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Sample records for binary trojan asteroid

  1. Trojan Binary Asteroid Systems as Future Mission Targets

    NASA Astrophysics Data System (ADS)

    Bellerose, Julie; Yano, Hajime

    To date, the Jupiter-Sun Lagrangian points are populated with almost 4500 asteroids, for which their formation and history are still debated. In the current work, we look at rationales for a mission to Jovian Trojan asteroids, and discuss the scientific benefits to investigate binary systems and contact binary systems. We summarized the dynamics for a solar sail mission, which is currently thought to go along the Europa Jupiter System Mission (EJSM), and we show a case study of the contact binary Hektor, and its moon S/2006, which offer the most suitable conditions for spacecraft operations. Trojans asteroids offer many opportunities, and we list some of the targets in time.

  2. Eclipses and occultations on binary Trojan asteroid (617) Patroclus

    NASA Astrophysics Data System (ADS)

    Marchis, Franck; Berthier, Jerome; Descamps, Pascal; Emery, Josh; Harris, Alan; Hestroffer, Daniel; Mottola, Stefano; Mueller, Michael; Vachier, Frederic

    2006-05-01

    We propose to observe a combined eclipse- and occultation event of the binary asteroid system (617) Patroclus, a member of the intriguing population of Jupiter Trojans. This will be the first thermal-IR observation of such a rare event. Patroclus, the only known Trojan binary, is a particularly well-suited target because its orbital parameters are well known (Marchis et al. 2006) and both components are of roughly equal size, which maximizes the observable effects of the eclipse event. Observing a nearly total eclipse allows the surface thermal inertia, which depends on key physical properties such as the surface porosity, to be determined in a uniquely direct way. Also, occultations allow one component to be studied without significant contamination from the other, thereby facilitating the determination of possible differences between their surface compositions. Note that the angular distance between the components does not exceed 0.15". The proposed Spitzer IRS observations will allow us to clarify the physical nature of the Patroclus system and constrain its mineralogy by providing measurements of the thermal inertia, size and albedo of each component, and the spectral silicate features around 10microns. From spatially resolved Keck imaging Marchis et al. (2006) have recently determined the orbital parameters of the Patroclus system. From these they determined the total mass of the system which, combined with a previous estimate of Patroclus' size, implies a bulk mass density of only 0.8 g cm-3, indicative of a composition dominated by water ice. This supports the idea that large Jupiter Trojans, such as Patroclus, are among the most primordial bodies in the solar system accessible to observations, and that they are basically collisionally unaltered since their formation.

  3. THE PUZZLING MUTUAL ORBIT OF THE BINARY TROJAN ASTEROID (624) HEKTOR

    SciTech Connect

    Marchis, F.; Cuk, M.; Durech, J.; Castillo-Rogez, J.; Vachier, F.; Berthier, J.; Wong, M. H.; Kalas, P.; Duchene, G.; Van Dam, M. A.; Hamanowa, H.; Viikinkoski, M.

    2014-03-10

    Asteroids with satellites are natural laboratories to constrain the formation and evolution of our solar system. The binary Trojan asteroid (624) Hektor is the only known Trojan asteroid to possess a small satellite. Based on W. M. Keck adaptive optics observations, we found a unique and stable orbital solution, which is uncommon in comparison to the orbits of other large multiple asteroid systems studied so far. From lightcurve observations recorded since 1957, we showed that because the large Req = 125 km primary may be made of two joint lobes, the moon could be ejecta of the low-velocity encounter, which formed the system. The inferred density of Hektor's system is comparable to the L5 Trojan doublet (617) Patroclus but due to their difference in physical properties and in reflectance spectra, both captured Trojan asteroids could have a different composition and origin.

  4. Search for Binary Trojans

    NASA Astrophysics Data System (ADS)

    Noll, Keith S.; Grundy, W. M.; Ryan, E. L.; Benecchi, S. D.

    2015-11-01

    We have reexamined 41 Trojan asteroids observed with the Hubble Space Telescope (HST) to search for unresolved binaries. We have identified one candidate binary with a separation of 53 milliarcsec, about the width of the diffraction limited point-spread function (PSF). Sub-resolution-element detection of binaries is possible with HST because of the high signal-to-noise ratio of the observations and the stability of the PSF. Identification and confirmation of binary Trojans is important because a Trojan Tour is one of five possible New Frontiers missions. A binary could constitute a potentially high value target because of the opportunity to study two objects and to test models of the primordial nature of binaries. The potential to derive mass-based physical information from the binary orbit could yield more clues to the origin of Trojans.

  5. The Search for Trojan Binaries

    NASA Astrophysics Data System (ADS)

    Merline, William J.; Tamblyn, P. M.; Dumas, C.; Close, L. M.; Chapman, C. R.; Durda, D. D.; Levison, H. F.; Hamilton, D. P.; Nesvorny, D.; Storrs, A.; Enke, B.; Menard, F.

    2007-10-01

    We report on observations of Jupiter Trojan asteroids in search of binaries. We made observations using HST/ACS of 35 small (V = 17.5-19.5) objects in Cycle 14, without detecting any binaires. We have also observed a few dozen Trojans in our ground-based study of larger Trojans, discovering only one binary. The result is that the frequency of moderately-separated binaries among the Trojans seem rather low, likely less than 5%. Although we have only statistics of small numbers, it appears that the binary frequencies are more akin to the larger Main-Belt asteroids, than to the frequency in the TNO region, which probably exceeds 10%. The low frequency is inconsistent with the projections based on Trojan contact binaries by Mann et al. (2006, BAAS 38, 6509), although our work cannot detect very close or contact binaries. We discovered and characterized the orbit and density of the first Trojan binary, (617) Patroclus using the Gemini AO system (Merline et al. 2001 IAUC 7741). A second binary, (624) Hecktor, has now been reported by Marchis et al. (2006, IAUC 8732). In a broad survey of Main Belt asteroids, we found that, among the larger objects, the binary fraction is about 2%, while we are finding that the fraction is significantly higher among smaller asteroids (and this is even more apparent from lightcurve discoveries). Further, characteristics of these smaller systems indicate a distinctly different formation mechanism the the larger MB binaries. Because the Trojans have compositions that are more like the KBOs, while they live in a collisional environment much more like the Main Belt than the KBOs, these objects should hold vital clues to binary formation mechanics. And because there seems to be a distinct difference in larger and smaller main-belt binaries, we sought to detect such differences among the Trojans as well.

  6. Earth's Trojan asteroid.

    PubMed

    Connors, Martin; Wiegert, Paul; Veillet, Christian

    2011-07-28

    It was realized in 1772 that small bodies can stably share the same orbit as a planet if they remain near 'triangular points' 60° ahead of or behind it in the orbit. Such 'Trojan asteroids' have been found co-orbiting with Jupiter, Mars and Neptune. They have not hitherto been found associated with Earth, where the viewing geometry poses difficulties for their detection, although other kinds of co-orbital asteroid (horseshoe orbiters and quasi-satellites) have been observed. Here we report an archival search of infrared data for possible Earth Trojans, producing the candidate 2010 TK(7). We subsequently made optical observations which established that 2010 TK(7) is a Trojan companion of Earth, librating around the leading Lagrange triangular point, L(4). Its orbit is stable over at least ten thousand years. PMID:21796207

  7. The Complex History of Trojan Asteroids

    NASA Astrophysics Data System (ADS)

    Emery, J. P.; Marzari, F.; Morbidelli, A.; French, L. M.; Grav, T.

    The Trojan asteroids, orbiting the Sun in Jupiter's stable Lagrange points, provide a unique perspective on the history of our solar system. As a large population of small bodies, they record important gravitational interactions in the dynamical evolution of the solar system. As primitive bodies, their compositions and physical properties provide windows into the conditions in the solar nebula in the region in which they formed. In the past decade, significant advances have been made in understanding their physical properties, and there has been a revolution in thinking about the origin of Trojans. The ice and organics generally presumed to be a significant part of Trojan composition have yet to be detected directly, although the low density of the binary system Patroclus (and possibly low density of the binary/moonlet system Hektor) is consistent with an interior ice component. By contrast, fine-grained silicates that appear to be similar to cometary silicates in composition have been detected, and a color bimodality may indicate distinct compositional groups among the Trojans. Whereas Trojans had traditionally been thought to have formed near 5 AU, a new paradigm has developed in which the Trojans formed in the proto-Kuiper belt, and were scattered inward and captured in the Trojan swarms as a result of resonant interactions of the giant planets. Whereas the orbital and population distributions of current Trojans are consistent with this origin scenario, there are significant differences between current physical properties of Trojans and those of Kuiper belt objects. These differences may be indicative of surface modification due to the inward migration of objects that became the Trojans, but understanding of appropriate modification mechanisms is poor and would benefit from additional laboratory studies. Many open questions about this intriguing population remain, and the future promises significant strides in our understanding of Trojans. The time is ripe for a

  8. Search of Binary Jupiter-Trojan Asteroids with Laser Guide Star AO systems: a moon around 624 Hektor

    NASA Astrophysics Data System (ADS)

    Marchis, Franck; Berthier, J.; Wong, M. H.; Descamps, P.; Hestroffer, D.; Colas, F.; de Pater, I.; Vachier, F.

    2006-09-01

    In 2006, we initiated a search for multiple asteroids in Jupiter Trojan L4 population with Laser Guide Star Adaptive Optics (LGS AO) technology on 8-10m class telescopes. To maximize the chance of detecting companion, we prioritized Trojan asteroids that could be member of collisional families in our search (see the PeTrA project and Beaugé and Roig (A&A, 2001)). Our first night was performed on July 17 2006 UT with the Keck LGS AO system. Twenty targets up to the 18th magnitude in R band were observed mostly in Kp broadband filter with an angular resolution 0.06 arcsec. Images of 624 Hektor, our brightest target (predicted V=14.4) revealed the presence of a moonlet companion (Marchis et al., IAU, 2006, provisional designation S/2006(624)1) located at 0.36” ( 1150 km) from the primary with a peak SNR 25. The resolved primary has a bilobated shape, but it is unclear if the primary is a contact or separated binary. It can be approximated as an ellipse with major and minor axes 2a = 350 km and 2b = 210 km (108 and 65 milli-arcseconds). The pole solution λ=329°, β=-25° in ecliptic B1950 (Magnusson 1989, and updated table) is in agreement with the observations. Based on the integrated brightness ratio between the moonlet and the primary of about 6.5, the diameter of S/2006(624)1 is estimated to be about 15 km. Additional observations will be recorded using the Keck and Gemini LGS AO system in Aug-Sept. 2006 aiming to estimate the orbit of the moonlet. The conditions of observations seem optimal since the system will be seen pole-on during this period. 624 Hektor is the first binary asteroid found in the L4 point and the first Trojan possessing a moonlet companion. The result of this campaign of observations, including Aug-Sept. observations, will be discussed.

  9. Binary Asteroids

    NASA Astrophysics Data System (ADS)

    Harris, Alan W.; Pravec, P.

    2006-06-01

    There are now nearly 100 binary asteroids known. In the last year alone, 30 binary asteroids have been discovered, half of them by lightcurves showing eclipse events. Similar to eclipsing binary stars, such observations allow determination of orbit period and sizes and shapes of the primary and secondary relative to the orbital dimension. From these parameters one can estimate the mean density of the system, and a number of dynamical properties such as total specific angular momentum, tidal evolution time scales of spins and orbit, and precession frequencies of the orbit about the primary and of the solar induced "general precession" of the system. We have extracted parameters for all systems with enough observations to allow meaningful determinations. Some preliminary results include: (1) Binaries are roughly as prevalent among small main-belt asteroids as among Near-Earth Asteroids. (2) Most binaries are partially asynchronous, with the secondary synchronized to the orbit period, but the primary still spinning much faster. This is consistent with estimated tidal damping time scales. (3) Most systems have near the critical maximum angular momentum for a single "rubble pile" body, but not much more, and some less. Thus fission appears not to be a viable formation mechanism for all binaries, although near-critical spin rate seems to play a role. (4) Orbits of the secondaries are essentially in the equatorial plane of the primary. Since most primary spins are still fast, the satellites must have been formed into low inclination orbits. (5) Precession frequencies are in the range of the shorter resonance frequencies in the solar system (tens of thousands of years), thus resonance interactions can be expected to have altered spin orientations as systems evolved slowly by tidal friction or other processes. (6) Primaries are unusually spheroidal, which is probably necessary for stability of the binary once formed.

  10. Opposition effect of Trojan asteroids

    NASA Astrophysics Data System (ADS)

    Shevchenko, V. G.; Belskaya, I. N.; Slyusarev, I. G.; Krugly, Yu. N.; Chiorny, V. G.; Gaftonyuk, N. M.; Donchev, Z.; Ivanova, V.; Ibrahimov, M. A.; Ehgamberdiev, Sh. A.; Molotov, I. E.

    2012-01-01

    CCD-photometry of three Jupiter Trojan asteroids were carried out to study their opposition effect. We obtained well-sampled magnitude-phase curves for (588) Achilles, (884) Priamus, and (1143) Odysseus in the maximal attainable phase angle range down to 0.1-0.2°. The magnitude-phase relations have a linear behavior in all observed range of phase angles and do not show any non-linear opposition brightening. We have not found any confident differences between phase slopes measured in B, V and R bands. The values of the measured phase slopes of Trojans are different from available data for Centaurs. They are within the range of phase slopes measured for some low-albedo main belt asteroids, also exhibit a linear behavior down to small phase angles. An absence of non-linear opposition brightening puts constraints on the surface properties of the studied objects, assuming very dark surfaces where single scattering plays dominating role. We also determined the rotation periods, amplitudes, the values of color indexes B-V and V-R, and the absolute magnitudes of these asteroids.

  11. A Troop of Trojans: Photometry of 24 Jovian Trojan Asteroids

    NASA Astrophysics Data System (ADS)

    French, Linda M.; Stephens, R. D.; Coley, D. R.; Wasserman, L. H.; La Rocca, D.; Vilas, F.

    2013-10-01

    Because of their greater distance from the Sun, the Jovian Trojans have been less studied than main belt asteroids. Although they are numerous (nearly 6000 have well determined orbits as of July 2013), the Trojans remain mysterious in many ways. Their spectra are unlike those of any meteorites in terrestrial collections. The spectra and the low albedos of Trojans, however, bear a strong resemblance to those of cometary nuclei (Abell et al. 2005; Fornasier et al. 2007; Emery et al. 2011). The Nice Model (Morbidelli et al. 2005; 2009) predicts that the Trojans may well be objects that originated with today's Kuiper Belt Objects. The rotation of asteroids larger than ~50 km in diameter seems to be determined largely by collisions, while that of smaller bodies is shaped primarily by YORP forces and torques (Pravec et al. 2008). We are surveying the rotation properties of Trojans to see whether similar trends are present. We find an abundance of slow rotators, including the first documented tumbler among the Trojans. We present 24 new Trojan lightcurves, mostly from objects ranging from 30-50 km in diameter. We also discuss observations of five sub-20 km Trojans, whose rotation properties are consistent with cometary densities. This research was supported by National Science Foundation Grant AST-1212115, by NASA Grant NNX-08AO29G, and by an American Astronomical Society Small Research Grant.

  12. The Nordtvedt Effect in the Trojan Asteroids

    NASA Astrophysics Data System (ADS)

    Orellana, R. B.; Vucetich, H.

    1993-06-01

    Bounds to the Nordtvedt parameter are obtained from the motion of the first twelve Trojan asteroids in the period 1906-1990. From the analysis performed, we derive a value for the inverse of the Saturn mass 3497.8O±O.81 and the Nordtvedt parameter -O.56±O.48, from a simultaneous solution for all asteroids.

  13. Rotation lightcurves of small jovian Trojan asteroids

    NASA Astrophysics Data System (ADS)

    French, Linda M.; Stephens, Robert D.; Coley, Daniel; Wasserman, Lawrence H.; Sieben, Jennifer

    2015-07-01

    Several lines of evidence support a common origin for, and possible hereditary link between, cometary nuclei and jovian Trojan asteroids. Due to their distance and low albedos, few comet-sized Trojans have been studied. We present new lightcurve information for 19 Trojans ≲ 30 km in diameter, more than doubling the number of objects in this size range for which some rotation information is known. The minimum densities for objects with complete lightcurves are estimated and are found to be comparable to those measured for cometary nuclei. A significant fraction (∼40%) of this observed small Trojan population rotates slowly (P > 24 h), with measured periods as long as 375 h (Warner, B.D., Stephens, R.D. [2011]. Minor Planet Bull. 38, 110-111). The excess of slow rotators may be due to the YORP effect. Results of the Kolmogorov-Smirnov test suggest that the distribution of Trojan rotation rates is dissimilar to those of Main Belt Asteroids of the same size. Concerted observations of a large number of Trojans could establish the spin barrier (Warner, B.D., Harris, A.W., Pravec, P. [2009]. Icarus 202, 134-146), making it possible to estimate densities for objects near the critical period.

  14. JHK photometry of selected Trojan and Hilda asteroids

    NASA Technical Reports Server (NTRS)

    Smith, Dale W.; Johnson, Paul E.; Buckingham, William L.; Shorthill, Richard W.

    1992-01-01

    No entirely satisfactory match has been established between the present JHK photometry of selected Hilda and Trojan asteroids and photometry for both main belt asteroids and laboratory samples. It is noted that while the leading Trojans and Hildas exhibit similar and homogeneous JHK colors, the trailing Trojans appear to be more heterogeneous. Charcoal and magnetite provide the best match in terms of JHK colors.

  15. Light-Curve Survey of Jupiter Trojan Asteroids

    NASA Astrophysics Data System (ADS)

    Duffard, R.; Melita, M.; Ortiz, J. L.; Licandro, J.; Williams, I. P.; Jones, D.

    2008-09-01

    Trojan asteroids are an interesting population of minor bodies due to their dynamical characteristics, their physical properties and that they are relatively isolated located at the snow-line The main hypotheses about the origin of the Jupiter Trojans assumed that they formed either during the final stages of the planetary formation (Marzari & Scholl 1998), or during the epoch of planetary migration (Morbidelli et al. 2005), in any case more than 3.8 Gy. ago. The dynamical configuration kept the Trojans isolated from the asteroid Main Belt throughout the history of the Solar System. In spite of eventual interactions with other populations of minor bodies like the Hildas, the Jupiter family comets, and the Centaurs, their collisional evolution has been dictated mostly by the intrapopulation collisions (Marzari et al. 1996, 1997). Therefore, the Jupiter Trojans may be considered primordial bodies, whose dynamical and physical properties can provide important clues about the environment of planetary formation. The available sample of Jupiter Trojans light-curves is small and mainly restricted to the largest objects. According to the MPC-website (updated last in March 2006), the present sample of rotation periods and light-curve-amplitudes of the Jupiter Trojan asteroids is composed by 25 objects with some information about their periods and by 10 of them with only an amplitude estimation. A survey of contact binary Trojan asteroids has been done by Mann et al. 2007, where they have recorded more than 100 amplitudes from sparse-sampled light-curves and very-wellresolved rotational periods. More than 2000 Trojan asteroids have been discovered up to date, so, there is an urgent need to enlarge the sample of intrinsic rotation periods and accurate light-curve amplitudes and to extend it to smaller sizes. Results and Discusions We requested 26 nights of observation in the second semester of 2007, to begin with the survey. They were scheduled for the following instruments

  16. A Genetic Cluster of Martian Trojan Asteroids

    NASA Astrophysics Data System (ADS)

    Christou, Apostolos

    2013-10-01

    Trojan asteroids lead 60 degrees ahead (L4) or trail 60 degrees behind (L5) a planet's position along its orbit. The Trojans of Jupiter and Neptune are thought to be primordial remnants from the solar system's early evolution (Shoemaker et al., 1989; Sheppard et al., 2006). Mars is the only terrestrial planet known to host stable Trojans (Scholl et al., 2005) with ~50 km-sized objects expected to exist (Tabachnik and Evans, 1999). I identified 6 additional candidate Martian Trojans within the Minor Planet Center database, including three with multi-opposition orbits. 100 dynamical clones for each of the three asteroids were integrated for 100 Myr under a force model that included the Yarkovsky effect. All clones persisted as L5 Trojans of Mars, implying that their residence time is longer still. This is further supported by recent Gyr numerical integrations (de la Fuente Marcos and de la Fuente Marcos, 2013). The number of stable Martian Trojans is thus raised to 7, 6 of which are at L5. To investigate this asymmetry, I apply a clustering test to their orbits and compare them with the Trojan population of Jupiter. I find that, while Jupiter Trojans are spread throughout the domain where long-term stability is expected, L5 martian Trojans are far more concentrated. The implication is that these objects may be genetically related to each other and to the largest member of the group, 5261 Eureka. If so, it represents the closest such group to the Earth's orbit, still recognizable due to the absence of planetary close encounters which quickly scatter NEO families (Schunova et al., 2012). I explore the origin and nature of this `Eureka cluster', including the thesis that its members are products of the collisional fragmentation and/or rotational fission of Trojan progenitors. I constrain the cluster's age under these scenarios and argue that collisions may be responsible for the observed paucity of km-sized objects. Finally, I discuss how the hypothesis of a genetic

  17. The composition of the Trojan asteroids

    NASA Technical Reports Server (NTRS)

    Gradie, J.; Veverka, J.

    1980-01-01

    Consideration is given to the composition of those Trojan asteroids, Hilda asteroids and 944 Hidalgo with very low albedos and spectral reddening between 0.4 and 1.1 microns with respect to the C asteroids, termed RD objects. It is proposed that the albedo and reddening of these objects can be explained by the presence of very opaque, very red, polymer-type organic compounds structurally similar to kerogen, presumably resulting from Fischer-Tropsch-type reactions in the early solar nebula. The spectra and various mixtures of powdered montmorillonite, magnetite, coal-tar residue containing kerogen substances and carbon black are shown to provide a good match to the RD asteroid spectral properties. It is suggested that the nonsoluble carbonaceous residue may have required lower temperatures for its formation and preservation than carbonaceous materials in the carbonaceous chondrites and C asteroids, and thus explain the absence of RD objects closer than 4 AU from the sun.

  18. Water in the Jovian Trojan Asteroids?

    NASA Astrophysics Data System (ADS)

    Yang, Bin

    2007-05-01

    Water, as a major constituent of the solar nebula, is believed to have played an important role in shaping the Solar System. In the terrestrial region, the concentration of water vapor is expected to determine the local oxidation state and chemical structure. Beyond 5 AU, water ice makes up nearly 50% of the mass of the solids and may have strongly influenced the formation of the giant planets. In addition, liquid water is thought to be necessary for life, as we know it, to form and survive. Jovian Trojan asteroids are orbiting the Sun at nearly the same heliocentric distance as Jupiter. Since these objects are located far from the Sun , they could contain significant amounts of volatile materials (e.g. water ice). We have obtained near-IR spectroscopic data of Trojan asteroids at H and K-band (from 1.4 - 2.5 micron) using the UKIRT, IRTF and Subaru telescopes on Mauna Kea. Our goal is to look for evidence of water ice, hydrated minerals and hydrocarbon features in order to determine compositions of Trojan asteroids and their possible origin. We will present the near-IR spectroscopic data and discuss the analysis and implications of these observations.

  19. Photometric Observations of Martian Trojan Asteroids

    NASA Astrophysics Data System (ADS)

    Borisov, Galin; Christou, Apostolos; Unda-Sanzana, Eduardo

    2016-07-01

    We present R filter photometry of the Martian Trojan asteroids (101429) 1998 VF31 and (385250) 2001 DH47, carried out with the 2-m RCC and 1.3-m SMARTS telescopes during 11 nights in 2015 November and 2016 January. A periodogram analysis of the lightcurves suggests a rotation period of P = 7.70h with a low amplitude (A < 0.1 mag) for 1998 VF31 and P = 3.97h with amplitude A ~ 0.6mag for 2001 DH47.

  20. Optimum Trajectory for Low-thrust Multiple Trojan Asteroids Flybys

    NASA Astrophysics Data System (ADS)

    Matsumoto, M.; Kawaguchi, J.

    It is known that there is an asteroid family around L4 or L5 Lagrange point of the Sun-Jupiter system, and it is called the Trojan asteroid family. As one of outer planet exploration mission, a plan to explore the Trojan asteroids using Jupiter swing-by is considered. Based on this mission, this paper discusses multiple flybys trajectory for Trojan asteroids exploration. A trajectory optimization of Trojan asteroids exploration using multiple flybys depends largely on objects of exploration. For this reason, the stage of choosing the candidates of exploration is important, and it is indispensable to choose most qualified candidate for the mission. As the first step, this paper proposes the flyby sequence search strategy which uses a ballistic orbit, and using these results, the multiple flybys trajectory to Trojan asteroids by impulsive velocity change is designed. Next, this paper considers an optimization of multiple slow-flybys trajectory of the spacecraft which uses low thrust propulsion. Furthermore feasibility of the sequence of main-belt asteroid flyby on the way to Trojan asteroid was studied.

  1. Voyage to Troy: A mission concept for the exploration of the Trojan asteroids

    NASA Astrophysics Data System (ADS)

    Saikia, S.; Das, A.; Laipert, F.; Dapkus, C.; Kendall, J.; Bowling, T.; Steckloff, J.; Holbert, S.; Graves, K.; Anthony, T.; Bobick, R.; Huang, Y.; Stuart, J.; Longuski, J.; Minton, D.

    2014-07-01

    red). Hektor is currently thought to be a contact binary with a companion in an unusually inclined orbit and presents itself as a target with diverse knowledge to offer. The possibility of potentially gathering data from a Hilda asteroid en route to the Trojans is also being investigated. The mission would consist of the rendezvous of one or two Trojan asteroids along with further flybys. Candidate instruments are a thermal mapper, multispectral imagers, gamma-ray, neutron, and UV-spectrometers, and a LIDAR. The mission is designed within the constraints of NASA New Frontiers mission with a less than 10-year trajectory. The mission concept will help in the future Trojan mission concept studies.

  2. Do Trojan Asteroids Have the Brightness Opposition Effect?

    NASA Astrophysics Data System (ADS)

    Shevchenko, V. G.; Krugly, Yu. N.; Belskaya, I. N.; Chiorny, V. G.; Gaftonyuk, N. M.; Slyusarev, I. G.; Tereschenko, I. A.; Donchev, Z.; Ivanova, V.; Borisov, G.; Ibrahimov, M. A.; Marshalkina, A. L.; Molotov, I. E.

    2009-03-01

    Photometric observations of the Trojan asteroids 588 Achilles are presented. The rotation period and the detailed magnitude phase dependence were obtained. We have not revealed any noticeable opposition brightening down to 0.1 deg of phase angle.

  3. BINARY CANDIDATES IN THE JOVIAN TROJAN AND HILDA POPULATIONS FROM NEOWISE LIGHT CURVES

    SciTech Connect

    Sonnett, S.; Mainzer, A.; Masiero, J.; Bauer, J.; Grav, T.

    2015-02-01

    Determining the binary fraction for a population of asteroids, particularly as a function of separation between the two components, helps describe the dynamical environment at the time the binaries formed, which in turn offers constraints on the dynamical evolution of the solar system. We searched the NEOWISE archival data set for close and contact binary Trojans and Hildas via their diagnostically large light curve amplitudes. We present 48 out of 554 Hilda and 34 out of 953 Trojan binary candidates in need of follow-up to confirm their large light curve amplitudes and subsequently constrain the binary orbit and component sizes. From these candidates, we calculate a preliminary estimate of the binary fraction without confirmation or debiasing of 14%-23% for Trojans larger than ∼12 km and 30%-51% for Hildas larger than ∼4 km. Once the binary candidates have been confirmed, it should be possible to infer the underlying, debiased binary fraction through estimation of survey biases.

  4. A CCD comparison of outer Jovian satellites and Trojan asteroids

    NASA Technical Reports Server (NTRS)

    Luu, Jane X.

    1991-01-01

    The eight small outer Jovian satellites are not as well known as the brighter, more illustrious Galilean satellites. They are divided into two groups, each containing four satellites; the inner group travels in prograde orbits while the outer group travels in retrograde orbits. From the distinct orbital characteristics of the two groups, most of the theories of their origin involve the capture and breakup of two planetesimals upon entry into the atmosphere of proto-Jupiter. Their proximity to the Trojans asteroids has led to conjectures of a link between them and the Trojans. However, Tholen and Zellner (1984) found no red spectrum among six of the satellites and postulated that they were all C-type objects; therefore, they were unlikely to be derivatives of the Trojan population. Charge-coupled device (CCD) photometry and spectroscopy of the eight outer Jovian satellites obtained from 1987 to 1989 and a comparison between these eight satellites and the Trojan asteroids are presented.

  5. Contact Binary Asteroids

    NASA Astrophysics Data System (ADS)

    Rieger, Samantha

    2015-05-01

    Recent observations have found that some contact binaries are oriented such that the secondary impacts with the primary at a high inclination. This research investigates the evolution of how such contact binaries came to exist. This process begins with an asteroid pair, where the secondary lies on the Laplace plane. The Laplace plane is a plane normal to the axis about which the pole of a satellites orbit precesses, causing a near constant inclination for such an orbit. For the study of the classical Laplace plane, the secondary asteroid is in circular orbit around an oblate primary with axial tilt. This system is also orbiting the Sun. Thus, there are two perturbations on the secondarys orbit: J2 and third body Sun perturbations. The Laplace surface is defined as the group of orbits that lie on the Laplace plane at varying distances from the primary. If the secondary is very close to the primary, the inclination of the Laplace plane will be near the equator of the asteroid, while further from the primary the inclination will be similar to the asteroid-Sun plane. The secondary will lie on the Laplace plane because near the asteroid the Laplace plane is stable to large deviations in motion, causing the asteroid to come to rest in this orbit. Assuming the secondary is asymmetrical in shape and the bodys rotation is synchronous with its orbit, the secondary will experience the BYORP effect. BYORP can cause secular motion such as the semi-major axis of the secondary expanding or contracting. Assuming the secondary expands due to BYORP, the secondary will eventually reach the unstable region of the Laplace plane. The unstable region exists if the primary has an obliquity of 68.875 degrees or greater. The unstable region exists at 0.9 Laplace radius to 1.25 Laplace radius, where the Laplace radius is defined as the distance from the central body where the inclination of the Laplace plane orbit is half the obliquity. In the unstable region, the eccentricity of the orbit

  6. Small Jovian Trojan Asteroids: An Excess of Slow Rotators

    NASA Astrophysics Data System (ADS)

    French, Linda M.

    2016-01-01

    Several lines of evidence support a common origin for, and possible hereditary link between, cometary nuclei and jovian Trojan asteroids. Due to their distance and low albedos, few comet-sized Trojans have been studied. We discuss the rotation properties of Jovian Trojan asteroids less than 30 km in diameter. Approximately half of the objects discussed here were studied using densely sampled lightcurves (French et al. 2015a, b); Stephens et al. 2015), and the other half were sparse lightcurves obtained by the Palomar Transient Factory (PTF; Waszcazk et al. 2015). A significant fraction (~40%) of the objects in the ground-based sample rotate slowly (P > 24h), with measured periods as long as 375 h (Warner and Stephens 2011). The PTF data show a similar excess of slow rotators. Only 5 objects in the combined data set have rotation periods of less than six hours. Three of these fast rotators were contained in the data set of French et al. these three had a geometric mean rotation period of 5.29 hours. A prolate spheroid held together by gravity rotating with this period would have a critical density of 0.43 gm/cm3, a density similar to that of comets (Lamy et al. 2004). Harris et al. (2012) and Warner et al. (2011) have explored the possible effects on asteroid rotational statistics with the results from wide-field surveys. We will examine Trojan rotation statistics with and without the results from the PTF.

  7. Identification of asteroid families in Trojans and Hildas

    NASA Astrophysics Data System (ADS)

    Vinogradova, T. A.

    2015-12-01

    A simple empirical method of asteroid proper elements calculation is proposed. The method uses distributions of osculating orbital elements, such as longitude of ascending node, inclination and longitude of perihelion, and eccentricity. These distributions make it possible to obtain forced elements. The forced elements define long-periodic variations of osculating elements. The proper elements are calculated by elimination of the short- and long-periodic perturbations from the osculating ones. In this paper, the short-period perturbations were removed by means of numerical integration, whereas the removal of long-periodic terms was done by using the coordinate transformation formula. The derived proper elements are accurate enough to search for asteroid families. The method is effective in both non-resonant and resonant cases. As an example, the asteroids in 3:2 and 1:1 mean-motion resonances with Jupiter were investigated. The proper elements were calculated for all multi-opposition asteroids in these zones. Due to the large number of the asteroids real families are clearly apparent in distributions of the proper elements. An approach similar to the hierarchical clustering method was used for identification of the families. Using this technique, two robust asteroid families of (1911) Schubart and (153) Hilda were identified in the Hilda-group. And four families were found among L4-trojans: (3548) Eurybates, (2148) Epeios, (624) Hektor, and (9799) 1996RJ. The taxonomy of these families was analysed. The most tight and populated families consist of C and X asteroids, while the D-type asteroids predominate in the background population. No reliable families have been identified near the libration point L5.

  8. Is Amalthea a Captured Trojan Asteroid of Jupiter?

    NASA Astrophysics Data System (ADS)

    Prentice, Andrew J.

    In 2002 the Galileo spacecraft discovered that the small irregular Jovian moon Amalthea is a porous assemblage of rock and ice. Its bulk density is ~1 g/cc. This is much less than the value ~3.8 g/cc expected of the mixture of rock and metal that would condense at its distance from Jupiter had Amalthea formed from a gas ring shed by the proto-Jovian cloud (Prentice 2001 Earth Moon Planets 87 11). Thus rather than being a native moon of Jupiter (and especially because of its small size relative to the Galilean satellites) Amalthea is probably a captured asteroid. Prentice and ter Haar (1979 Nature 280 300) had predicted Amalthea to be a C-type asteroid. Galileo has found Amalthea to be even less dense than the porous main-belt C-asteroid Mathilde so suggesting the presence of some ice. Most likely therefore Amalthea originally condensed as a planetesimal from the gas ring shed by the proto-Solar cloud at the orbit of Jupiter. The predicted bulk chemical composition by mass is asteroidal rock (65%) graphite (1%) and water ice (34%) [see Prentice 2001 in URL: www.lpi.usra.edu/meetings/mercury01]. The zero-porosity density is 1.8 g/cc. Amalthea is simply a first cousin of the Trojan asteroids of Jupiter

  9. Is Jupiter's Moon Amalthea a Captured Trojan Asteroid?

    NASA Astrophysics Data System (ADS)

    Prentice, Andrew J.

