctic latitudes, dramatically reducing the global impact on human health and agriculture compared with that reported by earlier studies. Lastly, our analysis demonstrates that the probability of significant global cooling from a limited exchange scenario as envisioned in the previous studies is highly unlikely, a conclusion supported by examination of natural analogs, such as large forest fires and volcanic eruptions.« less

An Earth-grazing fireball from the Daytime ζ-Perseid shower observed over Spain on 2012 June 10

NASA Astrophysics Data System (ADS)

Madiedo, José M.; Espartero, Francisco; Castro-Tirado, Alberto J.; Pastor, Sensi; de los Reyes, José A.

2016-07-01

On 2012 June 10, an Earth-grazer meteor which lasted over 17 s with an absolute magnitude of -4.0 ± 0.5 was observed over Spain. This work focuses on the analysis of this rare event which is, to our knowledge, the faintest Earth-grazing meteor reported in the scientific literature, but also the first one belonging to a meteor shower. Thus, the orbital parameters show that the parent meteoroid belonged to the Daytime ζ-Perseid meteoroid stream. According to our calculations, the meteor was produced by a meteoroid with an initial mass ranging between 115 and 1.5 kg. During its encounter with Earth, the particle travelled about 510 km in the atmosphere. Around 260 g were destroyed in the atmosphere during the luminous phase of the event as a consequence of the ablation process. The modified orbit of the remaining material, which left our planet with a fusion crust, is also calculated.

The Effect of Magnetic Fields on Gamma-Ray Bursts Inferred from Multi-Wavelength Observations of the Bursts of 23 January 1999

NASA Technical Reports Server (NTRS)

Galama, T. J.; Briggs, M. S.; Wijers, R. A. M. J.; Vreeswijk, P. M.; Rol, E.; Band, D.; vanParadijs, J.; Kouveliotou, C.; Preece, R. D.; Bremer, M.

1999-01-01

Gamma-ray bursts (GRBs) are thought to arise when an extremely relativistic outflow of particles from a massive explosion (the nature at which is still unclear) interacts with material surrounding the site of the explosion. Observations of the evolving changes in emission at many wavelengths allow us to investigate the origin of the photons, and so potentially determine the nature of the explosion. Here we report the results of gamma-ray, optical, infrared, submillimeter, millimeter and radio observations of the burst ORB990123 and its afterglow. Our interpretation of the data indicates that the initial and afterglow emissions are associated with three distinct regions in the fireball. The peak flux of the afterglow, one day after the burst, has a lower frequency than observed for other bursts; this explains the short-lived radio emission. We suggest that the differences between bursts reflect variations in the magnetic-field strength in the afterglow-emitting regions.

Development of heavy-flavour flow-harmonics in high-energy nuclear collisions

NASA Astrophysics Data System (ADS)

Beraudo, Andrea; De Pace, Arturo; Monteno, Marco; Nardi, Marzia; Prino, Francesco

2018-02-01

We employ the POWLANG transport setup, developed over the last few years, to provide new predictions for several heavy-flavour observables in relativistic heavy-ion collisions from RHIC to LHC center-of-mass energies. In particular, we focus on the development of the flow-harmonics v 2 and v 3 arising from the initial geometric asymmetry in the initial conditions and its associated event-by-event fluctuations. Within the same transport framework, for the sake of consistency, we also compare the nuclear modification factor of the p T spectra of charm and beauty quarks, heavy hadrons and their decay electrons. We compare our findings to the most recent data from the experimental collaborations. We also study in detail the contribution to the flow harmonics from the quarks decoupling from the fireball during the various stages of its evolution: although not directly accessible to the experiments, this information can shed light on the major sources of the final measured effect.

Successful twilight observations of eta-Aquarid shower in "Unified Churyumov Network"

NASA Astrophysics Data System (ADS)

Steklov, E. A.; Kruchynenko, V. G.; Steklov, A. F.; Vidmachenko, A. P.; Dashkiev, G. N.

2017-05-01

On March 29 2013, on the left bank of the Dnieper in Kiev, young amateur astronomers, in the evening twilight, observed almost simultaneous invasion of three large fragments of meteoroid. Then four images were obtained. It was proposed to create a "Club of Fireball tracks observers". As a result, in Kiev region a network of photo hunters on twilight and daytime tracks of dangerous invasions into the sky above us - was formed. This "Unified Churyumov Network" has been in operation for four years. From April 19 to May 28, we are actively observing a meteor shower of eta-Aquarids. The particles of this meteor shower are fragments of nucleus of the famous Halley comet. In May 10 at the same time four observers photographed very interesting trail of invasion from four points of Kiev. In the last few years, the authors have registered several hundred small and dozens of larger invasions in the sky over Kiev and Kiev region.

Operation Sun Beam, Shot Small Boy. Project Officers report. Project 1. 4. Shock photography

DOE Office of Scientific and Technical Information (OSTI.GOV)

Hanlon, P.; Dieter, C.F.

1985-09-01

The objective of this project was to measure the shock position as a function of time from which shock velocities and pressures in limited regions could be calculated, and any asymmetric growth both along along and above the surface could be detected. An outgrowth of the fireball along the surface was observed, and it was attributed to surface heating. The rate of growth along the surface was asymmetric. The growth along the 113 deg azimuth was markedly greater than in any of the other directions measured. Contrary to previous experience with surface shots, the peak pressures obtained above ground zeromore » were less than those obtained along the surface at the same distances. there is some evidence to suggest that the focusing noted on previous shots did not occur or was very much reduced. Scaled Small Boy peak pressure-distance data are in agreement with the composite surface-burst pressure-distance curve.« less

Large Directed Flow of Open Charm Mesons Probes the Three-Dimensional Distribution of Matter in Heavy-Ion Collisions

NASA Astrophysics Data System (ADS)

Chatterjee, Sandeep; BoŻek, Piotr

2018-05-01

Thermalized matter created in noncentral relativistic heavy-ion collisions is expected to be tilted in the reaction plane with respect to the beam axis. The most notable consequence of this forward-backward symmetry breaking is the observation of rapidity-odd directed flow for charged particles. On the other hand, the production points for heavy quarks are forward-backward symmetric and shifted in the transverse plane with respect to the fireball. The drag on heavy quarks from the asymmetrically distributed thermalized matter generates substantial directed flow for heavy flavor mesons. We predict a very large rapidity-odd directed flow of D mesons in noncentral Au-Au collisions at √{sN N}=200 GeV , several times larger than for charged particles. A possible experimental observation of a large directed flow for heavy flavor mesons would represent an almost direct probe of the three-dimensional distribution of matter in heavy-ion collisions.

The faint intergalactic-medium red-shifted emission balloon: future UV observations with EMCCDs

NASA Astrophysics Data System (ADS)

Kyne, Gillian; Hamden, Erika T.; Lingner, Nicole; Morrissey, Patrick; Nikzad, Shouleh; Martin, D. Christopher

2016-08-01

We present the latest developments in our joint NASA/CNES suborbital project. This project is a balloon-borne UV multi-object spectrograph, which has been designed to detect faint emission from the circumgalactic medium (CGM) around low redshift galaxies. One major change from FIREBall-1 has been the use of a delta-doped Electron Multiplying CCD (EMCCD). EMCCDs can be used in photon-counting (PC) mode to achieve extremely low readout noise (¡ 1e-). Our testing initially focused on reducing clock-induced-charge (CIC) through wave shaping and well depth optimisation with the CCD Controller for Counting Photons (CCCP) from Nüvü. This optimisation also includes methods for reducing dark current, via cooling and substrate voltage adjustment. We present result of laboratory noise measurements including dark current. Furthermore, we will briefly present some initial results from our first set of on-sky observations using a delta-doped EMCCD on the 200 inch telescope at Palomar using the Palomar Cosmic Web Imager (PCWI).

On the hazard of hydrogen explosions at space shuttle launch pads

NASA Technical Reports Server (NTRS)

Russell, John M.

1988-01-01

This report was prepared in support of efforts to assess the hazard of accidental explosions of unburned hydrogen at space shuttle launch pads. It begins with presentation of fundamental detonation theory and a review of relevent experiments. A scenario for a catastrophic explosion at a KSC launch pad and a list of necessary conditions contributing to it is proposed with a view to identifying those conditions which, if blocked, would prevent a catastrophe. The balance of the report is devoted to juxtaposition of reassuring and disquieting facts, presentation of a set of recommendations that ignition of hydrogen-air mixtures by weak ignition sources in unconfined geometries may produce a detonation, provided the effective flame area in the initial fireball is rapidly increased by turbulent mixing. Another conclusion is that detonability limits can be different from and narrower than flammability limits only if one restricts the rate of work that can be done on a flammable gas by mechanical agencies acting on its boundaries.

Neutron Generation by Laser-Driven Spherically Convergent Plasma Fusion.

PubMed

Ren, G; Yan, J; Liu, J; Lan, K; Chen, Y H; Huo, W Y; Fan, Z; Zhang, X; Zheng, J; Chen, Z; Jiang, W; Chen, L; Tang, Q; Yuan, Z; Wang, F; Jiang, S; Ding, Y; Zhang, W; He, X T

2017-04-21

We investigate a new laser-driven spherically convergent plasma fusion scheme (SCPF) that can produce thermonuclear neutrons stably and efficiently. In the SCPF scheme, laser beams of nanosecond pulse duration and 10^{14}-10^{15}  W/cm^{2} intensity uniformly irradiate the fuel layer lined inside a spherical hohlraum. The fuel layer is ablated and heated to expand inwards. Eventually, the hot fuel plasmas converge, collide, merge, and stagnate at the central region, converting most of their kinetic energy to internal energy, forming a thermonuclear fusion fireball. With the assumptions of steady ablation and adiabatic expansion, we theoretically predict the neutron yield Y_{n} to be related to the laser energy E_{L}, the hohlraum radius R_{h}, and the pulse duration τ through a scaling law of Y_{n}∝(E_{L}/R_{h}^{1.2}τ^{0.2})^{2.5}. We have done experiments at the ShengGuangIII-prototype facility to demonstrate the principle of the SCPF scheme. Some important implications are discussed.