    In 2002 the Galileo spacecraft discovered that the small irregular Jovian moon Amalthea is a porous assemblage of rock and ice. Its bulk density is ~1 g/cc. This is much less than the value ~3.8 g/cc expected of the mixture of rock and metal that would form at this Jovian orbit had Amalthea moon condensed from a gas ring shed by the proto-Jovian cloud (Prentice 2001 Earth Moon Planets 87 11). Thus rather than being a native moon of Jupiter and especially because of its small size relative to the Galilean satellites Amalthea is probably a captured asteroid. Prentice and ter Haar (1979 Nature 280 300) had predicted Amalthea to be a C-type asteroid. Galileo has found Amalthea to be even less dense than the porous main-belt C-asteroid Mathilde so suggesting the presence of ice. Most likely therefore Amalthea originally condensed as a planetesimal within the gas ring shed by the proto-Solar cloud at the orbit of Jupiter. The predicted bulk chemical composition by mass is asteroidal rock (65%) graphite (1%) and water ice (34%) [see Prentice in URL: www.lpi.usra.edu/meetings/mercury01]. The zero-porosity density is 1.8 g/cc. Amalthea is simply a first cousin of the Trojan asteroids of Jupiter.

  10. Is Amalthea a Captured Trojan Asteroid of Jupiter?

    NASA Astrophysics Data System (ADS)

    Prentice, Andrew J.

    In 2002 the Galileo spacecraft discovered that the small irregular Jovian moon Amalthea is a porous assemblage of rock and ice. Its bulk density is ~1 g/cc. This is much less than the value ~3.8 g/cc expected of the mixture of rock and metal that would condense at its distance from Jupiter had Amalthea formed from a gas ring shed by the proto-Jovian cloud (Prentice 2001 Earth Moon Planets 87 11). Thus rather than being a native moon of Jupiter (and especially because of its small size relative to the Galilean satellites) Amalthea is probably a captured asteroid. Prentice and ter Haar (1979 Nature 280 300) had predicted Amalthea to be a C-type asteroid. Galileo has found Amalthea to be even less dense than the porous main-belt C-asteroid Mathilde so suggesting the presence of some ice. Most likely therefore Amalthea originally condensed as a planetesimal from the gas ring shed by the proto-Solar cloud at the orbit of Jupiter. The predicted bulk chemical composition by mass is asteroidal rock (65%) graphite (1%) and water ice (34%) [see Prentice 2001 in URL: www.lpi.usra.edu/meetings/mercury01]. The zero-porosity density is 1.8 g/cc. Amalthea is simply a first cousin of the Trojan asteroids of Jupiter.

  11. Is Amalthea a Captured Trojan Asteroid of Jupiter?

    NASA Astrophysics Data System (ADS)

    Prentice, Andrew J. R.

    2005-01-01

    In 2002 the Galileo spacecraft discovered that the small irregular Jovian moon Amalthea is a porous assemblage of rock and ice. Its bulk density is ~1 g/cc. This is much less than the value ~3.8 g/cc expected of the mixture of rock and metal that would condense at its distance from Jupiter had Amalthea formed from a gas ring shed by the proto-Jovian cloud (Prentice 2001 Earth Moon Planets 87 11). Thus rather than being a native moon of Jupiter (and especially because of its small size relative to the Galilean satellites) Amalthea is probably a captured asteroid. Prentice and ter Haar (1979 Nature 280 300) had predicted Amalthea to be a C-type asteroid. Galileo has found Amalthea to be even less dense than the porous main-belt C-asteroid Mathilde so suggesting the presence of some ice. Most likely therefore Amalthea originally condensed as a planetesimal from the gas ring shed by the proto-Solar cloud at the orbit of Jupiter. The predicted bulk chemical composition by mass is asteroidal rock (65%) graphite (1%) and water ice (34%) [see Prentice 2001 in URL: www.lpi.usra.edu/meetings/mercury01]. The zero-porosity density is 1.8 g/cc. Amalthea is simply a first cousin of the Trojan asteroids of Jupiter.

  12. Trojan Asteroids Observed from GMARS and Santana Observatories: 2009 October - December

    NASA Astrophysics Data System (ADS)

    Stephens, Robert D.

    2010-04-01

    Lightcurves for six Trojan asteroids were obtained from Santana and GMARS Observatories from 2009 October to December: 588 Achilles, 1583 Antilochus, 2456 Palamedes, 3548 Eurybates, 3564 Talyhybius, and 3793 Leonteus.

  13. Near Infrared Spectroscopy of Jovian Trojan Asteroids: A Search for Silicate Features

    NASA Astrophysics Data System (ADS)

    Yang, Bin; Jewitt, D.

    2007-10-01

    Spectroscopic studies show that the reflectance spectra of Jovian Trojan asteroids generally appear to be linear and moderately red (with a few neutral ones) in the optical and near infrared wavelength regions. Cruikshank et al. (2001) demonstrated that synthetic models incorporating magnesium-rich pyroxene (Mg, Fe SiO3) and carbon could match the low albedo and the shape of the reflectance spectrum of Trojan Hektor from 0.3 to 3.6 micron. More importantly, Spitzer thermal emission spectra of three Trojan asteroids all showed an emissivity plateau near 10-micron, which was interpreted as an indication of fine-grained silicates (Emery et al. 2006). Interestingly, the previous survey (Howell 1995) noted that several Trojans showed a broad absorption band between 1.1 and 1.25 micron based on broadband infrared colors. This possible 1 micron feature is consistent with the 1 micron silicate band that has been observed and well studied on many main belt asteroids. We obtained near infrared (NIR) spectroscopy (0.8-2.5 micron) on 7 Trojan asteroids having reported silicate-related absorption bands. Also, the unique asteroid (279) Thule in the 3:4 mean-motion resonance was observed. The observations were made with the NASA Infrared Telescope Facility (IRTF) atop Mauna Kea. We will present the new spectra and simple scattering models employed to constrain the surface properties of Trojan asteroids.

  14. On some long time dynamical features of the Trojan asteroids of Jupiter

    NASA Astrophysics Data System (ADS)

    Érdi, Bálint; Forgács-Dajka, Emese; Süli, Áron

    2013-09-01

    The equation of motion of long periodic libration around the Lagrangian point in the restricted three-body problem is investigated. The range of validity of an approximate analytical solution in the tadpole region is determined by numerical integration. The predictions of the model of libration are tested on the Trojan asteroids of Jupiter. The long time evolution of the orbital eccentricity and the longitude of the perihelion of the Trojan asteroids, under the effect of the four giant planets, is also investigated and a slight dynamical asymmetry is shown between the two groups of Trojans at and.

  15. Testing Migration of the Jupiter Trojan Asteroids in the Lab

    NASA Astrophysics Data System (ADS)

    Poston, Michael; Blacksberg, Jordana; Brown, Mike; Carey, Elizabeth; Carlson, Robert; Ehlmann, Bethany; Eiler, John; Hand, Kevin; Hodyss, Robert; Mahjoub, Ahmed; Wong, Ian

    2015-11-01

    Today’s Jupiter Trojan asteroids may have orininated in the Kuiper Belt (eg. Morbidelli et al. Nature 2005, Nesvorny et al. ApJ 2013) and migrated to capture at their present locations. If this is the case, it is expected that their surfaces will contain chemical traces of this history. No distinct spectral bands have been conclusively identified in the literature, however, visible and near-infrared spectra of Kuiper Belt, Centaur, and Trojan populations each show two sub-populations distinguished by their spectral slopes (Brown et al. ApJL 2011; Emery et al. AJ 2011). The slopes are all positive (or “red”), steepest in the Kuiper Belt, and least steep in the Trojan population. Here we test the hypothesis that the asteroids formed spanning a stability line for a critical substance; in this case we test sulfur, as H2S. The hypothesis is that irradiating mixed ices containing H2S will result in a refractory residue of steeper slope than the same composition without the H2S. We have simulated this history in the Minos chamber at the Icy Worlds Simulation Laboratory at NASA’s Jet Propulsion Laboratory. Ices that will be discussed include a 3:3:3:1 mixture of H2S: NH3: CH3OH: H2O and a 3:3:1 mixture of NH3: CH3OH: H2O. After deposition at 50 K, the ices were irradiated with a beam of 10 keV electrons to form the refractory crust. The ices were then warmed (while continuing irradiation) to 120 K and observed for several days. Reflectance spectra were collected throughout the experiment in the visible and infrared. The spectral slope increased dramatically after irradiation of the mixture containing H2S, while the spectral slope for the mixture without any sulfur changed very little. This is consistent with sulfur being the critical component determining which of the spectral populations an object belongs to in the present inventory of outer solar system objects. Quantitative analysis is underway.This work has been supported by the Keck Institute for Space Studies

  16. Trojan Tour and Rendezvous (TTR): A New Frontiers Mission to Conduct the First Detailed Reconnaissance of the Jupiter Trojan Asteroids

    NASA Astrophysics Data System (ADS)

    Bell, James F.; Olkin, Cathy; Castillo-Rogez, Julie

    2015-11-01

    Among the most potentially diagnostic but least explored populations of small bodies are the Jupiter Trojan asteroids, which orbit at ~5 AU in the L4 and L5 Lagrange points of Jupiter. The Trojans provide a unique perspective on solar system history, because their locations and physical, compositional, and mineralogic properties preserve evidence for important gravitational interactions among the giant planets. The locations and orbital properties of more than 6200 Jupiter Trojans are now known, but that is likely only a small fraction of a population of up to ~1e6 Trojans >1 km in size. The Trojans are hypothesized to be either former KBOs scattered into the inner solar system by early giant planet migration and then trapped in L4 and L5, or bodies formed near 5 AU in a more quiescent early solar system.Important Planetary Decadal Survey questions that can be addressed by studying the Trojans include: (a) How did the giant planets and their satellite systems accrete, and is there evidence that they migrated to new orbital positions? (b) What is the relationship between large and small KBOs? Is the small population derived by impact disruption of the large one? (c) What kinds of surface evolution, radiation chemistry, and surface-atmosphere interactions occur on distant icy primitive bodies? And (d) What are the sources of asteroid groups (Trojans and Centaurs) that remain to be explored by spacecraft?Here we describe the Trojan Tour and Rendezvous (TTR) New Frontiers mission concept, which is designed to answer these Decadal questions and to test hypotheses for early giant planet migration and solar system evolution. Via close flybys of many of these objects, and orbital characterization of at least one large Trojan, TTR will enable the initial up-close exploration of this population. Our primary mission goals are to characterize the overall surface geology, geochemistry and mineralogy of these worlds; to characterize their internal structure and dynamical

  17. Constraints on the Composition of Trojan Asteroid 624 Hektor

    NASA Technical Reports Server (NTRS)

    Cruikshank, Dale P.; DalleOre, Cristina M.; Roush, Ted L.; Geballe, Thomas R.; Owen, Tobias C.; deBergh, Catherine; Cash, Michael D.; Hartmann, William K.; DeVincenzi, Donald L. (Technical Monitor)

    2001-01-01

    We present a composite spectrum of Trojan asteroid 624 Hektor, 0.3-3.6 microns, which shows that there is no discernible 3-micron absorption band. Such a band would indicate the presence of OH or H2O- bearing silicate minerals, or macromolecular carbon-rich organic material of the kind seen on the low-albedo hemisphere of Saturn's satellite Iapetus (Owen et al. 2000). The absence of spectral structure is itself indicative of the absence of the nitrogen-rich tholins (which show a distinctive absorption band attributed to N-H). The successful models in this study all incorporate the mineral pyroxene (Mg, Fe SiO3, the composition of hypersthene), which matches the red color of Hektor. Pyroxene is a mafic mineral common in terrestrial and lunar lavas, and is also seen in Main Belt asteroid spectra. An upper limit to the amount of crystalline H20 ice (30-micron grains) in the surface layer of Hektor is 3 weight percent. The upper limit for serpentine, as a representative of hydrous silicates, is much less stringent, at 40 percent, based on the shape of the spectral region around 3 gm. Thus, the spectrum at 3 gm does not preclude the presence of a few weight percent of volatile material in the surface layer of Hektor. All of the models we calculated require elemental carbon to achieve the low geometric albedo that matches Hektor. This carbon could be of organic or inorganic origin. By analogy, other D-type asteroids could achieve their red color, low albedo, and apparent absence of phyllosilicates, from compositions similar to the models presented here.

  18. Angular momentum of binary asteroids: Implications for their possible origin

    NASA Astrophysics Data System (ADS)

    Descamps, P.; Marchis, F.

    2008-01-01

    We describe in this work a thorough study of the physical and orbital characteristics of extensively observed main-belt and trojan binaries, mainly taken from the LAOSA (Large Adaptive Optics Survey of Asteroids [Marchis, F., Baek, M., Berthier, J., Descamps, P., Hestroffer, D., Kaasalainen, M., Vachier, F., 2006c. In: Workshop on Spacecraft Reconnaissance of Asteroid and Comet Interiors. Abstract #3042]) database, along with a selection of bifurcated objects. Dimensionless quantities, such as the specific angular momentum and the scaled primary spin rate, are computed and discussed for each system. They suggest that these asteroidal systems might be the outcome of rotational fission or mass shedding of a parent body presumably subjected to an external torque. One of the most striking features of separated binaries composed of a large primary ( R>100 km) with a much smaller secondary ( R<20 km) is that they all have total angular momentum of ˜0.27. This value is quite close to the Maclaurin-Jacobi bifurcation (0.308) of a spinning fluid body. Alternatively, contact binaries and tidally locked double asteroids, made of components of similar size, have an angular momentum larger than 0.48. They compare successfully with the fission equilibrium sequence of a rotating fluid mass. In conclusion, we find that total angular momentum is a useful proxy to assess the internal structure of such systems.

  19. Study of binary asteroids with three space missions

    NASA Astrophysics Data System (ADS)

    Kovalenko, Irina; Doressoundiram, Alain; Hestroffer, Daniel

    Binary and multiple asteroids are common in the Solar system and encountered in various places going from Near-Earth region, to the main-belt, Trojans and Centaurs, and beyond Neptune. Their study can provide insight on the Solar System formation and its subsequent dynamical evolution. Binaries are also objects of high interest because they provide fundamental physical parameters such as mass and density, and hence clues on the early Solar System, or other processes that are affecting asteroid over time. We will present our current project on analysis of such systems based on three space missions. The first one is the Herschel space observatory (ESA), the largest infrared telescope ever launched. Thirty Centaurs and trans-Neptunian binaries were observed by Herschel and the measurement allowed to define size, albedo and thermal properties [1]. The second one is the satellite Gaia (ESA). This mission is designed to chart a three-dimensional map of the Galaxy. Gaia will provide positional measurements of Solar System Objects - including asteroid binaries - with unprecedented accuracy [2]. And the third one is the proposed mission AIDA, which would study the effects of crashing a spacecraft into an asteroid [3]. The objectives are to demonstrate the ability to modify the trajectory of an asteroid, to precisely measure its trajectory change, and to characterize its physical properties. The target of this mission is a binary system: (65803) Didymos. This encompasses orbital characterisations for both astrometric and resolved binaries, as well as unbound orbit, study of astrometric binaries, derivation of densities, and general statistical analysis of physical and orbital properties of trans-Neptunian and other asteroid binaries. Acknowledgements : work supported by Labex ESEP (ANR N° 2011-LABX-030) [1] Müller T., Lellouch E., Stansberry J. et al. 2009. TNOs are Cool: A Survey of the Transneptunian Region. EM&P 105, 209-219. [2] Mignard F., Cellino A., Muinonen K. et

  20. Searching and Studying Binary Asteroids with AO Systems

    NASA Astrophysics Data System (ADS)

    Marchis, F.; Descamps, P.; Berthier, J.; Hestroffer, D.; de Pater, I.; Conrad, A.; Le Mignant, D.; Chaffee, F.; Gavel, D.

    2003-05-01

    Our group has conducted adaptive optics observations of asteroids since 2001. Our main goal is the search and study of binary asteroids using several AO systems (Lick, Keck, VLT) and related technique such as Appulse (Berthier and Marchis, 2002) and Laser Guide Star observations (Marchis et al., AGU-EGS, 2003) to broaden the sample of asteroids observed from the main-belt out to the Kuiper Belt. We focussed our program last year on Trojan Asteroids. Six of them were observed using Appulses with Keck AO ( ˜0.05-0.10", mv=15.4-18.5), 6 with the LGS at Lick ( ˜0.25-0.35", mv<16) and 12 with the VLT/NACO system ( ˜0.10-0.14"; mv<16.7). None of these observations reveals the presence of a companion. Based on this sample, and including 617 Patroclus binary asteroid discovered by Merline et al. (IAU, 7741, 2001), we deduce that the proportion of binary Trojan asteroids larger than 40 km is less than 4%. We will promote and discuss a technique of the analysis of negative discovery in large samples. In January 2003, we conducted an observing campaign spanning 5 days of 121 Hermione with NACO, the new AO system offered at VLT. This C-type asteroid was discovered by Merline et al. (IAU, 7980, 2002). The companion, 6.1 mag fainter than the primary, is easily detected despite the faintness of the asteroid (mv ˜13). We use the method described in Marchis et al. (Icarus, 2003) to determine the orbit of the companion. Its orbital elements are a=794.7+/-2.1 km, and P=1.643+/-0.005 days. We derived a mass =1.47E19 kg, and a density of 3.1+/-0.8 g cm-3 (using IRAS diameter of 209+/-4.7 km). Considering typical densities of meteorite analogues (CI or CM carboneceous chondrite) would led to an extremely low macro-porosity of p<3%. This suggests that the volume of Hermione is ˜30% larger, which is also supported by our resolved images of this body. This work supported by the National Science Foundation Science and Technology Center for Adaptive Optics, based partly on observations

  1. Dynamics of binary asteroids. I - Hill's case

    NASA Astrophysics Data System (ADS)

    Chauvineau, B.; Mignard, F.

    1990-02-01

    The present investigation of the dynamics of hypothesized binary (or multiple) asteroids attempts to evaluate the likelihood of their dynamic stability, giving attention to the trajectories of Hill's (1977) problem (including only the gravitational perturbation of the sun) to define the effects of solar perturbations on the relative motion of a binary asteroid. Only for the cases of close binary asteroids, can the Jacobian constant be unambiguously related to the semimajor axis of a weakly disturbed Keplerian ellipse. A greater likelihood is found for a stable asteroid with retrograde orbit, in both the synodic and the inertial frames, that with direct orbit.

  2. HST/FGS High Angular Resolution Observations of Binary Asteroids

    NASA Astrophysics Data System (ADS)

    Hestroffer, Daniel; Tanga, P.; Cellino, A.; Kaasalainen, M.; Torppa, J.; Marchis, F.; Richardson, D. C.; Elankumaran, P.; Berthier, J.; Colas, F.; Lounis, S.

    2006-09-01

    Binary or multiple asteroids are important bodies that provide insight into the physical properties of asteroids in general. The knowledge of the components orbit in a binary provides the total mass with high accuracy and generally permits a rough bulk-density estimate [1,2]. We have observed 10 selected binary or multiple asteroids (22 Kalliope, 45 Eugenia, 87 Sylvia, 90 Antiope, 107 Camilla, 121 Hermione, 283 Emma, 379 Huenna, 617 Patroclus, 762 Pulcova) with the HST/FGS interferometer in order to obtain high resolution data on the size and shape of their primaries (HST proposal ID 10614). All these systems except the Jupiter Trojan 617 Patroclus are located in the main-belt of asteroids. Combining these HST/FGS data to topographic models obtained from lightcurve inversion [3,4] yields the volume and hence the bulk density of these bodies with unprecedented accuracy [5]. This work will allow us to obtain important information on their internal structure, and insight into the possible gravitational re-accumulation process after a catastrophic disruptive collision [e.g. 6,7,8].In particular, one can see whether or not the surfaces of theses bodies closely follow an effective equipotential surface, and under what circumstances such a correspondence is or is not attained . We will present the preliminary results for the data reduction and the size and bulk density determination. [1] Merline et al. (2003). In: Asteroids III, pp 289. [2] Marchis et al. (2005) ACM 2005, Buzios, Brazil. [3] Kaasalainen et al. (2002) Icarus 159, 359. [4] Torppa et al. (2003) Icarus 164, 346. [5] Hestroffer et al. (2003) ACM 2002, ESA-SP 500, 493. [6] Michel et al. (2004) P&SS 52, 1109. [7] Durda et al. (2004) Icarus 167, 342. [8] Paolicchi et al. (1993) Cel. Mech., 57, 49.

  3. Are large Trojan asteroids salty? An observational, theoretical, and experimental study

    NASA Astrophysics Data System (ADS)

    Yang, Bin; Lucey, Paul; Glotch, Timothy

    2013-03-01

    With a total mass similar to the main asteroid belt, the jovian Trojan asteroids are a major feature in the Solar System. Based upon the thermal infrared spectra of the largest Trojans obtained with the Spitzer space telescope, Emery et al. (Emery, J.P., Cruikshank, D.P., van Cleve, J. [2006]. Icarus 182, 496) suggested that the surfaces of these Trojans may consist of fine-grained silicates suspended in a transparent matrix. To explore the transparent matrix hypothesis, we adopted a modified radiative transfer model to fit the Trojan spectra simultaneously both in the near and the thermal infrared regions. Our model shows that the Trojan spectra over a wide wavelength range can be consistently explained by fine grained silicates (1-5 wt.%) and highly absorbing material (e.g. carbon or iron, 2-10 wt.%) suspended in a transparent matrix. The matrix is consistent with a deposit of salt on the surfaces of the large Trojans. However, this consistency is not an actual detection of salt and other alternatives may still be possible. We suggest that early in the Solar System history, short-lived radionuclides heated ice-rich Trojans and caused melting, internal circulation of water and dissolution of soluble materials. Briny water volcanism were facilitated by internal volatiles and a possibly global sill of frozen brine was formed beneath the cold primitive crust. The frozen brine layer was likely to be evacuated by impact erosions and evaporation of the exposed brines eventually left a lag deposit of salt. Over the Solar System’s history, fine dust from comets or impacts contaminated and colored these salty surfaces of the Trojans to produce the spectral properties observed today.

  4. Orbital clustering of martian Trojans: An asteroid family in the inner Solar System?

    NASA Astrophysics Data System (ADS)

    Christou, Apostolos A.

    2013-05-01

    We report on the discovery of new martian Trojans within the Minor Planet Center list of asteroids. Their orbital evolution over 108 yr shows characteristic signatures of dynamical longevity (Scholl, H., Marzari, F., Tricarico, P. [2005]. Icarus 175, 397-408) while their average orbits resemble that of the largest known martian Trojan, 5261 Eureka. The group forms a cluster within the region where the most stable Trojans should reside. Based on a combinatorial analysis and a comparison with the jovian Trojan population, we argue that both this feature and the apparent paucity of km-sized martian Trojans (Trilling, D.E., Spahr, T.B., Rivkin, A.S., Hergenrother, C.W., Kortenkamp, S.J. [2006]. ID 2006A-0251) as compared to expectations from earlier work (Tabachnik, S., Evans, N.W. [1999]. Astrophys. J. 517, L63-L66) is not due to observational bias but instead a natural end result of the collisional comminution (Jutzi, M., Michel, P., Benz, W., Richardson, D.C. [2010]. Icarus 207, 54-65) or, alternatively, the rotational fission (Pravec, P. et al. [2010]. Nature 466, 1085-1088) of a progenitor L5 Trojan of Mars. Under the collisional scenario in particular, the new martian Trojans are dynamically young, in agreement with our age estimate of this "cluster" of <2 Gyr based on the earlier work of Scholl et al. (Scholl, H., Marzari, F., Tricarico, P. [2005]. Icarus 175, 397-408). This work highlights the Trojan regions of the terrestrial planets as natural laboratories to study processes important for small body evolution in the Solar System and provides the first direct evidence for an orbital cluster of asteroids close to the Earth.

  5. Constraining the shape distribution and binary fractions of asteroids observed by NEOWISE

    NASA Astrophysics Data System (ADS)

    Sonnett, Sarah M.; Mainzer, Amy; Grav, Tommy; Masiero, Joseph; Bauer, James; Vernazza, Pierre; Ries, Judit Gyorgyey; Kramer, Emily

    2015-11-01

    Knowing the shape distribution of an asteroid population gives clues to its collisional and dynamical history. Constraining light curve amplitudes (brightness variations) offers a first-order approximation to the shape distribution, provided all asteroids in the distribution were subject to the same observing biases. Asteroids observed by the NEOWISE space mission at roughly the same heliocentric distances have essentially the same observing biases and can therefore be inter-compared. We used the archival NEOWISE photometry of a statistically significant sample of Jovian Trojans, Hildas, and Main belt asteroids to compare the amplitude (and by proxy, shape) distributions of L4 vs. L5 Trojans, Trojans vs. Hildas of the same size range, and several subpopulations of Main belt asteroids.For asteroids with near-fluid rubble pile structures, very large light curve amplitudes can only be explained by close or contact binary systems, offering the potential to catalog and characterize binaries within a population and gleaning more information on its dynamical evolution. Because the structure of most asteroids is not known to a high confidence level, objects with very high light curve amplitudes can only be considered candidate binaries. In Sonnett et al. (2015), we identified several binary candidates in the Jovian Trojan and Hilda populations. We have since been conducting a follow-up campaign to obtain densely sampled light curves of the binary candidates to allow detailed shape and binary modeling, helping identify true binaries. Here, we present preliminary results from the follow-up campaign, including rotation properties.This research was carried out at the Jet Propulsion Laboratory (JPL), California Institute of Technology (CalTech) under a contract with the National Aeronautics and Space Administration (NASA) and was supported by the NASA Postdoctoral Program at JPL. We make use of data products from the Wide-field Infrared Survey Explorer, which is a joint project

  6. Spin-orbit coupling in binary asteroids

    NASA Astrophysics Data System (ADS)

    Margot, Jean-Luc; Naidu, Shantanu P.

    2016-01-01

    We use radar images with decameter resolution to measure the sizes, shapes, spin states, mutual orbits, masses, and densities of components of asteroid binaries and triples. We simulate the spin-orbit dynamics of these systems and map the possible spin configurations of the satellites on surface of section plots. The presence of chaotic regions in the phase space has important consequences for the evolution of binary asteroids. It may substantially increase spin synchronization timescales, delay BYORP-type evolution, and extend the lifetime of binaries.

  7. Rotation Frequencies of Small Jovian Trojan Asteroids: An Excess of Slow Rotators

    NASA Astrophysics Data System (ADS)

    French, Linda M.; Stephens, Robert D.; James, David J.; Coley, Daniel; Connour, Kyle

    2015-11-01

    Several lines of evidence support a common origin for, and possible hereditary link between, cometary nuclei and jovian Trojan asteroids. Due to their distance and low albedos, few comet-sized Trojans have been studied. We discuss the rotation properties of Jovian Trojan asteroids less than 30 km in diameter. Approximately half the 131 objects discussed here were studied using densely sampled lightcurves (French et al. 2015a, b); Stephens et al. 2015), and the other half were sparse lightcurves obtained by the Palomar Transient Factory (PTF; Waszcazk et al. 2015).A significant fraction (~40%) of the objects in the ground-based sample rotate slowly (P > 24h), with measured periods as long as 375 h (Warner and Stephens 2011). The PTF data show a similar excess of slow rotators. Only 5 objects in the combined data set have rotation periods of less than six hours. Three of these fast rotators were contained in the data set of French et al. these three had a geometric mean rotation period of 5.29 hours. A prolate spheroid held together by gravity rotating with this period would have a critical density of 0.43 gm/cm3, a density similar to that of comets (Lamy et al. 2004).Harris et al. (2012) and Warner et al. (2011) have explored the possible effects on asteroid rotational statistics with the results from wide-field surveys. We will examine Trojan rotation statistics with and without the results from the PTF.

  8. Where did the Trojan asteroids form? Constraints from composition and size distributions

    NASA Astrophysics Data System (ADS)

    Emery, Joshua; Bell, Jim; Trilling, David; Patience, Jennifer; Brown, Mike

    2014-08-01

    We propose to make near-infrared (0.8 - 2.5 μm) spectral observations of 15 small to medium sized (<100 km) Jovian Trojan asteroids. These objects are part of a substantial population of primitive bodies trapped in Jupiter's stable Lagrange regions. Because they may have become trapped in these orbits at the end of the initial phase of planetary formation and subsequent migration, the physical properties of Trojans provide unique perspectives on chemical and dynamical processes that shaped the Solar System. Indeed, in recognition of their importance, the Trojans are one of only five allowable target destinations for NASA's next New Frontiers mission. Previous observations have identified two spectral classes, suggesting that the Trojans are comprised of two distinct compositional groups, perhaps representing distinct outer Solar System reservoirs for their formation. These new proposed observations will: (a) Enable a search for minor absorptions due to ices, organics, and/or silicates in the smallest Trojans yet observed, near and below the size regime thought to represent the largest collisional fragments from impacts within the Trojan clouds; and (b) Test whether the two spectral groups previously identified have different cumulative size distributions, which would suggest different internal strengths and support the hypothesis of distinct compositions and origins.

  9. A NEAR-INFRARED SEARCH FOR SILICATES IN JOVIAN TROJAN ASTEROIDS

    SciTech Connect

    Yang Bin; Jewitt, David E-mail: jewitt@ucla.edu

    2011-03-15

    We obtained near-infrared (NIR; 0.8-2.5 {mu}m) spectra of seven Jovian Trojan asteroids that have been formerly reported to show silicate-like absorption features near 1 {mu}m. Our sample includes the Trojan (1172) Aneas, which is one of the three Trojans known to possess a comet-like 10 {mu}m emission feature, indicative of fine-grained silicates. Our observations show that all seven Trojans appear featureless in high signal-to-noise ratio spectra. The simultaneous absence of the 1 {mu}m band and the presence of the 10 {mu}m emission can be understood if the silicates on (1172) Aneas are iron-poor. In addition, we present NIR observations of five optically gray Trojans, including three objects from the collisionally produced Eurybates family. The five gray Trojans appear featureless in the NIR with no diagnostic absorption features. The NIR spectrum of Eurybates can be best fitted with the spectrum of a CM2 carbonaceous chondrite, which hints that the C-type Eurybates family members may have experienced aqueous alteration.

  10. Investigating Trojan Asteroids at the L4/L5 Sun-Earth Lagrange Points

    NASA Technical Reports Server (NTRS)

    John, K. K.; Graham, L. D.; Abell, P. A.

    2015-01-01

    Investigations of Earth's Trojan asteroids will have benefits for science, exploration, and resource utilization. By sending a small spacecraft to the Sun-Earth L4 or L5 Lagrange points to investigate near-Earth objects, Earth's Trojan population can be better understood. This could lead to future missions for larger precursor spacecraft as well as human missions. The presence of objects in the Sun-Earth L4 and L5 Lagrange points has long been suspected, and in 2010 NASA's Wide-field Infrared Survey Explorer (WISE) detected a 300 m object. To investigate these Earth Trojan asteroid objects, it is both essential and feasible to send spacecraft to these regions. By exploring a wide field area, a small spacecraft equipped with an IR camera could hunt for Trojan asteroids and other Earth co-orbiting objects at the L4 or L5 Lagrange points in the near-term. By surveying the region, a zeroth-order approximation of the number of objects could be obtained with some rough constraints on their diameters, which may lead to the identification of potential candidates for further study. This would serve as a precursor for additional future robotic and human exploration targets. Depending on the inclination of these potential objects, they could be used as proving areas for future missions in the sense that the delta-V's to get to these targets are relatively low as compared to other rendezvous missions. They can serve as platforms for extended operations in deep space while interacting with a natural object in microgravity. Theoretically, such low inclination Earth Trojan asteroids exist. By sending a spacecraft to L4 or L5, these likely and potentially accessible targets could be identified.

  11. Binary Candidates and Fractions in the Jovian Trojan and Hilda Populations from NEOWISE Lightcurves

    NASA Astrophysics Data System (ADS)

    Sonnett, Sarah M.; Mainzer, A.; Grav, T.; Masiero, J.; Bauer, J. M.

    2014-11-01

    Objects in orbital resonance with Jupiter, particularly Jovian Trojans (hereafter, Trojans) and Hildas, are some of the most diagnostic and accessible small body populations for constraining planetary migration patterns since their capture and physical state must be explained by dynamical evolution models. Different solar system formation models (e.g., gentle vs. rapid giant planet migration) predict different formation locations and dynamical histories for Trojans (and Hildas, which are likely fed from the Trojan region). Different dynamical environments can also produce different binary fractions as a function of separation between the two components. In order to explore whether the dynamical environment during early solar system evolution was mild or turbulent by helping discern which binary formation mechanism dominated for Trojans and Hildas, we searched the Trojan and Hilda thermal rotational lightcurves cataloged by NEOWISE for anomalously large lightcurve amplitudes indicative of close or contact binaries. These tight binary candidates are in need of dense follow-up observations to confirm their binarity. We also compared binary fractions between various Trojan subpopulations and for Trojans versus Hildas. We present binary fractions corrected for sampling and sensitivity biases and for survey efficiency at detecting tight binaries.

  12. Photometric constraints on binary asteroid dynamics

    NASA Astrophysics Data System (ADS)

    Scheirich, Peter

    2015-08-01

    To date, about 50 binary NEAs, 20 Mars-crossing and 80 small MB asteroids are known. We observe also a population of about 200 unbound asteroid systems (asteroid pairs). I will review the photometric observational data we have for the best observed cases and compare them with theories of binary and paired asteroids evolution.The observed characteristics of asteroid systems suggest their formation by rotational fission of parent rubble-pile asteroids after being spun up by the YORP effect. The angular momentum content of binary asteroids is close to critical. The orientations of satellite orbits of observed binary systems are non-random; the orbital poles concentrate near the obliquities of 0 and 180 degrees, i.e., near the YORP asymptotic states.Recently, a significant excess of retrograde satellite orbits was detected, which is not yet explained characteristic.An evolution of binary system depend heavily on the BYORP effect. If BYORP is contractive, the primary and secondary could end in a tidal-BYORP equilibrium. Observations of mutual events between binary components in at least four apparitions are needed for BYORP to be revealed by detecting a quadratic drift in mean anomaly of the satellite. I will show the observational evidence of single-synchronous binary asteroid with tidally locked satellite (175706 1996 FG3), i.e, with the quadratic drift equal to zero, and binary asteroid with contracting orbit (88710 2001 SL9), with positive value of the quadratic drift (the solution for the quadratic drift is ambiguous so far, with possible values of 5 and 8 deg/yr2).The spin configuration of the satellite play a crucial role in the evolution of the system under the influence of the BYORP effect. I will show that the rotational lightcurves of the satellites show that most of them have small libration amplitudes (up to 20 deg.), with a few interesting exceptions.Acknowledgements: This work has been supported by the Grant Agency of the Czech Republic, Grant P209

  13. Spectroscopic Search for Water Ice on Jovian Trojan Asteroids

    NASA Astrophysics Data System (ADS)

    Yang, Bin; Jewitt, D.