Comprehensive Parameterization of the p-Meson Spectral Function in Hot and Dense Matter

NASA Astrophysics Data System (ADS)

Onyango, Thomas; Rapp, Ralf

2017-09-01

The goal of this research is to study how hadronic matter transitions into quark-gluon plasma. This transition is believed to have occurred in the early universe about 10 microseconds after the big bang. In particular, this transition created more than 95% of the visible mass in the universe, and confined quarks and gluons into hadrons. Hot nuclear matter can be recreated in the laboratory by colliding heavy atomic nuclei at very high energies. This transition into the quark-gluon plasma can be probed by analyzing the invariant mass distributions of ρ-mesons. The ρ-meson was chosen because it decays into dilepton pairs, e.g. or . Dilepton pairs are a preferred observable because they do not interact through the strong nuclear force inside the strongly interacting fireball, therefore ρ-mesons decay into dileptons in the medium and can be measured during heavy ion collisions. In this project, we developed a parameterization of this process which will help to describe quark-gluon plasma which filled the early universe.

Neutron Generation by Laser-Driven Spherically Convergent Plasma Fusion

NASA Astrophysics Data System (ADS)

Ren, G.; Yan, J.; Liu, J.; Lan, K.; Chen, Y. H.; Huo, W. Y.; Fan, Z.; Zhang, X.; Zheng, J.; Chen, Z.; Jiang, W.; Chen, L.; Tang, Q.; Yuan, Z.; Wang, F.; Jiang, S.; Ding, Y.; Zhang, W.; He, X. T.

2017-04-01

We investigate a new laser-driven spherically convergent plasma fusion scheme (SCPF) that can produce thermonuclear neutrons stably and efficiently. In the SCPF scheme, laser beams of nanosecond pulse duration and 1 014- 1 015 W /cm2 intensity uniformly irradiate the fuel layer lined inside a spherical hohlraum. The fuel layer is ablated and heated to expand inwards. Eventually, the hot fuel plasmas converge, collide, merge, and stagnate at the central region, converting most of their kinetic energy to internal energy, forming a thermonuclear fusion fireball. With the assumptions of steady ablation and adiabatic expansion, we theoretically predict the neutron yield Yn to be related to the laser energy EL, the hohlraum radius Rh, and the pulse duration τ through a scaling law of Yn∝(EL/Rh1.2τ0.2 )2.5. We have done experiments at the ShengGuangIII-prototype facility to demonstrate the principle of the SCPF scheme. Some important implications are discussed.

Controlled Impact Demonstration

NASA Image and Video Library

1984-12-01

The Controlled Impact Demonstration (or colloquially the Crash In the Desert) was a joint project between NASA and the Federal Aviation Administration (FAA) that intentionally crashed a remotely controlled Boeing 720 aircraft to acquire data and test new technologies that might help passengers and crew survive. The crash required more than four years of preparation by NASA Ames Research Center, Langley Research Center, Dryden Flight Research Center, the FAA, and General Electric. After numerous test runs, the plane was crashed on December 1, 1984. The test went generally according to plan, and produced a spectacular fireball that required more than an hour to extinguish. The FAA concluded that about one-quarter of the passengers would have survived, that the antimisting kerosene test fuel did not sufficiently reduce the risk of fire, and that several changes to equipment in the passenger compartment of aircraft were needed. NASA concluded that a head-up display and with microwave landing system would have helped the pilot more safely fly the aircraft.

CTBT infrasound network performance to detect the 2013 Russian fireball event

DOE PAGES

Pilger, Christoph; Ceranna, Lars; Ross, J. Ole; ...

2015-03-18

The explosive fragmentation of the 2013 Chelyabinsk meteorite generated a large airburst with an equivalent yield of 500 kT TNT. It is the most energetic event recorded by the infrasound component of the Comprehensive Nuclear-Test-Ban Treaty-International Monitoring System (CTBT-IMS), globally detected by 20 out of 42 operational stations. This study performs a station-by-station estimation of the IMS detection capability to explain infrasound detections and nondetections from short to long distances, using the Chelyabinsk meteorite as global reference event. Investigated parameters influencing the detection capability are the directivity of the line source signal, the ducting of acoustic energy, and the individualmore » noise conditions at each station. Findings include a clear detection preference for stations perpendicular to the meteorite trajectory, even over large distances. Only a weak influence of stratospheric ducting is observed for this low-frequency case. As a result, a strong dependence on the diurnal variability of background noise levels at each station is observed, favoring nocturnal detections.« less

Mercury contamination study for flight system safety

NASA Technical Reports Server (NTRS)

Gorzynski, C. S., Jr.; Maycock, J. N.

1972-01-01

The effects and prevention of possible mercury pollution from the failure of solar electric propulsion spacecraft using mercury propellant were studied from tankage loading of post launch trajector injection. During preflight operations and initial flight mode there is little danger of mercury pollution if proper safety precautions are taken. Any spillage on the loading, mating, transportation, or launch pad areas is obvious and can be removed by vacuum cleaning soil and chemical fixing. Mercury spilled on Cape Kennedy ground soil will be chemically complexed and retained by the sandstone subsoil. A cover layer of sand or gravel on spilled mercury which has settled to the bottom of a water body adjacent to the system operation will control and eliminate the formation of toxic organic mercurials. Mercury released into the earth's atmosphere through leakage of a fireball will be diffused to low concentration levels. However, gas phase reactions of mercury with ozone could cause a local ozone depletion and result in serious ecological hazards.

Entropy and cosmology.

NASA Astrophysics Data System (ADS)

Zucker, M. H.

This paper is a critical analysis and reassessment of entropic functioning as it applies to the question of whether the ultimate fate of the universe will be determined in the future to be "open" (expanding forever to expire in a big chill), "closed" (collapsing to a big crunch), or "flat" (balanced forever between the two). The second law of thermodynamics declares that entropy can only increase and that this principle extends, inevitably, to the universe as a whole. This paper takes the position that this extension is an unwarranted projection based neither on experience nonfact - an extrapolation that ignores the powerful effect of a gravitational force acting within a closed system. Since it was originally presented by Clausius, the thermodynamic concept of entropy has been redefined in terms of "order" and "disorder" - order being equated with a low degree of entropy and disorder with a high degree. This revised terminology more subjective than precise, has generated considerable confusion in cosmology in several critical instances. For example - the chaotic fireball of the big bang, interpreted by Stephen Hawking as a state of disorder (high entropy), is infinitely hot and, thermally, represents zero entropy (order). Hawking, apparently focusing on the disorderly "chaotic" aspect, equated it with a high degree of entropy - overlooking the fact that the universe is a thermodynamic system and that the key factor in evaluating the big-bang phenomenon is the infinitely high temperature at the early universe, which can only be equated with zero entropy. This analysis resolves this confusion and reestablishes entropy as a cosmological function integrally linked to temperature. The paper goes on to show that, while all subsystems contained within the universe require external sources of energization to have their temperatures raised, this requirement does not apply to the universe as a whole. The universe is the only system that, by itself can raise its own temperature and thus, by itself; reverse entropy. The vast encompassing gravitational forces that the universe has at its disposal, forces that dominate the phase of contraction, provide the compacting, compressive mechanism that regenerates heat in an expanded, cooled universe and decreases entropy. And this phenomenon takes place without diminishing or depleting the finite amount of mass/energy with which the universe began. The fact that the universe can reverse the entropic process leads to possibilities previously ignored when assessing which of the three models (open, closed, of flat) most probably represents the future of the universe. After analyzing the models, the conclusion reached here is that the open model is only an expanded version of the closed model and therefore is not open, and the closed model will never collapse to a big crunch and, therefore, is not closed. Which leaves a modified model, oscillating forever between limited phases of expansion and contraction (a universe in "dynamic equilibrium") as the only feasible choice.

Transverse energy per charged particle in heavy-ion collisions: Role of collective flow

NASA Astrophysics Data System (ADS)

Kumar Tiwari, Swatantra; Sahoo, Raghunath

2018-03-01

The ratio of (pseudo)rapidity density of transverse energy and the (pseudo)rapidity density of charged particles, which is a measure of the mean transverse energy per particle, is an important observable in high energy heavy-ion collisions. This ratio reveals information about the mechanism of particle production and the freeze-out criteria. Its collision energy and centrality dependence is almost similar to the chemical freeze-out temperature until top Relativistic Heavy-Ion Collider (RHIC) energy. The Large Hadron Collider (LHC) measurement at √{s_{NN}} = 2.76 TeV brings up new challenges towards understanding the phenomena like gluon saturation and role of collective flow, etc. being prevalent at high energies, which could contribute to the above observable. Statistical Hadron Gas Model (SHGM) with a static fireball approximation has been successful in describing both the centrality and energy dependence until top RHIC energies. However, the SHGM predictions for higher energies lie well below the LHC data. In order to understand this, we have incorporated collective flow in an excluded-volume SHGM (EV-SHGM). Our studies suggest that the collective flow plays an important role in describing E T/ N ch and it could be one of the possible parameters to explain the rise observed in E T/ N ch from RHIC to LHC energies. Predictions are made for E T/ N ch , participant pair normalized-transverse energy per unit rapidity and the Bjorken energy density for Pb+Pb collisions at √{s_{NN}} = 5.02 TeV at the Large Hadron Collider.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Ben-Ami, Sagi; Gal-Yam, Avishay; Yaron, Ofer

We present the discovery and extensive early-time observations of the Type Ic supernova (SN) PTF12gzk. Our light curves show a rise of 0.8 mag within 2.5 hr. Power-law fits (f(t){proportional_to}(t - t{sub 0}) {sup n}) to these data constrain the explosion date to within one day. We cannot rule out a quadratic fireball model, but higher values of n are possible as well for larger areas in the fit parameter space. Our bolometric light curve and a dense spectral sequence are used to estimate the physical parameters of the exploding star and of the explosion. We show that the photometricmore » evolution of PTF12gzk is slower than that of most SNe Ic. The high ejecta expansion velocities we measure ({approx}30, 000 km s{sup -1} derived from line minima four days after explosion) are similar to the observed velocities of broad-lined SNe Ic associated with gamma-ray bursts (GRBs) rather than to normal SN Ic velocities. Yet, this SN does not show the persistent broad lines that are typical of broad-lined SNe Ic. The host-galaxy characteristics are also consistent with GRB-SN hosts, and not with normal SN Ic hosts. By comparison with the spectroscopically similar SN 2004aw, we suggest that the observed properties of PTF12gzk indicate an initial progenitor mass of 25-35 M{sub Sun} and a large ((5-10) Multiplication-Sign 10{sup 51} erg) kinetic energy, the later being close to the regime of GRB-SN properties.« less

Things begin to happen around Supernova 1987A

NASA Astrophysics Data System (ADS)

1994-01-01

On 23 February 1994, it will be exactly seven years since the explosion of Supernova 1987A in the Large Magellanic Cloud [1] was first observed, at a distance of approx. 160,000 light-years. It was the first naked-eye supernova to be seen in almost four hundred years. Few events in modern astronomy have met with such an enthusiastic response by the scientists and this famous object has been under constant surveillance ever since. After several years of relative quiescence, things are now beginning to happen in the immediate neighbourhood of SN 1987A. Recent observations with the ESO 3.5 m New Technology Telescope (NTT) indicate that interaction between the stellar material which was ejected during the explosion and the surrounding ring-shaped nebulae has started. This signals the beginning of a more active phase during which the supernova is likely to display a number of new and interesting phenomena, never before observed. SEVEN YEARS IN THE LIFE OF A SUPERNOVA After brightening to maximum light at about magnitude 3 a few months after the explosion, the long period of steady fading which is typical for supernovae, set in by mid-1987. The matter ejected by the explosion took the form of an expanding fireball, which began to spread through the nearly empty space around the supernova with a velocity of almost 10,000 km/sec. As it cooled, the temperature and therefore the total brightness decreased and the supernova became fainter and fainter. At the present moment, the magnitude of SN 1987A is about 18.5, that is almost 2 million times fainter than it was at maximum. Various phenomena have been observed around SN 1987A during the past years. Already in early 1988, light echoes were seen as concentric, slowly expanding luminous circles; they represent the reflections of the explosion light flash in interstellar clouds inside the Large Magellanic Cloud, between the supernova and us. In 1989, high-resolution observations with the NTT showed an elliptical ``ring-nebula'', only two arcsec across, surrounding SN 1987A; it was interpreted as interactions between pre-existing circumstellar material and a shell of matter which was thrown off a few thousand years ago when a red giant star evolved into the blue star that eventually exploded. The best images of this nebula were first obtained by the Hubble Space Telescope in 1990. There are also faint outer nebular loops around SN 1987A. It is thought that they trace the outer rim of a large bubble that was formed by the outflowing ``wind'' of matter from the star that later exploded. During the past years, astronomers working at large telescopes in the southern hemisphere have conducted unsuccessful searches for a pulsar inside SN 1987A. Although most theories predict the emergence of a very compact object at the centre of a supernova, even very detailed investigations reaching very faint light levels have so far not been able to prove the existence of such an object in SN 1987A. RECENT CHANGES IN THE RING But the development of SN 1987A is not yet over. After the first seven years, it is now about to enter a new phase. In a Circular of the International Astronomical Union, astronomers Li-Fan Wang (Beijing Observatory) and E. Joseph Wampler (European Southern Observatory) have just reported that changes are seen in the inner ring nebula around SN 1987A when the latest NTT observations are compared with those carried out over the past two years. The distribution of light along the ring has recently changed dramatically. It is now found to be gradually increasing in brightness at several locations. This is most easily seen on images obtained in the light of ionised nitrogen which enhances the contrast between the SN 1987A ring nebulae and their surroundings. Following computer sharpening of December 1993 CCD pictures to a resolution of 0.2 arcseconds - corresponding to the angle subtended by a coin of 1 cm diameter at a distance of 10 km - it is clear that the ring emission regions are now highly clumped. BEGINNING OF THE ``FIREWORKS'' ? It is most interesting that these new bright patches in the inner ring coincide roughly with the recently observed structure of the radio emission received from SN 1987A. The astronomers believe that these changes in the ring may herald the beginning of the predicted collision between the matter in the expanding fireball and the nebular material which was ejected from the star during the evolutionary phase that preceded the explosion. The supernova shell is ``catching up'' with the material that was ejected earlier. This interpretation is also supported by the recent observation of weak X-ray emission from the supernova with the ROSAT satellite. It probably signifies a beginning heating of the gas inside the nebular ring when the particles collide at high speeds. Further observations at ESO show that no significant amount of the expanding matter has yet reached the ring. Detailed spectra, obtained with the NTT by the same astronomers, still do not show the violent motions that would signal a collision between the main mass of the expanding supernova envelope and the ring material. These important observations have alerted astronomers to watch out for sudden, possibly quite dramatic changes in the ring. As a result, SN 1987A will now be monitored much more intensively. Never before has it been possible to observe such an event directly; the observed phenomena will undoubtedly provide completely new information about the chemical and physical state of the matter in the colliding clouds. FIRST IMAGE OF THE FIREBALL FROM THE GROUND The NTT has scored another first during these observations: thanks to its excellent optical properties, high-resolution images of the supernova in near-infrared light with a ground-based telescope for the first time show the exact extension of the fireball. Until now, this had only been possible with the Hubble Space Telescope. The measured diameter in the sky is only 0.37 arcseconds. At the distance of the supernova, this corresponds to a size of about 0.29 light-years. The mean expansion rate during the past seven years is therefore about 0.04 light-years per year, or about 6000 km/sec, a value which is very close to that obtained from spectroscopic observations. [1] See ESO Press Releases 04/87, 05/87, 06/87, 07/87, 11/87, 2/88, 2/89 and 01/90. FIGURE CAPTION ESO PR PHOTO 01/94-1: CHANGES IN THE RING NEBULA AROUND SN 1987A This computer-processed picture is an average of two 15-min exposures, obtained in the light of ionised nitrogen during the morning of December 20, 1993, with the Super Seeing Instrument (SuSI) at the 3.58 m ESO New Technology Telescope. It shows the complex structure of the faint nebulae around SN 1987A in the Large Magellanic Cloud. The inner ring was formed from interaction with matter ejected during an earlier phase by the star that later exploded as a supernova. Spectra and theoretical models suggest that the faint outer nebular loops trace the outer rim of a large bubble which was also formed by outflowing matter. The supernova itself, at the centre of the inner ring, emits very little light in the narrow spectral band used for this observation and is not visible on this picture. Because of the very large range of intensities in these nebulosities, and in order to better show the structure, the intensities of the low surface brightness parts of the image have been greatly enhanced, relative to the brighter parts. Most of the light from the inner ring is concentrated in a narrow, bright band which has been given relatively little prominence in this modified picture. However, the uneven structure, in particular the greater intensity in the North-West (upper right part), is clearly visible. This picture shows very faint structures and therefore a greater overall width of the ring than do earlier pictures. The nominal resolution of this picture as determined by the size of the stellar images in the field, is 0.20 arcsec. The gap in the upper right quadrant of the outer ring is an artifact caused by subtracting a bright star at this location. The pixel size is 0.032 arcsec. This photo (ESO PR Photo 01/94-1) accompanies ESO Press Release 01/94 and may be reproduced, if credit is given to the European Southern Observatory.

Towards a theoretical determination of the geographical probability distribution of meteoroid impacts on Earth

NASA Astrophysics Data System (ADS)

Zuluaga, Jorge I.; Sucerquia, Mario

2018-06-01

Tunguska and Chelyabinsk impact events occurred inside a geographical area of only 3.4 per cent of the Earth's surface. Although two events hardly constitute a statistically significant demonstration of a geographical pattern of impacts, their spatial coincidence is at least tantalizing. To understand if this concurrence reflects an underlying geographical and/or temporal pattern, we must aim at predicting the spatio-temporal distribution of meteoroid impacts on Earth. For this purpose we designed, implemented, and tested a novel numerical technique, the `Gravitational Ray Tracing' (GRT) designed to compute the relative impact probability (RIP) on the surface of any planet. GRT is inspired by the so-called ray-casting techniques used to render realistic images of complex 3D scenes. In this paper we describe the method and the results of testing it at the time of large impact events. Our findings suggest a non-trivial pattern of impact probabilities at any given time on the Earth. Locations at 60-90° from the apex are more prone to impacts, especially at midnight. Counterintuitively, sites close to apex direction have the lowest RIP, while in the antapex RIP are slightly larger than average. We present here preliminary maps of RIP at the time of Tunguska and Chelyabinsk events and found no evidence of a spatial or temporal pattern, suggesting that their coincidence was fortuitous. We apply the GRT method to compute theoretical RIP at the location and time of 394 large fireballs. Although the predicted spatio-temporal impact distribution matches marginally the observed events, we successfully predict their impact speed distribution.