    2006-09-01

    We are conducting a systematic study of the Jovian Trojans using the Subaru 8-m, UKIRT 4-m and IRTF 3-m telescopes atop Mauna Kea, Hawaii. Theoretical models show that the Jovian Trojans formed beyond the snow-line and they may contain considerable amounts of water ice. We seek spectroscopic evidence for this pristine ice. Object (4709) Ennomos has a geometric albedo of 0.13+/-0.02, which is significantly above the mean Trojan albedo of 0.041+/- 0.002 (Fernandez et al., 2003). An intriguing possibility is that the albedo of Ennomos is high because a recent impact has coated part of the surface with freshly excavated ice. We obtained near-IR (0.8-2.5 micron) spectra of (4709) Ennomos in search of the 1.5 and 2.0 micron bands of water ice. Four other Trojans, (911) Agamemnon, (617) Patroclus, (1143) Odysseus and (2797) Teucer, were also observed. These objects have been reported to show possible weak absorptions at 1.7 and 2.3 micron respectively (Emery and Brown, 2003). All five targets appear spectrally featureless, even in our highest signal-to-noise ratio data. We present the data and a simple model consisting of mixtures of water ice and a spectrally featureless material, to quantify the limits to surface ice.

  14. Phase Curves of 10 Trojan Asteroids in BVI over a Wide Phase Range

    NASA Astrophysics Data System (ADS)

    Schaefer, Martha W.; Schaefer, B. E.; Rabinowitz, D. L.; Tourtellotte, S. W.

    2008-09-01

    We have used the SMARTS 1.3 m telescope at CTIO to acquire 50 nights of B, V, and I observations from very low to high phase angles of the following 10 Trojans: 588 Achilles, 1208 Troilus, 1383 Limburgia, 4348 Poulydamas, 6998 Tithonus, 8317 Eurysaces, 12126 (1999 RM11), 13323 (1998 SQ), 24506 (2001 BS15), and 51378 (2001 AT33). Due to the queue scheduling of this telescope we were able to obtain many observations over a wide range of phase angles in only a few years, including a significant number at < 0.5 deg. All the phase curves are roughly linear over the entire phase range (as much as +/- 10 deg), with slopes between about 0.045 and 0.075 mag/deg (except for 51378, which displays an anomalous slope near zero). There may be evidence for rotational modulation in some cases. There appear to be no pronounced opposition spikes, and no differences between the phase curves in different colors. With the exception of 51378, these slopes are higher than is possible with shadow-hiding alone; therefore coherent backscatter must be involved. The slopes are consistent with similar published slopes for many types of asteroids. In particular, the phase curves of the Trojan asteroids are similar to the phase curves of non-Trojan P-type asteroids. However, the phase curves are not consistent with those of E- and S-type asteroids, which show prominent opposition spikes. The slopes are not inconsistent with those of gray Centaurs, but are greatly inconsistent with the slopes of red Centaurs. This agrees with the prediction (see B. E. Schaefer et al. poster, this conference) that the Trojans should have similar surge properties to the gray Centaurs. We thank the NASA Planetary Astronomy Program for support.

  15. Collisional Histories of Comets and Trojan Asteroids: Insights from Forsterite and Enstatite Impact Studies

    NASA Technical Reports Server (NTRS)

    Lederer. S. M.; Jensen, E. A.; Wooden, D. H.; Lindsay, S. S.; Smith, D. C.; Cintala, M. J.; Nakamura-Messenger, K.; Keller, L. P.

    2012-01-01

    Impacts into forsterite and orthoenstatite at speeds typically encountered by comets demonstrate that shock imparted by collisions is detectable in the infrared signatures of their dust. The spectral signatures can be traced to physical alterations in their crystalline structures, as observed in TEM imaging and modeled using a dipole approximation. These results yield tantalizing insights into the collisional history of our solar system, as well as the history of individual comets and Trojan asteroids.

  16. BINARY YORP EFFECT AND EVOLUTION OF BINARY ASTEROIDS

    SciTech Connect

    Steinberg, Elad; Sari, Re'em

    2011-02-15

    The rotation states of kilometer-sized near-Earth asteroids are known to be affected by the Yarkevsky O'Keefe-Radzievskii-Paddack (YORP) effect. In a related effect, binary YORP (BYORP), the orbital properties of a binary asteroid evolve under a radiation effect mostly acting on a tidally locked secondary. The BYORP effect can alter the orbital elements over {approx}10{sup 4}-10{sup 5} years for a D{sub p} = 2 km primary with a D{sub s} = 0.4 km secondary at 1 AU. It can either separate the binary components or cause them to collide. In this paper, we devise a simple approach to calculate the YORP effect on asteroids and the BYORP effect on binaries including J{sub 2} effects due to primary oblateness and the Sun. We apply this to asteroids with known shapes as well as a set of randomly generated bodies with various degrees of smoothness. We find a strong correlation between the strengths of an asteroid's YORP and BYORP effects. Therefore, statistical knowledge of one could be used to estimate the effect of the other. We show that the action of BYORP preferentially shrinks rather than expands the binary orbit and that YORP preferentially slows down asteroids. This conclusion holds for the two extremes of thermal conductivities studied in this work and the assumption that the asteroid reaches a stable point, but may break down for moderate thermal conductivity. The YORP and BYORP effects are shown to be smaller than could be naively expected due to near cancellation of the effects at small scales. Taking this near cancellation into account, a simple order-of-magnitude estimate of the YORP and BYORP effects as a function of the sizes and smoothness of the bodies is calculated. Finally, we provide a simple proof showing that there is no secular effect due to absorption of radiation in BYORP.

  17. NEAR-INFRARED SPECTROSCOPY OF TROJAN ASTEROIDS: EVIDENCE FOR TWO COMPOSITIONAL GROUPS

    SciTech Connect

    Emery, J. P.; Burr, D. M.; Cruikshank, D. P.

    2011-01-15

    The Trojan asteroids, a very substantial population of primitive bodies trapped in Jupiter's stable Lagrange regions, remain quite poorly understood. Because they occupy these orbits, the physical properties of Trojans provide a unique perspective on the chemical and dynamical processes that shaped the Solar System. The current study was therefore undertaken to investigate surface compositions of these objects. We present 66 new near-infrared (NIR; 0.7-2.5 {mu}m) spectra of 58 Trojan asteroids, including members of both the leading and trailing swarms. We also include in the analysis previously published NIR spectra of 13 Trojans (3 of which overlap with the new sample). This data set permits not only a direct search for compositional signatures, but also a search for patterns that may reveal clues to the origin of the Trojans. We do not report any confirmed absorption features in the new spectra. Analysis of the spectral slopes, however, reveals an interesting bimodality among the NIR data. The two spectral groups identified appear to be equally abundant in the leading and trailing swarms. The spectral groups are not a result of family membership; they occur in the background, non-family population. The average albedos of the two groups are the same within uncertainties (0.051 {+-} 0.016 and 0.055 {+-} 0.016). No correlations between spectral slope and any other physical or orbital parameter are detected, with the exception of a possible weak correlation with inclination among the less-red spectral group. The NIR spectral groups are consistent with a similar bimodality previously suggested among visible colors and spectra. Synthesizing the present results with previously published properties of Trojans, we conclude that the two spectral groups represent objects with different intrinsic compositions. We further suggest that whereas the less-red group originated near Jupiter or in the main asteroid belt, the redder spectral group originated farther out in the Solar

  18. Automated Design of Propellant-Optimal, End-to-End, Low-Thrust Trajectories for Trojan Asteroid Tours

    NASA Technical Reports Server (NTRS)

    Stuart, Jeffrey; Howell, Kathleen; Wilson, Roby

    2013-01-01

    The Sun-Jupiter Trojan asteroids are celestial bodies of great scientific interest as well as potential resources offering water and other mineral resources for longterm human exploration of the solar system. Previous investigations under this project have addressed the automated design of tours within the asteroid swarm. This investigation expands the current automation scheme by incorporating options for a complete trajectory design approach to the Trojan asteroids. Computational aspects of the design procedure are automated such that end-to-end trajectories are generated with a minimum of human interaction after key elements and constraints associated with a proposed mission concept are specified.

  19. SEARCHING FOR TROJAN ASTEROIDS IN THE HD 209458 SYSTEM: SPACE-BASED MOST PHOTOMETRY AND DYNAMICAL MODELING

    SciTech Connect

    Moldovan, Reka; Matthews, Jaymie M.; Gladman, Brett; Bottke, William F.; Vokrouhlicky, David

    2010-06-10

    We have searched Microvariability and Oscillations of Stars (MOST) satellite photometry obtained in 2004, 2005, and 2007 of the solar-type star HD 209458 for Trojan asteroid swarms dynamically coupled with the system's transiting 'hot Jupiter' HD 209458b. Observations of the presence and nature of asteroids around other stars would provide unique constraints on migration models of exoplanetary systems. Our results set an upper limit on the optical depth of Trojans in the HD 209458 system that can be used to guide current and future searches of similar systems by upcoming missions. Using cross-correlation methods with artificial signals implanted in the data, we find that our detection limit corresponds to a relative Trojan transit depth of 1 x10{sup -4}, equivalent to {approx}1 lunar mass of asteroids, assuming power-law Trojan size distributions similar to Jupiter's Trojans in our solar system. We confirm with dynamical interpretations that some asteroids could have migrated inward with the planet to its current orbit at 0.045 AU, and that the Yarkovsky effect is ineffective at eliminating objects of >1 m in size. However, using numerical models of collisional evolution we find that, due to high relative speeds in this confined Trojan environment, collisions destroy the vast majority of the asteroids in <10 Myr. Our modeling indicates that the best candidates to search for exoTrojan swarms in 1:1 mean resonance orbits with 'hot Jupiters' are young systems (ages of about 1 Myr or less). Years of Kepler satellite monitoring of such a system could detect an asteroid swarm with a predicted transit depth of 3 x 10{sup -7}.

  20. 6384 Kervin: A Possible Hungaria Binary Asteroid

    NASA Astrophysics Data System (ADS)

    Warner, Brian D.; Aznar Macia, Amadeo

    2016-04-01

    Analysis of CCD photometric observations in late 2015 of the Hungaria asteroid 6384 Kervin indicates that it may be a binary asteroid with a primary lightcurve of P1 = 3.6194 ± 0.0001 h, A1 = 0.06 ± 0.01 mag. The secondary lightcurve parameters are P2 = 15.94 ± 0.01 h, A2 = 0.03 ± 0.01 mag. No mutual events (occultations or eclipses) were observed. However, other indicators give an estimated diameter ratio on the order of Ds/Dp ~ 0.3, possibly greater.

  1. A preliminary analysis of the orbit of the Mars Trojan asteroid (5261) Eureka

    NASA Astrophysics Data System (ADS)

    Mikkola, S.; Innanen, K.; Muinonen, K.; Bowell, E.

    1994-01-01

    Observations and results of orbit determination of the first known Mars Trojan asteroid (5261) Eureka are presented. We have numerically calculated the evolution of the orbital elements, and have analyzed the behavior of the motion during the next 2 Myr. Strong perturbations by planets other than Mars seem to stabilize the eccentricity of the asteroid by stirring the high order resonances present in the elliptic restricted problem. As a result, the orbit appears stable at least on megayear timescales. The difference of the mean longitudes of Mars and Eureka and the semimajor axis of the asteroid form a pair of variables that essentially behave in an adiabatic manner, while the evolution of the other orbital elements is largely determined by the pertubations due to other planets.

  2. Mission to the Trojan asteroids: Lessons learned during a JPL Planetary Science Summer School mission design exercise

    NASA Astrophysics Data System (ADS)

    Diniega, Serina; Sayanagi, Kunio M.; Balcerski, Jeffrey; Carande, Bryce; Diaz-Silva, Ricardo A.; Fraeman, Abigail A.; Guzewich, Scott D.; Hudson, Jennifer; Nahm, Amanda L.; Potter-McIntyre, Sally; Route, Matthew; Urban, Kevin D.; Vasisht, Soumya; Benneke, Bjoern; Gil, Stephanie; Livi, Roberto; Williams, Brian; Budney, Charles J.; Lowes, Leslie L.

    2013-02-01

    The 2013 Planetary Science Decadal Survey identified a detailed investigation of the Trojan asteroids occupying Jupiter's L4 and L5 Lagrange points as a priority for future NASA missions. Observing these asteroids and measuring their physical characteristics and composition would aid in identification of their source and provide answers about their likely impact history and evolution, thus yielding information about the makeup and dynamics of the early Solar System. We present a conceptual design for a mission to the Jovian Trojan asteroids: the Trojan ASteroid Tour, Exploration, and Rendezvous (TASTER) mission, that is consistent with the NASA New Frontiers candidate mission recommended by the Decadal Survey and the final result of the 2011 NASA-JPL Planetary Science Summer School. Our proposed mission includes visits to two Trojans in the L4 population: a 500 km altitude fly-by of 1999 XS143, followed by a rendezvous with and detailed observations of 911 Agamemnon at orbital altitudes of 1000-100 km over a 12 month nominal science data capture period. Our proposed instrument payload - wide- and narrow-angle cameras, a visual and infrared mapping spectrometer, and a neutron/gamma ray spectrometer - would provide unprecedented high-resolution, regional-to-global datasets for the target bodies, yielding fundamental information about the early history and evolution of the Solar System. Although our mission design was completed as part of an academic exercise, this study serves as a useful starting point for future Trojan mission design studies. In particular, we identify and discuss key issues that can make large differences in the complex trade-offs required when designing a mission to the Trojan asteroids.

  3. The Orbit of 617 Patroclus Binary Trojan System from Keck LGS AO observations

    NASA Astrophysics Data System (ADS)

    Marchis, F.; Hestroffer, D.; Descamps, P.; Berthier, J.; Bouchez, A. H.; Campbell, R. D.; Chin, J. C. Y.; van Dam, M. A.; Hartman, S. K.; Johansson, E. M.; Lafon, R. E.; Le Mignant, D.; de Pater, I.; Stomski, P. J.; Summers, D. M.; Wizinovitch, P. L.; Wong, M. H.

    2005-08-01

    We report the results from Laser Guide Star Adaptive Optics observations in 2004-2005 of 617 Patroclus using the NIRC2 camera at the W. M. Keck Observatory. An observing campaign which focuses on this only known binary Trojan asteroid, was initiated by our group. Both components of the system were detected at 5 different epochs between Nov. 2004 and May 2005 with an angular separation between 45 and 190 mas and a Dm ˜0.17. The orbital parameters were estimated independently using two algorithms, a Monte-Carlo technique (Hestroffer and Vachier, IAU-ACM, 2005), and a visual binary method (Descamps, Cel. Mech., 2005): a= 685±40 km, e = 0.02±0.02, P = 4.287±0.002 or P= 2.391±0.003 corresponding to a total mass of 1.4 x 1018 or 4.3 x 1018 ± 0.2 kg. Considering recent radiometric measurements by Fernandez et al., (AJ, 126, 2003), the radii of components would be R1= 60.9 km and R2=56.3 km (error ˜1.6 km and with η =0.94), leading to an averaged bulk density of 0.8 or 2.6 ±0.1 g/cm3. The factor of ˜2 uncertainty in the period will be removed using additional observations from CADC archive (in progress). In contrast to what was observed for a Kuiper-belt binary system (1998WW31 in Veillet et al., Nature, 2002), the low eccentricity is more common of main-belt binaries, indicating that dissipation effects must be considered. This work was partly supported by the National Science Foundation Science and Technology Center for Adaptive Optics and a KPAC NASA grant.

  4. Tidal and Dynamical Evolution of Binary Asteroids

    NASA Astrophysics Data System (ADS)

    Jacobson, Seth A.; Scheeres, D. J.

    2009-05-01

    We derive a realistic model for the evolution of a tidally perturbed binary, using classical theory, to examine the system just after a spin-up fission event. The spin rate of an asteroid can be increased by the Yarkovsky-O'Keefe-Radzievskii-Paddack (YORP) effect -- thermal re-radiation from an asymmetric body, which induces torques that can rotationally accelerate the body. If the asteroid is modeled as a "rubble pile", a collection of gravitationally bound gravel with no tensile strength, increasing the spin rate will lead to a fission process that would resemble that of a viscous fluidic body [Holsapple 2007]. However, high-resolution imagery of an asteroid's constituents indicates that there is a significant distribution of size scales. A specific example is the asteroid Itokawa, which appears to be two such rubble piles in contact with each other [Fujiwara 2006]. The shape of these bodies will be irregular (modeled as tri-axial ellipsoids with a gravitational potential expanded up to second order). Their motions will raise tides on the opposing body. These tides will dissipate energy, potentially providing enough energy loss for the system to settle into a stable orbit. Fissioned binary systems are always initially unstable [Scheeres 2009, 2008]. We expect tidal dissipation rates to vary widely during the initial evolution of the system, due to this instability. The model applies instantaneous tidal torques to determine energy loss. Our preliminary results indicate that tidal energy dissipation could relax the system to a state of relative equilibrium on order 100,000 years, creating systems similar to those observed. Holsapple, K. A., Icarus, 187, 2007. Fujiwara, A., Science, 312, 2006. Scheeres, D., CMDA, 2009 (Accepted Jan 10, 2009). Scheeres, D., AAS, DDA meeting #39, #9.01, 2008.

  5. Figures of Equilibrium among Binary Asteroids

    NASA Astrophysics Data System (ADS)

    Hestroffer, D.; Tanga, P.

    2005-12-01

    The original idea of Farinella et al. [1] that rubble pile asteroids can have figures of equilibrium, is rehabilitated. Albeit asteroids generally have a broad distribution of shapes and do not follow sequences of (hydrostatic) equilibrium, we show that some asteroids are indeed Jacobi or Darwin ellipsoids. Such statement is obtained from an analysis of their ellipsoidal shape (a:b:c) together with recent measures of their mass and bulk density [2,3]. This means that both their shape and adimensional rotation frequency sbond Ω =Ω /(π ρ G) follow sequences of equilibrium [4,5]. Jacobi and Darwin figures are obtained for uniformly rotating mass of (inviscid as well as compressible) fluids and relatively large angular momentum. Interestingly these objects appear to preferably be binaries. We moreover show that the porosity of such objects is relatively large (approx. 40%) indicating that they are loose rubble piles, yet with dense packing. Last we show that, given the observed bulk-densities, these bodies must be homogeneous bodies of uniform density distribution. Thus, though solid-solid friction must occur in such aggregates, the surface of these bodies is a surface of level similar to that of inviscid fluids. Comparison to other asteroids of similar mass either possessing a moonlet or with no known satellites should shed light on their formation history and/or constrains on collisional evolution. Binaries with low eccentricities and inclination (hence prograde orbit) should preferably be the outcome of catastrophic disruption as is supposed for members of dynamical family [6,7]. Future work and analysis of the typical reaccumulation time scales, typical angular momentum, possible post-reaccumulation cosmic shaking, etc. shall help to know how the fate of collisions or catastrophic breakup of a parent body can differ yielding to binaries with equilibrium figures. In any case the existence of a figure of equilibrium appears to be highly correlated to the presence

  6. Spin-Spin Coupling in Asteroidal Binaries

    NASA Astrophysics Data System (ADS)

    Batygin, Konstantin; Morbidelli, Alessandro

    2015-11-01

    Gravitationally bound binaries constitute a substantial fraction of the small body population of the solar system, and characterization of their rotational states is instrumental to understanding their formation and dynamical evolution. Unlike planets, numerous small bodies can maintain a perpetual aspheroidal shape, giving rise to a richer array of non-trivial gravitational dynamics. In this work, we explore the rotational evolution of triaxial satellites that orbit permanently deformed central objects, with specific emphasis on quadrupole-quadrupole interactions. Our analysis shows that in addition to conventional spin-orbit resonances, both prograde and retrograde spin-spin resonances naturally arise for closely orbiting, highly deformed bodies. Application of our results to the illustrative examples of (87) Sylvia and (216) Kleopatra multi-asteroid systems implies capture probabilities slightly below ~10% for leading-order spin-spin resonances. Cumulatively, our results suggest that spin-spin coupling may be consequential for highly elongated, tightly orbiting binary objects.

  7. Surface Experiments on a Jupiter Trojan Asteroid in the Solar Powered Sail Mission

    NASA Astrophysics Data System (ADS)

    Okada, Tatsuaki

    2016-04-01

    Introduction: A new mission to a Jupiter Trojan asteroid is under study us-ing a solar-powered sail (SPS), and a science lander is being investigated in the joint study between Japan and Europe [1]. We present here the key sci-entific objectives and the strawman payloads of science experiments on the asteroid. Science Objectives: Jupiter Trojan asteroids are located around the Sun-Jupiter Lagrange points (L4 or L5) and most of them are classified as D- or P-type in asteroid taxonomy, but their origin still remains unknown. A classi-cal (static) model of solar system evolution indicates that they were formed around the Jupiter region and survived until now as the outer end members of asteroids. A new (dynamical) model such as Nice model suggests that they were formed at the far end of the solar system and transferred inward due to dynamical migration of giant planets [2]. Therefore physical, miner-alogical, and isotopic studies of surface materials and volatile compounds could solve their origin, and then the solar system formation [3]. Strawman Payloads: The SPS orbiter will be able to carry a 100 kg class lander with 20 kg mission payloads. Just after landing of the lander, geolog-ical, mineralogical, and geophysical observations will be performed to char-acterize the site using a panoramic optical camera, an infrared hyperspectral imager, a magnetometer, and a thermal radiometer. The surface and subsur-face materials of the asteroid will be collected into a carousel by the bullet-type and the pneumatic drill type samplers, respectively. Samples in the carousel will be investigated by a visible and an infrared microscope, and transferred for performing high resolution mass spectrometry (HRMS). Mass resolution m/dm > 30,000 is expected to investigate isotopic ratios of D/H, 15N/14N, and 18O/16O, as well as molecules from organic matters. A set of strawman payloads are tentatively determined during the lander system study [4]. The constraints to select the strawman

  8. Jupiter Magnetospheric Orbiter and Trojan Asteroid Explorer in EJSM (Europa Jupiter System Mission)

    NASA Astrophysics Data System (ADS)

    Sasaki, Sho; Fujimoto, Masaki; Takashima, Takeshi; Yano, Hajime; Kasaba, Yasumasa; Takahashi, Yukihiro; Kimura, Jun; Tsuda, Yuichi; Funase, Ryu; Mori, Osamu

    2010-05-01

    thick. Currently we are studying a mission to Jupiter and one (or two) of Trojan asteroids using a large (100m-scale) solar power sail that can transfer large payload mass as far as Jupiter. Trojan asteroids are primitive bodies with information of the early solar system as well as raw solid materials of Jovian system. According to the mission plan, as the main spacecraft flies by Jupiter, it will deploy a JMO spinner around Jupiter. Proposed instruments on board Trojan spacecraft are cameras, IR spectrometers, XRS, a laser altimeter, and a surface vehicle (if rendezvous with the target is possible). An instrument for measuring cosmic background is also proposed. Currently JEO and JGO will be launched in 2020 and the Trojan spacecraft with JMO shall be launched at the same window. The mission (Trojan-JMO) will take 6 years to Jupiter and 5 years more to a Trojan asteroid around L4. The mission study team also includes J. Kawaguchi, Y. Kawakatsu, and M. Morimoto of JAXA.

  9. A Power Sailer Mission for a Jovian Orbiter and Trojan Asteroid Flybys

    NASA Astrophysics Data System (ADS)

    Kawaguchi, J.

    The paper presents an innovative Solar Power Sail spacecraft mission that ushers the the century's new planetary explorations. The plan has been studied at ISAS/JAXA in Japan for the start of the project in very new future. The mission is defined as an engineering technology demonstrator, similar to the 'Hayabusa' (MUSES-C) that is currently flying toward an asteroid for a world's first sample-return attempt. The spacecraft studied here uses a world's first hybrid photon / ion propulsions taking the advantage of thin film photo-volatic technology. The mission has very new multi-purposes: First of all, the mission aims at flying-bys to the Trojan asteroids for the first time. And it is simply the first spacecraft to the Jupiter's distance powered only by solar cells. Utilizing the power surplus available at the Earth distance, the spacecraft is supposed to drive its ultra-high specific impulse ion engines aboard with the combination of the Earth gravity assist. The intended specific impulse will be 10,000 seconds, almost as 3.3 times efficient as existing contemporary ion engines. Not only the technology demonstration, in addition to the Trojan asteroid flybys, there are still more new innovative science purposes carried by this spacecraft. Among them, what should be emphasized is a background emission mapping excluding ecliptic dust cloud, which is cleared beyond four AU distance from the Sun. This will reveal the fundamental questions as to the extraordinary young stars observed only in deep IR region. Furthermore, this single spacecraft carries both a Jovian orbiter and an atmospheric reentry probe, both of which will constitute a spacious and simultaneous magnetoshere measurement at the Jovian polar region, via a formation flight. This is what has yet been tried so far in long solar planetary exploration history. ISAS/JAXA is now seriously investigating the spacecraft development and it may put a budgetary proposal for the start of the project hopefully very

  10. Initial Results of a Survey of Earth's L4 Point for Possible Earth Trojan Asteroids

    NASA Astrophysics Data System (ADS)

    Connors, M.; Veillet, C.; Wiegert, P.; Innanen, K.; Mikkola, S.

    2000-10-01

    Using the Canada-France-Hawaii 3.6 m telescope and the new CFH12k wide-field CCD imager, a survey of the region near Earth's L4 (morning) Lagrange Point was conducted in May and July/August 2000, in hopes of finding asteroids at or near this point. This survey was motivated by the dynamical interest of a possible Earth Trojan asteroid (ETA) population and by the fact that they would be the easiest asteroids to access from Earth. Recent calculations (Wiegert, Innanen and Mikkola, 2000, Icarus v. 145, 33-43) indicate stability of objects in ETA orbits over a million year timescale and that their on-sky density would be greatest roughly five degrees sunward of the L4 position. An optimized search technique was used, with tracking at the anticipated rate of the target bodies, near real-time scanning of images, and duplication of fields to aid in detection and permit followup. Limited time is available on any given night to search near the Lagrange points, and operations must be conducted at large air mass. Approximately 9 square degrees were efficiently searched and two interesting asteroids were found, NEA 2000 PM8 and our provisionally named CFZ001. CFZ001 cannot be excluded from being an Earth Trojan although that is not the optimal solution for the short arc we observed. This object, of R magnitude 22, was easily detected, suggesting that our search technique worked well. This survey supports the earlier conclusion of Whitely and Tholen (1998, Icarus v. 136, 154-167) that a large population of several hundred meter diameter ETAs does not exist. However, our effective search technique and the discovery of two interesting asteroids suggest the value of completing the survey with approximately 10 more square degrees to be searched near L4 and a comparable search to be done at L5. Funding from Canada's NSERC and HIA and the Academic Research Fund of Athabasca University is gratefully acknowledged.

  11. Electron Irradiation and Thermal Processing of Mixed-ices of Potential Relevance to Jupiter Trojan Asteroids

    NASA Astrophysics Data System (ADS)

    Mahjoub, Ahmed; Poston, Michael J.; Hand, Kevin P.; Brown, Michael E.; Hodyss, Robert; Blacksberg, Jordana; Eiler, John M.; Carlson, Robert W.; Ehlmann, Bethany L.; Choukroun, Mathieu

    2016-04-01

    In this work we explore the chemistry that occurs during the irradiation of ice mixtures on planetary surfaces, with the goal of linking the presence of specific chemical compounds to their formation locations in the solar system and subsequent processing by later migration inward. We focus on the outer solar system and the chemical differences for ice mixtures inside and outside the stability line for H2S. We perform a set of experiments to explore the hypothesis advanced by Wong & Brown that links the color bimodality in Jupiter's Trojans to the presence of H2S in the surface of their precursors. Non-thermal (10 keV electron irradiation) and thermally driven chemistry of CH3OH-NH3-H2O (“without H2S”) and H2S-CH3OH-NH3-H2O (“with H2S”) ices were examined. Mid-IR analyses of ice and mass spectrometry monitoring of the volatiles released during heating show a rich chemistry in both of the ice mixtures. The “with H2S” mixture experiment shows a rapid consumption of H2S molecules and production of OCS molecules after a few hours of irradiation. The heating of the irradiated “with H2S” mixture to temperatures above 120 K leads to the appearance of new infrared bands that we provisionally assign to SO2and CS. We show that radiolysis products are stable under the temperature and irradiation conditions of Jupiter Trojan asteroids. This makes them suitable target molecules for potential future missions as well as telescope observations with a high signal-to-noise ratio. We also suggest the consideration of sulfur chemistry in the theoretical modeling aimed at understanding the chemical composition of Trojans and KOBs.

  12. Searching for Multiple Systems in Trojan Collisional Families and Centaurs

    NASA Astrophysics Data System (ADS)

    Marchis, Franck

    2006-08-01

    We propose to finalize our search for moonlet companions around Trojan asteroids using the Keck LGS AO capability at their opposition (Aug. for L5). We will focus on Trojans members of a collisional family to maximize the chance of detection, since recent study indicated than ~20% of the main-belt asteroid of the Koronis family are binary (Merline et al. 2005) and the discovery two moonlets orbiting around 87 Sylvia rubble-pile asteroid (Marchis et al. 2005) confirms that the collisions play a major role in the formation of binary systems. A search for binary Centaur asteroids, which may be connected to the Trojan family, will be initiated to complete the night.

  13. Dumb-bell-shaped equilibrium figures for fiducial contact-binary asteroids and EKBOs

    NASA Astrophysics Data System (ADS)

    Descamps, Pascal

    2015-01-01

    In this work, we investigate the equilibrium figures of a dumb-bell-shaped sequence with which we are still not well acquainted. Studies have shown that these elongated and nonconvex figures may realistically replace the classic “Roche binary approximation” for modeling putative peanut-shaped or contact binary asteroids. The best-fit dumb-bell shapes, combined with the known rotational period of the objects, provide estimates of the bulk density of these objects. This new class of mathematical figures has been successfully tested on the observed light curves of three noteworthy small bodies: main-belt Asteroid 216 Kleopatra, Trojan Asteroid 624 Hektor and Edgeworth-Kuiper-belt object 2001 QG298. Using the direct observations of Kleopatra and Hektor obtained with high spatial resolution techniques and fitting the size of the dumb-bell-shaped solutions, we derived new physical characteristics in terms of equivalent radius, 62.5 ± 5 km and 92 ± 5 km, respectively, and bulk density, 4.4 ± 0.4 g cm-3 and 2.43 ± 0.35 g cm-3, respectively. In particular, the growing inadequacy of the radar shape model for interpreting any type of observations of Kleopatra (light curves, AO images, stellar occultations) in a satisfactory manner suggests that Kleopatra is more likely to be a dumb-bell-shaped object than a “dog-bone.”

  14. Eclipse timing variations to detect possible Trojan planets in binary systems

    NASA Astrophysics Data System (ADS)

    Schwarz, R.; Bazsó, Á.; Funk, B.; Zechner, R.

    2015-11-01

    This paper is devoted to study the circumstances favourable to detect Trojan planets in close binary star systems by the help of eclipse timing variations (ETVs). To determine the probability of the detection of such variations with ground-based telescopes and space telescopes (like former missions CoRoT and Kepler and future space missions like PLATO, TESS and CHEOPS), we investigated the dynamics of binary star systems with a planet in tadpole motion. We did numerical simulations by using the full three-body problem as a dynamical model. The stability and the ETVs are investigated by computing stability/ETV maps for different masses of the secondary star and the Trojan planet. In addition, we changed the eccentricity of the possible Trojan planet. By the help of the libration amplitude σ, we could show whether or not all stable objects are moving in tadpole orbits. We can conclude that many amplitudes of ETVs are large enough to detect Earth-like Trojan planets in binary star systems. As an application, we prepared a list of possible candidates.

  15. Doublet craters and the tidal disruption of binary asteroids

    NASA Technical Reports Server (NTRS)

    Melosh, H. J.; Stansberry, J. A.

    1991-01-01

    An evaluation is conducted of the possibility that the tidal disruption of a population of contact binary asteroids can account for terrestrial-impact 'doublet' craters. Detailed orbital integrations indicate that while such asteroids are often disrupted by tidal forces outside the Roche limit, the magnitude of the resulting separations is too small to account for the observed doublet craters. It is hypothesized that an initial population of km-scale earth-crossing objects encompassing 10-20 percent binaries must be responsible for doublet impacts, as may be verified by future observations of earth-approaching asteroids.

  16. Binary-YORP Coefficients for Known Asteroid Shapes

    NASA Astrophysics Data System (ADS)

    McMahon, Jay W.; Scheeres, D. J.

    2012-10-01

    The binary YORP (bYORP) effect has been hypothesized to be a significant factor in the evolution of near-Earth binary asteroid systems (Cuk and Burns, Icarus, v.176, pp.418-431, 2005; McMahon and Scheeres, CMDA, v.106, pp.261-300, 2010). However, understanding of the coefficient values for realistic asteroid shapes is lacking due to the small number of shape models available for the generally smaller secondary asteroids. Until now, we have only calculated the coefficients based on the shape of 1999 KW4 Beta, although various studies by other authors have computed coefficients for artificially generated asteroids based on Gaussian Spheres and some shape models without self-shadowing (Steinberg and Sari, The Astronomical Journal, v.141, pp.55-64, 2011). We also scaled the 1999 KW4 Beta coefficients to other binary systems with no knowledge of the other systems' secondary shapes in order to make evolutionary predictions (McMahon and Scheeres, Icarus Vol. 209, pp 494-509, 2010). In this study, we compute the bYORP coefficient for a range of asteroid shapes, using these as a stand-in for actual secondaries. This allows us to circumvent the lack of information on binary asteroid secondaries and to develop a richer database of realistic coefficients. While this approach may miss some key features of binary secondaries, at the least it provides some statistics on the expected variability of the bYORP coefficient. We analyze all available asteroid shape models on the PDS-SBN, including radar-based shape models and models estimated from past spacecraft missions. The coefficients are computed with an updated algorithm that includes the effects of self-shadowing. We also present the coefficients for perturbed versions of the available shape models, which give effective error bars to the computed coefficients due to inexact shape models. Finally, we discuss the dynamical implications of the derived bYORP coefficients on binary asteroid evolution.

  17. Lifetime of binary asteroids versus gravitational encounters and collisions

    NASA Technical Reports Server (NTRS)

    Chauvineau, Bertrand; Farinella, Paolo; Mignard, F.

    1992-01-01

    We investigate the effect on the dynamics of a binary asteroid in the case of a near encounter with a third body. The dynamics of the binary is modeled as a two-body problem perturbed by an approaching body in the following ways: near encounters and collisions with a component of the system. In each case, the typical value of the two-body energy variation is estimated, and a random walk for the cumulative effect is assumed. Results are applied to some binary asteroid candidates. The main conclusion is that the collisional disruption is the dominant effect, giving lifetimes comparable to or larger than the age of the solar system.

  18. Observation of asteroids with GRAVITY - Physical characterization of binary systems

    NASA Astrophysics Data System (ADS)

    Matter, A.; Delbo, M.; Carry, B.; Tanga, P.

    2014-12-01

    Density and internal structures are among the most important characteristics of asteroids, yet these properties are also some of the least known. For distant asteroids (in the Main Belt and beyond) these properties were up to now accessible only for the largest (>100 km in size) asteroids. Going to smaller and fainter asteroids can revolutionize our understanding because we will be sampling a new regime in physical properties. Here we discuss how ground-based optical interferometry with the GRAVITY instrument can be used to observe the motion of asteroid satellites to determine the mass of small binary systems. Following the expected sensitivity performances in K-band of GRAVITY, we present a sample of binary targets potentially observable in single-field mode. The feasibility of such observations will strongly be dependent on the ability of the control software of GRAVITY to track objects moving at high rate on the sky (differential motion ˜f 10 mas.s^{-1}). Although the dual-field mode could allow to increase the sample of small binary asteroids observable, it seems to be currently unfeasible given the high differential motion of asteroids.

  19. Spectrophotometry of J8, J9, and four Trojan asteroids from 0.32 to 1.05 microns

    NASA Technical Reports Server (NTRS)

    Smith, D. W.; Johnson, P. E.; Shorthill, R. W.

    1981-01-01

    New 30-channel narrowband photometry from 0.32 to 1.05 microns of the retrograde Jovian satellites J9 (to 0.7 micron) and J8 and the trailing Trojan asteroids 617, 884, 1172, and 1173 is presented. The data confirm previous measurements of J8, 617, 884, and 1172 at wavelengths less than 0.8 micron, but the extension into the infrared shows that the normalized spectral reflectance of these objects rises steadily from approximately 0.8 at 0.4 micron to approximately 1.4 at 1.05 microns, suggesting they are too bright in the near infrared to be C-type asteroids. The C classification of 1173 is confirmed. J9 is markedly redder than J8 at visible wavelengths. The results indicate a greater taxonomic contrast between these distant objects and main-belt asteroids than previously thought.

  20. Occultation/Eclipse Events in Binary Asteroid 1991 VH

    NASA Astrophysics Data System (ADS)

    Pravec, Petr; Wolf, Marek; Šarounová, Lenka

    1998-05-01

    We present the results of photometric observations of the Apollo asteroid 1991 VH. Its lightcurve consists of two components: the first is the rotational lightcurve with periodPs= (0.109327 ± 0.000003) d and amplitude 0.09 mag, while the second, with periodPl= (1.362 ± 0.001) d, shows two minima with depth 0.16-0.19 mag, each with a duration of about 0.10 d, and little or no variation at phases between them. We present a model of the occulting/eclipsing binary asteroid with the secondary-to-primary diameter ratiods/dp= 0.40 that explains the observed lightcurve. In this model, the primary's rotation is not synchronized with the orbital motion and produces the short-period lightcurve component (Ps). The orbital period isPl. The mutual orbit's semimajor axis is estimated to bea= (2.7 ± 0.3)dp; the eccentricity is 0.07 ± 0.02. The similarity between the lightcurve of 1991 VH and those of 1994 AW1(Pravec and Hahn,Icarus127, 431, 1997) and (3671) Dionysus (Mottolaet al.1997,IAU Circular6680) suggests that binary asteroids may be common among near-Earth asteroids. Based on the three known cases, we tentatively derive some typical characteristics of this new class of asteroids. They are mostly consistent with the hypothesis that binary asteroids are generated by tidal disruptions of weak, gravitationally bound aggregates (so-called “rubble piles”) during encounters with the Earth (Bottke and Melosh,Nature281, 51, 1996). A possible relationship between the population of binary asteroids and the belt of small near-Earth asteroids is discussed.

  1. LONG-TERM STABLE EQUILIBRIA FOR SYNCHRONOUS BINARY ASTEROIDS

    SciTech Connect

    Jacobson, Seth A.; Scheeres, Daniel J.

    2011-07-20

    Synchronous binary asteroids may exist in a long-term stable equilibrium, where the opposing torques from mutual body tides and the binary YORP (BYORP) effect cancel. Interior of this equilibrium, mutual body tides are stronger than the BYORP effect and the mutual orbit semimajor axis expands to the equilibrium; outside of the equilibrium, the BYORP effect dominates the evolution and the system semimajor axis will contract to the equilibrium. If the observed population of small (0.1-10 km diameter) synchronous binaries are in static configurations that are no longer evolving, then this would be confirmed by a null result in the observational tests for the BYORP effect. The confirmed existence of this equilibrium combined with a shape model of the secondary of the system enables the direct study of asteroid geophysics through the tidal theory. The observed synchronous asteroid population cannot exist in this equilibrium if described by the canonical 'monolithic' geophysical model. The 'rubble pile' geophysical model proposed by Goldreich and Sari is sufficient, however it predicts a tidal Love number directly proportional to the radius of the asteroid, while the best fit to the data predicts a tidal Love number inversely proportional to the radius. This deviation from the canonical and Goldreich and Sari models motivates future study of asteroid geophysics. Ongoing BYORP detection campaigns will determine whether these systems are in an equilibrium, and future determination of secondary shapes will allow direct determination of asteroid geophysical parameters.

  2. Rotational breakup as the origin of small binary asteroids.

    PubMed

    Walsh, Kevin J; Richardson, Derek C; Michel, Patrick

    2008-07-10

    Asteroids with satellites are observed throughout the Solar System, from subkilometre near-Earth asteroid pairs to systems of large and distant bodies in the Kuiper belt. The smallest and closest systems are found among the near-Earth and small inner main-belt asteroids, which typically have rapidly rotating primaries and close secondaries on circular orbits. About 15 per cent of near-Earth and main-belt asteroids with diameters under 10 km have satellites. The mechanism that forms such similar binaries in these two dynamically different populations was hitherto unclear. Here we show that these binaries are created by the slow spinup of a 'rubble pile' asteroid by means of the thermal YORP (Yarkovsky-O'Keefe-Radzievskii-Paddack) effect. We find that mass shed from the equator of a critically spinning body accretes into a satellite if the material is collisionally dissipative and the primary maintains a low equatorial elongation. The satellite forms mostly from material originating near the primary's surface and enters into a close, low-eccentricity orbit. The properties of binaries produced by our model match those currently observed in the small near-Earth and main-belt asteroid populations, including 1999 KW(4) (refs 3, 4). PMID:18615078

  3. Bayesian statistical approach to binary asteroid orbit determination

    NASA Astrophysics Data System (ADS)

    Kovalenko, Irina D.; Stoica, Radu S.; Emelyanov, N. V.; Doressoundiram, A.; Hestroffer, D.

    2016-01-01

    The problem of binary asteroids orbit determination is of particular interest, given knowledge of the orbit is the best way to derive the mass of the system. Orbit determination from observed points is a classic problem of celestial mechanics. However, in the case of binary asteroids, particularly with a small number of observations, the solution is not evident to derive. In the case of resolved binaries the problem consists in the determination of the relative orbit from observed relative positions of a secondary asteroid with respect to the primary. In this work, the problem is investigated as a statistical inverse problem. Within this context, we propose a method based on Bayesian modelling together with a global optimisation procedure that is based on the simulated annealing algorithm.

  4. Binary asteroids in the near-Earth object population.

    PubMed

    Margot, J L; Nolan, M C; Benner, L A M; Ostro, S J; Jurgens, R F; Giorgini, J D; Slade, M A; Campbell, D B

    2002-05-24

    Radar images of near-Earth asteroid 2000 DP107 show that it is composed of an approximately 800-meter-diameter primary and an approximately 300-meter-diameter secondary revolving around their common center of mass. The orbital period of 1.755 +/- 0.007 days and semimajor axis of 2620 +/- 160 meters constrain the total mass of the system to 4.6 +/- 0.5 x 10(11) kilograms and the bulk density of the primary to 1.7 +/- 1.1 grams per cubic centimeter. This system and other binary near-Earth asteroids have spheroidal primaries spinning near the breakup point for strengthless bodies, suggesting that the binaries formed by spin-up and fission, probably as a result of tidal disruption during close planetary encounters. About 16% of near-Earth asteroids larger than 200 meters in diameter may be binary systems. PMID:11951001

  5. BINARY ASTEROID ENCOUNTERS WITH TERRESTRIAL PLANETS: TIMESCALES AND EFFECTS

    SciTech Connect

    Fang, Julia; Margot, Jean-Luc

    2012-01-15

    Many asteroids that make close encounters with terrestrial planets are in a binary configuration. Here, we calculate the relevant encounter timescales and investigate the effects of encounters on a binary's mutual orbit. We use a combination of analytical and numerical approaches with a wide range of initial conditions. Our test cases include generic binaries with close, moderate, and wide separations, as well as seven well-characterized near-Earth binaries. We find that close approaches (<10 Earth radii) occur for almost all binaries on 1-10 million year timescales. At such distances, our results suggest substantial modifications to a binary's semimajor axis, eccentricity, and inclination, which we quantify. Encounters within 30 Earth radii typically occur on sub-million year timescales and significantly affect the wider binaries. Important processes in the lives of near-Earth binaries, such as tidal and radiative evolution, can be altered or stopped by planetary encounters.

  6. An experimental path to constraining the origin of Jupiter’s Trojan asteroids by identifying chemical fingerprints

    NASA Astrophysics Data System (ADS)

    Blacksberg, Jordana; Mahjoub, Ahmed; Poston, Michael; Brown, Mike; Eiler, John; Ehlmann, Bethany; Hand, Kevin; Carlson, Robert W.; Hodyss, Robert; Wong, Ian

    2015-11-01

    We present an experimental study aimed at exploring the hypothesis suggested by recent dynamical models - that the Jupiter Trojan asteroids originated in the outer solar system, were scattered by the same instability responsibility for the radical rearrangement of the giant planets, and were subsequently captured in their current location (e.g. Morbidelli et al., 2005, Nesvorny et al., 2013). We seek to identify spectroscopic, chemical and isotopic properties that can tie the Trojan populations to these evolutionary pathways, providing experimental support of dynamical models, and providing testable hypotheses that can feed into the design of experiments that might be performed on potential future missions to these and other primitive bodies.We present the results of experiments devised to explore the hypothesis that Kuiper Belt Objects (KBOs) represent the parent populations of the Trojan asteroids. Numerous thin ice films composed of select solar system volatiles (H2O, H2S, CH3OH, NH3) were grown in various mixtures to simulate compositional changes of icy bodies as a function of volatility and radial distance of formation from the Sun. Subsequent processing of these icy bodies was simulated using electron irradiation and heating. Visible reflectance spectra show significant reddening when H2S is present. Mid-infrared spectra confirm the formation of non-volatile sulfur-containing molecules in the products of H2S-containing ices. These experiments suggest that the presence of specific sulfur-bearing chemical species may play an important role in the colors of both the KBOs and Trojans today. Finally, we discuss the role of the silicate component expected on the surface of the Trojan asteroids (Emery et al., 2006), and the implications of a surface composed of silicates in intimate contact with the nonvolatile organic residues generated by ice irradiation.This work has been supported by the Keck Institute for Space Studies (KISS). The research described here was

  7. Origin of Martian Moons from Binary Asteroid Dissociation

    NASA Technical Reports Server (NTRS)

    Landis, Geoffrey A.; Lyons, Valerie J. (Technical Monitor)

    2001-01-01

    The origin of the Martian moons Deimos and Phobos is controversial. A common hypothesis for their origin is that they are captured asteroids, but the moons show no signs of having been heated by passage through a (hypothetical) thick martian atmosphere, and the mechanism by which an asteroid in solar orbit could shed sufficient orbital energy to be captured into Mars orbit has not been previously elucidated. Since the discovery by the space probe Galileo that the asteroid Ida has a moon 'Dactyl', a significant number of asteroids have been discovered to have smaller asteroids in orbit about them. The existence of asteroid moons provides a mechanism for the capture of the Martian moons (and the small moons of the outer planets). When a binary asteroid makes a close approach to a planet, tidal forces can strip the moon from the asteroid. Depending on the phasing, either or both can then be captured. Clearly, the same process can be used to explain the origin of any of the small moons in the solar system.

  8. Evidence for an Extrasolar Trojan Asteroid Population from Kepler Phase Curve Stacking

    NASA Astrophysics Data System (ADS)

    Angerhausen, Daniel

    2016-01-01

    We present the results of a statistical search for exo-trojans in the Kepler Data Set. By super-stacking ˜4000 Kepler planets with a total of ˜90000 full orbital curves, searching for an average Trojan transit dip in the Langrange points, we find an upper limit to the average Trojan transiting area (per planet) that corresponds to one body of radius 460 km with 2σ confidence. We find a significant Trojan-like signal in a sub-sample for planets with more and/or larger Trojans for periods >60 days. Our tentative results can and should be checked with improved data from future missions like PLATO 2.0, and can guide planetary formation theories.

  9. Lightcurves from the Initial Discovery of Four Hungaria Binary Asteroids

    NASA Astrophysics Data System (ADS)

    Warner, Brian D.; Pravec, Petr; Kusnirak, Peter; Harris, Alan W.; Cooney, Walter R., Jr.; Gross, John; Terrell, Dirk; Nudds, Shannon; Vilagi, Josef; Gajdos, Stefan; Masi, Gianluca; Pray, Donald P.; Dyvig, Ron; Reddy, Vishnu

    2011-04-01

    Lightcurves from the initial discovery of four Hungaria binary asteroids are presented: 3309 Brorfeld, (5477) 1989 UH2, 9069 Hovland, and (76818) 2000 RG79. Announcements and some web postings were made at the time of the discoveries but the lightcurves were not formally published.

  10. Searching for Multiple Systems in L5-Trojan Collisional Families

    NASA Astrophysics Data System (ADS)

    Marchis, Franck

    2007-02-01

    After our successfull search for binary moonlet in the L4 Trojan swarm, leading to the discovery of a moonlet around 624 Hektor (Marchis et al., 2006), we propose to conduct the same program in the L5 Trojan population at opposition in Apr. 2007. We will focus also on Trojans members of a collisional family to maximize the chance of detection, since recent study indicated than ~20% of the main-belt asteroid of the Koronis family are binary (Merline et al. 2005) and the discovery two moonlets orbiting around 87 Sylvia rubble-pile asteroid (Marchis et al. 2005) confirms that the collisions play a major role in the formation of binary systems.

  11. Visible-Wavelength Integrated Spectroscopy of Binary Asteroids

    NASA Astrophysics Data System (ADS)

    Reiss, A. E.; Marchis, F.; Emery, J. P.

    2009-12-01

    Binary asteroid systems consist of two small planetary bodies orbiting a common center of mass. To date, approximately 65 systems have been imaged using adaptive optics, Hubble Space Telescope observations, and various radar imaging methods. An additional 100 binaries are suspected to exist based on light curve analysis and new discoveries are being announced every month. One important task involved in the study of these systems is the classification of their surface mineralogy. The compositional characterization of asteroid surfaces requires observations across a wide wavelength range. A number of rigorous classification methods have been used to group asteroids into classes based on their observed characteristics. Most recently, a feature-based taxonomy was developed by Bus and Binzel [Bus S. J. and Binzel R. P. (2002) Icarus 158, 146-177]. Bus and Binzel decomposed the visible-wavelength (0.44 - 0.92 μm) spectra of asteroids into three major groups—complexes C-, S-, and X-. Each complex was then further refined into 26 sub-classes associated with distinct mineralogical surface features. Using the Shane 3-meter telescope at Lick Observatory, we observed twelve binary asteroid systems with the KAST double spectrograph. The primary observations were conducted on three nights between May and July of 2009 as a part of an observation program to complete the Virtual Observatory Binary Asteroids Database (VOBAD). The spectrograph at the Shane telescope provides wavelength coverage between 0.3 and 1.0 μm using both blue (0.3-0.57 μm) and red (0.53-1.0 μm) channels, with each spectrograph optimized for its wavelength range. Using this instrument, we obtained a comprehensive measurement of our targets' visible spectra, exceeding the wavelength range over which Bus and Binzel taxonomy is based. We obtained visible-wavelength (0.3 - 1.0 μm) spectra for twelve binary asteroid systems, including six objects not previously classified using Bus and Binzel taxonomic

  12. Anisotropic distribution of orbit poles of binary asteroids

    NASA Astrophysics Data System (ADS)

    Pravec, P.; Scheirich, P.; Vokrouhlický, D.; Harris, A. W.; Kusnirak, P.; Hornoch, K.; Pray, D. P.; Higgins, D.; Galád, A.; Világi, J.; Gajdos, S.; Kornos, L.; Oey, J.; Husárik, M.; Cooney, W. R.; Gross, J.; Terrell, D.; Durkee, R.; Pollock, J.; Reichart, D.; Ivarsen, K.; Haislip, J.; Lacluyze, A.; Krugly, Y. N.; Gaftonyuk, N.; Dyvig, R.; Reddy, V.; Stephens, R. D.; Chiorny, V.; Vaduvescu, O.; Longa, P.; Tudorica, A.; Warner, B. D.; Masi, G.; Brinsfield, J.; Gonçalves, R.; Brown, P.; Krzeminski, Z.; Gerashchenko, O.; Marchis, F.

    2011-10-01

    Our photometric observations of 18 mainbelt binary systems in more than one apparition revealed a strikingly high number of 15 having positively re-observed mutual events in the return apparitions. Our simulations of the survey showed that the data strongly suggest that poles of mutual orbits between components of binary asteroids are not distributed randomly: The null hypothesis of the isotropic distribution of orbit poles is rejected at a confidence level greater than 99.99%. Binary orbit poles concentrate at high ecliptic latitudes, within 30° of the poles of the ecliptic. We propose that the binary orbit poles oriented preferentially up/down-right are due to formation of small binary systems by rotational fission of critically spinning parent bodies with poles near the YORP asymptotic states with obliquities near 0 and 180°. An alternative process of elimination of binaries with poles closer to the ecliptic by the Kozai dynamics of gravitational perturbations from the sun does not explain the observed orbit pole concentration as in the close asteroid binary systems the J2 perturbation due to the primary dominates the solar-tide effect.

  13. Markov Chain Monte-Carlo Orbit Computation for Binary Asteroids

    NASA Astrophysics Data System (ADS)

    Oszkiewicz, D.; Hestroffer, D.; Pedro, David C.

    2013-11-01

    We present a novel method of orbit computation for resolved binary asteroids. The method combines the Thiele, Innes, van den Bos method with a Markov chain Monte Carlo technique (MCMC). The classical Thiele-van den Bos method has been commonly used in multiple applications before, including orbits of binary stars and asteroids; conversely this novel method can be used for the analysis of binary stars, and of other gravitationally bound binaries. The method requires a minimum of three observations (observing times and relative positions - Cartesian or polar) made at the same tangent plane - or close enough for enabling a first approximation. Further, the use of the MCMC technique for statistical inversion yields the whole bundle of possible orbits, including the one that is most probable. In this new method, we make use of the Metropolis-Hastings algorithm to sample the parameters of the Thiele-van den Bos method, that is the orbital period (or equivalently the double areal constant) together with three randomly selected observations from the same tangent plane. The observations are sampled within their observational errors (with an assumed distribution) and the orbital period is the only parameter that has to be tuned during the sampling procedure. We run multiple chains to ensure that the parameter phase space is well sampled and that the solutions have converged. After the sampling is completed we perform convergence diagnostics. The main advantage of the novel approach is that the orbital period does not need to be known in advance and the entire region of possible orbital solutions is sampled resulting in a maximum likelihood solution and the confidence regions. We have tested the new method on several known binary asteroids and conclude a good agreement with the results obtained with other methods. The new method has been implemented into the Gaia DPAC data reduction pipeline and can be used to confirm the binary nature of a suspected system, and for deriving

  14. Two New Binaries and Continuing Observations of Hungaria Group Asteroids

    NASA Astrophysics Data System (ADS)

    Warner, Brian D.

    2015-04-01

    Analysis of CCD photometry for five asteroids lead to the discovery of two new binary objects. (190208) 2006 AQ, is a rare “wide binary” example with a primary period of 182 h and secondary period of 2.62002 h. 2014 WZ120 is a near-Earth asteroid with a primary period of 3.361 h and orbital period of 13.665 h. The estimated effective diameter ratio for the pair is Ds/Dp >= 0.32. The other three asteroids, 1103 Sequoia, 2083 Smither, and 3880 Kaiserman, all members of the Hungaria group, show varying signs of a secondary period but no mutual events that would confirm the existence of a satellite.

  15. Bayesian Statistical Approach To Binary Asteroid Orbit Determination

    NASA Astrophysics Data System (ADS)

    Dmitrievna Kovalenko, Irina; Stoica, Radu S.

    2015-08-01

    Orbit determination from observations is one of the classical problems in celestial mechanics. Deriving the trajectory of binary asteroid with high precision is much more complicate than the trajectory of simple asteroid. Here we present a method of orbit determination based on the algorithm of Monte Carlo Markov Chain (MCMC). This method can be used for the preliminary orbit determination with relatively small number of observations, or for adjustment of orbit previously determined.The problem consists on determination of a conditional a posteriori probability density with given observations. Applying the Bayesian statistics, the a posteriori probability density of the binary asteroid orbital parameters is proportional to the a priori and likelihood probability densities. The likelihood function is related to the noise probability density and can be calculated from O-C deviations (Observed minus Calculated positions). The optionally used a priori probability density takes into account information about the population of discovered asteroids. The a priori probability density is used to constrain the phase space of possible orbits.As a MCMC method the Metropolis-Hastings algorithm has been applied, adding a globally convergent coefficient. The sequence of possible orbits derives through the sampling of each orbital parameter and acceptance criteria.The method allows to determine the phase space of every possible orbit considering each parameter. It also can be used to derive one orbit with the biggest probability density of orbital elements.

  16. The Cool Surfaces of Binaries Near-Earth Asteroids

    NASA Astrophysics Data System (ADS)

    Delbo, Marco; Walsh, K.; Mueller, M.

    2008-09-01

    We present results from thermal-infrared observations of binary near-Earth asteroids (NEAs). These objects, in general, have surface temperatures cooler than the average values for non-binary NEAs. We discuss how this may be evidence of higher-than-average surface thermal inertia. The comparison of these binary NEAs with all NEAs and rapidly rotating NEAs suggests a binary formation mechanism capable of altering surface properties, possibly removing regolith: an obvious candidate is the YORP effect. --- Acknowledgments This research was carried out while Marco Delbo and Kevin Walsh were Henri Poincare Fellows at the Observatoire de la Cote d'Azur. The Henri Poincare Fellowship is funded by the CNRS-INSU, the Conseil General des Alpes-Maritimes and the Rotary International -- District 1730.

  17. Formation of the wide asynchronous binary asteroid population

    SciTech Connect

    Jacobson, Seth A.; Scheeres, Daniel J.; McMahon, Jay

    2014-01-01

    We propose and analyze a new mechanism for the formation of the wide asynchronous binary population. These binary asteroids have wide semimajor axes relative to most near-Earth and main belt asteroid systems. Confirmed members have rapidly rotating primaries and satellites that are not tidally locked. Previously suggested formation mechanisms from impact ejecta, from planetary flybys, and directly from rotational fission events cannot satisfy all of the observations. The newly hypothesized mechanism works as follows: (1) these systems are formed from rotational fission, (2) their satellites are tidally locked, (3) their orbits are expanded by the binary Yarkovsky-O'Keefe-Radzievskii-Paddack (BYORP) effect, (4) their satellites desynchronize as a result of the adiabatic invariance between the libration of the secondary and the mutual orbit, and (5) the secondary avoids resynchronization because of the YORP effect. This seemingly complex chain of events is a natural pathway for binaries with satellites that have particular shapes, which define the BYORP effect torque that acts on the system. After detailing the theory, we analyze each of the wide asynchronous binary members and candidates to assess their most likely formation mechanism. Finally, we suggest possible future observations to check and constrain our hypothesis.

  18. On the Trojan asteroid sample and return mission via solar-power sail -- an innovative engineering demonstration

    NASA Astrophysics Data System (ADS)

    Kawaguchi, J.; Mori, O.; Shirasawa, Y.; Yoshikawa, M.

    2014-07-01

    The science and engineering communities in the world are seeking what comes next. Especially for asteroids and comets, as those objects lie in relatively far area in our solar system, and new engineering solutions are essential to explore them. JAXA has studied the next-step mission since 2000, a solar-power sail demonstrator combining the use of photon propulsion with electric propulsion, ion thruster, targeting the untrodden challenge for the sample return attempt from a Trojan asteroid around the libration points in the Sun-Jupiter system. The Ikaros spacecraft was literally developed and launched as a preliminary technology demonstration. The mission will perform in-situ measurement and on-site analysis of the samples in addition to the sample return to the Earth, and will also deploy a small lander on the surface for collecting surface samples and convey them to the mother spacecraft. From a scientific point of view, there is an enormous reward in the most primitive samples containing information about the ancient solar system and also about the origin of life in our solar system. JAXA presently looks for international partners to develop and build the lander. The presentation will elaborate the current mission scenario as well as what we think the international collaboration will be.

  19. Asteroid Impact and Deflection Assessment (AIDA) mission: science investigation of a binary system and mitigation test

    NASA Astrophysics Data System (ADS)

    Michel, P.; Cheng, A. F.; Küppers, M.

    2015-10-01

    The Asteroid Impact & Deflection Assessment (AIDA) mission will be the first space experiment to investigate a binary near-Earth asteroid (NEA) and to demonstrate asteroid impact hazard mitigation by using a kinetic impactor. AIDA is a joint ESA-NASA cooperative project, which includes the ESA Asteroid Impact Mission (AIM) rendezvous spacecraft and the NASA Double Asteroid Redirection Test (DART) mission. The primary goals of AIDA are (i) to investigate the binary NEA (65803) Didymos, (ii) to test our ability to impact its moon by an hypervelocity projectile in 2022 and (iii) to measure and characterize the impact deflection both from space with AIM and from ground based observatories.

  20. Binary Asteroid Formation via Slow Spin-Up

    NASA Astrophysics Data System (ADS)

    Walsh, Kevin J.; Richardson, D. C.; Michel, P.

    2007-10-01

    Recent theoretical and observational research has suggested that tidal disruption is not a sufficient mechanism to produce all of the kilometer-sized binary asteroids in the inner solar system (Walsh & Richardson 2007, Pravec et al. 2006). We present simulation results from the slow spin-up of strengthless bodies in a way designed to mimic thermal spin-up effects acting on small asteroids (the so-called YORP effect). These simulations employ cohesionless bodies represented by identical self-gravitating spheres. The spin rate of these bodies is increased slowly allowing time for transient responses of the body to decay. The simulations track the changes in shape and spin to the bodies as their spin rate increases, as well as the fate of particles which are ejected. Included in this work are simulations with rubble piles made up of small rigid aggregates of two-particle "dumbbells" rather than simply single spherical particles. This provides the body with some extra resistance against flows of particles during re-shaping and mass loss. We find that binary formation is a possible outcome from slow spin-up and discuss the parameters leading to this result as well as the properties of the binaries produced. We also discuss the shapes of bodies in relation to the Jacobi sequence and other theoretical equilibrium limits as they approach rotational disruption and reshaping. DCR and KJW acknowledge support from NSF grants AST0307549 & AST0708110. PM acknowledges support of the ESA Advanced Concepts Team on the basis of the Ariadna study 07/4111, "Asteroid Centrifugal Fragmentation". References: Pravec, P. et al. 2006. Icarus 181, 63. Walsh, K.J., Richardson, D.C. 2007. Icarus, in press.

  1. Feedback stabilization of displaced periodic orbits: Application to binary asteroids

    NASA Astrophysics Data System (ADS)

    Simo, Jules; McInnes, Colin R.

    2014-03-01

    This paper investigates displaced periodic orbits at linear order in the circular restricted Earth-Moon system (CRTBP), where the third massless body utilizes a hybrid of solar sail and solar electric propulsion (SEP). A feedback linearization control scheme is implemented to perform stabilization and trajectory tracking for the nonlinear system. Next, attention is directed to binary asteroid systems as an application of the restricted problem. The idea of combining a solar sail with an SEP auxiliary system to obtain a hybrid sail system is important especially due to the challenges of performing complex trajectories.

  2. Radar Imaging of Binary Near-Earth Asteroid 2004 DC

    NASA Astrophysics Data System (ADS)

    Taylor, Patrick A.; Margot, J. L.; Nolan, M. C.; Benner, L. A.; Ostro, S. J.; Giorgini, J. D.; Magri, C.

    2006-09-01

    Arecibo S-band (2380 MHz, 13 cm) and Goldstone X-band (8560 MHz, 3.5 cm) radar observations on June 2-6, 2006 show that Apollo asteroid 2004 DC is a binary system [IAU CBET 535]. Preliminary estimates of the diameters, based on visible range extents in the delay-Doppler images, are 300 m for the primary and 60 m for the secondary. The motion of the secondary in the delay-Doppler images suggests an orbital period of roughly 23 hours and a maximum primary-to-secondary separation of at least 0.6 km. The bandwidth of the primary increases from May 29 to June 3, then decreases until the end of observations on June 6, implying 2004 DC was viewed closest to equatorial on June 3. Assuming an equatorial view, the bandwidth suggests a rotation period of about 2 hours, which is in agreement with lightcurve observations [R. Behrend, pers. comm.]. The radar albedo and circular polarization ratio are 0.4 and 0.8 at S-band and 0.3 and unity at X-band. The circular polarization ratios are larger than those of the majority of radar-observed asteroids and imply that 2004 DC has extreme decimeter-scale near-surface roughness. We will estimate the parameters of the mutual orbit and the shape of the primary, and will place the orbital and physical properties of the system into the context of the existing binary near-Earth asteroid population.

  3. Asteroid Satellites

    NASA Astrophysics Data System (ADS)

    Merline, W. J.

    2001-11-01

    Discovery and study of small satellites of asteroids or double asteroids can yield valuable information about the intrinsic properties of asteroids themselves and about their history and evolution. Determination of the orbits of these moons can provide precise masses of the primaries, and hence reliable estimates of the fundamental property of bulk density. This reveals much about the composition and structure of the primary and will allow us to make comparisons between, for example, asteroid taxonomic type and our inventory of meteorites. The nature and prevalence of these systems will also give clues as to the collisional environment in which they formed, and have further implications for the role of collisions in shaping our solar system. A decade ago, binary asteroids were more of a theoretical curiosity. In 1993, the Galileo spacecraft allowed the first undeniable detection of an asteroid moon, with the discovery of Dactyl, a small moon of Ida. Since that time, and particularly in the last year, the number of known binaries has risen dramatically. Previously odd-shaped and lobate near-Earth asteroids, observed by radar, have given way to signatures indicating, almost certainly, that at least four NEAs are binary systems. The tell-tale lightcurves of several other NEAs reveal a high likelihood of being double. Indications are that among the NEAs, there may be a binary frequency of several tens of percent. Among the main-belt asteroids, we now know of 6 confirmed binary systems, although their overall frequency is likely to be low, perhaps a few percent. The detections have largely come about because of significant advances in adaptive optics systems on large telescopes, which can now reduce the blurring of the Earth's atmosphere to compete with the spatial resolution of space-based imaging (which itself, via HST, is now contributing valuable observations). Most of these binary systems have similarities, but there are important exceptions. Searches among other

  4. An Observing Campaign of the Mutual Events Within (617) Patroclus-Menoetius Binary Trojan System

    NASA Astrophysics Data System (ADS)

    Berthier, Jerome; Marchis, F.; Descamps, P.; Assafin, M.; Bouley, S.; Colas, F.; Dubos, G.; Emery, J. P.; De Cat, P.; Farrell, J. A.; Leroy, A.; Pauwels, T.; Pollock, J. T.; Reddy, V.; Sada, P. V.; Vingerhoets, P.; Vachier, F.; Vieira-Martins, R.; Wong, M. H.; Reichart, D. E.; Ivarsen, K. M.; Crain, J. A.; LaCluyze, A. P.; Nysewander, M. C.

    2007-10-01

    In 2006-2007, the binary Trojan system (617) Patroclus-Menotius reached one of its annual equinoxes. As a consequence, the system underwent a 6 months season of mutual eclipses and occultations. We organized a campaign of observations of these mutual events mostly centered along the first semester of 2007. We took advantage of an orbit solution of the similary-sized binary system published by Marchis et al. (Nature, 2006) to predict the timing of mutual eclipses and occultations observable from January to July 2007. During the campaign, the magnitude of Patroclus system varied from 15.8 to 16.6 and its solar phase from 9°.5 to 2°.7 at opposition (end of March). The amplitude of the events ranged between 0.2 and 0.3 magnitude. A large number of stations around the world were involved in the campaign and 20 lightcurves with mutual events signature were collected (http://www.imcce.fr/page.php?nav=en/observateur/campagnes_obs/patroclus/). With such favorable circumstances, photometric observations of the events will provide tight constraints regarding physical properties of the system such as sizes, shapes, sidereal spin period and surface composition. Combining AO observations collected at Keck and Gemini with this lightcurve data, we have refined the orbital parameters of the binary system to an unprecedented accuracy. We will present these findings, the determination of the sizes and shapes, and other results from the data analysis. This material is partly based upon work supported by the National Aeronautics and Space Administration issue through the Science Mission Directorate Research and Analysis Programs number NNG05GF09G.

  5. Dynamics of Satellites in Binary Near-Earth Asteroid Systems: A Study Based on Radar Observations

    NASA Astrophysics Data System (ADS)

    Naidu, Shantanu

    In the past 15 years, three previously unrecognized sub-populations of near-Earth asteroids (NEAs) have been discovered. About 15% of NEAs are binaries, at least 10% of NEAs are contact binaries, and dozens of asteroid pairs have been identified. Numerous science questions have arisen about the formation and evolution processes of these systems and about the inter-relationships between these groups. Addressing these questions informs us about a wide range of important solar system processes that shape small bodies and planetesimals. Here I have chosen to focus on providing one of the most complete characterizations of a binary system among all known asteroid binaries, and on studying the spin-orbit interactions in this and 8 additional binary systems. One hypothesis that has not been fully explored is the possibility of chaotic rotation of asteroid satellites and the impact that such a state has on the evolution of the binary systems. I examine this problem as well as the possibility of detecting librational motions in synchronous satellites. Because the Arecibo and Goldstone radar systems enable superb characterizations of binaries and NEAs in general, this dissertation makes abundant use of radar data. Radar observations provide images of asteroids at decameter resolution, and these images can be inverted to determine the 3D shapes of the components, which are essential to properly model the system dynamics. Radar data also enable precise determination of the mutual orbit, which is another crucial ingredient. In the first two chapters of the dissertation, I describe the observations and physical characterizations of asteroid 2000~ET70 and binary asteroid 2000 DP107. The characterization of 2000 DP107 includes size, shape, spin, mass, and density of each component, making this binary one of the best-characterized asteroid binary to date. In the last chapter of the dissertation, I describe a computationally efficient fourth-order numerical integrator that I used to

  6. Collisional Histories of Comets and Trojan Asteroids: Diopside, Magnesite, and Fayalite Impact Studies

    NASA Astrophysics Data System (ADS)

    Lederer, Susan M.; Jensen, E. A.; Wooden, D. H.; Lindsay, S. S.; Nakamura-Messenger, K.; Smith, D. C.; Keller, L. P.; Cintala, M. J.; Zolensky, M. E.