Ar-Ar Analysis of Chelyabinsk: Evidence for a Recent Impact

NASA Technical Reports Server (NTRS)

Beard, S. P.; Kring, D. A.; Isachsen, C. E.; Lapen, T. J.; Zolensky, M. E.; Swindle, T. D.

2014-01-01

The Chelyabinsk meteorite is an LL5 ordinary chondrite that fell as a spectacular fireball on February 15th, 2013, over the Ural region in Russia. The meteoroid exploded at an altitude of 25-30 km, producing shockwaves that broke windowpanes in Chelyabinsk and surrounding areas, injuring some 1500 people. Analyses of the samples show that the meteorite underwent moderate shock metamorphism (stage S4; 25-35 GPa) [1]. Most of the samples have a fusion crust ranging from 0.1-1mm thick, and roughly a third of the samples were composed of a dark fine-grained impact melt with chondrule fragments which were targeted for chronometry. A Pb-Pb age obtained by [2] of a shock-darkened and potentially melted sample of Chelyabinsk is reported as 4538.3 +/- 2.1 Ma, while a U-Pb study [3] gave an upper concordia intercept of 4454 +/- 67 Ma and a lower intercept of 585 +/- 390. Galimov et al. 2013 [1] suggest the Sm-Nd system records a recent impact event [290 Ma] that may represent separation from the parent body, while the Rb-Sr isotopic system is disturbed and does not give any definitive isochron. In order to better understand its history, we have performed 40Ar-39Ar analysis on multiple splits of two Chelyabinsk samples; clast- rich MB020f,2 and melt-rich MB020f,5. The term "clast-rich" lithology is meant to indicate a mechanical mixture of highly shock-darkened and less shocked components, both with some shock melt veining.

A Spectacular Radio Flare from XRF 050416a at 40 Days and Implications for the Nature of X-Ray Flashes

NASA Technical Reports Server (NTRS)

Soderberg, A. M.; Nakar, E.; Cenko, S. B.; Cameron, P. B.; Frail, D. A.; Kulkarni, S. R.; Fox, D. B.; Berger, E.; Gal-Yam, A.; Moon, D-S.;

Neuschwanstein and Pribram: Two solitaire meteorites or members of a stream?

NASA Astrophysics Data System (ADS)

Oberst, J.; Spurny, P.; Heinlein, D.

2003-04-01

The fall of the Neuschwanstein enstatite chondrite EL6 at 20:20:17.7 UTC on April 6, 2002, in Southern Bavaria is well documented. Using photographic records obtained by the European Fireball Network (EN), the heliocentric orbit of the object before its collision with Earth could be determined [Spurny et al., Nature, submitted]. Surprisingly, its orbit is practically identical to that of another meteorite, which was photographed by the EN 43 years earlier: the Pribram H5-chondrite, which fell on April 7, 1959. The orbital elements are extremely similar indeed, as is indicated by a D-criterion of D=0.025. By analysis of the orbital elements of all available (approx. 200) ''meteorite candidates'', we estimate that the chances of finding two meteorites with orbital elements matching as well as in the case of Pribram and Neuschwanstein is 1:100,000. Therefore, we believe that the paired fall is not a coincidence and that the meteorites are members of a stream of objects. Considering Innisfree and Ridgedale, another paired fall, observed by the Canadian MORP (Meteorite Observation and Recovery Project), in 1977 and 1980 [Halliday, Icarus 69, 550-556, 1987], it appears that meteorite streams are not uncommon among Earth-approaching objects. On the basis of the observational efficiency of the EN, we estimate that the Pribram/Neuschwanstein meteorite stream contains approx. 10^9 members; all of them combined would form an asteroid with a minimum radius of 300m. From studies of cometary-type meteor streams it is known that these cometary stream members have separated from their parent body fairly recently. However, judging from the different classifications of the meteorites, and from their long cosmic exposure (Pribram has a cosmic ray age of 19 Million years) both, a common parent and a recent separation, are not very likely.

The Achromatic Light Curve of the Optical Afterglow of GRB 030226 at a Redshift of z Approximately 2

NASA Technical Reports Server (NTRS)

Klose, S.; Greiner, J.; Rau, A.; Henden, A. A.; Hartmann, D. H.; Zeh, A.; Masetti, N.; Guenther, E.; Stecklum, B.; Lindsay, K.

2003-01-01

Abstract. We report on optical and near-infrared (NIR) follow-up observations of the afterglow of GRB 030226, mainly performed with the telescopes at ESO La Silla and Paranal, with additional data obtained at other places. Our first observations started 0.2 days after the burst when the afterglow was at a magnitude of R approximately equal to 19 . One week later the magnitude of the afterglow had fallen to R=25, and at two weeks after the burst it could no longer be detected (R > 26). Our VLT blueband spectra show two absorption line systems at redshifts z = 1.962 +/- 0.001 and at z = 1.986 +/- 0.001, placing the redshift of the burster close to 2. Within our measurement errors no evidence for variations in the line strengths has been found between 0.2 and 1.2 days after the burst. An overabundance of alpha-group elements might indicate that the burst occurred in a chemically young interstellar region shaped by the nucleosynthesis from type II supernovae. The spectral slope of the afterglow shows no signs for cosmic dust along the line of sight in the GRB host galaxy, which itself remained undetected (R > 26.2). At the given redshift no supernova component affected the light from the GRB afterglow, so that the optical transient was essentially only powered by the radiation from the GRB fireball, allowing for a detailed investigation of the color evolution of the afterglow light. In our data set no obvious evidence for color changes has been found before, during, or after the smooth break in the light curve approximately 1 day after the burst. In comparison with investigations by others, our data favor the interpretation that the afterglow began to develop into a homogeneous interstellar medium before the break in the light curve became apparent.

Real-Time Detection of Sporadic Meteors in the Intensified TV Imaging Systems.

PubMed

Vítek, Stanislav; Nasyrova, Maria

2017-12-29

The automatic observation of the night sky through wide-angle video systems with the aim of detecting meteor and fireballs is currently among routine astronomical observations. The observation is usually done in multi-station or network mode, so it is possible to estimate the direction and the speed of the body flight. The high velocity of the meteorite flying through the atmosphere determines the important features of the camera systems, namely the high frame rate. Thanks to high frame rates, such imaging systems produce a large amount of data, of which only a small fragment has scientific potential. This paper focuses on methods for the real-time detection of fast moving objects in the video sequences recorded by intensified TV systems with frame rates of about 60 frames per second. The goal of our effort is to remove all unnecessary data during the daytime and make free hard-drive capacity for the next observation. The processing of data from the MAIA (Meteor Automatic Imager and Analyzer) system is demonstrated in the paper.

Detailed records of many unrecovered meteorites in western Canada for which further searches are recommended

NASA Astrophysics Data System (ADS)

Halliday, I.; Blackwell, A. T.; Griffin, A. A.

1989-04-01

Photographic records of the meteoritic fireballs observed between 1971 and 1985 with the Canadian camera network were used to obtain essential data for those events that are believed to have dropped significant meteorites. The mass of the largest surviving fragment for each event was estimated from the dynamic data near the end of the photographic trail. In 28 of these events, the mass of the largest fragment was found to be larger than 0.5 kg; these included the recovered Innisfree meteorite and three events with mass of about 10 kg. Sixteen events had mass estimates from 0.1 to 0.5 kg. Twelve other events were in the smaller mass range. Data are presented on height, velocity, brightness, ground location, and the orbit for each of the 44 events in the mass range 0.1-10 kg. Special attention is given to the probable degree of fragmentation during flight and the effects of flight geometry and the upper atmospheric winds on the expected 'ellipse of fall' distribution on the ground.

Gamma-ray bursts appear simpler than expected?

NASA Astrophysics Data System (ADS)

Chardonnet, P.; Filina, A. A.; Popov, M. V.; Chechetkin, V. M.; Baranov, A. A.

The cosmic gamma-ray bursts are certainly an enigma in astrophysics. The "standard fireball" scenario developed during many years has provided a possible explanation of this phenomenon. The aim of this work is simply to explore a new possible interpretation by developing a coherent scenario inside the global picture of stellar evolution. At the basis of our scenario is the fact that maybe we have not fully understood how the core of a pair instability supernovae explode. In such a way, we have proposed a new paradigm assuming that the core of such massive star, instead of doing a symmetrical explosion, is completely fragmented in hot spots of burning nuclear matter. We have tested our scenario using some observational data like GRB spectrum, light curves, Amati relation and GRB-SN connection, and for each set of data we have proposed a possible physical interpretation. We have also suggested some possible tests of this scenario by measurement at high redshift. If this scenario is correct, it tells us simply that cosmic gamma-ray bursts are simply a missing link in stellar evolution.

Rocket propulsion by thermonuclear micro-bombs ignited with intense relativistic electron beams.

NASA Technical Reports Server (NTRS)

Winterberg, F.

1971-01-01

Discussion of a method for the ignition of a thermonuclear microbomb by means of an intense relativistic electron beam with regard to its potential application to rocket propulsion. With such a system, exhaust velocities up to 1000 km/sec, corresponding to a specific impulse of 100,000 sec, seem to be within the realm of possibility. The rocket is propelled by a chain of thermonuclear microbombs exploded in a concave magnetic mirror produced by superconducting field coils. The magnetic pressure of the field reflects the fireball generated by the explosion. For the large capacitor bank required to generate the intense relativistic electron beam, a desirable lightweight design may be possible through use of ferroelectric materials. Because of the high cost of the T-D and He 3-D thermonuclear material, the system has to be optimized by minimizing the T-D and He 3-D consumption by a proper TD and He 3-D fuel to hydrogen propellant mass ratio, leading to a larger total system mass than would be absolutely necessary.