    2012-10-01

    Comets and asteroids have weathered dynamic histories, as evidenced by their rough surfaces. The Nice model describes a violent reshuffling of small bodies during the Late Heavy Bombardment, with collisions acting to grind these planetesimals away. This creates an additional source of impact material that can re-work the surfaces of the larger bodies over the lifetime of the solar system. Here, we investigate the possibility that signatures due to impacts (e.g. from micrometeoroids or meteoroids) could be detected in their spectra, and how that can be explained by the physical manifestation of shock in the crystalline structure of minerals. All impact experiments were conducted in the Johnson Space Center Experimental Impact Laboratory using the vertical gun. Impact speeds ranged from 2.0 km/s to 2.8 km/s. All experiments were conducted at room temperature. Minerals found in comets and asteroids were chosen as targets, including diopside (MgCaSi2O6, monoclinic pyroxene), magnesite (MgCO3, carbonate), and fayalite (FeSiO4, olivine). Impacted samples were analyzed using a Fourier Transform Infrared Spectrometer (FTIR) and a Transmission Electron Microscope (TEM). Absorbance features in the 8-13 µm spectral region demonstrate relative amplitude changes as well as wavelength shifts. Corresponding TEM images exhibit planar shock dislocations in the crystalline structure, attributed to deformation at high strain and low temperatures. Elongating or shortening the axes of the crystalline structure of forsterite (Mg2SiO4, olivine) using a discrete dipole approximation model (Lindsay et al., submitted) yields changes in spectral features similar to those observed in our impacted laboratory minerals. Results on forsterite and orthoenstatite can be found in Jensen, et al., this meeting. Funding was provided by the NASA PG&G grant 09-PGG09-0115, NSF grant AST-1010012, and a Cottrell College Scholarship through the Research Corporation.

  7. Collisional Histories of Comets and Trojan Asteroids: Diopside, Magnesite, and Fayalite Impact Studies

    NASA Technical Reports Server (NTRS)

    Lederer, S. M.; Jensen, E. A.; Wooden, D. H.; Lindsay, S. S.; Nakamura-Messenger, K.; Smith, D. C.; Keller, L. P.; Cintala, M. J.; Zolensky, M. E.

    2012-01-01

    Comets and asteroids have weathered dynamic histories, as evidenced by their rough surfaces. The Nice model describes a violent reshuffling of small bodies during the Late Heavy Bombardment, with collisions acting to grind these planetesimals away. This creates an additional source of impact material that can re-work the surfaces of the larger bodies over the lifetime of the solar system. Here, we investigate the possibility that signatures due to impacts (e.g. from micrometeoroids or meteoroids) could be detected in their spectra, and how that can be explained by the physical manifestation of shock in the crystalline structure of minerals. All impact experiments were conducted in the Johnson Space Center Experimental Impact Laboratory using the vertical gun. Impact speeds ranged from approx.2.0 km/s to approx.2.8 km/s. All experiments were conducted at room temperature. Minerals found in comets and asteroids were chosen as targets, including diopside (MgCaSi2O6, monoclinic pyroxene), magnesite (MgCO3, carbonate), and fayalite (FeSiO4, olivine). Impacted samples were analyzed using a Fourier Transform Infrared Spectrometer (FTIR) and a Transmission Electron Microscope (TEM). Absorbance features in the 8-13 m spectral region demonstrate relative amplitude changes as well as wavelength shifts. Corresponding TEM images exhibit planar shock dislocations in the crystalline structure, attributed to deformation at high strain and low temperatures. Elongating or shortening the axes of the crystalline structure of forsterite (Mg2SiO4, olivine) using a discrete dipole approximation model (Lindsay et al., submitted) yields changes in spectral features similar to those observed in our impacted laboratory minerals.

  8. Dynamical Explanation for the Lack of Binary Asteroids Among the Plutinos

    NASA Astrophysics Data System (ADS)

    Compère, Audrey; Farrelly, D.; Lemaître, A.; Hestroffer, D.

    2013-05-01

    Abstract (2,250 Maximum Characters): Binary asteroids are really common among the trans-Neptunians. However, they seem to be scarce among the Plutinos, i.e. the part of the Kuiper belt population situated inside the 3:2 mean-motion resonance with Neptune. Our hypothesis is that this phenomenon, unexplained up to now, is due to the impact of the 3:2 resonance on the formation of Kuiper belt binaries. Numerical simulations are done in the context of the 2+2 bodies problem (here, Sun, Neptune and two asteroids). As is known, mean-motion resonances between a planet and an asteroid usually have the effect of increasing the eccentricity of the asteroid. Therefore, we include the increase of the eccentricity of the centre of mass of the binary system due to the resonance in the simulations. Chaos maps (obtained using the MEGNO chaos indicator) and histograms of residence times for tests particles are computed in order to analyse the behavioural differences of potential Kuiper belt binaries inside and outside the resonance. The results suggest the following: the stable zones in the MEGNO maps are mainly disrupted in the resonant eccentric case and the number of binary asteroids created in the resonant eccentric case is significantly lower than in the non-resonant one. This provides a clue to explain the lack of binaries among the Plutinos.

  9. Binary asteroid population. 3. Secondary rotations and elongations

    NASA Astrophysics Data System (ADS)

    Pravec, P.; Scheirich, P.; Kušnirák, P.; Hornoch, K.; Galád, A.; Naidu, S. P.; Pray, D. P.; Világi, J.; Gajdoš, Š.; Kornoš, L.; Krugly, Yu. N.; Cooney, W. R.; Gross, J.; Terrell, D.; Gaftonyuk, N.; Pollock, J.; Husárik, M.; Chiorny, V.; Stephens, R. D.; Durkee, R.; Reddy, V.; Dyvig, R.; Vraštil, J.; Žižka, J.; Mottola, S.; Hellmich, S.; Oey, J.; Benishek, V.; Kryszczyńska, A.; Higgins, D.; Ries, J.; Marchis, F.; Baek, M.; Macomber, B.; Inasaridze, R.; Kvaratskhelia, O.; Ayvazian, V.; Rumyantsev, V.; Masi, G.; Colas, F.; Lecacheux, J.; Montaigut, R.; Leroy, A.; Brown, P.; Krzeminski, Z.; Molotov, I.; Reichart, D.; Haislip, J.; LaCluyze, A.

    2016-03-01

    We collected data on rotations and elongations of 46 secondaries of binary and triple systems among near-Earth, Mars-crossing and small main belt asteroids. 24 were found or are strongly suspected to be synchronous (in 1:1 spin-orbit resonance), and the other 22, generally on more distant and/or eccentric orbits, were found or are suggested to have asynchronous rotations. For 18 of the synchronous secondaries, we constrained their librational angles, finding that their long axes pointed to within 20° of the primary on most epochs. The observed anti-correlation of secondary synchroneity with orbital eccentricity and the limited librational angles agree with the theories by Ćuk and Nesvorný (Ćuk, M., Nesvorný, D. [2010]. Icarus 207, 732-743) and Naidu and Margot (Naidu, S.P., Margot, J.-L. [2015]. Astron. J. 149, 80). A reason for the asynchronous secondaries being on wider orbits than synchronous ones may be longer tidal circularization time scales at larger semi-major axes. The asynchronous secondaries show relatively fast spins; their rotation periods are typically < 10 h. An intriguing observation is a paucity of chaotic secondary rotations; with an exception of (35107) 1991 VH, the secondary rotations are single-periodic with no signs of chaotic rotation and their periods are constant on timescales from weeks to years. The secondary equatorial elongations show an upper limit of a2 /b2 ∼ 1.5 . The lack of synchronous secondaries with greater elongations appears consistent, considering uncertainties of the axis ratio estimates, with the theory by Ćuk and Nesvorný that predicts large regions of chaotic rotation in the phase space for a2 /b2 ≳√{ 2 } . Alternatively, secondaries may not form or stay very elongated in gravitational (tidal) field of the primary. It could be due to the secondary fission mechanism suggested by Jacobson and Scheeres (Jacobson, S.A., Scheeres, D.J. [2011]. Icarus 214, 161-178), as its efficiency is correlated with the

  10. The Binary Asteroid in-situ Explorer (BASiX) Mission

    NASA Astrophysics Data System (ADS)

    Dissly, Richard; Scheeres, D. J.; Nilsen, E.; Roark, S.; Frazier, W.; Bank, T.; Rosing, D.; Jordan, E.; BASiX Science Team

    2010-10-01

    The Binary Asteroid in-situ Explorer (BASiX) Mission represents the next phase of asteroid exploration, carrying out geophysical experiments by active engagement with an asteroid in a controlled and repeatable manner. BASiX will address new and timely scientific goals that address unresolved issues at the heart of our understanding of these bodies and which serve as barriers to their future exploration. A primary objective of the BASiX Mission is to determine the fundamental mechanical and strength properties of an asteroid through the creation of craters on the asteroid surface using calibrated charges. BASiX also takes advantage of these experiments to further understand the weathering and seismic properties of an asteroid. By carrying out these experiments at a binary Near Earth Asteroid (NEA), BASiX also advances our understanding of these ubiquitous bodies in the small asteroid population. BASiX is an efficient and simple mission concept that can deliver revolutionary science with its threshold mission and adds substantial enhancements with its baseline mission. BASiX assembles an international team of top small body scientists and astronomers and is led by PI Dan Scheeres (University of Colorado). BASiX is managed by JPL, which is also where mission and science operations will be based. The BASiX Spacecraft is built by Ball Aerospace & Technologies Corp. Instruments are built by JPL and Ball with additional contributed instruments from CNES.

  11. New insights on the binary Asteroid 121 Hermione

    NASA Astrophysics Data System (ADS)

    Descamps, P.; Marchis, F.; Durech, J.; Emery, J.; Harris, A. W.; Kaasalainen, M.; Berthier, J.; Teng-Chuen-Yu, J.-P.; Peyrot, A.; Hutton, L.; Greene, J.; Pollock, J.; Assafin, M.; Vieira-Martins, R.; Camargo, J. I. B.; Braga-Ribas, F.; Vachier, F.; Reichart, D. E.; Ivarsen, K. M.; Crain, J. A.; Nysewander, M. C.; Lacluyze, A. P.; Haislip, J. B.; Behrend, R.; Colas, F.; Lecacheux, J.; Bernasconi, L.; Roy, R.; Baudouin, P.; Brunetto, L.; Sposetti, S.; Manzini, F.

    2009-09-01

    We report on the results of a 6-month photometric study of the main-belt binary C-type Asteroid 121 Hermione, performed during its 2007 opposition. We took advantage of the rare observational opportunity afforded by one of the annual equinoxes of Hermione occurring close to its opposition in June 2007. The equinox provides an edge-on aspect for an Earth-based observer, which is well suited to a thorough study of Hermione's physical characteristics. The catalog of observations carried out with small telescopes is presented in this work, together with new adaptive optics (AO) imaging obtained between 2005 and 2008 with the Yepun 8-m VLT telescope and the 10-m Keck telescope. The most striking result is confirmation that Hermione is a bifurcated and elongated body, as suggested by Marchis, et al. [Marchis, F., Hestroffer, D., Descamps, P., Berthier, J., Laver, C., de Pater, I., 2005. Icarus 178, 450-464]. A new effective diameter of 187 ± 6 km was calculated from the combination of AO, photometric and thermal observations. The new diameter is some 10% smaller than the hitherto accepted radiometric diameter based on IRAS data. The reason for the discrepancy is that IRAS viewed the system almost pole-on. New thermal observations with the Spitzer Space Telescope agree with the diameter derived from AO and lightcurve observations. On the basis of the new AO astrometric observations of the small 32-km diameter satellite we have refined the orbit solution and derived a new value of the bulk density of Hermione of 1.4 + 0.5/-0.2 g cm -3. We infer a macroscopic porosity of ˜33 + 5/-20%.

  12. First known terrestrial impact of a binary asteroid from a main belt breakup event.

    PubMed

    Ormö, Jens; Sturkell, Erik; Alwmark, Carl; Melosh, Jay

    2014-01-01

    Approximately 470 million years ago one of the largest cosmic catastrophes occurred in our solar system since the accretion of the planets. A 200-km large asteroid was disrupted by a collision in the Main Asteroid Belt, which spawned fragments into Earth crossing orbits. This had tremendous consequences for the meteorite production and cratering rate during several millions of years following the event. The 7.5-km wide Lockne crater, central Sweden, is known to be a member of this family. We here provide evidence that Lockne and its nearby companion, the 0.7-km diameter, contemporaneous, Målingen crater, formed by the impact of a binary, presumably 'rubble pile' asteroid. This newly discovered crater doublet provides a unique reference for impacts by combined, and poorly consolidated projectiles, as well as for the development of binary asteroids. PMID:25340551

  13. Flux of icy asteroids towards the habitable zone in binary stars

    NASA Astrophysics Data System (ADS)

    Pilat-Lohinger, Elke; Bancelin, David; Bazso, Akos; Eggl, Siegfried

    2015-08-01

    From studies of habitability in our solar system we can conclude that a fraction of the water on Earth was transported via asteroids and comets to our planet. Assuming that other planetary systems would need similar water-bringing-scenarios we studied the efficiency of the water transport in binary star systems where we considered S-type planetary motion. We will show a detailed analysis of the dynamcial perturbations in the disk for different binary-planet configurations and analyse the efficiency of water transport via icy asteroids into the circumstellar habitable zone.

  14. Numerical analysis of orbital motion around a contact binary asteroid system

    NASA Astrophysics Data System (ADS)

    Feng, Jinglang; Noomen, Ron; Visser, Pieter; Yuan, Jianping

    2016-08-01

    The general orbital motion around a contact binary asteroid system is investigated in this study. System 1996 HW1 is explored in detail, as it is the mostly bifurcated asteroid known to date. The location of its equilibrium points (EPs) is obtained and their linear stability is studied. Families of Lyapunov, Halo and vertical periodic orbits (POs) in the vicinity of these EPs as well as their stability are found and examined, respectively. The influence of the relative size of each lobe and the shape of the ellipsoidal lobe and the rotation rate of the asteroid on the location and stability of the EPs are studied. Additionally, two families of equatorial orbits are obtained at a wide range of distances: from far away to nearby. Their stability is examined against the distance to the asteroid and the rotation rate of the asteroid, to uncover the influence of highly non-spherical gravitational field and the rotation of the asteroid on the orbital motion. Finally, resonant orbits in N commensurability with the rotation of the asteroid are found and their stability is discussed. The fast rotation of the asteroid has a stabilizing effect on the equatorial orbital motion.

  15. The Lockne - Målingen doublet impacts, the result of a binary asteroid from the 470 Ma Main Asteroid Belt event

    NASA Astrophysics Data System (ADS)

    Sturkell, E. C.; Ormo, J.; Alwmark, C.; Melosh, H., IV

    2015-12-01

    Approximately 470 million years ago one of the largest cosmic catastrophes occurred in our solar system since the accretion of the planets. A 200-km large asteroid was disrupted by a collision in the Main Asteroid Belt (MAB), which spawned fragments into Earth crossing orbits. This had tremendous consequences for the meteorite production and cratering rate during several millions of years following the event. The 7.5-km wide Lockne crater, central Sweden, is known to be a member of this family. The 600 m large Lockne asteroid was a binary and had a companion in space by a smaller 150 m satellite. The recent discovery of the nearby, 0.7-km diameter, synchronous Målingen crater suggests it to form a doublet impact structure together with the larger Lockne crater, and as we will show here, most likely by a binary, 'rubble pile' asteroid. Despite observational evidence that about 16% of the Near Earth Asteroids (NEA's) are binary, only a handful of the approximately 188 known craters on Earth have been suggested as potential doublets. The stratigraphic and geographic relationship with Lockne suggests the Lockne and Målingen craters to be the first described doublet impact structure by a binary asteroid into a marine-target setting. In addition, the precise dating of the Lockne-Målingen impact in relation to the MAB breakup event provides a hands-on reference for studies of the formation of binaries from asteroid breakup events.

  16. Compositional Investigation of Binary Near-Earth Asteroid 66063 (1998 RO1): A Potentially Undifferentiated Assemblage

    NASA Technical Reports Server (NTRS)

    Abell, P. A.; Gaffey, M. J.; Landis, R. R.; Jarvis, K. S.

    2005-01-01

    It is now thought that approximately 16% of all asteroids among the near-Earth population may be binary objects. Several independent lines of evidence, such as the presence of doublet craters on the Earth and Moon [1, 2], complex lightcurves of near-Earth objects exhibiting mutual events [3], and radar images of near-Earth asteroids revealing distinct primary and secondary objects, have supported this conclusion [4]. To date at least 23 near-Earth objects have been discovered as binary systems with expectations that many more have yet to be identified or recognized. Little is known about the physical characteristics of binary objects except that they seem to have fairly rapid rotation rates, generally have primaries in the approx. 1 km diameter range with smaller secondaries on the order of a few hundred meters, and apart from a few exceptions, are in synchronous orbits [4, 5]. Previously only two of these binary near-Earth asteroids (1998 ST27 and 2003 YT1) have been characterized in terms of detailed mineralogical investigations [6, 7]. Such investigations are required to fully understand the formation mechanisms of these binary objects and their possible source regions. In addition, detailed knowledge of these objects may play an important role for planning future spacecraft missions and for the development of impact mitigation strategies. The work presented here represents a continued effort to characterize this particular sub-group of the near- Earth asteroid population.

  17. Period Determination of Binary Asteroid Targets Observed at Hunters Hill Observatory: May-September 2009

    NASA Astrophysics Data System (ADS)

    Higgins, David; Oey, Julian; Pravec, Petr

    2011-01-01

    Lightcurves for seven confirmed or possible binary asteroids were obtained at the Hunters Hill Observatory (HHO) and Leura Observatory from 2009 May through 2010 September: 1453 Fennia, 2501 Lohja, 3076 Garbor, 4029 Bridges, 5325 Silver, 6244 Okamoto, and (6265) 1985 TW3.

  18. Non-destructive collisions and the evolution of the orbits of binary asteroid systems in the Main Belt

    NASA Astrophysics Data System (ADS)

    Dell'Oro, A.; Cellino, A.; Paolicchi, P.

    2012-09-01

    The effect of collisions on the stability of binary asteroids is discussed. The following mechanisms are taken into account: (1) complete disruption of one of the members of the system and (2) increase of linear momentum imparted by non-disruptive collisions. The latter effect is found to progressively increase the orbital energy of the systems up to the limit of binary gravitational instability. We focus on the case of binary asteroids belonging to the Main Belt. We show that the probability that a binary system 'evaporates' before collisional disruption of one of the two members is not negligible. As a consequence, the expected lifetime of a binary system can decrease significantly. Binary 'evaporation' causes the two former members to continue to exist as independent asteroids forming a so-called asteroid pair. The efficiency of this mechanism critically depends on the properties of the binary system and on the collisional environment. Several different scenarios have been taken into account concerning the size distribution of possible projectiles in the asteroid Main Belt, while the estimate of the fragmentation threshold in energetic impacts is based on the work of Benz & Asphaug. We estimate the expected average lifetime of a binary system as a function of different parameters including the size of the primary, the size ratio of the members and the orbital properties of the system. Moreover, the expected lifetimes of binary asteroids which are known today have been computed as a function of different possible collisional environments.

  19. Seeing Double Old and New: Observations and Lightcurve Analysis at the Palmer Divide Observatory of Six Binary Asteroids

    NASA Astrophysics Data System (ADS)

    Warner, Brian D.

    2013-04-01

    Results of the analysis of lightcurves of six binary asteroids obtained at the Palmer Divide Observatory are reported. Of the six, three were previously known to be binary: 9069 Hovland, (26471) 2000 AS152, and 1994 XD. The remaining three are new confirmed or probable binary discoveries made at PDO: 2047 Smetana, (5646) 1990 TR, and (52316) 1992 BD.

  20. Jovian Trojan Exploration and Deep Space Cruising Sciences by the Solar Power Sail

    NASA Astrophysics Data System (ADS)

    Yano, Hajime

    2012-07-01

    Jovian Trojan asteroids are as one of a few remaining final frontiers within our Solar System, which may hold fundamental clues of the Solar System formation and revolution. Their genesis is discussed by two competing hypotheses between the classic model and the more recent Nice model. The former suggests that Trojan asteroids are mainly survivors of building blocks of the Jupiter system, while the latter claims that they must be intruders from outer regions after the planetary migration of gas planets settled. In previous years, scientific investigations of these dark, distant asteroid reservoirs were largely depended upon ground observations by large optical and spectroscopic telescopes, while few D-type asteroid analog meteorites were collected on the earth with an exception of Tagish Lake meteorites. However, thanks to recent development of observational technologies such as adaptive optics, statistical studies of asteroids in Jovian L4 and L5 regions have been made possible and raised new questions about their compositions far beyond the current snow line and internal structures implied by binary system measurements. This presentation discusses major scientific objectives of an exploration mission to Jovian Trojans for the first time in the history, its mission design and spacecraft system using solar power sail, a hybrid propulsion system of electric propulsion and photon sail, which inherited from the IKAROS deep space solar sail spacecraft, together with major engineering challenges, in-situ observation instruments and operational options.

  1. The two-body interaction potential in the STF tensor formalism: an application to binary asteroids

    NASA Astrophysics Data System (ADS)

    Compère, A.; Lemaître, A.

    2014-08-01

    The symmetric trace free (STF) tensor formalism, developed by Hartmann et al. (Celest Mech Dyn Astron 60:139-159. doi: 10.1007/BF00693097, 1994), is a nice tool, not much used in Celestial Mechanics. It is fully equivalent to the usual spherical harmonics but permits more elegant and compact formulations. The coupling between the gravitational fields of extended bodies with this formalism has been used in Mathis and Le Poncin-Lafitte (Astron Astrophys 497:889-910. doi: 10.1051/0004-6361/20079054, 2009) for binary stars or planetary systems, but not yet applied to binary asteroids. However, binary asteroids are common in the Solar System and usually their study requires a full two rigid body approach. The formulation of the two-body interaction potential in the STF formalism in the full two rigid body problem is detailed and completed in this article. An application to the binary asteroid (66391) 1999 KW4 is presented with a comparison of our results with other results of the literature for validation.

  2. A Jovian Trojan-Satellite Population Exchange

    NASA Astrophysics Data System (ADS)

    Stenborg, T. N.

    2003-07-01

    In Special Session 1, Recent Progress in Planetary Exploration, Monash University's Andrew Prentice discusses the possible origin of Jovian satellite Amalthea as a captured Trojan asteroid. Galileo spacecraft data gives a low bulk density (~1 g/cc) for Amalthea, more consistent with a captured minor body, rather than one formed in-situ. Its 83 km radius is within the size range of the known Jovian Trojans, less than that of Trojan 624 Hektor, for example.

  3. Spitzer/IRS Observations Of Multiple Main-Belt And Binary Near-Earth Asteroids

    NASA Astrophysics Data System (ADS)

    Enriquez, J. Emilio; Marchis, F.; Emery, J. P.; Im, S.

    2010-10-01

    Since the discovery of Ida's companion in 1993, 195 companions of asteroids have been discovered. To understand the formation process of these interesting bodies, their physical properties such as their bulk density, size, shape, and surface roughness need to be determined. During the Spitzer Cycle-4, we obtained IRS thermal emission spectra (5-42 um) of 23 known binary systems. The majority of asteroids are from the main-belt (16), while the rest are NEOs (7). After extracting the thermal spectra, we used a modified Standard Thermal Model (STM) to calculate their equivalent diameter (from 0.8 km to 237 km), their albedo (from 0.04 for C-type to 0.394 for a V-type) and their beaming factor related to the surface roughness and thermal inertia. We derive their emissivity spectra, which is useful to detect silicate features. Combining these measurements with 3D-models of these multiple asteroid systems obtained by lightcurve inversion, we should be able to derive an accurate estimate of their bulk-density and contrast them with their taxonomic classes. Preliminary studies by Marchis et al. (2008)1, suggested a relationship between bulk density and the taxonomic class of asteroids, which varies from 0.9 g/cc for C-complex to 2.4 g/cc for S-complex asteroids. The National Science Foundation supported this research under award number AAG-0807468. It was conducted with the Spitzer space telescope, which is operated by JPL under a contract with NASA. 1 Marchis et al. , 2008, "Mid-infrared Spectra of Binary Asteroids With Spitzer/IRS", 40th DPS Meeting, Bulletin of the American Astronomical Society, 40, 508

  4. The Effect of Shape Model Uncertainty on the Geophysical Predictions of Binary Asteroids

    NASA Astrophysics Data System (ADS)

    McMahon, Jay W.; Scheeres, Daniel

    2014-11-01

    Recent work by Jacobson and Scheeres (ApJ Vol. 736, L19) have shown that for a binary asteroid system in and equilibrium between tides and the binary YORP effect, the ratio Q/k can be determined, where Q is the tidal dissipation number and k is the tidal Love number. In their work, the value for B (the binary YORP coefficient) was that computed by McMahon and Scheeres (Icarus Vol. 209, pp 494-509, 2010) for binary asteroid 1999 KW4. Using this value, it was shown that the geophysical parameters Q/k can be estimated. Furthermore, we can similarly compute μQ based on the relationship between μ and k (where μ is the rigidity parameter), as discussed by Scheirich et al (ACM, Niigata, Japan, 2012, No. 1667, id.6123). These geophysical predictions, however, depend directly on the value of the binary YORP coefficient used, which is uncertain due to the limited shape model accuracy.In this study, we analyze the effect of shape model uncertainty on the predictions of Q/k and μQ. The 1999 KW4 secondary shape model is stochastically perturbed based on the radar observation accuracy (Ostro et al, Science Vol. 314, pp 1276-1280, 2006). Furthermore the detail of the topography is varied by adding more vertices to create a higher resolution shape model. For each newly perturbed shape model, the binary YORP coefficient is computed using our most advanced modeling software, and is used to derive new values for the geophysical parameter relationships. Furthermore we compute the B for a variety of known asteroid shape models as investigated by McMahon and Scheeres (44th AAS DPS, Reno, NV, 2012. Abstract No. 105.08). The results give effective error bounds on the Q/k (and derived μQ) predictions based on the shape model uncertainties.

  5. Asteroid flux and water transport towards circumprimary habitable zones in binary star systems

    NASA Astrophysics Data System (ADS)

    Bancelin, D.; Pilat-Lohinger, E.; Eggl, S.; Lammer, H.; Johnston, C.; Maindl, T. I.; Dvorak, R.

    2015-10-01

    Dynamical simulations show that the outcome of planetary formation process can lead to various planetary architectures (i.e. location, size, mass and water content) when the star system is single or double. In the late phase of planetary formation, when embryosized objects dominate the inner region of the system, asteroids are also present and can provide additional material for objects inside the habitable zone (HZ). In this study, we make a comparison of several binary star systems' characteristics and their efficiency to move icy asteroids from beyond the snow-line into orbits crossing the HZ. In our results, we highlight the key role of secular and mean motion resonances, causing an efficient flux of asteroids to the HZ on a short timescale. This in turn leads to asteroids bearing a non negligeable amount of water towards the HZ and available for any planets or embryos moving in this area. We also discuss how mass loss mechanisms can alter the water content on asteroids' surface.

  6. Near-Earth Asteroid 2005 CR37: Radar Images and Photometry of a Candidate Contact Binary

    NASA Technical Reports Server (NTRS)

    Benner, Lance A. M.; Nolan, Michael C.; Ostro, Steven J.; Giorgini, Jon D.; Pray, Donald P.; Harris, Alan W.; Magri, Christopher; Margot, Jean-Luc

    2006-01-01

    Arecibo (2380 MHz, 13 cm) radar observations of 2005 CR37 provide detailed images of a candidate contact binary: a 1.8-km-long, extremely bifurcated object. Although the asteroid's two lobes are round, there are regions of modest topographic relief, such as an elevated, 200-m-wide facet, that suggest that the lobes are geologically more complex than either coherent fragments or homogeneous rubble piles. Since January 1999, about 9% of NEAs larger than approx.200 m imaged by radar can be described as candidate contact binaries.

  7. Periodic orbits in the doubly synchronous binary asteroid systems and their applications in space missions

    NASA Astrophysics Data System (ADS)

    Shang, Haibin; Wu, Xiaoyu; Cui, Pingyuan

    2015-01-01

    This paper investigates the periodic motion of a particle in the doubly synchronous binary asteroid systems. Two typical doubly synchronous systems, 809 Lundia and 3169 Ostro, are discussed in detail. Under the Roche figure assumption, the two bodies of doubly synchronous system can be modeled as two triaxial ellipsoids. The Ivory's theorem is used to derive the gravitational potential of the system. Then, a global numerical method, which combines grid searching and differential correction, is developed for systematically searching periodic orbits in the doubly synchronous systems. A total of 30 and 28 families of periodic orbits around Lundia and Ostro are found, respectively. Furthermore, on the basis of the analysis of morphology, stabilities and invariant manifolds, the potential applications of these periodic orbit families are studied. Several quasi-circular orbit families with low instability index are found to be suitable for the observation of the two typical binary systems. The invariant manifolds of some periodic orbits near the equilibrium points can provide the fuel-free trajectories to achieve the ballistic landing to the surface of the asteroids and transfer between the binary asteroids.

  8. Thersites: a `jumping' Trojan?

    NASA Astrophysics Data System (ADS)

    Tsiganis, K.; Dvorak, R.; Pilat-Lohinger, E.

    2000-02-01

    In this paper, we examine the dynamical evolution of the asteroid (1868) Thersites, a member of the Trojan belt. Thersites is librating around the Lagrangian point L_4, following, however, a chaotic orbit. The equations of motion for Thersites as well as for a distribution of neighboring initial conditions are integrated numerically for 50 million years in the Outer Solar System model (OSS), which consists of the Sun and the four giant planets. Our results indicate that the probability that this asteroid will eventually escape from the Trojan swarm is rather high. In fact, 20% from our initial distribution escaped within the integration time. Many of the remaining ones also show characteristic `jumps' in the orbital elements, especially the inclination. Secular resonances involving the nodes of the outer planets are found to be responsible for this chaotic behavior. The width of libration and eccentricity values that lead to grossly unstable orbits are calculated and compared with previously known results on the stability of the Trojans. Finally, a very interesting behavior has been observed for one of the escaping asteroids as he `jumped' from L_4 to L_5 where he remained performing a highly inclined libration for ~ 2 Myrs before escaping from the Trojan swarm. According to Homer, Thersites was not only the ugliest of all Greeks that took part in the Trojan war, but also had the most intolerable personality. His nasty habit of making fun of everybody cost him his life, as the last person for whom he spoke ironically about was Achilles, the mightiest warrior of all Greeks, who killed Thersites with just one punch!

  9. Asteroides

    NASA Video Gallery

    Los asteroides son más que una roca metálica que orbita alrededor del sol. Al igual que la Tierra, es posible que Ceres, el asteroide más grande del sistema solar, tenga casquetes polares. Únete a ...

  10. Refining the Orbits of Known Main-Belt Binary Asteroids

    NASA Astrophysics Data System (ADS)

    Marchis, Franck; Berthier, Jerome; Descamps, Pascal; Hestroffer, Daniel

    2006-02-01

    We propose to use the high angular resolution provided by NIRI/ALTAIR to follow-up the orbits of binary main-belt systems already discovered (121 Hermione, 130 Elektra, 379 Huenna, 762 Pulcova, 1509 Esclangona) to improve their orbital elements. Determination of the precise orbital elements of the secondary can be done by multiple observations spanning large periods of time (on several years). Our group developed two independent visual methods to separate the geometrical orbit determination from the dynamical one including secular variations of the orbital plane and the pericenter. Without any assumptions, they led to the determination of the main orbital elements (a, P, e, i) of binary systems (see Marchis et al., 2004, 2005bcd). Additional observations will allow to detect unambiguously the precession of their orbit and constrain the distribution of mass in their interior (density, mass, porosity) giving direct insights on their formation processes. The recent discovery of two moonlets orbiting 87 Sylvia (Marchis et al.,2005e) indicates that multiple systems exist and should be discovered with large AO campaign.

  11. New observations and new models of spin-orbit coupling in binary asteroids

    NASA Astrophysics Data System (ADS)

    Margot, Jean-Luc; Naidu, Shantanu

    2015-08-01

    The YORP-induced rotational fission hypothesis is the leading candidate for explaining the formation of binaries, triples, and pairs among small (<20 km) asteroids (e.g., Margot et al, Asteroids IV, subm., 2015). Various evolutionary paths following rotational fission have been suggested, but many important questions remain about the evolutionary mechanisms and timescales. We test hypotheses about the evolution of binary asteroids by obtaining precise descriptions of the orbits and components of binary systems with radar and by examining the system dynamics with detailed numerical simulations. Predictions for component spin states and orbital precession rates can then be compared to observables in our data sets or in other data sets to elucidate the states of various systems and their likely evolutionary paths.Accurate simulations require knowledge of the masses, shapes, and spin states of individual binary components. Because radar observations can provide exquisite data sets spanning days with spatial resolutions at the decameter level, we can invert for the component shapes and measure spin states. We can also solve for the mutual orbit by fitting the observed separations between components. In addition, the superb (10e-7--10e-8) fractional uncertainties in range allow us to measure the reflex motions directly, allowing masses of individual components to be determined.We use recently published observations of the binary 2000 DP107 (Naidu et al. AJ, subm., 2015) and that of other systems to simulate the dynamics of components in well-characterized binary systems (Naidu and Margot, AJ 149, 80, 2015). We model the coupled spin and orbital motions of two rigid, ellipsoidal bodies under the influence of their mutual gravitational potential. We use surface of section plots to map the possible spin configurations of the satellites. For asynchronous satellites, the analysis reveals large regions of phase space where the spin state of the satellite is chaotic. The

  12. Primary Surface Particle Motion as a Mechanism for YORP-Driven Binary Asteroid Evolution

    NASA Astrophysics Data System (ADS)

    Fahnestock, Eugene G.; Scheeres, D. J.

    2008-09-01

    Within the largest class of binary asteroid systems -- asynchronous binaries typified by 1999 KW4 -- we hypothesize continued YORP spin-up of the rapidly rotating primary leads to recurring episodic lofting motion of primary equator regolith. We theorize this is a mechanism for transporting YORP-injected angular momentum from primary spin into the mutual orbit. This both enables binary primaries to continue to spin at near surface fission rates and produces continued orbit expansion on time scales several times faster than expansion predicted by tidal dissipation alone. This is distinct from the Binary Yorp (BYORP) phenomenon, not studied in this work but to be added to it later. We evaluate our hypotheses using a combination of techniques for an example binary system. First high-fidelity dynamic simulation of surface-originating particles in the full-detail gravity field of the binary components, themselves propagated according to the full two body problem, gives particle final disposition (return impact, transfer impact, escape). Trajectory end states found for regolith lofted at different initial primary spin rates and relative poses are collected into probability matrices, allowing probabilistic propagation of surface particles for long durations at low computational cost. We track changes to mass, inertia dyad, rotation state, and centroid position and velocity for each component in response to this mapped particle motion. This allows tracking of primary, secondary, and mutual orbit angular momenta over time, clearly demonstrating the angular momentum transfer mechanism and validating our hypotheses. We present current orbit expansion rates and estimated orbit size doubling times consistent with this mechanism, for a few binary systems. We also discuss ramifications of this type of rapid binary evolution towards separation, including the frequency with which "divorced binaries" on similar heliocentric orbits are produced, formation of triple systems such as

  13. The Asteroid Redirect Mission (ARM): Exploration of a Former Binary NEA?

    NASA Technical Reports Server (NTRS)

    Abell, P. A.; Mazanek, D. D.; Reeves, D. M.; Chodas, P. W.; Gates, M. M.; Johnson, L. N.; Ticker, R. L.