Real-Time Detection of Sporadic Meteors in the Intensified TV Imaging Systems

PubMed Central

2017-01-01

The automatic observation of the night sky through wide-angle video systems with the aim of detecting meteor and fireballs is currently among routine astronomical observations. The observation is usually done in multi-station or network mode, so it is possible to estimate the direction and the speed of the body flight. The high velocity of the meteorite flying through the atmosphere determines the important features of the camera systems, namely the high frame rate. Thanks to high frame rates, such imaging systems produce a large amount of data, of which only a small fragment has scientific potential. This paper focuses on methods for the real-time detection of fast moving objects in the video sequences recorded by intensified TV systems with frame rates of about 60 frames per second. The goal of our effort is to remove all unnecessary data during the daytime and make free hard-drive capacity for the next observation. The processing of data from the MAIA (Meteor Automatic Imager and Analyzer) system is demonstrated in the paper. PMID:29286294

Is Chicxulub Too Small to be the Source of the K/Pg Boundary Layer and the Cause of the Dinosaur Extinction Event and would the Amazon Basin Considered as an Impact Feature fit the Evidence Better?

NASA Astrophysics Data System (ADS)

Burgener, J. A.

2016-12-01

The Chicxulub impact is well associated with the K/Pg boundary layer and extinction event [Schulte et al., 2010]. However, most agree that Chicxulub is considered to be too small to have caused the extinction in itself [Kring, 2007; Keller, 2014]. Keller [2014] discusses how the K/Pg extinction event may have been due to many factors, of which Chicxulub would be part, but global warming or volcanic fumes or other factors were the main killers. There are several features in the K/Pg layer that require a much higher energy impact than Chicxulub. The worldwide distribution of shocked crystals does not fit Chicxulub - Chicxulub would only send such granules 400 km away [Morgan et al, 2006]. The Fern Spore anomaly extends too far from Chicxulub indicating a much larger fireball and impact [Fleming 1990; Robertson, 2103]. Fireballs falling around the planet have been proposed and dismissed as not possible. [Goldin & Melosh, 2009] and [Adair,2010] rule out a firestorm from ejecta. One of the reasons that Chicxulub is convincingly attributed with the K/Pg boundary layer is the calculation that the size of the impacting asteroid should have been about 10 km in diameter, based on the thickness of the boundary layer and the amount of iridium in the boundary layer [Alvarez, 1980]. Alvarez used the factor from the Krakatoa eruption (0.22) as the amount of asteroid material that would stay in the atmosphere. More recent studies imply that far less than 0.22 of an asteroid would stay in the atmosphere after an impact. When a comet hits at 55 - 72 km/sec, the vast majority of the comet material will be buried deep into the Earth or ejected at speeds in excess of the escape velocity, and very little would remain [Jeffers et al.2001]. Therefore a comet impact should leave a relatively small boundary layer, requiring a much larger impact by a comet to form what Alvaraz calculated for a 10 km asteroid. If a much larger impact occurred at the end of the Cretaceous, it would resolve the challenges of Chicxulub as long as it was near the location of Chicxulub. If the Amazon Basin was considered as an impact, it would be large enough to fit the K/Pg boundary layer details much better than Chicxulub, and it would explain the extinction event without any need to rely on extenuating factors - the impact itself would have been sufficient to cause the extinction.

The Košice meteorite fall: Atmospheric trajectory, fragmentation, and orbit

NASA Astrophysics Data System (ADS)

BorovičKa, Jiří; Tóth, Juraj; Igaz, Antal; Spurný, Pavel; Kalenda, Pavel; Haloda, Jakub; Svoreå, Ján; Kornoš, Leonard; Silber, Elizabeth; Brown, Peter; HusáRik, Marek

2013-10-01

The Košice meteorite fall occurred in eastern Slovakia on February 28, 2010, 22:25 UT. The very bright bolide was imaged by three security video cameras from Hungary. Detailed bolide light curves were obtained through clouds by radiometers on seven cameras of the European Fireball Network. Records of sonic waves were found on six seismic and four infrasonic stations. An atmospheric dust cloud was observed the next morning before sunrise. After careful calibration, the video records were used to compute the bolide trajectory and velocity. The meteoroid, of estimated mass of 3500 kg, entered the atmosphere with a velocity of 15 km s-1 on a trajectory with a slope of 60° to the horizontal. The largest fragment ceased to be visible at a height of 17 km, where it was decelerated to 4.5 km s-1. A maximum brightness of absolute stellar magnitude about -18 was reached at a height of 36 km. We developed a detailed model of meteoroid atmospheric fragmentation to fit the observed light curve and deceleration. We found that Košice was a weak meteoroid, which started to fragment under the dynamic pressure of only 0.1 MPa and fragmented heavily under 1 MPa. In total, 78 meteorites were recovered in the predicted fall area during official searches. Other meteorites were found by private collectors. Known meteorite masses ranged from 0.56 g to 2.37 kg. The meteorites were classified as ordinary chondrites of type H5 and shock stage S3. The heliocentric orbit had a relatively large semimajor axis of 2.7 AU and aphelion distance of 4.5 ± 0.5 AU. Backward numerical integration of the preimpact orbit indicates possible large variations of the orbital elements in the past due to resonances with Jupiter.

Bomb-produced radiocarbon in the western tropical Pacific Ocean: Guam coral reveals operation-specific signals from the Pacific Proving Grounds

NASA Astrophysics Data System (ADS)

Andrews, Allen H.; Asami, Ryuji; Iryu, Yasufumi; Kobayashi, Donald R.; Camacho, Frank

2016-08-01

High-resolution radiocarbon (14C) analyses on a coral core extracted from Guam, a western tropical Pacific island, revealed a series of early bomb-produced 14C spikes. The typical marine bomb 14C signal—phase lagged and attenuated relative to atmospheric records—is present in the coral and is consistent with other regional coral records. However, 14C levels well above what can be attributed to air-sea diffusion alone punctuate this pattern. This anomaly was observed in other Indo-Pacific coral records, but the Guam record is unmatched in magnitude and temporal resolution. The Guam coral Δ14C record provided three spikes in 1954-1955, 1956-1957, and 1958-1959 that are superimposed on a normal 14C record. Relative to mean prebomb levels, the first peak rises an incredible ˜700‰ and remained elevated for ˜1.2 years. A follow up assay with finer resolution increased the peak by ˜300‰. Subsequent spikes were less intense with a rise of ˜35 and ˜70‰. Each can be linked to thermonuclear testing in the Pacific Proving Grounds at Bikini and Enewetak atolls in Operations Castle (1954), Redwing (1956), and Hardtack I (1958). These 14C signals can be explained by vaporization of coral reef material in the nuclear fireball, coupled with neutron activation of atmospheric nitrogen (14C production), and subsequent absorption of 14CO2 to form particulate carbonates of close-in fallout. The lag time in reaching Guam and other coral records abroad was tied to ocean surface currents and modeling provided validation of 14C arrival observations.

GRB 090417B and its Host Galaxy: A Step Towards an Understanding of Optically-Dark Gamma-Ray Bursts

NASA Technical Reports Server (NTRS)

Holland, Stephen T.; Sbarufatti, Boris; Shen, Rongfeng; Schady, Patricia; Cummings, Jay R.; Fonseca, Emmanuel; Fynbo, Johan P. U.; Jakobsson, Pall; Leitet, Elisabet; Linne, Staffan;

Identification and properties of the photospheric emission in GRB090902B

DOE PAGES

Ryde, F.; Axelsson, M.; Zhang, B. B.; ...

2010-01-14

We observed the Fermi Gamma-ray Space Telescope using the bright and long GRB090902B, lying at a redshift of z = 1.822. Together the Large Area Telescope (LAT) and the Gamma-ray Burst Monitor (GBM) cover the spectral range from 8 keV to >300 GeV. Here we show that the prompt burst spectrum is consistent with emission from the jet photosphere combined with nonthermal emission described by a single power law with photon index –1.9. The photosphere gives rise to a strong quasi-blackbody spectrum which is somewhat broader than a single Planck function and has a characteristic temperature of ~290 keV. Wemore » model the photospheric emission with a multicolor blackbody, and its shape indicates that the photospheric radius increases at higher latitudes. We derive the averaged photospheric radius R ph = (1.1 ± 0.3) × 10 12 Y 1/4 cm and the bulk Lorentz factor of the flow, which is found to vary by a factor of 2 and has a maximal value of Γ = 750 Y 1/4. Here, Y is the ratio between the total fireball energy and the energy emitted in the gamma rays. Here, we find that during the first quarter of the prompt phase the photospheric emission dominates, which explains the delayed onset of the observed flux in the LAT compared to the GBM. We also interpret the broadband emission as synchrotron emission at R ~ 4 × 10 15 cm. Our analysis emphasizes the importance of having high temporal resolution when performing spectral analysis on gamma-ray bursts, since there is strong spectral evolution.« less

iPTF Archival Search for Fast Optical Transients

NASA Astrophysics Data System (ADS)

Ho, Anna Y. Q.; Kulkarni, S. R.; Nugent, Peter E.; Zhao, Weijie; Rusu, Florin; Cenko, S. Bradley; Ravi, Vikram; Kasliwal, Mansi M.; Perley, Daniel A.; Adams, Scott M.; Bellm, Eric C.; Brady, Patrick; Fremling, Christoffer; Gal-Yam, Avishay; Kann, David Alexander; Kaplan, David; Laher, Russ R.; Masci, Frank; Ofek, Eran O.; Sollerman, Jesper; Urban, Alex

2018-02-01

There has been speculation about a class of relativistic explosions with an initial Lorentz factor Γinit smaller than that of classical gamma-ray bursts (GRBs). These “dirty fireballs” would lack prompt GRB emission but could be pursued via their optical afterglow, appearing as transients that fade overnight. Here we report a search for such transients (that fade by 5-σ in magnitude overnight) in four years of archival photometric data from the intermediate Palomar Transient Factory (iPTF). Our search criteria yielded 50 candidates. Of these, two were afterglows to GRBs that had been found in dedicated follow-up observations to triggers from the Fermi GRB Monitor. Another (iPTF14yb) was a GRB afterglow discovered serendipitously. Eight were spurious artifacts of reference image subtraction, and one was an asteroid. The remaining 38 candidates have red stellar counterparts in external catalogs. The photometric and spectroscopic properties of the counterparts identify these transients as strong flares from M dwarfs of spectral type M3–M7 at distances of d ≈ 0.15–2.1 kpc; three counterparts were already spectroscopically classified as late-type M stars. With iPTF14yb as the only confirmed relativistic outflow discovered independently of a high-energy trigger, we constrain the all-sky rate of transients that peak at m = 18 and fade by Δm = 2 mag in Δt = 3 hr to be 680 {{yr}}-1, with a 68% confidence interval of 119{--}2236 {{yr}}-1. This implies that the rate of visible dirty fireballs is at most comparable to that of the known population of long-duration GRBs.