    2016-01-01

    The National Aeronautics and Space Administration (NASA) is developing the Asteroid Redirect Mission (ARM) as a capability demonstration for future human exploration, including use of high-power solar electric propulsion, which allows for the efficient movement of large masses through deep space. The ARM will also demonstrate the capability to conduct proximity operations with natural space objects and crewed operations beyond the security of quick Earth return. The Asteroid Redirect Robotic Mission (ARRM), currently in formulation, will visit a large near-Earth asteroid (NEA), collect a multi-ton boulder from its surface, conduct a demonstration of a slow push planetary defense technique, and redirect the multi-ton boulder into a stable orbit around the Moon. Once returned to cislunar space in the mid-2020s, astronauts aboard an Orion spacecraft will dock with the robotic vehicle to explore the boulder and return samples to Earth. The ARM is part of NASA's plan to advance technologies, capabilities, and spaceflight experience needed for a human mission to the Martian system in the 2030s. The ARM and subsequent availability of the asteroidal material in cis-lunar space, provide significant opportunities to advance our knowledge of small bodies in the synergistic areas of science, planetary defense, and in-situ resource utilization (ISRU). The current reference target for the ARM is NEA (341843) 2008 EV5, which may have been the primary body of a former binary system (Busch et al., 2011; Tardivel et al., 2016). The ARRM will perform several close proximity operations to investigate the NEA and map its surface. A detailed investigation of this object may allow a better understanding of binary NEA physical characteristics and the possible outcomes for their evolution. An overview of the ARM robotic and crewed segments, including mission operations, and a discussion of potential opportunities for participation with the ARM will be provided in this presentation.

  14. Radar-Derived Shape Model of Near-Earth Binary Asteroid System (285263) 1998 QE2

    NASA Astrophysics Data System (ADS)

    Springmann, Alessondra; Taylor, Patrick A.; Nolan, Michael C.; Howell, Ellen S.; Brozovi?, Marina; Benner, Lance A.; Giorgini, Jon D.; Busch, Michael W.; Margot, Jean-Luc; Lee, Clement; Jao, Joseph S.; Lauretta, Dante S.

    2014-11-01

    We report on shape modeling of binary asteroid 1998 QE2, a 3.2-km asteroid with a 800-m moon. We observed this asteroid with both Arecibo Observatory planetary radar (2380 MHz, 12.6 cm) and Goldstone Solar System Radar (8560 MHz, 3.5 cm) between May 31-Jun 9, 2013. The close approach on May 31, 2013 (0.039 au) presented an outstanding opportunity for radar delay-Doppler imaging with resolutions as fine as 7.5 m of both objects. The extensive radar dataset was used for shape modeling of both components. Our SHAPE 3D modeling software (Hudson, 1993 and Magri et al., 2007) uses a constrained, weighted least-squares minimization procedure to invert radar delay-Doppler images.The rotation rate of the primary, 4.749 ± 0.002 h, was well constrained from optical lightcurves (P. Pravec, pers. comm.) and rotates prograde as determined from radar data. The primary is roughly spheroidal, showing prominent concavities and surface features, with effective diameter 3.2 ± 0.3 km.The secondary is irregularly shaped, with an effective diameter of 800 ± 80 m and significant elongation. The radar data suggest it is tidally locked, with an orbital period of 31.31 ± 0.01 h hours and a semi-major orbital axis of 6.2 ± 0.1 km. The orbit is approximately circular (e < 0.01), which is typical of most near-Earth asteroid binary system orbits. We estimate a preliminary density for the primary of 0.7 ± 0.2 g/cm^3. The low density is consistent with a "rubble pile" structure.

  15. The Trojans' Odyssey space mission

    NASA Astrophysics Data System (ADS)

    Lamy, P.; Vernazza, P.; Groussin, O.; Poncy, J.; Martinot, V.; Hinglais, E.; Bell, J.; Cruikshank, D.; Helbert, J.; Marzari, F.; Morbidelli, A.; Rosenblatt, P.

    2011-10-01

    In our present understanding of the Solar System, small bodies (asteroids, Jupiter Trojans, comets and TNOs) are the most direct remnants of the original building blocks that formed the planets. Jupiter Trojan and Hilda asteroids are small primitive bodies located beyond the "snow line", around respectively the L4 and L5 Lagrange points of Jupiter at 5.2 AU (Trojans) and in the 2:3 mean-motion resonance with Jupiter near 3.9 AU (Hildas). They are at the crux of several outstanding and still conflicting issues regarding the formation and evolution of the Solar System. They hold the potential to unlock the answers to fundamental questions about planetary migration, the late heavy bombardment, the formation of the Jovian system, the origin and evolution of trans-neptunian objects, and the delivery of water and organics to the inner planets. The proposed Trojans' Odyssey mission is envisioned as a reconnaissance, multiple flyby mission aimed at visiting several objects, typically five Trojans and one Hilda. It will attempt exploring both large and small objects and sampling those with any known differences in photometric properties. The orbital strategy consists in a direct trajectory to one of the Trojan swarms. By carefully choosing the aphelion of the orbit (typically 5.3 AU), the trajectory will offer a long arc in the swarm thus maximizing the number of flybys. Initial gravity assists from Venus and Earth will help reducing the cruise to 7 years as well as the ?V needed for injection thus offering enough capacity to navigate among Trojans. This solution further opens the unique possibility to flyby a Hilda asteroid when leaving the Trojan swarm. During the cruise phase, a Main Belt Asteroid could be targeted if requiring a modest ?V. The specific science objectives of the mission will be best achieved with a payload that will perform high-resolution panchromatic and multispectral imaging, thermal-infrared imaging/ radiometry, near- and mid-infrared spectroscopy

  16. On the Possibility of Habitable Trojan Planets in Binary Star Systems.

    PubMed

    Schwarz, Richard; Funk, Barbara; Bazsó, Ákos

    2015-12-01

    Approximately 60% of all stars in the solar neighbourhood (up to 80% in our Milky Way) are members of binary or multiple star systems. This fact led to the speculations that many more planets may exist in binary systems than are currently known. To estimate the habitability of exoplanetary systems, we have to define the so-called habitable zone (HZ). The HZ is defined as a region around a star where a planet would receive enough radiation to maintain liquid water on its surface and to be able to build a stable atmosphere. We search for new dynamical configurations-where planets may stay in stable orbits-to increase the probability to find a planet like the Earth. PMID:26113154

  17. Stable Orbits in the Didymos Binary Asteroid System - Useful Platforms for Exploration

    NASA Astrophysics Data System (ADS)

    Damme, Friedrich; Hussmann, Hauke; Wickhusen, Kai; Enrico, Mai; Oberst, Jürgen

    2016-04-01

    We have analyzed particle motion in binary asteroid systems to search for stable orbits. In particular, we studied the motion of particles near the asteroid 1996 GT (Didymos), proposed as a target for the AIDA mission. The combined gravity fields of the odd-shaped rotating objects moving about each other are complex. In addition, orbiting spacecraft or dust particles are affected by radiation pressure, possibly exceeding the faint gravitational forces. For the numerical integrations, we adopt parameters for size, shape, and rotation from telescopic observations. To simulate the effect of radiation pressure during a spacecraft mission, we apply a spacecraft wing-box shape model. Integrations were carried out beginning in near-circular orbits over 11 days, during which the motion of the particles were examined. Most orbits are unstable with particles escaping quickly or colliding with the asteroid bodies. However, with carefully chosen initial positions, we found stable motion (in the orbiting plane of the secondary) associated with the Lagrangian points (L4 and L5), in addition to horseshoe orbits, where particles move from one of the Lagrangian point to the other. Finally, we examined orbits in 1:2 resonances with the motion of the orbital period of the secondary. Stable conditions depend strongly on season caused by the inclination of the mutual orbit plane with respect to Didymos solar orbit. At larger distance from the asteroid pair, we find the well-known terminator orbits where gravitational attraction is balanced against radiation pressure. Stable orbits and long motion arcs are useful for long tracking runs by radio or Laser instruments and are well-suited for modelling of the ephemerides of the asteroid pair and gravity field mapping. Furthermore, these orbits may be useful as observing posts or as platforms for approach. These orbits may also represent traps for dust particles, an opportunity for dust collection - or possibly a hazard to spacecraft

  18. Tidal Evolution of Asteroidal Binaries. Ruled by Viscosity. Ignorant of Rigidity.

    NASA Astrophysics Data System (ADS)

    Efroimsky, Michael

    2015-10-01

    This is a pilot paper serving as a launching pad for study of orbital and spin evolution of binary asteroids. The rate of tidal evolution of asteroidal binaries is defined by the dynamical Love numbers kl divided by quality factors Q. Common in the literature is the (oftentimes illegitimate) approximation of the dynamical Love numbers with their static counterparts. Since the static Love numbers are, approximately, proportional to the inverse rigidity, this renders a popular fallacy that the tidal evolution rate is determined by the product of the rigidity by the quality factor: {k}l/Q\\propto 1/(μ Q). In reality, the dynamical Love numbers depend on the tidal frequency and all rheological parameters of the tidally perturbed body (not just rigidity). We demonstrate that in asteroidal binaries the rigidity of their components plays virtually no role in tidal friction and tidal lagging, and thereby has almost no influence on the intensity of tidal interactions (tidal torques, tidal dissipation, tidally induced changes of the orbit). A key quantity that overwhelmingly determines the tidal evolution is a product of the effective viscosity η by the tidal frequency χ . The functional form of the torque’s dependence on this product depends on who wins in the competition between viscosity and self-gravitation. Hence a quantitative criterion, to distinguish between two regimes. For higher values of η χ , we get {k}l/Q\\propto 1/(η χ ), {while} for lower values we obtain {k}l/Q\\propto η χ . Our study rests on an assumption that asteroids can be treated as Maxwell bodies. Applicable to rigid rocks at low frequencies, this approximation is used here also for rubble piles, due to the lack of a better model. In the future, as we learn more about mechanics of granular mixtures in a weak gravity field, we may have to amend the tidal theory with other rheological parameters, ones that do not show up in the description of viscoelastic bodies. This line of study provides

  19. Analysis of GSC 2475-1587 and GSC 841-277: Two Eclipsing Binary Stars Found During Asteroid Lightcurve Observations

    NASA Astrophysics Data System (ADS)

    Stephens, R. D.; Warner, B. D.

    2006-05-01

    When observing asteroids we select from two to five comparison stars for differential photometry, taking the average value of the comparisons for the single value to be subtracted from the value for the asteroid. As a check, the raw data of each comparison star are plotted as is the difference between any single comparison and the average of the remaining stars in the set. On more than one occasion, we have found that at least one of the comparisons was variable. In two instances, we took time away from our asteroid lightcurve work to determine the period of the two binaries and attempted to model the system using David Bradstreet's Binary Maker 3. Unfortunately, neither binary showed a total eclipse. Therefore, our results are not conclusive and present only one of many possibilities.

  20. Dynamical model of binary asteroid systems through patched three-body problems

    NASA Astrophysics Data System (ADS)

    Ferrari, Fabio; Lavagna, Michèle; Howell, Kathleen C.

    2016-04-01

    The paper presents a strategy for trajectory design in the proximity of a binary asteroid pair. A novel patched approach has been used to design trajectories in the binary system, which is modeled by means of two different three-body systems. The model introduces some degrees of freedom with respect to a classical two-body approach and it is intended to model to higher accuracy the peculiar dynamical properties of such irregular and low gravity field bodies, while keeping the advantages of having a full analytical formulation and low computational cost required. The neighborhood of the asteroid couple is split into two regions of influence where two different three-body problems describe the dynamics of the spacecraft. These regions have been identified by introducing the concept of surface of equivalence (SOE), a three-dimensional surface that serves as boundary between the regions of influence of each dynamical model. A case of study is presented, in terms of potential scenario that may benefit of such an approach in solving its mission analysis. Cost-effective solutions to land a vehicle on the surface of a low gravity body are selected by generating Poincaré maps on the SOE, seeking intersections between stable and unstable manifolds of the two patched three-body systems.

  1. Dynamics of ejecta from the binary asteroid Didymos, the target of the AIDA mission

    NASA Astrophysics Data System (ADS)

    Michel, Patrick; Yu, Yang; Schwartz, Stephen; Naidu, Shantanu; Benner, Lance

    2016-04-01

    The AIDA space mission, a collaborative effort between ESA and NASA, aims to characterize the near-Earth asteroid binary (65803) Didymos and to perform a kinetic impactor demonstration on the small moon of the binary system. Our study presents a multi-scale dynamical model of the ejecta cloud produced by a hypervelocity impact, which enables us to compute the ejecta properties at different spatial and time scales. This model is applied to the impact into the small moon of Didymos on October 2022 as considered by the AIDA mission. We model the process by including as much practical information as possible, e.g., the gravitational environment influenced by the non-spherical shapes of the bodies (based on the observed shape of the primary), the solar tides, and the solar radiation pressure. Our simulations show where and for how long the ejecta cloud evolves with time for the considered ejecta initial conditions. This information is used to assess the potential hazard to the ESA Asteroid Impact Mission (AIM) observing spacecraft and to determine the safest positions. This study is performed with support of the European Space Agency and in the framework of the NEOShield-2 project that has received funding from the European Union's Horizon 2020 research and innovation program under grant agreement No 640351.

  2. Dynamical model of binary asteroid systems through patched three-body problems

    NASA Astrophysics Data System (ADS)

    Ferrari, Fabio; Lavagna, Michèle; Howell, Kathleen C.

    2016-08-01

    The paper presents a strategy for trajectory design in the proximity of a binary asteroid pair. A novel patched approach has been used to design trajectories in the binary system, which is modeled by means of two different three-body systems. The model introduces some degrees of freedom with respect to a classical two-body approach and it is intended to model to higher accuracy the peculiar dynamical properties of such irregular and low gravity field bodies, while keeping the advantages of having a full analytical formulation and low computational cost required. The neighborhood of the asteroid couple is split into two regions of influence where two different three-body problems describe the dynamics of the spacecraft. These regions have been identified by introducing the concept of surface of equivalence (SOE), a three-dimensional surface that serves as boundary between the regions of influence of each dynamical model. A case of study is presented, in terms of potential scenario that may benefit of such an approach in solving its mission analysis. Cost-effective solutions to land a vehicle on the surface of a low gravity body are selected by generating Poincaré maps on the SOE, seeking intersections between stable and unstable manifolds of the two patched three-body systems.

  3. PHYSICAL CHARACTERIZATION AND ORIGIN OF BINARY NEAR-EARTH ASTEROID (175706) 1996 FG{sub 3}

    SciTech Connect

    Walsh, Kevin J.; Delbo, Marco; Mueller, Michael; Binzel, Richard P.; DeMeo, Francesca E.

    2012-04-01

    The near-Earth asteroid (NEA) (175706) 1996 FG{sub 3} is a particularly interesting spacecraft target: a binary asteroid with a low-{Delta}v heliocentric orbit. The orbit of its satellite has provided valuable information about its mass density while its albedo and colors suggest it is primitive or part of the C-complex taxonomic grouping. We extend the physical characterization of this object with new observations of its emission at mid-infrared wavelengths and with near-infrared reflection spectroscopy. We derive an area-equivalent system diameter of 1.90 {+-} 0.28 km (corresponding to approximate component diameters of 1.83 km and 0.51 km, respectively) and a geometric albedo of 0.039 {+-} 0.012. (175706) 1996 FG{sub 3} was previously classified as a C-type asteroid, though the combined 0.4-2.5 {mu}m spectrum with thermal correction indicates classification as B-type; both are consistent with the low measured albedo. Dynamical studies show that (175706) 1996 FG{sub 3} most probably originated in the inner main asteroid belt. Recent work has suggested the inner Main Belt (142) Polana family as the possible origin of another low-{Delta}v B-type NEA, (101955) 1999 RQ{sub 36}. A similar origin for (175706) 1996 FG{sub 3} would require delivery by the overlapping Jupiter 7:2 and Mars 5:9 mean motion resonances rather than the {nu}{sub 6}, and we find this to be a low probability, but possible, origin.

  4. Asteroid flux towards circumprimary habitable zones in binary star systems. II. Dynamics

    NASA Astrophysics Data System (ADS)

    Bancelin, D.; Pilat-Lohinger, E.; Bazsó, Á.

    2016-06-01

    Context. Secular and mean motion resonances (MMR) are effective perturbations for shaping planetary systems. In binary star systems, they play a key role during the early and late phases of planetary formation, as well as for the dynamical stability of a planetary system. Aims: In this study, we aim to correlate the presence of orbital resonances with the rate of icy asteroids crossing the habitable zone (HZ) from a circumprimary disk of planetesimals in various binary star systems. Methods: We modelled a belt of small bodies in the inner and outer regions, interior and exterior to the orbit of a gas giant planet, respectively. The planetesimals are equally placed around a primary G-type star and move under the gravitational influence of the two stars and the gas giant. We numerically integrated the system for 50 Myr, considering various parameters for the secondary star. Its stellar type varies from a M- to F-type; its semimajor axis is either 50 au or 100 au, and its eccentricity is either 0.1 or 0.3. For comparison, we also varied the gas giant's orbital and physical parameters. Results: Our simulations highlight that a disk of planetesimals will suffer from perturbations owing to a perturbed gas giant, mean motion, and secular resonances. We show that a secular resonance - with location and width varying according to the secondary star's characteristics - can exist in the icy asteroid belt region and overlap with MMRs, which have an impact on the dynamical lifetime of the disk. In addition, we point out that, in any case, the 2:1 MMR, the 5:3 MMR, and the secular resonance are powerful perturbations for the flux of icy asteroids towards the HZ and the transport of water therein.

  5. Radar Imaging of Binary Near-Earth Asteroid (357439) 2004 BL86

    NASA Astrophysics Data System (ADS)

    Benner, Lance AM; Brozovic, Marina; Giorgini, Jon D.; Jao, Joseph S.; Lee, Clement G.; Taylor, Patrick A.; Howell, Ellen S.; Busch, Michael W.; Ford, H. Alyson; Ghigo, Frank; Nolan, Michael C.; Slade, Martin A.; Lawrence, Kenneth J.; Richardson, James E.; Rivera-Valentin, Edgard G.; Rozek, Agata

    2015-08-01

    We report radar observations of near-Earth asteroid 2004 BL86 obtained during 2015 Jan. 26-31 at the 70 m and 34 m Goldstone facilities, Arecibo, Green Bank, and elements of the Very Long Baseline Array. 2004 BL86 approached within 0.0080 au (3.1 lunar distances) on Jan. 26, the closest known approach by any object with an absolute magnitude brighter than ~19 until 2027. Prior to the encounter, virtually nothing was known about its physical properties other than its absolute magnitude of 19, which suggested a diameter within a factor of two of 500 m. Due to its size and the extremely close approach, 2004 BL86 was a very strong radar target that provided an outstanding opportunity for radar imaging and physical characterization. The radar images confirmed photometric results reported by Pravec et al. (2015, CBET 4063) that 2004 BL86 is a binary system. This is the 43rd near-Earth asteroid binary detected by radar. Delay-Doppler images placed thousands of 3.75 m-resolution pixels on the object and reveal a rounded and oblate primary with an equatorial diameter of ~300 m, suggesting it is optically-bright, evidence for ridges, small-scale topography including boulders, and a large angular feature near one of the poles. A preliminary estimate for the diameter of the secondary is ~70 m. The images hint that the secondary’s rotation is synchronous with its orbital period. The observations also yielded the first detection of an asteroid with a new 80 kW C-band radar (7190 MHz, 4.2 cm) at the 34 m DSS-13 antenna at the Goldstone Deep Space Communications Complex. This new radar can achieve a range resolution up to 1.875 m/pixel that is twice as fine as the highest resolution previously achievable.

  6. Radar observations and physical modeling of binary near-Earth asteroid (1862) Apollo

    NASA Astrophysics Data System (ADS)

    Ford, Thomas F.; Benner, Lance A.; Brozovic, Marina; Leford, Bruce; Nolan, Michael C.; Giorgini, Jon D.; Ostro, Steve J.; Margot, Jean-Luc

    2014-11-01

    Binary asteroid 1862 Apollo has an extensive observational history allowing many of its characteristics to be investigated. Apollo was one of the first objects to show evidence for the YORP effect (Kaasalainen et al. 2007, Nature 446, 420) and its mass has been estimated by detection of the Yarkovsky effect (Nugent et al. 2012, AJ 144, 60; Farnocchia et al. 2013, Icarus 224, 1). We observed Apollo at Arecibo and Goldstone from Oct. 29-Nov. 13, 2005, obtaining a series of echo power spectra and delay-Doppler images that achieved resolutions as high as 7.5 m/pixel. The Arecibo images show that Apollo is a binary system with a rounded primary that has two large protrusions about 120 deg apart in longitude. We used the Arecibo data and published lightcurves to estimate the primary's 3D shape. Our best fit has major axes of ~1.8x1.5x1.3 km and a volume of ~1.6 km^3. The protrusions have lengths of ~300 and 200 m, are on the primary's equator, and give Apollo a distinctly different appearance from the primaries with equatorial ridges seen with other binary near-Earth asteroids. We estimated the pole by starting with the Kaasalainen et al. spin vector of ecliptic (longitude, latitude)=(50 deg, -71 deg) +- 7 deg and letting it float. Our best fit has a pole within 11 deg of (longitude, latitude)=(71, -72). Convex models produced from inversion of lightcurves by Kaasalainen et al. and thermal infrared data by Rozitis et al. (2013, A&A 555, A20) are more oblate than our model, do not show protrusions, and have somewhat different pole directions. The Arecibo images reveal weak but persistent echoes from a satellite on Nov. 1 and 2 but cover only a fraction of its orbit. The images are insufficient to estimate the satellite's shape and yield a rough estimate for its long axis of 190 m. Preliminary fits give an orbital period of ~27.0-27.5 h and a semimajor axis of ~3.5-4.0 km, implying a mass of 2.8-3.9E12 kg and a bulk density of 1.7-2.4 g/cm^3. The density is consistent with

  7. Broadband linear polarization of Jupiter Trojans

    NASA Astrophysics Data System (ADS)

    Bagnulo, S.; Belskaya, I.; Stinson, A.; Christou, A.; Borisov, G. B.

    2016-01-01

    Context. Trojan asteroids orbit in the Lagrange points of the system Sun-planet-asteroid. Their dynamical stability make their physical properties important proxies for the early evolution of our solar system. Aims: To study their origin, we want to characterize the surfaces of Jupiter Trojan asteroids and check possible similarities with objects of the main belt and of the Kuiper Belt. Methods: We have obtained high-accuracy broadband linear polarization measurements of six Jupiter Trojans of the L4 population and tried to estimate the main features of their polarimetric behaviour. We have compared the polarimetric properties of our targets among themselves, and with those of other atmosphere-less bodies of our solar system. Results: Our sample show approximately homogeneous polarimetric behaviour, although some distinct features are found between them. In general, the polarimetric properties of Trojan asteroids are similar to those of D- and P-type main-belt asteroids. No sign of coma activity is detected in any of the observed objects. Conclusions: An extended polarimetric survey may help to further investigate the origin and the surface evolution of Jupiter Trojans.

  8. Shape model of the binary near-Earth asteroid (285263) 1998 QE_2

    NASA Astrophysics Data System (ADS)

    Springmann, A.; Taylor, P.; Nolan, M.; Howell, E.; Benner, L.; Brozović, M.; Giorgini, J.; Busch, M.; Margot, J.; Lee, C.; Gao, J.

    2014-07-01

    Binary systems comprise ˜1/6 of the near-Earth object population larger than 200 meters in diameter, providing important clues to asteroids' masses and densities. On May 31, 2013, the binary near-Earth-asteroid system (285263) 1998 QE_2 had a 0.04-au close approach to the Earth. We observed the binary system from May 30 to June 27 with the Goldstone Solar System Radar (which discovered the system's binary nature, operating at 3.5 cm / 8.56 GHz) and Arecibo Observatory planetary radar system (operating at 12.6 cm / 2.38 GHz). The size of the QE_2 primary and the short light travel time afforded us an excellent data set of high resolution delay-Doppler images as fine as 7.5 meters/pixel of this asteroid and its moon. We used the extensive radar dataset to fit 3D shape models for both primary and secondary using a nonlinear iterative inverse process [1,2]. A preliminary scale model for both system components is shown in the figure. The preliminary primary model is a roughly spherical body, 3.2 ± 0.3 km in effective diameter. Some radar-bright spots in the delay-Doppler images may be indicative of boulders. Lightcurve data show a rotation period of 4.749 ± 0.002 h for the primary [3]. The best fit to a subset of radar data suggests a prograde pole at (119°, +35°) in ecliptic coordinates [4]. The secondary model indicates an effective diameter of 800 ± 80 m (for a primary:secondary diameter ratio of ≈4:1) for an elongated object with a concavity on one side of the long axis. The secondary is in a tidally locked spin state with an orbital period of 31.31 ± 0.01 h hours derived from radar, and a semimajor orbital axis of 6.2 ± 0.1 km (approximately quadruple the radius of the primary). The orbit is approximately circular (e < 0.01), which is typical of most near-Earth-asteroid binary-system orbits. We assume that the primary and secondary poles are aligned with the best-fit mutual-orbit pole. All orbital parameters were derived from radar data. From orbital fits

  9. A thick cloud of Neptune Trojans and their colors.

    PubMed

    Sheppard, Scott S; Trujillo, Chadwick A

    2006-07-28

    The dynamical and physical properties of asteroids offer one of the few constraints on the formation, evolution, and migration of the giant planets. Trojan asteroids share a planet's semimajor axis but lead or follow it by about 60 degrees near the two triangular Lagrangian points of gravitational equilibrium. Here we report the discovery of a high-inclination Neptune Trojan, 2005 TN(53). This discovery demonstrates that the Neptune Trojan population occupies a thick disk, which is indicative of "freeze-in" capture instead of in situ or collisional formation. The Neptune Trojans appear to have a population that is several times larger than the Jupiter Trojans. Our color measurements show that Neptune Trojans have statistically indistinguishable slightly red colors, which suggests that they had a common formation and evolutionary history and are distinct from the classical Kuiper Belt objects. PMID:16778021

  10. Non-convex model of the binary asteroid (809) Lundia and its density estimation

    NASA Astrophysics Data System (ADS)

    Kryszczynska, A.; Bartczak, P.; Polinska, M.; Colas, F.

    2014-07-01

    Introduction: (809) Lundia was classified as a V-type asteroid in the Flora family (Florczak et.al. 2002). The binary nature of (809) Lundia was discovered in September 2005 based on photometric observations. The first modeling of the Lundia synchronous binary system was based on 22 lightcurves obtained at Borowiec and Pic du Midi Observatories during two oppositions in 2005/2006 and 2006/2007. Two methods of modeling --- modified Roche ellipsoids and kinematic --- gave similar parameters for the system (Kryszczynska et al. 2009). The poles of the orbit in ecliptic coordinates were: longitude 118° and latitude 28° in the modified Roche model and 120°, 18°, respectively, in the kinematic model. The orbital period obtained from the lightcurve analysis as well as from modeling was 15.418 h. The obtained bulk density of both components was 1.64 or 1.71 g/ccm. Observations: We observed (809) Lundia in the 2008, 2009/2010, 2011, and 2012 oppositions at the Borowiec, Pic du Midi, Prompt, and Rozhen Observatories. As predicted, the visible eclipses/occultation events were observed only in 2011. Currently, our dataset consists of 45 individual lightcurves and they were all used in the new modeling. Method: We used new method of modeling based on a genetic algorithm that is able to create a non-convex asteroid shape model, rotational period, and spin-axis orientation of a single or binary asteroid, using only photometric observations. The details of the method are presented in the poster by Bartczak et al., at this conference. Results: The new non-convex model of (809) Lundia is presented in the figure. The parameters of the system in the ecliptic coordinates are: longitude 122°, latitude 22°, and sidereal period 15.41574 h. They are very similar to the values obtained before. However, assuming an equivalent diameter of a single body of 9.1 km from the Spitzer observations (Marchis et al. 2012) and the volume of the two modeled bodies, the separation of the components

  11. Radar Imaging and Characterization of the Binary Near-Earth Asteroid (185851) 2000 DP107

    NASA Astrophysics Data System (ADS)

    Naidu, S. P.; Margot, J. L.; Taylor, P. A.; Nolan, M. C.; Busch, M. W.; Benner, L. A. M.; Brozovic, M.; Giorgini, J. D.; Jao, J. S.; Magri, C.

    2015-08-01

    The potentially hazardous asteroid (185851) 2000 DP107 was the first binary near-Earth asteroid to be imaged. Radar observations in 2000 provided images at 75 m resolution that revealed the shape, orbit, and spin-up formation mechanism of the binary. The asteroid made a more favorable flyby of the Earth in 2008, yielding images at 30 m resolution. We used these data to obtain shape models for the two components and to improve the estimates of the mutual orbit, component masses, and spin periods. The primary has a sidereal spin period of 2.7745 ± 0.0007 hr and is roughly spheroidal with an equivalent diameter of 863 m +/- 5%. It has a mass of 4.656+/- 0.43× {10}11 kg and a density of 1381 ± 244 kg m-3. It exhibits an equatorial ridge similar to the (66391) 1999 KW4 primary; however, the equatorial ridge in this case is not as regular and has a ˜300 m diameter concavity on one side. The secondary has a sidereal spin period of 1.77 ± 0.02 days commensurate with the orbital period. The secondary is slightly elongated and has overall dimensions of 377× 314× 268 m (6% uncertainties). Its mass is 0.178+/- 0.021× {10}11 kg and its density is 1047 ± 230 kg m-3. The mutual orbit has a semimajor axis of 2.659 ± 0.08 km, an eccentricity of 0.019 ± 0.01, and a period of 1.7556 ± 0.0015 days. The normalized total angular momentum of this system exceeds the amount required for the expected spin-up formation mechanism. An increase of angular momentum from non-gravitational forces after binary formation is a possible explanation. The two components have similar radar reflectivity, suggesting a similar composition consistent with formation by spin-up. The secondary appears to exhibit a larger circular polarization ratio than the primary, suggesting a rougher surface or subsurface at radar wavelength scales.

  12. The binary near-Earth Asteroid (175706) 1996 FG3 - An observational constraint on its orbital evolution

    NASA Astrophysics Data System (ADS)

    Scheirich, P.; Pravec, P.; Jacobson, S. A.; Ďurech, J.; Kušnirák, P.; Hornoch, K.; Mottola, S.; Mommert, M.; Hellmich, S.; Pray, D.; Polishook, D.; Krugly, Yu. N.; Inasaridze, R. Ya.; Kvaratskhelia, O. I.; Ayvazian, V.; Slyusarev, I.; Pittichová, J.; Jehin, E.; Manfroid, J.; Gillon, M.; Galád, A.; Pollock, J.; Licandro, J.; Alí-Lagoa, V.; Brinsfield, J.; Molotov, I. E.

    2015-01-01

    Using our photometric observations taken between April 1996 and January 2013 and other published data, we derived properties of the binary near-Earth Asteroid (175706) 1996 FG3 including new measurements constraining evolution of the mutual orbit with potential consequences for the entire binary asteroid population. We also refined previously determined values of parameters of both components, making 1996 FG3 one of the most well understood binary asteroid systems. With our 17-year long dataset, we determined the orbital vector with a substantially greater accuracy than before and we also placed constraints on a stability of the orbit. Specifically, the ecliptic longitude and latitude of the orbital pole are 266 ° and - 83 ° , respectively, with the mean radius of the uncertainty area of 4 ° , and the orbital period is 16.1508 ± 0.0002 h (all quoted uncertainties correspond to 3σ). We looked for a quadratic drift of the mean anomaly of the satellite and obtained a value of 0.04 ± 0.20 deg /yr2 , i.e., consistent with zero. The drift is substantially lower than predicted by the pure binary YORP (BYORP) theory of McMahon and Scheeres (McMahon, J., Scheeres, D. [2010]. Icarus 209, 494-509) and it is consistent with the tigidity and quality factor of μQ = 1.3 ×107 Pa using the theory that assumes an elastic response of the asteroid material to the tidal forces. This very low value indicates that the primary of 1996 FG3 is a 'rubble pile', and it also calls for a re-thinking of the tidal energy dissipation in close asteroid binary systems.

  13. Compositional Investigation of Binary Potentially-Hazardous Asteroid 2008 BT18: A Basaltic Achondrite

    NASA Astrophysics Data System (ADS)

    Reddy, Vishnu; Emery, J. P.; Gaffey, M. J.

    2008-09-01

    The binary nature of potentially-hazardous asteroid (PHA) 2008 BT18 was discovered during radar observations on July 6 and 7, 2008, from the Arecibo observatory. The primary has a diameter of 600 meters with a rotation period 2.57 hours (Pravec, Pers. Comm.) and the secondary has a diameter of >200; meters (CBET 1450). Near-IR spectroscopic observations of 2008 BT18 were obtained remotely using the SpeX instrument on NASA IRTF on July 26 UT, 2008. The data were reduced based on reduction techniques developed by Gaffey et al. (2003). The near-IR spectrum (0.7-2.5 µm) of 2008 BT18 shows deep band I (band depth 62±1%) and an equally deep band II (band depth 48±1%). The estimated band I and II centers are 0.926±0.001 µm and 1.94±0.01 µm respectively, with a band area ratio (BAR) of 2.0±0.1. A weak inflection is also noted at 1.3 µm. Based on the spectral parameters it can be suggested that the PHA's surface assemblage is dominated by high-Fe orthopyroxene with little or no olivine. This suggests that the asteroid's parent body experienced at least partial melting temperatures producing large eutectic melt similar to basaltic achondrites. The spectral parameters of the PHA plot it in the basaltic achondrites region on the Gaffey S-asteroid subtype plot (Gaffey et al., 1993) suggesting a V-type taxonomic classification. This research was supported by NASA NEOO Program Grants NNG04GI17G and NNX07AL29G. VR would like to thank J. Iglesias (UC Berkeley) and H. Stewart (Villanova University) for their support.