Trajectories of ballistic impact ejecta on a rotating Earth

NASA Technical Reports Server (NTRS)

Alvarez, W.

1994-01-01

On an airless, slowly rotating planetary body like the Moon, ejecta particles from an impact follow simple ballistic trajectories. If gaseous interactions in the fireball are ignored, ejecta particles follow elliptical orbits with the center of the planetary body at one focus until they encounter the surface at the point of reimpact. The partial elliptical orbit of the ejecta particle lies in a plane in inertial (galactic) coordinates. Because of the slow rotation rate (for example, 360 degrees/28 days for the Moon), the intersection of the orbital plane and the surface remains nearly a great circle during the flight time of the ejecta. For this reason, lunar rays, representing concentrations of ejecta with the same azimuth but different velocities and/or ejecta angles, lie essentially along great circles. Ejecta from airless but more rapidly rotating bodies will follow more complicated, curving trajectories when plotted in the coordinate frame of the rotating planet or viewed as rays on the planetary surface. The curvature of trajectories of ejecta particles can be treated as a manifestation of the Coriolis effect, with the particles being accelerated by Coriolis pseudoforces. However, it is more straightforward to calculate the elliptical orbit in inertial space and then determine how far the planet rotates beneath the orbiting ejecta particle before reimpact. The Earth's eastward rotation affects ballistic ejecta in two ways: (1) the eastward velocity component increases the velocity of eastbound ejecta and reduces the velocity of westbound ejecta; and (2) the Earth turns underneath inflight ejecta, so that although the latitude of reimpact is not changed, the longitude is displaced westward, with the displacement increasing as a function of the time the ejecta remains aloft.

The Chelyabinsk superbolide: a fragment of asteroid 2011 EO40?

NASA Astrophysics Data System (ADS)

de la Fuente Marcos, C.; de la Fuente Marcos, R.

2013-11-01

Bright fireballs or bolides are caused by meteoroids entering the Earth's atmosphere at high speed. Some have a cometary origin, a few may have originated within the Venus-Earth-Mars region as a result of massive impacts in the remote past but a relevant fraction is likely the result of the break-up of asteroids. Disrupted asteroids produce clusters of fragments or asteroid families and meteoroid streams. Linking a bolide to a certain asteroid family may help to understand its origin and pre-impact dynamical evolution. On 2013 February 15, a superbolide was observed in the skies near Chelyabinsk, Russia. Such a meteor could be the result of the decay of an asteroid and here we explore this possibility applying a multistep approach. First, we use available data and Monte Carlo optimization (validated using 2008 TC3 as template) to obtain a robust solution for the pre-impact orbit of the Chelyabinsk impactor (a = 1.62 au, e = 0.53, i = 3.82°, Ω = 326.41° and ω = 109.44°). Then, we use this most probable orbit and numerical analysis to single out candidates for membership in, what we call, the Chelyabinsk asteroid family. Finally, we perform N-body simulations to either confirm or reject any dynamical connection between candidates and impactor. We find reliable statistical evidence on the existence of the Chelyabinsk cluster. It appears to include multiple small asteroids and two relatively large members: 2007 BD7 and 2011 EO40. The most probable parent body for the Chelyabinsk superbolide is 2011 EO40. The orbits of these objects are quite perturbed as they experience close encounters not only with the Earth-Moon system but also with Venus, Mars and Ceres. Under such conditions, the cluster cannot be older than about 20-40 kyr.

[The forensic medical characteristics of the entrance bullet holes created by the shots from pneumatic rifles].

PubMed

Legin, G A; Bondarchuk, A O; Perebetjuk, A N

2015-01-01

The objective of the present study was to compare the injurious action of three types of the bullets for the pneumatic weapons shot from different distances using the Gamo pump air pistol and the BAM B22-1 pneumatic rifle. The following four kinds of the bullets were tested: "the fireball", "Luman cap 0.3", "Luman Field Target 0.68" and "DIABOLO". It was experimentally shown that the injurious action of the bullets fired from the same distance from the pneumatic weapons depends on the type of both the bullet and the weapon, as well as the properties of the target material. Specifically, the action of bullets fired from the piston pneumatic rifle remained stable whereas that of the bullets shot from the gas-balloon air pistol decreased as the gas was exhausted. The studies by the contact-diffusion method have demonstrated that the entrance bullet holes created by the shots from pneumatic weapons are surrounded by dispersed metal particles which makes it possible to estimate the shooting distance. Moreover, the bullets fired from the pneumatic weapons leave the muzzle face imprint on certain target materials.

An Empirical Fitting Method for Type Ia Supernova Light Curves: A Case Study of SN 2011fe

DOE Office of Scientific and Technical Information (OSTI.GOV)

Zheng, WeiKang; Filippenko, Alexei V., E-mail: zwk@astro.berkeley.edu

We present a new empirical fitting method for the optical light curves of Type Ia supernovae (SNe Ia). We find that a variant broken-power-law function provides a good fit, with the simple assumption that the optical emission is approximately the blackbody emission of the expanding fireball. This function is mathematically analytic and is derived directly from the photospheric velocity evolution. When deriving the function, we assume that both the blackbody temperature and photospheric velocity are constant, but the final function is able to accommodate these changes during the fitting procedure. Applying it to the case study of SN 2011fe givesmore » a surprisingly good fit that can describe the light curves from the first-light time to a few weeks after peak brightness, as well as over a large range of fluxes (∼5 mag, and even ∼7 mag in the g band). Since SNe Ia share similar light-curve shapes, this fitting method has the potential to fit most other SNe Ia and characterize their properties in large statistical samples such as those already gathered and in the near future as new facilities become available.« less

Reactivity and Fragmentation of Aluminum-based Structural Energetic Materials under Explosive Loading

NASA Astrophysics Data System (ADS)

Glumac, Nick; Clemenson, Michael; Guadarrama, Jose; Krier, Herman

2015-06-01

Aluminum-cased warheads have been observed to generate enhanced blast and target damage due to reactivity of the aluminum fragments with ambient air. This effect can more than double the output of a conventional warhead. The mechanism by which the aluminum reacts under these conditions remains poorly understood. We undertake a highly controlled experimental study to investigate the phenomenon of aluminum reaction under explosive loading. Experiments are conducted with Al 6061 casings and PBX-N9 explosive with a fixed charge to case mass ratio of 1:2. Results are compared to inert casings (steel), as well as to tests performed in nitrogen environments to isolate aerobic and anaerobic effects. Padded walls are used in some tests to isolate the effects of impact-induced reactions, which are found to be non-negligible. Finally, blast wave measurements and quasi-static pressure measurements are used to isolate the fraction of case reaction that is fast enough to drive the primary blast wave from the later time reaction that generates temperature and overpressure only in the late-time fireball. Fragment size distributions, including those in the micron-scale range, are collected and quantified.

Pattern of (Multi)strange (Anti)baryon Production and Search for Deconfinement

NASA Astrophysics Data System (ADS)

Rafelski, Johann

1998-04-01

We study (multi)strange particle abundances obtained recently in relativistic heavy ion collisions and determine thermal and chemical source parameters(J. Letessier et al., Phys. Lett. B410 (1997) 315--322 hep-ph/9710310 and: Acta Physica Polonica in press, hep- ph/9710340). These are primarily constrained by (multi)strange (anti)baryon relative abundances, which have been measured for Pb--Pb 158 A GeV interactions(I. Kralik, for WA97 collaboration, QM97 Tsukuba, to appear in Nucl. Phys. A) and S-S/W/Pb 200 A GeV interactions(See: proceedings of S'96-Budapest, APH N.S., Heavy Ion Physics 4 (1996) vii--x). We have extended our analysis and have now determined the properties of the particle source using the fitted macro canonical parameters, allowing as required for non-equilibrium dynamics of the locally thermal fireball. We find that in the 158 A GeV Pb--Pb collisions the entropy per baryon, energy per baryon, strangeness per baryon implied by particle spectra are all in the range of values associated commonly with the deconfined QGP phase.

Infrasound detection of meteors

NASA Astrophysics Data System (ADS)

ElGabry, M. N.; Korrat, I. M.; Hussein, H. M.; Hamama, I. H.