  14. Investigating the surface and subsurface properties of the Didymos binary asteroid with a landed CubeSat

    NASA Astrophysics Data System (ADS)

    Murdoch, Naomi; Cadu, Alexandre; Mimoun, David; Karatekin, Ozgur; Garcia, Raphael; Carrasco, José; Garcia de Quiros, Javier; Vasseur, Hugues; Ritter, Birgit; Eubanks, Marshall; Radley, Charles; Dehant, Veronique

    2016-04-01

    Despite the successes of recent space missions (e.g., Cheng et al., 1997; Fujiwara et al., 2006), there is still no clear understanding of the asteroid internal structure(s). Depending on their size, evolution and physical properties, many different asteroid internal structure models have been suggested from completely cohesive bodies, through to rubble pile objects. The Asteroid Geophysical Explorer (AGEX), a COPINS payload selected by ESA*, will land geophysical instrument packages on the surface of Didymoon; the secondary object in the (65803) Didymos (1996 GT) binary system (Karatekin et al 2016). The instruments will characterize the asteroid surface mechanical properties and probe, for the first time, the sub-surface structure of an asteroid. AGEX will be deployed from AIM on a ballistic transfer to the asteroid surface, several days before the MASCOT-2 package. We expect that AGEX will bounce multiple times before coming to rest on the surface of the asteroid thus providing a unique opportunity to study the asteroid surface properties, perhaps at several locations, using accelerometers. Once stationary, the seismological surface-monitoring phase, using a three-axis set of geophones, can begin. The high speed DART impact will be a major seismic source on Didymoon. However, the seismic payload may also be able to perform seismological investigations using natural seismic sources such as micrometeoroid impacts (e.g., Garcia et al., 2015), thermal cracks (e.g., Delbo et al., 2014), internal quakes due to tidal forces (e.g., Richardson et al. 1998) and other geophysical processes (see Murdoch et al., 2015). We will present the expected signal characteristics of the landing and also of the natural seismic sources that may occur on Didymoon. An understanding of the amplitude and frequency content of such signals is necessary in order to design the optimal geophysical payload for small body exploration using a CubeSat platform. [1.] Cheng, A. et al., Journal of

  15. Search for Asteroid Satellites

    NASA Astrophysics Data System (ADS)

    Merline, W. J.; Close, L. M.; Menard, F.; Dumas, C.; Chapman, C. R.; Slater, D. C.

    2001-11-01

    We report on the recent progress of our comprehensive search for satellites of asteroids. In 1998, we began our survey using newly newly developed technologies in adaptive optics to explore the close environs of several hundred main-belt asteroids. Adaptive optics (AO) removes the blurring caused by the Earth's atmosphere and allows diffraction-limited imaging in the near-IR (J-,H-,K'-bands) at the world's largest telescopes. Angular resolutions as high as 0.04 arcsec are possible. We have employed the excellent facilities at the Canada-France-Hawaii Telescope, the W.M. Keck II telescope, and the new Gemini North 8m telescope. Each of these facilities provides unique capabilities and are each complementary to the other. So far we have discovered or recovered a half-dozen small moons or double asteroids by this AO-assisted direct-imaging technique. Our sample now exceeds 300 main-belt targets, and we have expanded the survey to include near-Earth and Trojan asteroids. Other groups are using AO, direct HST imaging, direct ground-based imaging, advanced lightcurve analysis, and radar techniques to further sample these populations, as well as the Kuiper Belt. Our results show that the frequency of binary asteroids (at least to our detection limits) is rather small in the main belt, possibly a few percent. Frequencies among other populations, such as the NEAs, are seen to be much higher. We also find that although there are similarities among the detected systems, there are also significant differences. Thus, it is likely that several different formation mechanisms will be required to explain the observed systems. All of the proposed mechanisms for formation involve collisions of one type or another (physical or gravitational). Study of these systems will provide significant insight to the collisional history and evolution of these asteroid populations. Further, the presence of a companion allows accurate determination of the density of the primary, and thus yields

  16. Fine Analysis of 121 Hermione, 45 Eugenia, and 90 Antiope Binary Asteroid Systems With AO Observations

    NASA Astrophysics Data System (ADS)

    Marchis, F.; Descamps, P.; Hestroffer, D.; Berthier, J.; de Pater, I.

    2004-11-01

    We report on a campaign of adaptive optics observations which focuses on 121 Hermione, 45 Eugenia, and 90 Antiope binary asteroids performed with ESO-VLT and Keck II telescopes in 2003-2004. A precessing Keplerian model was used to describe the motion of their companion. The orbital elements are determined accurately using data spanning more than 2 years. The satellite of 121 Hermione revolves at a= 775+/-14 km from the primary in P=2.5714+/-0.001 days with a low eccentricity (e=0.008+/-0.004) and retrograde orbit w.r.t. to the primary's equator (i=175+/-4 deg considering a pole solution (1.9,13.2) deg in ecliptic EQJ2000). The sense of revolution was unambiguously estimated from images separated by a few hours. Keck AO data taken in December 2003 revealed the bi-lobated shape of the primary. The nominal bulk density as derived from observed size of the primary and its 209 km IRAS diameter is 1.2+/-0.3 g/cm3 (Marchis et al., Icarus, 2004). Future observations with better angular resolution will allow us to see if 121 Hermione is a triple system. The orbit of Petit-Prince, moonlet of 45 Eugenia, was constrained using Feb. and Mar. 2004 AO data recorded at the VLT (a=1196+/-4 km, P= 4.7244+/-0.001 days, e=0, i=163+/-6 deg with a pole solution (133+/-3,-40+/-3 deg) in ecliptic B1950), leading to a bulk density of 1.17 g/cm3 considering its 215 km IRAS diameter. Both models predict successfully the positions reported for the discovery of Petit-Prince on Nov. 1998 and of S/2001 (121) 1 by Merline et al. (1999 and 2002). We will also present results on the same-size binary asteroid 90 Antiope, using the same analysis. Feb. and Mar. 2004 VLT-NACO data confirmed that both components are similar (with a Dm 2.4 and a diameter of 110+/-16 km). A preliminary analysis of Feb. and Mar. 2004 VLT data confirms that both components, separated by 170+/-1 km, with a revolution period P=16.5268 +- 0.0001h, are quasi-similar (with a Dm ˜ 2.4% and a diameter of 110+/-16 km) leading to

  17. Radar imaging of binary near-Earth asteroid (357439) 2004 BL86

    NASA Astrophysics Data System (ADS)

    Benner, Lance A. M.; Brozovic, Marina; Giorgini, Jon D.; Taylor, Patrick A.; Howell, Ellen S.; Busch, Michael W.; Nolan, Michael C.; Jao, Joseph S.; Lee, Clement G.; Ford, H. Alyson; Ghigo, Frank D.

    2015-11-01

    We report radar imaging of near-Earth asteroid 2004 BL86 obtained at Goldstone, Arecibo, Green Bank, and elements of the Very Long Baseline Array between 2015 January 26-31. 2004 BL86 approached within 0.0080 au on January 26, the closest known approach by any object with an absolute magnitude brighter than ~19 until 2027. Prior to the encounter, virtually nothing was known about its physical properties other than its absolute magnitude of 19, which suggested a diameter within a factor of two of 500 m. 2004 BL86 was a very strong radar target that provided an outstanding opportunity for radar imaging and physical characterization. Delay-Doppler images with range resolutions as fine as 3.75 m placed thousands of pixels on the object and confirmed photometric results reported by Pravec et al. (2015, CBET 4063) that 2004 BL86 is a binary system. During the observations, the asteroid moved more than 90 deg and provided a range of viewing geometries. The bandwidth was relatively narrow on Jan. 26, reached a maximum on Jan. 27, and then narrowed on Jan. 28, a progression indicating that the subradar latitude moved across the equator during those days. The images reveal a rounded primary with an equatorial diameter of ~350 m, evidence for ridges, possible boulders, and a pronounced angular feature ~100 m in diameter near one of the poles. Images from Jan. 26 show arcs of radar-bright pixels on the approaching and receding limbs that extend well behind the trailing edge in the middle of the echo. This is the delay-Doppler signature of an oblate shape seen at least a few tens of degrees off the equator. A rough estimate for the diameter of the secondary is ~70 m and its narrow bandwidth is consistent with the 14-h orbital period reported by Pravec et al. (2015). The images are suitable for 3D shape, pole, orbit, and mass estimation. The observations utilized new data taking equipment at Green Bank to receive X-band (8560 MHz, 3.5 cm) transmissions from the 70 m DSS-14

  18. Spectroscopy and Photometry of Mars Trojans

    NASA Technical Reports Server (NTRS)

    Rivkin, A. S.; Binzel, R. P.; Howell, E. S.; Bus, S. J.; Grier, J. A.

    2003-01-01

    Mars is the only terrestrial planet known to have co-orbiting "Trojan" asteroids. We have obtained visible and near-IR reflectance spectra of three of these objects: 5261 Eureka and 1998 VF31 in the L5 region and 1999 UJ7 in the L4 region. We also obtained JHK spectrophotometry and a visible lightcurve for 5261 Eureka. The asteroid 5261 Eureka has a visible spectrum that is classified as Sr in the Bus taxonomy, and has infrared colors consistent with the A-class asteroids. The data for 1998 VF31 have a restricted wavelength range, but are most consistent with the Sr or Sa class, though we note a marginal consistency with the D class. We can rule out a C-class classification. 1999 UJ7 has an X-class or T-class spectrum, which is unlike that of the other two Mars Trojans. The photometric data for Eureka are limited, but we can constrain the period to longer than 5 hours (likely 5.556 hours) and lightcurve amplitude of at least 0.15 magnitude at this viewing geometry. The spectral differences among the Mars Trojans suggests that either they did not all form at their present solar distances or that they have not always been at their present sizes. 0 2003 Elsevier Inc. All rights reserved. Keywords: Asteroids; Asteroids, composition; Spectroscopy; Satellites of Mars

  19. Rotational Properties of Jupiter Trojan 1173 Anchises

    NASA Astrophysics Data System (ADS)

    Chatelain, Joseph; Henry, Todd; French, Linda; Trilling, David

    2015-11-01

    Anchises (1173) is a large Trojan asteroid librating about Jupiter’s L5 Lagrange point. Here we examine its rotational and lightcurve properties by way of data collected over a 3.5 year observing campaign. The length of the campaign means that data were gathered for more than a quarter of Anchises' full orbital revolution which allows for accurate determinations of pole orientation and bulk shape properties for the asteroid that can then be compared to results of previous work (i.e. French 1987, Horner et al. 2012). In addition to light curves, photometric data taken during this campaign could potentially detect color differences between hemispheres as the viewing geometry changes over time. Understanding these details about a prominent member of the Jupiter Trojans may help us better understand the history of this fascinating and important group of asteroids.

  20. Concept of Operations for Deploying a Lander on the Secondary Body of Binary Asteroid 1996 FG3

    NASA Astrophysics Data System (ADS)

    Tardivel, Simon; Michel, P.; Scheeres, D.

    2012-10-01

    The European Space Agency is currently performing an assessment study of the MarcoPolo-R space mission, in the framework of the M3 class competition of its Cosmic Vision Program. MarcoPolo-R is a sample return mission to a primitive asteroid, whose baseline target is the binary asteroid 1996FG3. The baseline mission, including the sample, is focused on the primary of the binary system. To date, little has yet been considered for the investigation of the secondary, apart from remote observations from the spacecraft. However, MarcoPolo-R may carry an optional lander, and if such a lander could be accommodated it may be relevant to use it for a more detailed investigation of the secondary. This poster presents a strategy for deploying a lander using an unpowered trajectory towards the secondary. This ballistic deployment allows for the design of a light lander with minimum platform overhead and maximum payload. The deployment operations are shown to be very simple and require minimum preparation. The main spacecraft is set on an orbit that reaches a specific point near the binary system L2 Lagrange Point facing the far side of the secondary, about 220 meters from the secondary surface, with a relative speed of about 10cm/s. The lander is then jettisoned using a spring-release mechanism that sets it on an impact trajectory that robustly intersects with the secondary surface. On impact, the lander only needs to dissipate a small amount of kinetic energy in order to ensure that it is energetically and dynamically trapped on the surface. Considering errors on spacecraft GNC and on the spring-release mechanism, and very large uncertainties on the gravity field of the asteroids, the strategy presented here yields a successful landing in more than 99.9% of cases, while ensuring the absolute safety of the spacecraft before, during and after deployment operations.

  1. A new non-convex model of the binary asteroid 90 Antiope obtained with the SAGE modelling technique

    NASA Astrophysics Data System (ADS)

    Bartczak, P.; Michałowski, T.; Santana-Ros, T.; Dudziński, G.

    2014-09-01

    We present a new non-convex model of the 90 Antiope binary asteroid, derived with a modified version of the Shaping Asteroids with Genetic Evolution (SAGE) method using disc-integrated photometry only. A new variant of the SAGE algorithm capable of deriving models of binary systems is described. The model of 90 Antiope confirms the system's pole solution (λ = 199°, β = 38°, σ = ±5°) and the orbital period (16.505 046 ± 0.000 005 h). A comparison between the stellar occultation chords obtained during the 2011 occultation and the projected shape solution has been used to scale the model. The resulting scaled model allowed us to obtain the equivalent radii (R1 = 40.4 ± 0.9 km and R2 = 40.2 ± 0.9 km) and the distance between the two system components (176 ± 4 km), leading to a total system mass of (9.14 ± 0.62) · 1017 kg. The non-convex shape description of the components permitted a refined calculation of the components' volumes, leading to a density estimation of 1.67 ± 0.23 g cm-3. The intermediate-scale features of the model may also offer new clues on the components' origin and evolution.

  2. Dynamics of ejecta from a binary asteroid impact in the framework of the AIDA mission: a NEOShield-2 contribution

    NASA Astrophysics Data System (ADS)

    Yu, Y.; Schwartz, S. R.; Michel, P.; Benner, L. A. M.

    2015-10-01

    The dynamics of the ejecta cloud that results from a binary asteroid impact is one of the tasks of the NEOShield-2 project, funded by the European Commission in its program Horizon 2020. Results from such an investigation will have great relevance to the Phase-A study of the AIDA space mission, a collaborative effort between ESA and NASA, which aims to perform a kinetic impactor demonstration. Our study presents a multi-scale dynamical model of the ejecta cloud produced by a hypervelocity impact, which enables us to check the behaviors of the ejecta at different spatial and time scales. This model is applied to the impact into the small moon of the binary Near- Earth asteroid (65803) Didymos on October 2022 as considered by the AIDA mission. We attempt to model the process by including as much practical information as possible, e.g., the gravitational environment influenced by the non-spherical shapes of the bodies based on observed shape of the primary), the solar tides, and the solar radiation pressure. Our simulations show the general patterns of motion of the ejecta cloud, which we use to assess the potential hazard to an observing spacecraft. We also look into the grain-scale dynamics of the ejecta during this process, which has influence on the re-accumulation of particles orbiting in the vicinity.

  3. Lunar and Planetary Science XXXV: Asteroids, Meteors, Comets

    NASA Technical Reports Server (NTRS)

    2004-01-01

    Reports included:Long Term Stability of Mars Trojans; Horseshoe Asteroids and Quasi-satellites in Earth-like Orbits; Effect of Roughness on Visible Reflectance Spectra of Planetary Surface; SUBARU Spectroscopy of Asteroid (832) Karin; Determining Time Scale of Space Weathering; Change of Asteroid Reflectance Spectra by Space Weathering: Pulse Laser Irradiation on Meteorite Samples; Reflectance Spectra of CM2 Chondrite Mighei Irradiated with Pulsed Laser and Implications for Low-Albedo Asteroids and Martian Moons; Meteorite Porosities and Densities: A Review of Trends in the Data; Small Craters in the Inner Solar System: Primaries or Secondaries or Both?; Generation of an Ordinary-Chondrite Regolith by Repetitive Impact; Asteroid Modal Mineralogy Using Hapke Mixing Models: Validation with HED Meteorites; Particle Size Effect in X-Ray Fluorescence at a Large Phase Angle: Importance on Elemental Analysis of Asteroid Eros (433); An Investigation into Solar Wind Depletion of Sulfur in Troilite; Photometric Behaviour Dependent on Solar Phase Angle and Physical Characteristics of Binary Near-Earth-Asteroid (65803) 1996 GT; Spectroscopic Observations of Asteroid 4 Vesta from 1.9 to 3.5 micron: Evidence of Hydrated and/or Hydroxylated Minerals; Multi-Wavelength Observations of Asteroid 2100 Ra-Shalom: Visible, Infrared, and Thermal Spectroscopy Results; New Peculiarities of Cometary Outburst Activity; Preliminary Shape Modeling for the Asteroid (25143) Itokawa, AMICA of Hayabusa Mission; Scientific Capability of MINERVA Rover in Hayabusa Asteroid Mission; Characteristics and Current Status of Near Infrared Spectrometer for Hayabusa Mission; Sampling Strategy and Curation Plan of Hayabusa Asteroid Sample Return Mission; Visible/Near-Infrared Spectral Properties of MUSES C Target Asteroid 25143 Itokawa; Calibration of the NEAR XRS Solar Monitor; Modeling Mosaic Degradation of X-Ray Measurements of 433 Eros by NEAR-Shoemaker; Scattered Light Remediation and Recalibration of

  4. The full two-body-problem: Simulation, analysis, and application to the dynamics, characteristics, and evolution of binary asteroid systems

    NASA Astrophysics Data System (ADS)

    Fahnestock, Eugene Gregory

    The Full Two-Body-Problem (F2BP) describes the dynamics of two unconstrained rigid bodies in close proximity, having arbitrary spatial distribution of mass, charge, or similar field quantity, and interacting through a mutual potential dependent on that distribution. While the F2BP has applications in areas as wide ranging as molecular dynamics to satellite formation flying, this dissertation focuses on its application to natural bodies in space with nontrivial mass distribution interacting through mutual gravitational potential, i.e. binary asteroids. This dissertation first describes further development and implementation of methods for accurate and efficient F2BP propagation based upon a flexible method for computing the mutual potential between bodies modeled as homogenous polyhedra. Next application of these numerical tools to the study of binary asteroid (66391) 1999 KW4 is summarized. This system typifies the largest class of NEO binaries, which includes nearly half of them, characterized by a roughly oblate spheroid primary rotating rapidly and roughly triaxial ellipsoid secondary in on-average synchronous rotation. Thus KW4's dynamics generalize to any member of that class. Analytical formulae are developed which separately describe the effects of primary oblateness and secondary triaxial ellipsoid shape on frequencies of system motions revealed through the F2BP simulation. These formulae are useful for estimating inertia elements and highest-level internal mass distributions of bodies in any similar system, simply from standoff observation of these motion frequencies. Finally precise dynamical simulation and analysis of the motion of test particles within the time-varying gravity field of the F2BP system is detailed. This Restricted Full-detail Three-Body-Problem encompasses exploration of three types of particle motion within a binary asteroid: (1) Orbital motion such as that for a spacecraft flying within the system about the primary, secondary, or

  5. New Martian Trojans and an update on the Eureka cluster

    NASA Astrophysics Data System (ADS)

    Christou, A.; Vaduvescu, O.; Tudor, V.; Asher, D.; Toma, R.; Knapen, J.

    2014-07-01

    The number of known Trojan asteroids of Mars has recently increased twofold [1,2]. This has led to claims of a cluster [2] associated with the first Mars Trojan discovered, 5261 Eureka. The existence of an asteroid family so close to the Sun has implications for our understanding of asteroid evolution in general. Depending on the formation mechanism, studying these NEO-sized objects will provide insight on their collisional history and their long-term physical/dynamical evolution under the Yarkovsky and YORP effects [3]. Martian Trojans may also be an important control population for the study of the resetting of asteroid surfaces by planetary close encounters [4]. The clustering claim is based on an overall sample of 6 Trojans. To confirm it, we are presently carrying out an observational programme to (a) recover single-opposition Martian Trojan candidates and increase the sample size, and (b) improve the orbits of known Trojans. At the time of abstract submission, we have confirmed two additional asteroids as Martian Trojans. One was observed previously on multiple apparitions but not considered in [2]; the other is a recovery of a single-opposition object using the 2.5 m lsaac Newton Telescope (Isaac Newton Group, La Palma, Canary Islands). In addition, we have recovered 2011 UN63 using the 2 m Faulkes Telescope South in Siding Spring, Australia. This is a confirmed cluster member that had nevertheless been observed previously on only two apparitions. During the conference, we will present results for the two additional objects, in particular whether they are cluster members or not. Using the improved statistics and orbits, we will re-assess the significance of the clustering and discuss its origin.

  6. New Martian Trojans and an update on the Eureka cluster

    NASA Astrophysics Data System (ADS)

    Christou, A. A.; Vaduvescu, O.; Tudor, V.; Asher, D. J.; Toma, R.; Knapen, J.; Ponomareva, A. A.

    2014-04-01

    The number of known Trojan asteroids of Mars has recently increased twofold [1, 2]. This has led to claims of a cluster [2] associated with the first Mars Trojan discovered, 5261 Eureka. The existence of an asteroid family so close to the Sun has implications for our understanding of asteroid evolution in general. Depending on the formation mechanism, studying these objects will provide insight on their collisional history and their long-term physical & dynamical evolution under the Yarkovsky and YORP effects [3]. Martian Trojans are also a useful control population for the study of the resetting of asteroid surfaces by planetary close encounters [4]. The clustering claim is based on an overall sample of 6 Trojans. To confirm it, we are presently carrying out an observational programme to (a) recover singleopposition Martian Trojan candidates and increase the sample size, and (b) improve the orbits of known Trojans. At the time of abstract submission, we have con-firmed several additional asteroids as Martian Trojans, including a single-opposition object - 2011 SL25 - recovered early in 2014 using the 2.5m Isaac Newton Telescope (Isaac Newton Group, La Palma, Canary Islands; Fig. 1). We have also recovered 2011 UN63 using the 2m Faulkes Telescope South (Siding Spring, Australia), a confirmed cluster member that was nevertheless previously observed on only two apparitions. During the conference, we will present results for the additional objects, in particular whether they are cluster members or not. Using the improved statistics and orbits, we re-assess the different scenarios for the cluster's origin.

  7. Photometry of L4 Jovian Trojans and 279 Thule

    NASA Astrophysics Data System (ADS)

    French, Linda M.; Narayan, G.

    2008-09-01

    We present BVRI photometric observations of several L4 Trojan asteroids and of asteroid 279 Thule (located at the 4:3 orbital resonance with Jupiter). Observations were made using the 0.9-meter SMARTS telescope on Cerro Tololo near La Serena, Chile in May and October 2003. In addition to determining the rotation period and lightcurve amplitude, we chose targets passing through very low phase angles in the hope of investigating the phase curves of Trojan asteroids. Previous work (French 1987) showed that L5 Trojans 1173 Anchises and 2674 Pandarus (P and D spectral classifications, respectively) showed little or no opposition effect. Our results will be compared with previous work by other authors. Reference: French, L. M. 1987. Icarus 72, 325-341. GN's participation in this work was supported by a grant from the Research Corporation.

  8. THE ROLE OF KOZAI CYCLES IN NEAR-EARTH BINARY ASTEROIDS

    SciTech Connect

    Fang, Julia; Margot, Jean-Luc

    2012-03-15

    We investigate the Kozai mechanism in the context of near-Earth binaries and the Sun. The Kozai effect can lead to changes in eccentricity and inclination of the binary orbit, but it can be weakened or completely suppressed by other sources of pericenter precession, such as the oblateness of the primary body. Through numerical integrations including primary oblateness and three bodies (the two binary components and the Sun), we show that Kozai cycles cannot occur for the closely separated near-Earth binaries in our sample. We demonstrate that this is due to pericenter precession around the oblate primary, even for very small oblateness values. Since the majority of observed near-Earth binaries are not well separated, we predict that Kozai cycles do not play an important role in the orbital evolution of most near-Earth binaries. For a hypothetical wide binary modeled after 1998 ST27, the separation is large at 16 primary radii and so the orbital effects of primary oblateness are lessened. For this wide binary, we illustrate the possible excursions in eccentricity and inclination due to Kozai cycles as well as depict stable orientations for the binary's orbital plane. Unstable orientations lead to collisions between binary components, and we suggest that the Kozai effect acting in wide binaries may be a route to the formation of near-Earth contact binaries.

  9. Planetary migration effects on the formation of Neptune Trojans

    NASA Astrophysics Data System (ADS)

    Ma, Yuehua; Chen, Yuanyuan

    2016-07-01

    Trojan asteroids formation mechanisms are closely related to giant planet formation/migration. Using test particle simulations, we investigate the orbital element distributions of Neptune Trojans affected by the processes of planetary migration and the orbital damping of Uranus and Neptune. We examine the stability of primordial Neptune Trojans, objects that were initially Trojans with Neptune prior to migration, and also study Trans-Neptunian objects captured into resonance with Neptune and becoming Neptune Trojans during planet migration. We find that most primordial Neptune Trojans were unstable and lost if eccentricity and inclination damping took place during planetary migration. With damping, secular resonances with Neptune can increase a low eccentricity and inclination population of Trans-Neptunian objects increasing the probability that they are captured into 1:1 resonance with Neptune, becoming high inclination Neptune Trojans. We suggest that the resonant trapping scenario is a promising and more effective mechanism to explain the origin of Neptune Trojans if Uranus and Neptune had orbital damping during planetary migration.

  10. Spectroscopy and Photometry of Mars Trojans

    NASA Technical Reports Server (NTRS)

    Rivkin, A. S.; Binzel, R. P.; Howell, E. S.; Bus, S. J.; Grier, J. A.

    2003-01-01

    Mars is the only terrestrial planet known to have co-orbiting Trojan asteroids. We have obtained visible and near-IR reflectance spectra of three of these objects: 5261 Eureka and 1998 VF31 in the L5 region and 1999 UJ7 in the LA region. We also obtained JHK spectrophotometry and a visible lightcurve for 5261 Eureka. The asteroid 5261 Eureka has a visible spectrum that is classified as Sr in the Bus taxonomy, and has infrared colors consistent with the A-class asteroids. The data for 1998 VF31 have a restricted wavelength range, but are most consistent with the Sr or Sa class, though we note a marginal consistency with the D class. We can rule out a C-class classification. 1999 UJ7 has an X-class or T-class spectrum, which is unlike that of the other two Mars Trojans. The photometric data for Eureka are limited, but we can constrain the period to longer than 5 hours (likely 5.5-6 hours) and lightcurve amplitude of at least 0.15 magnitude at this viewing geometry. The spectral differences among the Mars Trojans suggests that either they did not all form at their present solar distances or that they have not always been at their present sizes.

  11. Arecibo and Goldstone Radar Observations of the First-Recognized Binary Near-Earth Asteroid: (385186) 1994 AW1

    NASA Astrophysics Data System (ADS)

    Richardson, James E.; Taylor, Patrick A.; Rivera-Valentin, Edgard G.; Rodriguez-Ford, Linda A.; Benner, Lance A. M.; Naidu, Shantanu P.; Giorgini, Jon D.; Busch, Michael W.; Ghigo, Frank d.; Kobelski, Adam; Warner, Brian D.; Springmann, Alessondra; Marshall, Sean E.; Steckloff, Jordan K.; Sharkey, Benjamin

    2015-11-01

    Near-Earth asteroid (385186) 1994 AW1 was discovered at Palomar Observatory on 11 January 1994. Subsequent observations of this Amor family, Sa-class asteroid also identified it as the first candidate binary NEA, as indicated by multiple periodicities and possible mutual eclipsing/occulting events in the object’s lightcurve. On 15 July 2015 this asteroid made its closest approach to Earth since its discovery, coming within 0.065 AU (25 lunar distances), and prompting an extended observation campaign using both the JPL-Goldstone and Arecibo Observatory planetary radars. Goldstone observations covered the 14-19 July period of closest approach (0.066-0.070 AU) while the object remained below Arecibo’s observing horizon, with Arecibo picking up the observations between 20-30 July, as the object moved from 0.075 to 0.126 AU distance. At Goldstone, we were able to observe this object with range resolutions of 150 m using a Goldstone (DSS-14) to Green Bank Telescope (GBT) bistatic configuration, while at Arecibo, we conducted monostatic observations of 1994 AW1 using the 2380 MHz (12.6 cm) radar at resolutions of 30 m and 75 m.As a result, and twenty years after its discovery, these observations have confirmed the binary nature of 1994 AW1, showing the primary body to be about 600 m in diameter, the secondary body to be about half the diameter of the primary, with the two orbiting a common center of mass at a distance of about 1.2 km apart. Delay-Doppler image comparisons of the primary over the course of six nights (at 30 m resolution) confirm a lightcurve-derived rotation period of 2.518 +/- 0.002 hr, as >90% longitude coverage was achieved, revealing a slightly elongated, irregular surface morphology. Delay-Doppler images of the secondary reveal an elongated, irregular body which appears to be tidally locked, with its long axis pointed towards the primary as it orbits with a period of about 22 hr (also consistent with the lightcurve analysis). These very early

  12. Sub-populations among the Jupiter Trojans

    NASA Astrophysics Data System (ADS)

    Wong, I.; Brown, M.

    2014-07-01

    The Jupiter Trojans are a significant population of minor bodies in the middle Solar System. Lying in a 1:1 mean-motion resonance with Jupiter and concentrated in two swarms centered about the L4 and L5 Lagrangian points, their peculiar location and dynamical properties place the Trojans at the intersection of several of the most important topics in planetary science. The origin and evolution of this population have been a subject of particular interest. While earlier theories proposed a scenario in which the Trojans formed at the same heliocentric distance as Jupiter, a recent theory, known as the Nice model, suggests a more complex picture in which the Trojan population originated in a region beyond the primordial orbit of Neptune. Through interactions with neighboring planetesimals, the gas giants underwent a rapid migration, setting off a period of chaotic dynamical alterations in the outer Solar System. It is hypothesized that during this time, the primordial transneptunian planetesimals were disrupted, and a fraction of them were scattered inwards and captured by Jupiter as Trojan asteroids, while the remaining objects were thrown outwards to larger heliocentric distances and eventually formed the Kuiper belt. If this is the case, a study of the nature of the Trojans may shed light on the relationships between the Trojans and other minor body populations in the outer Solar System, and more broadly, crucially constrain models of late Solar System evolution. Several past spectroscopic studies of Trojans have revealed notable bimodalities with respect to near-infrared spectra, infrared albedo, and color, which point toward the existence of two distinct groups among the Trojan population. In our work, we have carried out an analysis of the magnitude distributions of these two groups, which we refer to as the red and less-red color populations. By compiling spectral data from previous works and photometric data from the Sloan Digital Sky Survey, we show that the

  13. The Trojan. [supersonic transport

    NASA Technical Reports Server (NTRS)

    1992-01-01

    The Trojan is the culmination of thousands of engineering person-hours by the Cones of Silence Design Team. The goal was to design an economically and technologically viable supersonic transport. The Trojan is the embodiment of the latest engineering tools and technology necessary for such an advanced aircraft. The efficient design of the Trojan allows for supersonic cruise of Mach 2.0 for 5,200 nautical miles, carrying 250 passengers. The per aircraft price is placed at $200 million, making the Trojan a very realistic solution for tomorrows transportation needs. The following is a detailed study of the driving factors that determined the Trojan's super design.

  14. Photometric colors of the brightest members of the Jupiter L5 Trojan cloud

    NASA Astrophysics Data System (ADS)

    Chatelain, Joseph P.; Henry, Todd J.; French, Linda M.; Winters, Jennifer G.; Trilling, David E.

    2016-06-01

    The L5 Jupiter Trojan asteroids are minor bodies that orbit 60 degrees behind Jupiter. Because these orbits are stable over the lifetime of the Solar System, the properties of these objects may inform us about the conditions under which the Solar System formed. We present BVRKCIKC photometry for the 42 intrinsically brightest and presumably largest members of the L5 Jupiter Trojans. We define a new principal color component aT* that is indicative of taxonomic types relevant to the Jupiter Trojan asteroids. We find that 76% of the largest L5 Jupiter Trojans are consistent with a D-type classification, while 24% show shallower slopes more consistent with X-type and C-Type classifications. Such a breakdown is consistent with other surveys and will help to place the Trojans in the larger context of the Solar System.

  15. Probing surface properties of Jupiter Trojans by polarimetric observations

    NASA Astrophysics Data System (ADS)

    Belskaya, I.; Bagnulo, S.; Stinson, A.; Christou, A.; Muinonen, K.

    2014-07-01

    We present the first polarimetric observations of six Jupiter Trojans, namely (588) Achilles, (1583) Antilochus, (3548) Eurybates, (4543) Phoinix, (6545) 1986 TR_6, and (21601) 1998 XO_{89}. All these objects belong to the L4 population of Jupiter Trojans and have diameters in the range of 50-160 km (Grav et al. 2011). The observations were carried out in 2013 at ESO VLT. Each object was observed at 3-4 different phase angles in the phase-angle range from 7 deg up to 11-12 deg, the largest possible phase angles in the ground-based observations of Trojans. Observations were made in the R band with a typical accuracy of 0.05 %. We have measured negative polarization branch for each object with polarization minima varying from -1 % to -1.3 %. The polarization-phase-angle behavior of the observed Trojans is found to be very similar to that of some low-albedo main-belt asteroids, in particular, the P-type asteroids. We compare photometric and polarimetric phase dependencies of Trojans to the phase curves of inner and outer Solar System bodies. Possible relationships of phase-curve parameters with albedos and spectral properties are investigated. Constraints on the surface properties of Jupiter Trojans from the polarimetric observations are discussed.

  16. Trojans' Odyssey: Unveiling the early history of the Solar System

    NASA Astrophysics Data System (ADS)

    Lamy, Philippe; Vernazza, Pierre; Poncy, Joel; Martinot, Vincent; Hinglais, Emmanuel; Canalias, Elisabet; Bell, Jim; Cruikshank, Dale; Groussin, Olivier; Helbert, Joern; Marzari, Francesco; Morbidelli, Alessandro; Rosenblatt, Pascal; Sierks, Holger

    2012-04-01

    In our present understanding of the Solar System, small bodies (asteroids, Jupiter Trojans, comets and TNOs) are the most direct remnants of the original building blocks that formed the planets. Jupiter Trojan and Hilda asteroids are small primitive bodies located beyond the `snow line', around respectively the L4 and L5 Lagrange points of Jupiter at ˜5.2 AU (Trojans) and in the 2:3 mean-motion resonance with Jupiter near 3.9 AU (Hildas). They are at the crux of several outstanding and still conflicting issues regarding the formation and evolution of the Solar System. They hold the potential to unlock the answers to fundamental questions about planetary migration, the late heavy bombardment, the formation of the Jovian system, the origin and evolution of trans-neptunian objects, and the delivery of water and organics to the inner planets. The proposed Trojans' Odyssey mission is envisioned as a reconnaissance, multiple flyby mission aimed at visiting several objects, typically five Trojans and one Hilda. It will attempt exploring both large and small objects and sampling those with any known differences in photometric properties. The orbital strategy consists in a direct trajectory to one of the Trojan swarms. By carefully choosing the aphelion of the orbit (typically 5.3 AU), the trajectory will offer a long arc in the swarm thus maximizing the number of flybys. Initial gravity assists from Venus and Earth will help reducing the cruise time as well as the ΔV needed for injection thus offering enough capacity to navigate among Trojans. This solution further opens the unique possibility to flyby a Hilda asteroid when leaving the Trojan swarm. During the cruise phase, a Main Belt Asteroid could be targeted if requiring a modest ΔV. The specific science objectives of the mission will be best achieved with a payload that will perform high-resolution panchromatic and multispectral imaging, thermal-infrared imaging/ radiometry, near- and mid-infrared spectroscopy, and

  17. Binary Near-Earth Asteroid (285263) 1998 QE2: Goldstone and Arecibo Radar Imaging and Lightcurve Observations

    NASA Astrophysics Data System (ADS)

    Springmann, Alessondra; Brozović, M.; Pravec, P.; Taylor, P. A.; Howell, E. S.; Nolan, M. C.; Benner, L. M.; Busch, M. W.; Giorgini, J. D.; Magri, C.; Margot, J.; Naidu, S. P.; Shepard, M. K.; Marshall, S. E.; Law, M. C.; Galád, A.; Világi, J.; Gary, B. L.; Hicks, M. D.; Hills, K.; Pray, D. P.; Vodniza, A. Q.