2017-06-01

Meteorites that penetrate the atmosphere generate infrasound waves of very low frequency content. These waves can be detected even at large distances. In this study, we analyzed the infrasound waves produced by three meteors. The October 7, 2008 TC3 meteor fell over the north Sudan Nubian Desert, the February 15, 2013 Russian fireball, and the February 6, 2016 Atlantic meteor near to the Brazil coast. The signals of these three meteors were detected by the infrasound sensors of the International Monitoring System (IMS) of the Comprehensive Test Ban Treaty Organization (CTBTO). The progressive Multi Channel Technique is applied to the signals in order to locate these infrasound sources. Correlation of the recorded signals in the collocated elements of each array enables to calculate the delays at the different array element relative to a reference one as a way to estimate the azimuth and velocity of the coming infrasound signals. The meteorite infrasound signals show a sudden change in pressure with azimuth due to its track variation at different heights in the atmosphere. Due to movement of the source, a change in azimuth with time occurs. Our deduced locations correlate well with those obtained from the catalogues of the IDC of the CTBTO.

Source, dispersion and combustion modelling of an accidental release of hydrogen in an urban environment.

PubMed

Venetsanos, A G; Huld, T; Adams, P; Bartzis, J G

2003-12-12

Hydrogen is likely to be the most important future energy carrier, for many stationary and mobile applications, with the potential to make significant reductions in greenhouse gas emissions especially if renewable primary energy sources are used to produce the hydrogen. A safe transition to the use of hydrogen by members of the general public requires that the safety issues associated with hydrogen applications have to be investigated and fully understood. In order to assess the risks associated with hydrogen applications, its behaviour in realistic accident scenarios has to be predicted, allowing mitigating measures to be developed where necessary. A key factor in this process is predicting the release, dispersion and combustion of hydrogen in appropriate scenarios. This paper illustrates an application of CFD methods to the simulation of an actual hydrogen explosion. The explosion occurred on 3 March 1983 in a built up area of central Stockholm, Sweden, after the accidental release of approximately 13.5 kg of hydrogen from a rack of 18 interconnected 50 l industrial pressure vessels (200 bar working pressure) being transported by a delivery truck. Modelling of the source term, dispersion and combustion were undertaken separately using three different numerical tools, due to the differences in physics and scales between the different phenomena. Results from the dispersion calculations together with the official accident report were used to identify a possible ignition source and estimate the time at which ignition could have occurred. Ignition was estimated to occur 10s after the start of the release, coinciding with the time at which the maximum flammable hydrogen mass and cloud volume were found to occur (4.5 kg and 600 m(3), respectively). The subsequent simulation of the combustion adopts initial conditions for mean flow and turbulence from the dispersion simulations, and calculates the development of a fireball. This provides physical values, e.g. maximum overpressure and far-field overpressure that may be used as a comparison with the known accident details to give an indication of the validity of the models. The simulation results are consistent with both the reported near-field damage to buildings and persons and with the far-field damage to windows. The work was undertaken as part of the European Integrated Hydrogen Project-Phase 2 (EIHP2) with partial funding from the European Commission via the Fifth Framework Programme.

Cratering on Titan: A Pre-Cassini Perspective

NASA Technical Reports Server (NTRS)

Lorenz, R. D.

1997-01-01

The NASA-ESA Cassini mission, comprising a formidably instrumented orbiter and parachute-borne probe to be launched this October, promises to reveal a crater population on Titan that has been heretofore hidden by atmospheric haze. This population on the largest remaining unexplored surface in the solar system will be invaluable in comparative planetological studies, since it introduces evidence of the atmospheric effects of cratering on an icy satellite. Here, I highlight some impact features we may hope to find and could devote some modeling effort toward. Titan in a Nutshell: Radius= 2575 km. Density= 1880 kg/cubic m consistent with rock-ice composition. Surface pressure = 1.5 bar. Surface gravity = 1.35 m/square s Atmosphere -94% N2 6% CH, Surface temperature = 94K Tropopause temperature = 70K at 40 km alt. Probable liquid hydrocarbon deposits exist on or near the surface.Titan in a Nutshell: Radius= 2575 km. Density= 1880 kg/cubic m consistent with rock-ice composition. Surface pressure = 1.5 bar. Surface gravity = 1.35 m/square s; Atmosphere about 94% N2 6% CH, Surface temperature = 94K Tropopause temperature = 70K at 40 km alt. Probable liquid hydrocarbon deposits exist on or near the surface. Titan is comparable to Callisto and Ganymede for strength/gravity, Mars/Earth/Venus for atmospheric interaction, and Hyperion, Rhea, and Iapetus for impactor distribution. The leading/trailing asymmetry of crater density from heliocentric impactors is expected to be about 5-6, in the absence of resurfacing. Any Saturnocentric impactor population is likely to alter this. In particular the impact disruption of Hyperion is noted; because of the 3:4 orbital resonance with Titan, fragments from the proto-Hyperion breakup would have rapidly accreted onto Titan. Titan's resurfacing history is of course unknown. The disruption of impactors into fragments that individually create small craters is expected to occur. A crude estimate suggests a maximum separation of about 2 km (compared with 4 km on Venus, or 0.5 km on Earth). Crater chains are unlikely on Titan, since impactors must pass close enough to Saturn to be tidally disrupted; as a result, they would suffer aerodynamic disruption. Crater counting on adjacent satellites gives densities of about 200 per 10 (exp 6) square km for 20-km-diameter craters. However, the presence of a thick atmosphere leads to atmospheric shielding, depleting the relative abundance of small craters. This has been evaluated by models, and the relative abundance of small craters may be due to a diagnostic atmospheric collapse. A number of radar-dark "splotches" have been detected on Venus; these have been attributed to the interaction of the surface with the atmospheric shockwave produced by the Tunguska-like explosion of a bolide in the atmosphere. Simple analogy suggests that similar features might occur on Titan, but the shocked mass density (which controls the momentum coupling between the surface and the shockwave) of Titan's cold N2 atmosphere is about 20x smaller than that of Venus's hot CO2 atmosphere. Unless ice is much more easily turned to rubble than is rock, such features seem less probable on Titan. When the energy deposited by an impact forms a fireball with an equilibrate greater than one scale height, the fireball expands upward and can distribute ejecta. on ballistic exoatmospheric trajectories. On Venus this process is believed to be responsible for the parabolic features; the interaction of various-sized particles falling through the atmosphere with the zonal wind field winnows the particles to form a parabolic deposit. Although such a process is possible on Titan, the large scale height at higher altitudes would make it more difficult. Comparison with craters on other icy satellites suggests that craters on Titan will be fairly shallow (depth/diameter about 0.1) and craters greater than 10 km in diameter will have central peaks or domed bases, perhaps with central pits. The formation of ejecta. blankets may involve the atmosphere in a significant way, both by restraining the expansion of the ejecta cloud and by influencing the thermal history of the ejecta. Compared with Venus, Titan's atmosphere will chill an impact melt somewhat quickly, so the long ejecta flows seen on Venus seem less likely, detailed modeling needs to be performed to determine the impact melt production. Crater topography on Titan may be highlighted by the influence of liquids forming crater lakes. Craters with central peaks will typically form ring-shaped lakes, although horseshoe-shaped takes may be common; domed craters with central pits may even form bullseye lakes with islands with central ponds. If liquids have covered a substantial part of Titan's surface for a substantial period, hydroblemes and tsunami deposits may be common.

Cratering on Titan: A Pre-Cassini Perspective

NASA Astrophysics Data System (ADS)

Lorenz, R. D.

1997-01-01

The NASA-ESA Cassini mission, comprising a formidably instrumented orbiter and parachute-borne probe to be launched this October, promises to reveal a crater population on Titan that has been heretofore hidden by atmospheric haze. This population on the largest remaining unexplored surface in the solar system will be invaluable in comparative planetological studies, since it introduces evidence of the atmospheric effects of cratering on an icy satellite. Here, I highlight some impact features we may hope to find and could devote some modeling effort toward. Titan in a Nutshell: Radius= 2575 km. Density= 1880 kg/cubic m consistent with rock-ice composition. Surface pressure = 1.5 bar. Surface gravity = 1.35 m/square s Atmosphere -94% N2 6% CH, Surface temperature = 94K Tropopause temperature = 70K at 40 km alt. Probable liquid hydrocarbon deposits exist on or near the surface.Titan in a Nutshell: Radius= 2575 km. Density= 1880 kg/cubic m consistent with rock-ice composition. Surface pressure = 1.5 bar. Surface gravity = 1.35 m/square s; Atmosphere about 94% N2 6% CH, Surface temperature = 94K Tropopause temperature = 70K at 40 km alt. Probable liquid hydrocarbon deposits exist on or near the surface. Titan is comparable to Callisto and Ganymede for strength/gravity, Mars/Earth/Venus for atmospheric interaction, and Hyperion, Rhea, and Iapetus for impactor distribution. The leading/trailing asymmetry of crater density from heliocentric impactors is expected to be about 5-6, in the absence of resurfacing. Any Saturnocentric impactor population is likely to alter this. In particular the impact disruption of Hyperion is noted; because of the 3:4 orbital resonance with Titan, fragments from the proto-Hyperion breakup would have rapidly accreted onto Titan. Titan's resurfacing history is of course unknown. The disruption of impactors into fragments that individually create small craters is expected to occur. A crude estimate suggests a maximum separation of about 2 km (compared with 4 km on Venus, or 0.5 km on Earth). Crater chains are unlikely on Titan, since impactors must pass close enough to Saturn to be tidally disrupted; as a result, they would suffer aerodynamic disruption. Crater counting on adjacent satellites gives densities of about 200 per 10 6 square km for 20-km-diameter craters. However, the presence of a thick atmosphere leads to atmospheric shielding, depleting the relative abundance of small craters. This has been evaluated by models, and the relative abundance of small craters may be due to a diagnostic atmospheric collapse. A number of radar-dark "splotches" have been detected on Venus; these have been attributed to the interaction of the surface with the atmospheric shockwave produced by the Tunguska-like explosion of a bolide in the atmosphere. Simple analogy suggests that similar features might occur on Titan, but the shocked mass density (which controls the momentum coupling between the surface and the shockwave) of Titan's cold N2 atmosphere is about 20x smaller than that of Venus's hot CO2 atmosphere. Unless ice is much more easily turned to rubble than is rock, such features seem less probable on Titan. When the energy deposited by an impact forms a fireball with an equilibrate greater than one scale height, the fireball expands upward and can distribute ejecta. on ballistic exoatmospheric trajectories. On Venus this process is believed to be responsible for the parabolic features; the interaction of various-sized particles falling through the atmosphere with the zonal wind field winnows the particles to form a parabolic deposit. Although such a process is possible on Titan, the large scale height at higher altitudes would make it more difficult. Comparison with craters on other icy satellites suggests that craters on Titan will be fairly shallow (depth/diameter about 0.1) and craters greater than 10 km in diameter will have central peaks or domed bases, perhaps with central pits. The formation of ejecta. blankets may involve the atmosphere in a significant way, both by restraining the expansion of the ejecta cloud and by influencing the thermal history of the ejecta. Compared with Venus, Titan's atmosphere will chill an impact melt somewhat quickly, so the long ejecta flows seen on Venus seem less likely, detailed modeling needs to be performed to determine the impact melt production. Crater topography on Titan may be highlighted by the influence of liquids forming crater lakes. Craters with central peaks will typically form ring-shaped lakes, although horseshoe-shaped takes may be common; domed craters with central pits may even form bullseye lakes with islands with central ponds. If liquids have covered a substantial part of Titan's surface for a substantial period, hydroblemes and tsunami deposits may be common.

An all-sky, three-flavor search for neutrinos from gamma-ray bursts with the icecube neutrino observatory

NASA Astrophysics Data System (ADS)

Hellauer, Robert Eugene, III

Ultra high energy cosmic rays (UHECRs), defined by energy greater than 10. 18 eV, have been observed for decades, but their sources remain unknown. Protons and heavy ions, which comprise cosmic rays, interact with galactic and intergalactic magnetic fields and, consequently, do not point back to their sources upon measurement. Neutrinos, which are inevitably produced in photohadronic interactions, travel unimpeded through the universe and disclose the directions of their sources. Among the most plausible candidates for the origins of UHECRs is a class of astrophysical phenomena known as gamma-ray bursts (GRBs). GRBs are the most violent and energetic events witnessed in the observable universe. The IceCube Neutrino Observatory, located in the glacial ice 1450 m to 2450 m below the South Pole surface, is the largest neutrino detector in operation. IceCube detects charged particles, such as those emitted in high energy neutrino interactions in the ice, by the Cherenkov light radiated by these particles. The measurement of neutrinos of 100 TeV energy or greater in IceCube correlated with gamma-ray photons from GRBs, measured by spacecraft detectors, would provide evidence of hadronic interaction in these powerful phenomena and confirm their role in ultra high energy cosmic ray production. This work presents the first IceCube GRB-neutrino coincidence search optimized for charged-current interactions of electron and tau neutrinos as well as neutral-current interactions of all neutrino flavors, which produce nearly spherical Cherenkov light showers in the ice. These results for three years of data are combined with the results of previous searches over four years of data optimized for charged-current muon neutrino interactions, which produce extended Cherenkov light tracks. Several low significance events correlated with GRBs were detected, but are consistent with the background expectation from atmospheric muons and neutrinos. The combined results produce limits that place the strongest constraints thus far on models of neutrino and UHECR production in GRB fireballs.

Polarization of gamma-ray burst afterglows in the synchrotron self-Compton process from a highly relativistic jet

NASA Astrophysics Data System (ADS)

Lin, Hai-Nan; Li, Xin; Chang, Zhe

2017-04-01

Linear polarization has been observed in both the prompt phase and afterglow of some bright gamma-ray bursts (GRBs). Polarization in the prompt phase spans a wide range, and may be as high as ≳ 50%. In the afterglow phase, however, it is usually below 10%. According to the standard fireball model, GRBs are produced by synchrotron radiation and Compton scattering process in a highly relativistic jet ejected from the central engine. It is widely accepted that prompt emissions occur in the internal shock when shells with different velocities collide with each other, and the magnetic field advected by the jet from the central engine can be ordered on a large scale. On the other hand, afterglows are often assumed to occur in the external shock when the jet collides with interstellar medium, and the magnetic field produced by the shock through, for example, Weibel instability, is possibly random. In this paper, we calculate the polarization properties of the synchrotron self-Compton process from a highly relativistic jet, in which the magnetic field is randomly distributed in the shock plane. We also consider the generalized situation where a uniform magnetic component perpendicular to the shock plane is superposed on the random magnetic component. We show that it is difficult for the polarization to be larger than 10% if the seed electrons are isotropic in the jet frame. This may account for the observed upper limit of polarization in the afterglow phase of GRBs. In addition, if the random and uniform magnetic components decay with time at different speeds, then the polarization angle may change 90° during the temporal evolution. Supported by Fundamental Research Funds for the Central Universities (106112016CDJCR301206), National Natural Science Fund of China (11375203, 11603005), and Open Project Program of State Key Laboratory of Theoretical Physics, Institute of Theoretical Physics, Chinese Academy of Sciences, China (Y5KF181CJ1)

Orbit determination based on meteor observations using numerical integration of equations of motion

NASA Astrophysics Data System (ADS)

Dmitriev, V.; Lupovka, V.; Gritsevich, M.

2014-07-01

We review the definitions and approaches to orbital-characteristics analysis applied to photographic or video ground-based observations of meteors. A number of camera networks dedicated to meteors registration were established all over the word, including USA, Canada, Central Europe, Australia, Spain, Finland and Poland. Many of these networks are currently operational. The meteor observations are conducted from different locations hosting the network stations. Each station is equipped with at least one camera for continuous monitoring of the firmament (except possible weather restrictions). For registered multi-station meteors, it is possible to accurately determine the direction and absolute value for the meteor velocity and thus obtain the topocentric radiant. Based on topocentric radiant one further determines the heliocentric meteor orbit. We aim to reduce total uncertainty in our orbit-determination technique, keeping it even less than the accuracy of observations. The additional corrections for the zenith attraction are widely in use and are implemented, for example, here [1]. We propose a technique for meteor-orbit determination with higher accuracy. We transform the topocentric radiant in inertial (J2000) coordinate system using the model recommended by IAU [2]. The main difference if compared to the existing orbit-determination techniques is integration of ordinary differential equations of motion instead of addition correction in visible velocity for zenith attraction. The attraction of the central body (the Sun), the perturbations by Earth, Moon and other planets of the Solar System, the Earth's flattening (important in the initial moment of integration, i.e. at the moment when a meteoroid enters the atmosphere), atmospheric drag may be optionally included in the equations. In addition, reverse integration of the same equations can be performed to analyze orbital evolution preceding to meteoroid's collision with Earth. To demonstrate the developed technique, we provide calculated orbits for several cases, including well-known meteorite-producing fireballs. A comparison of our estimates with previously published ones is also provided.

SU(2) x U(1) vacuum and the Centauro events

NASA Technical Reports Server (NTRS)

Kazanas, D.; Balasubrahmanyan, V. K.; Streitmatter, R. E.

1984-01-01

It is proposed that the fireballs invoked to explain the Centauro events are bubbles of a metastable superdense state of nuclear matter, created in high energy (E is approximately 10 to the 15th power eV) cosmic ray collisions at the top of the atmosphere. If these bubbles are created with a Lorentz factor gamma approximately = 10 at their CM frame, the objections against the origin of these events in cosmic ray interactions are overcome. Assuming further, that the Centauro events are to the explosive decay of these metastable bubbles, a relationship between their lifetime, tau, and the threshold energy for bubble formation, E sub th, is derived. The minimum lifetime consistent with such an interpretation in tau is approximately 10 to the -8th power sec, while the E sub th appears to be insensitive to the value of tau and always close to E sub th is approximately 10 to the 15th power eV. Finally it is speculated that if the available CM energy is thermalized in such collisions, these bubbles might be manifestations of excitations of the SU(2) x U(1) false vacuum. The absence of neutral pions in the Centauro events is then explained by the decay of these excitations.

Multi-instrument Observations of Transient Luminous Events Associated with a Small-scale Winter Thunderstorm

NASA Astrophysics Data System (ADS)

Kolmasova, I.; Santolik, O.; Spurny, P.; Borovicka, J.; Mlynarczyk, J.; Popek, M.; Lan, R.; Uhlir, L.; Diendorfer, G.; Slosiar, R.

2017-12-01

We present observations of transient luminous events (TLEs) produced by a small-scale winter thunderstorm which occurred on 2 April 2017 in the southwest of Czechia. Elves, sprites and associated positive lightning strokes have been simultaneously recorded by different observational techniques. Optical data include video recordings of TLEs from Nydek (Czechia) and data recorded by high time-resolution photometers at several stations of the Czech fireball network which measured the all-sky brightness originating from lightning return strokes. Electromagnetic data sets include 3-component VLF measurements conducted in Rustrel (France), 2-component ELF measurements recorded at the Hylaty station (Poland) and signal intensity variations of a VLF transmitter (DHO38, Rhauderfehn, Germany) recorded in Bojnice (Slovakia). Optical and electromagnetic data are completed by positions and peak currents of all strokes recorded during the observed thunderstorm by the EUCLID lightning detection network. We focus our analysis on positive lightning discharges with high peak currents and we compare properties of those which produced TLE with properties of discharges for which TLE was not detected. The current moment waveforms and charge moment changes associated with the TLE events are reconstructed from the ELF electromagnetic signals. Obtained current moment waveforms show excellent agreement with high time-resolution optical data.