    2013-10-01

    We observed near-Earth Amor asteroid 1998 QE2 with the Goldstone and Arecibo Observatory planetary radar systems, as well as with infrared and optical telescopes in the United States, Slovakia, Australia, and Colombia. Using radar, we observed the asteroid and its moon for 12 days in May and June of 2013 with a close approach of 0.039 AU to Earth on May 31, providing high signal-to-noise delay-Doppler radar images of the binary system. On June 4 we covered one full rotation of the primary (4.75 ± 0.01 hours) with 19 meter resolution delay-Doppler images. The imaging resolution varied with observing circumstances from 7.5-75 meters/pixel, with most of the observations made at 15-30 meters/pixel resolution. Radar images show a cratered primary 3 kilometers across with an elongated secondary about 600 meters in size. For the primary to have a discovery H magnitude of 16.4, it must be optically quite dark, with a geometric albedo of about 0.06 to be consistent with the diameter of the primary. Infrared spectra taken at the IRTF show QE2 as dark and reddened, perhaps primitive. The rotation period of 4.75 hours, photometrically derived, is one of the slowest known for a primary in any NEA binary system with a similar size ratio to that of QE2. The secondary appears to be in a synchronous, approximately circular orbit of approximately 32 hours with a semimajor axis of at least four primary radii. Features in the Goldstone images show evidence for an equatorial ridge, subtle in single radar frames but evident in animations. An optical lightcurve amplitude observed between 0.17 and 0.22 magnitudes confirms modest elongation of the primary as seen in radar images. Photometric observations detected seven mutual events; more data remains to be reduced and may cover more events. We will present more detailed information on the shape of the QE2 primary as well as the orbit of the secondary, and also additional surface properties from both the infrared and optical data.

  18. The Asteroid Impact Mission (AIM)

    NASA Astrophysics Data System (ADS)

    Küppers, M.; Carnelli, I.; Galvez, A.; Mellab, K.; Michel, P.; AIM Team

    2015-10-01

    The Asteroid Impact Mission (AIM) is ESA's contribution to an international cooperation targeting the demonstration of deflection of a hazardous nearearth asteroid as well as the first in-depth investigation of a binary asteroid. After launch in 2020, AIM will rendezvous the binary near-Earth asteroid (65803) Didymos in 2022 and observe the system before, during, and after the impact of NASA's Double Asteroid Redirection Test (DART) spacecraft. The AIM mission will test new technologies like optical telecommunications by laser and Cubesats with nano-payloads and will perform scientific measurements at the asteroid system.

  19. The Discovery of Binary Asteroid 5674 Wolff at Isaac Aznar Observatory

    NASA Astrophysics Data System (ADS)

    Aznar Macias, Amadeo; Pravec, Petr; Oey, Julian; Groom, Roger

    2016-07-01

    We report on the discovery that minor planet 5674 Wolff is a fully-synchronous binary system with an orbital period of 93.7 ± 0.2 h. The combined primary+secondary rotation amplitude is 0.52 ± 0.02 mag. A lower limit on the secondary-to-primary mean diameter ratio is D2/D1 = 0.80.

  20. Continued activity in P/2013 P5 PANSTARRS. Unexpected comet, rotational break-up, or rubbing binary asteroid?

    NASA Astrophysics Data System (ADS)

    Hainaut, O. R.; Boehnhardt, H.; Snodgrass, C.; Meech, K. J.; Deller, J.; Gillon, M.; Jehin, E.; Kuehrt, E.; Lowry, S. C.; Manfroid, J.; Micheli, M.; Mottola, S.; Opitom, C.; Vincent, J.-B.; Wainscoat, R.

    2014-03-01

    The object P/2013 P5 PANSTARRS was discovered in August 2013, displaying a cometary tail, but its orbital elements indicated that it was a typical member of the inner asteroid main belt. We monitored the object from 2013 August 30 until 2013 October 05 using the CFHT 3.6 m telescope (Mauna Kea, HI), the NTT (ESO, La Silla), the CA 1.23 m telescope (Calar Alto), the Perkins 1.8m (Lowell) and the 0.6 m TRAPPIST telescope (La Silla). We measured its nuclear radius to be r ≲ 0.25-0.29 km, and its colours g' - r' = 0.58 ± 0.05 and r' - i' = 0.23 ± 0.06, typical for an S-class asteroid, as expected for an object in the inner asteroid belt and in the vicinity of the Flora collisional family. We failed to detect any rotational light curve with an amplitude <0.05 mag and a double-peaked rotation period <20 h. The evolution of the tail during the observations was as expected from a dust tail. A detailed Finson-Probstein analysis of deep images acquired with the NTT in early September and with the CFHT in late September indicated that the object was active since at least late January 2013 until the time of the latest observations in 2013 September, with at least two peaks of activity around 2013 June 14 ± 10 d and 2013 July 22 ± 3 d. The changes of activity level and the activity peaks were extremely sharp and short, shorter than the temporal resolution of our observations (~1 d). The dust distribution was similar during these two events, with dust grains covering at least the 1-1000 μm range. The total mass ejected in grains <1 mm was estimated to be 3.0 × 106 kg and 2.6 × 107 kg around the two activity peaks. Rotational disruption cannot be ruled out as the cause of the dust ejection. We also propose that the components of a contact binary might gently rub and produce the observed emission. Volatile sublimation might also explain what appears as cometary activity over a period of 8 months. However, while main belt comets best explained by ice sublimation are found

  1. Evolutionary Pathways for Asteroid Satellites

    NASA Astrophysics Data System (ADS)

    Jacobson, Seth Andrew

    2015-08-01

    The YORP-induced rotational fission hypothesis is a proposed mechanism for the creation of small asteroid binaries, which make up approximately 1/6-th of the near-Earth asteroid and small Main Belt asteroid populations. The YORP effect is a radiative torque that rotationally accelerates asteroids on timescales of thousands to millions of years. As asteroids rotationally accelerate, centrifugal accelerations on material within the body can match gravitational accelerations holding that material in place. When this occurs, that material goes into orbit. Once in orbit that material coalesces into a companion that undergoes continued dynamical evolution.Observations with radar, photometric and direct imaging techniques reveal a diverse array of small asteroid satellites. These systems can be sorted into a number of morphologies according to size, multiplicity of members, dynamical orbit and spin states, and member shapes. For instance, singly synchronous binaries have short separation distances between the two members, rapidly rotating oblate primary members, and tidally locked prolate secondary members. Other confirmed binary morphologies include doubly synchronous, tight asynchronous and wide asynchronous binaries. Related to these binary morphologies are unbound paired asteroid systems and bi-lobate contact binaries.A critical test for the YORP-induced rotational fission hypothesis is whether the binary asteroids produced evolve to the observed binary and related systems. In this talk I will review how this evolution is believed to occur according to gravitational dynamics, mutual body tides and the binary YORP effect.

  2. The binary Kuiper-belt object 1998 WW31.

    PubMed

    Veillet, Christian; Parker, Joel Wm; Griffin, Ian; Marsden, Brian; Doressoundiram, Alain; Buie, Marc; Tholen, David J; Connelley, Michael; Holman, Matthew J

    2002-04-18

    The recent discovery of a binary asteroid during a spacecraft fly-by generated keen interest, because the orbital parameters of binaries can provide measures of the masses, and mutual eclipses could allow us to determine individual sizes and bulk densities. Several binary near-Earth, main-belt and Trojan asteroids have subsequently been discovered. The Kuiper belt-the region of space extending from Neptune (at 30 astronomical units) to well over 100 AU and believed to be the source of new short-period comets-has become a fascinating new window onto the formation of our Solar System since the first member object, not counting Pluto, was discovered in 1992 (ref. 13). Here we report that the Kuiper-belt object 1998 WW31 is binary with a highly eccentric orbit (eccentricity e approximately 0.8) and a long period (about 570 days), very different from the Pluto/Charon system, which was hitherto the only previously known binary in the Kuiper belt. Assuming a density in the range of 1 to 2 g cm-3, the albedo of the binary components is between 0.05 and 0.08, close to the value of 0.04 generally assumed for Kuiper-belt objects. PMID:11961547

  3. Asteroids IV

    NASA Astrophysics Data System (ADS)

    Michel, Patrick; DeMeo, Francesca E.; Bottke, William F.

    easy and pleasant as possible for the editors, authors, and referees. They also thank Richard Binzel, the General Editor of the Space Science Series, for his strong support and advice during this process, as well as the staff at the University of Arizona Press. Finally, editor Patrick Michel would like to thank his wife Delphine, who married him on June 14, 2013, almost at the birth of the book process. He is grateful that she was willing to put up with him as he spent many of his nights and weekends working on the book. Thanks to her support, their trajectories are as bounded as a perfectly stable asteroid binary system, and this was probably the best way to experience from the start what her life would be like with a researcher! Co-editor Bottke would also like to thank his wife Veronica and his children Kristina-Marie, Laura, and Julie, who make up his own favorite asteroid family. Since Asteroids III, the size distribution of the family members has been steadily changing, and who knows how many tiny new members it will contain by Asteroids V! Co-editor DeMeo would like to thank her husband Alfredo for his support and encouragement throughout the process of creating this book. They met at the beginning of her career in research, becoming an asteroid pair and now continuing on the same orbit in life.

  4. Asteroid structure

    NASA Astrophysics Data System (ADS)

    Asphaug, E.

    2014-07-01

    Even before the first space missions to asteroids, in the mid-1990s, it was known that asteroids have weird structures. Photometry indicated complicated shapes, and the pioneering radar investigations by Ostro and colleagues followed by adaptive optics campaigns and flybys showed odd binary forms, and confirmed the common presence of satellites, and indications of highly varying surface roughness. Some asteroids turned out to be dominated by a single major cratering event, while others showed no evidence of a major crater, or perhaps for global crater erasure. The first space mission to orbit an asteroid, NEAR, found a mixture of heavily cratered terrains and geomorphically active 'ponds', and indicated evidence for global seismicity from impact. The next mission to orbit an asteroid, Hayabusa, found what most agree is a rubble pile, with no major craters and an absence of fines. There is to date no direct evidence of asteroid interior geology, other than measurements of bulk density, and inferences made for mass distribution asymmetry based on dynamics, and inferences based on surface lineaments. Interpolating from the surface to the interior is always risky and usually wrong, but of course the answer is important since we are someday destined to require this knowledge in order to divert a hazardous asteroid from impact with the Earth. Even considering the near-subsurface, here we remain as ignorant as we were about the Moon in the early 1960s, whether the surface will swallow us up in dust, or will provide secure landing and anchoring points. Laboratory experimentation in close to zero-G is still in its early stages. Adventures such as mining and colonization will surely have to wait until we better know these things. How do we get from here to there? I will focus on 3 areas of progress: (1) asteroid cratering seismology, where we use the surface craters to understand what is going on inside; (2) numerical modeling of collisions, which predicts the internal

  5. Deployment of a lander on the binary asteroid (175706) 1996 FG3, potential target of the european MarcoPolo-R sample return mission

    NASA Astrophysics Data System (ADS)

    Tardivel, Simon; Michel, Patrick; Scheeres, Daniel J.

    2013-08-01

    The idea of deploying a lander on the secondary body of the binary primitive asteroid (175706) 1996 FG3 is investigated. 1996 FG3 is the backup target of the European sample return space mission MarcoPolo-R under assessment study at the European Space Agency in the framework of the M3 Medium-Class mission competition. The launch will take place in 2022-2024, depending on its selection at the end of 2013. A lander is indicated as an optional payload, depending on mass availability on the spacecraft. Obviously, the possible complexity of a lander deployment is also an important parameter to take into account. Here we demonstrate that, considering worst case scenarios and low requirements on the spacecraft GNC and deployment mechanism, the operations are easy to implement and safe for the main spacecraft. The concept of operations is to deploy a light lander from the L2 Lagrange point of the binary system, on a ballistic trajectory that will impact the secondary asteroid. The fundamental principles of this strategy are briefly presented and a detailed model of 1996 FG3 is considered, to which the strategy is applied. We show that the deployment is successful in 99.94% of cases.

  6. Trojan Horse particle invariance in fusion reactions

    NASA Astrophysics Data System (ADS)

    Pizzone, R. G.; Spitaleril, C.; Bertulani, C.; Mukhamedzhanov, A.; Blokhintsev, L.; La Cognata, M.; Lamia, L.; Spartá, R.; Tumino, A.

    2015-01-01

    Trojan Horse method plays an important part for the measurement of several charged particle induced reactions cross sections of astrophysical interest. In order to better understand its cornerstones and the related applications to different astrophysical scenarios several tests were performed to verify all its properties and the possible future perspectives. The Trojan Horse nucleus invariance for the binary reactions d(d,p)t, 6,7Li(p,α)3,4He was therefore tested using the appropriate quasi free break- ups, respectively. In the first cases results from 6Li and 3He break up were used, while for the lithium fusion reactions break-ups of 2H and 3He were compared. The astrophysical S(E)-factors for the different processes were then extracted in the framework of the PlaneWave Approximation applied to the different break-up schemes. The obtained results are compared with direct data as well as with previous indirect investigations. The very good agreement between data coming from different break-up schemes confirms the applicability of the plane wave approximation and suggests the independence of binary indirect cross section on the chosen Trojan Horse nucleus also for the present cases. Moreover the astrophysical implications of the results will also be discussed in details.

  7. Shape Shifting Satellites in Binary Near-Earth Asteroids: Do Meteoroid Impacts Play a Role in BYORP Orbital Evolution?

    NASA Technical Reports Server (NTRS)

    Rubincam, David Parry

    2012-01-01

    Less than catastrophic meteoroid impacts over 10(exp 5) years may change the shape of small rubble-pile satellites in binary NEAs, lengthening the average BYORP (binary Yarkovsky-Radzievskii-Paddack) rate of orbital evolution. An estimate of shape-shifting meteoroid fluxes give numbers close enough to causing random walks in the semimajor axis of binary systems to warrant further investigation

  8. Trojan Horse Particle Invariance: An Extensive Study

    NASA Astrophysics Data System (ADS)

    Pizzone, R. G.; Spitaleri, C.; Sergi, M. L.; Lamia, L.; Tumino, A.; Bertulani, C. A.; Blokhintsev, L.; Burjan, V.; Kroha, V.; La Cognata, M.; Mrazek, J.; Mukhamedzhanov, A. M.; Spartá, R.

    2014-08-01

    In the last decades, the Trojan Horse method (THM) has played a crucial role for the measurement of several particle (both neutron and charged one) induced cross sections for reactions of astrophysical interest. To better understand its cornerstones and its applications to physical cases, many tests were performed to verify all its properties and the possible future perspectives. The Trojan Horse nucleus invariance proves the relatively simple approach allowed by the pole approximation and sheds light in the involved reaction mechanisms. Here we shortly review the complete work for the binary 2H(d,p)3H, 6Li(d, α)4He, 6Li(p, α)3He, 7Li(p, α)4He reactions, by using the quasi free reactions after break-ups of different nuclides. Results are compared assuming the 6Li and 3He break-up in the case of the d(d,p)t, 6Li(d, α)4He reactions and considering the 2H and 3He break-up for 6Li(p, α)3He, 7Li(p, α)4He reactions. These results, regardless of the Trojan Horse particle or the break-up scheme, confirms the applicability of the standard description of the THM and suggests the independence of binary indirect cross section on the chosen Trojan Horse nuclei for a whole spectra of different cases. This gives a strong basis for the understanding of the quasi-free mechanism which is the foundation on which the THM lies.

  9. THE SIZE DISTRIBUTION OF THE NEPTUNE TROJANS AND THE MISSING INTERMEDIATE-SIZED PLANETESIMALS

    SciTech Connect

    Sheppard, Scott S.; Trujillo, Chadwick A.

    2010-11-10

    We present an ultra-deep survey for Neptune Trojans using the Subaru 8.2 m and Magellan 6.5 m telescopes. The survey reached a 50% detection efficiency in the R band at m{sub R} = 25.7 mag and covered 49 deg{sup 2} of sky. m{sub R} = 25.7 mag corresponds to Neptune Trojans that are about 16 km in radius (assuming an albedo of 0.05). A paucity of smaller Neptune Trojans (radii < 45 km) compared with larger ones was found. The brightest Neptune Trojans appear to follow a steep power-law slope (q = 5 {+-} 1) similar to the brightest objects in the other known stable reservoirs such as the Kuiper Belt, Jupiter Trojans, and main belt asteroids. We find a roll-over for the Neptune Trojans that occurs around a radius of r = 45 {+-} 10 km (m{sub R} = 23.5 {+-} 0.3), which is also very similar to the other stable reservoirs. All the observed stable regions in the solar system show evidence for Missing Intermediate-Sized Planetesimals (MISPs). This indicates a primordial and not collisional origin, which suggests that planetesimal formation proceeded directly from small to large objects. The scarcity of intermediate- and smaller-sized Neptune Trojans may limit them as being a strong source for the short period comets.

  10. Trojan Tour Enabled by Solar Electric Based Mission Architecture

    NASA Astrophysics Data System (ADS)

    Klaus, Kurt K.; Elsperman, M.; Smith, D. B.; Behrens, J.; Bingaman, G.; Horsewood, J.

    2012-10-01

    A Trojan Tour and Rendezvous mission was recommended by the most recent Planetary Science Decadal Survey. We utilize this concept as a basis for re-examining the feasibility of a Solar Electric Propulsion (SEP) mission using a Boeing bus and Advanced Modular Power System (AMPS) for solar power generation. The concept study for the Decadal survey concluded that a SEP mission is not viable because of low solar intensity levels. With the new AMPS Technology that involves a Solar Concentrator array, SEP missions to the outer planets become viable. The mission objective is 1143 Odysseus, a Trojan within the Trojan cloud, consistent with the Decadal Survey REP (Radioisotope Electric Propulsion) mission objective. The REP mission concept flight time was 8 years. Our cruise time is 6 years. The Trojan asteroid exploration spacecraft is based around our flight proven 702HP bus. The bus has been slightly modified for this mission. Two 30 kW FAST solar wings replace the 9 kW 6 panel solar wings. The AMPS array has a 12.5:1 concentration ratio. At Jupiter (5.2 AU), the AMPS array solar cells still see .46 suns, which is high enough that LILT effects are negligible. The science payload instruments, data rates, mass and power requirements are identical to the Trojan Decadal study. The AMPS Technology benefits from over $30M in development investment by DARPA and the AFRL. The investments focused on lightweight structures, advanced deployment systems, linear concentrator arrays, high voltage power systems, and high efficiency solar cells. Additional investment in a flight demonstration mission is needed to reach TRL 7. Utilizing the AMPS technology with the concentrator array, SEP becomes a viable alternative. SEP with the AMPS concentrator also provides efficient on-station maneuvering for science at the Trojan. We seek support for Technology Demonstration Mission through the NASA OCT.

  11. A large, long-lived structure near the trojan L5 point in the post common-envelope binary SDSS J1021+1744

    NASA Astrophysics Data System (ADS)

    Irawati, P.; Richichi, A.; Bours, M. C. P.; Marsh, T. R.; Sanguansak, N.; Chanthorn, K.; Hermes, J. J.; Hardy, L. K.; Parsons, S. G.; Dhillon, V. S.; Littlefair, S. P.

    2016-03-01

    SDSS J1021+1744 is a detached, eclipsing white dwarf/M dwarf binary discovered in the Sloan Digital Sky Survey (SDSS). Outside the primary eclipse, the light curves of such systems are usually smooth and characterized by low-level variations caused by tidal distortion and heating of the M star component. Early data on SDSS J1021+1744 obtained in 2012 June were unusual in showing a dip in flux of uncertain origin shortly after the white dwarf's eclipse. Here we present high-time resolution, multiwavelength observations of 35 more eclipses over 1.3 yr, showing that the dip has a lifetime extending over many orbits. Moreover the `dip' is in fact a series of dips that vary in depth, number and position, although they are always placed in the phase interval 1.06-1.26 after the white dwarf's eclipse, near the L5 point in this system. Since SDSS J1021+1744 is a detached binary, it follows that the dips are caused by the transit of the white dwarf by material around the Lagrangian L5 point. A possible interpretation is that they are the signatures of prominences, a phenomenon already known from H α observations of rapidly rotating single stars as well as binaries. What makes SDSS J1021+1744 peculiar is that the material is dense enough to block continuum light. The dips appear to have finally faded out around 2015 May after the first detection by Parsons et al. in 2012, suggesting a lifetime of years.

  12. Multiplicity in the Jupiter Trojan Population: Low density of 617 Patroclus with Keck LGS AO and Perspective

    NASA Astrophysics Data System (ADS)

    Marchis, F.; Hestroffer, D.; Descamps, P.; Berthier, J.; Bouchez, A. H.; Campbell, R. D.; Chin, J. C. Y.; van Dam, M. A.; Hartman, S. K.; Johnasson, E. M.; Lafon, R. E.; Le Mignant, D.; de Pater, I.; Stomski, P. J.; Summers, D. M.; Wizinovich, P. L.; Wong, M. H.

    2005-12-01

    The system 617 Patroclus, the only binary Trojan known, was discovered in 2001 with the Hokupa'a Gemini-8m AO system. Because of their faintness (magnitude in visible mv>15.5), Trojan asteroids cannot be directly observed by most of the AO systems. In 2004, a Laser Guide Star (LGS) AO system was offered on the Keck-10m. We initiated an observing campaign, recording direct images of the 617 Patroclus double system in broadband filters with the NIRC2 near-infrared camera. The orbital parameters of the system were estimated using two methods and by including additional Gemini archive data (2001-2002), we obtained a consistent and accurate solution. The two components, separated by 680±20 km, revolve around their center of mass in 4.289±0.004 days in a roughly circular orbit (e ˜0.02-0.02). Using the thermal measurements by Fernandez et al. (2003), we derive (with a beaming parameter η =0.94) a radius of R1= 60.9 km and R2= 56.3 km (with an error of 1.6 km and an Av= 0.04). Even considering the uncertainty in the volume of the components, the density of 617 Patroclus (ρ = 0.8±0.15 g/cm3) is extremely low, if compared with the bulk-density of known binary C-type main-belt asteroids (ρ 1.2 g/cm3, see Marchis et al., ACM, 2005). Assuming that the system is made of the same material as Ganymede or Callisto (uncompressed density of 1.6 g/cm3), the bulk density yields to a macro-porosity of ˜50%. A more realistic smaller porosity (p ˜15 different composition, such as more water ice in the interior of 617 Patroclus, suggesting a formation in the distant outer regions of the solar system (Morbidelli et al., Nature, 2005). The origin of this tightly bound system will be also discussed (Marchis et al., Nature, in press, 2005). We will present a quality comparison of the LGS Keck system with various techniques and different AO systems, discussing the interest of this technique to broaden the search for multiple asteroids in all minor planet populations. This work was

  13. Asteroid Lightcurve Analysis at Elephant Head Observatory: 2012 November - 2013 April

    NASA Astrophysics Data System (ADS)

    Alkema, Michael S.

    2013-07-01

    Thirteen asteroids were observed from Elephant Head Observatory from 2012 November to 2013 April: the main-belt asteroids 227 Philosophia, 331 Etheridgea, 577 Rhea, 644 Cosima, 850 Altona, 906 Repsolda, 964 Subamara, 973 Aralia, 1016 Anitra, 1024 Hale, 2034 Bernoulli, 2556 Louise, and Jupiter Trojan 3063 Makhaon.

  14. New Hamiltonian expansions adapted to the Trojan problem

    NASA Astrophysics Data System (ADS)

    Páez, Rocío Isabel; Locatelli, Ugo; Efthymiopoulos, Christos

    2016-07-01

    A number of studies, referring to the observed Trojan asteroids of various planets in our Solar System, or to hypothetical Trojan bodies in extrasolar planetary systems, have emphasized the importance of so-called secondary resonances in the problem of the long term stability of Trojan motions. Such resonances describe commensurabilities between the fast, synodic, and secular frequency of the Trojan body, and, possibly, additional slow frequencies produced by more than one perturbing bodies. The presence of secondary resonances sculpts the dynamical structure of the phase space. Hence, identifying their location is a relevant task for theoretical studies. In the present paper we combine the methods introduced in two recent papers (Páez and Efthymiopoulos in Celest Mech Dyn Astron 121(2):139, 2015; Páez and Locatelli in MNRAS 453(2):2177, 2015) in order to analytically predict the location of secondary resonances in the Trojan problem. In Páez and Efthymiopoulos (2015), the motion of a Trojan body was studied in the context of the planar Elliptic Restricted Three Body or the planar Restricted Multi-Planet Problem. It was shown that the Hamiltonian admits a generic decomposition H=H_b+H_{sec} . The term H_b , called the basic Hamiltonian, is a model of two degrees of freedom characterizing the short-period and synodic motions of a Trojan body. Also, it yields a constant `proper eccentricity' allowing to define a third secular frequency connected to the body's perihelion precession. H_{sec} contains all remaining secular perturbations due to the primary or to additional perturbing bodies. Here, we first investigate up to what extent the decomposition H=H_b+H_{sec} provides a meaningful model. To this end, we produce numerical examples of surfaces of section under H_b and compare with those of the full model. We also discuss how secular perturbations alter the dynamics under H_b . Secondly, we explore the normal form approach introduced in Páez and Locatelli (2015

  15. Asteroid Catalog Using Akari: AKARI/IRC Mid-Infrared Asteroid Survey

    NASA Astrophysics Data System (ADS)

    Usui, Fumihiko; Kuroda, Daisuke; Müller, Thomas G.; Hasegawa, Sunao; Ishiguro, Masateru; Ootsubo, Takafumi; Ishihara, Daisuke; Kataza, Hirokazu; Takita, Satoshi; Oyabu, Shinki; Ueno, Munetaka; Matsuhara, Hideo; Onaka, Takashi

    2011-10-01

    We present the results of an unbiased asteroid survey in the mid-infrared wavelength region with the Infrared Camera (IRC) on board the Japanese infrared satellite AKARI. About 20% of the point source events recorded in the AKARI All-Sky Survey observations are not used for the IRC Point Source Catalog (IRC-PSC) in its production process because of a lack of multiple detection by position. Asteroids, which are moving objects on the celestial sphere, remain in these ``residual events''. We identify asteroids out of the residual events by matching them with the positions of known asteroids. For the identified asteroids, we calculate the size and albedo based on the Standard Thermal Model. Finally we have a new brand of asteroid catalog, named the Asteroid Catalog Using AKARI (AcuA), which contains 5120 objects, about twice as many as the IRAS asteroid catalog. The catalog objects comprise 4953 main belt asteroids, 58 near-Earth asteroids, and 109 Jovian Trojan asteroids. The catalog is publicly available via the Internet.

  16. NEOWISE: The Physical and Dynamical Properties of the Cybele, Hilda and Jovian Trojan Populations

    NASA Astrophysics Data System (ADS)

    Grav, Tommy; Mainzer, Amy; Bauer, James; Masiero, Joseph; Nugent, Carolyn; Sonnett, Sarah; Cutri, Roc Michael; Kramer, Emily

    2015-08-01

    The solar-system portion of NASA’s Wide-field Infrared Survey Explorer (WISE) mission, known as NEOWISE, has collected more than 2 million observations of more than 160,000 asteroids (Wright et al. 2010; Mainzer et al. 2010, 2012, 2014). The dataset is by far the most comprehensive set of thermal observations of asteroids and comets to date and allows for an unprecedented opportunity to derive the true, de-biased size- and albedo-frequencies of the large primitive asteroids in our Solar System. The distribution of the primitive asteroids found in the Cybele, Hilda and Jovian Trojan population are key in understanding and testing the current theories of early solar system formation and evolution.NEOWISE provided observations of more than 1200 asteroids in the Cybele population, more than 1000 in the Hilda population, and more than 1700 Jovian Trojans (Grav et al. 2011, 2012a). Through thermal modeling and de-biasing of the observed population we derive the true size and albedo distributions for these populations down to 3, 6 and 10km for the Cybele, Hilda and Jovian Trojan populations, respectively. Through an innovative method of analysis of the reflective albedo in the shortest WISE band we are able to determine the taxonomic distribution of more than 100 of the largest objects in each population (Grav et al, 2012b). We will present updated and refined de-biased models for these three populations and discuss their relationship, origins and evolutions.

  17. Lightcurve Analysis of Asteroids from Blue Mountains Observatory in 2014

    NASA Astrophysics Data System (ADS)

    Oey, Julian

    2016-01-01

    Photometric observations of a number of asteroids were done from Blue Mountains Observatory in 2014. The observations were made in support of the binary asteroid and asteroid pairs campaigns by Petr Pravec, and to obtain new data at favorable apparitions for asteroids with poorly defined lightcurves.

  18. The Advanced Jovian Asteroid Explorer (AJAX)

    NASA Astrophysics Data System (ADS)

    Murchie, S. L.; Adams, E. Y.; Mustard, J. F.; Rivkin, A.; Peplowski, P. N.

    2015-12-01

    The Advanced Jovian Asteroid eXplorer (AJAX) is the first mission to characterize the geology, morphology, geophysical properties, and chemistry of a Trojan asteroid. The Decadal Survey outlined a notional New Frontiers class Trojan asteroid rendezvous mission to conduct geological, elemental composition, mineralogical, and geophysical investigations. AJAX, our Discovery mission proposal, addresses the Decadal Survey science goals by using a focused payload and an innovative mission design. By responding to the most important questions about the Trojan asteroids, AJAX advances our understanding of all of the Solar System. Are these objects a remnant population of the local primordial material from which the outer planets and their satellites formed, or did they originate in the Kuiper Belt? Landed measurements of major and minor elements test hypotheses for the Trojan asteroid origin, revealing the outer Solar System dynamical history. How and when were prebiotic materials delivered to the terrestrial planets? AJAX's landed measurements include C and H concentrations, necessary to determine their inventories of volatiles and organic compounds, material delivered to the inner Solar System during the Late Heavy Bombardment. What chemical and geological processes shaped the small bodies that merged to form the planets in our Solar System? AJAX investigates the asteroid internal structure, geology, and regolith by using global high-resolution stereo and multispectral imaging, determining density and estimating interior porosity by measuring gravity, and measuring regolith mechanical properties by landing. AJAX's science phase starts with search for natural satellites and dust lifted by possible cometary activity and shape and pole position determination. AJAX descends to lower altitudes for global mapping, and conducts a low flyover for high-resolution surface characterization and measurement of hydrogen abundance. Finally, it deploys a small landed package, which

  19. Trojans in habitable zones.

    PubMed

    Schwarz, Richard; Pilat-Lohinger, Elke; Dvorak, Rudolf; Erdi, Balint; Sándor, Zsolt

    2005-10-01

    With the aid of numerical experiments we examined the dynamical stability of fictitious terrestrial planets in 1:1 mean motion resonance with Jovian-like planets of extrasolar planetary systems. In our stability study of the so-called "Trojan" planets in the habitable zone, we used the restricted three-body problem with different mass ratios of the primary bodies. The application of the three-body problem showed that even massive Trojan planets can be stable in the 1:1 mean motion resonance. From the 117 extrasolar planetary systems only 11 systems were found with one giant planet in the habitable zone. Out of this sample set we chose four planetary systems--HD17051, HD27442, HD28185, and HD108874--for further investigation. To study the orbital behavior of the stable zone in the different systems, we used direct numerical computations (Lie Integration Method) that allowed us to determine the escape times and the maximum eccentricity of the fictitious "Trojan planets." PMID:16225431

  20. WISE/NEOWISE OBSERVATIONS OF THE JOVIAN TROJAN POPULATION: TAXONOMY

    SciTech Connect

    Grav, T.; Mainzer, A. K.; Bauer, J. M.; Masiero, J. R.; Nugent, C. R.

    2012-11-01

    We present updated/new thermal model fits for 478 Jovian Trojan asteroids observed with the Wide-field Infrared Survey Explorer (WISE). Using the fact that the two shortest bands used by WISE, centered on 3.4 and 4.6 {mu}m, are dominated by reflected light, we derive albedos of a significant fraction of these objects in these bands. While the visible albedos of both the C-, P-, and D-type asteroids are strikingly similar, the WISE data reveal that the albedo at 3.4 {mu}m is different between C-/P- and D-types. The albedo at 3.4 {mu}m can thus be used to classify the objects, with C-/P-types having values less than 10% and D-types have values larger than 10%. Classifying all objects larger than 50 km shows that the D-type objects dominate both the leading cloud (L {sub 4}), with a fraction of 84%, and trailing cloud (L {sub 5}), with a fraction of 71%-80%. The two clouds thus have very similar taxonomic distribution for these large objects, but the leading cloud has a larger number of these large objects, L {sub 4}/L {sub 5} = 1.34. The taxonomic distribution of the Jovian Trojans is found to be different from that of the large Hildas, which is dominated by C- and P-type objects. At smaller sizes, the fraction of D-type Hildas starts increasing, showing more similarities with the Jovian Trojans. If this similarity is confirmed through deeper surveys, it could hold important clues to the formation and evolution of the two populations. The Jovian Trojans does have similar taxonomic distribution to that of the Jovian irregular satellites, but lacks the ultra red surfaces found among the Saturnian irregular satellites and Centaur population.

  1. Rendezvous, Landing and Sample Return Mission to Jupiter Trojans by the Solar Power Sail

    NASA Astrophysics Data System (ADS)

    Yano, Hajime; Matsuura, Shuji; Mori, Osamu; Yonetoku, Daisuke; Nakamura, Ryosuke; Sekine, Yasuhito; Abe, Shinsuke

    JAXA/ISAS has been preparing for the Solar Power Sail mission, Japan’s first outer planet region exploration. Its precursor was successfully realized by IKAROS, the world's first deep space solar sail spacecraft, in 2010 between the Earth and Venus orbits. The Solar Power Sail is defined primarily as a technology demonstration mission; yet it will also present game-changing opportunities for both space astronomy and solar system exploration. The former will benefit the cruising operation, which will enable ”dust free” infrared astronomy beyond the cocoon of the zodiacal light to search for the first generation light of the Universe. Interplanetary-long baseline will allow gamma-ray burst observation to identify their source locations much more precise than ever. As for solar system exploration, the Solar Power Sail, which is not depended upon RTG technology, will offer the world's first possibility of rendezvous, landing and sample return from the outer planet region, i.e., in the Jupiter region and beyond. With this technology, we are aiming to visit Jupiter Trojan asteroids, one of the last uncharted frontiers of the Solar System. Jupiter Trojans may hold fundamental clues of the Solar System formation and revolution discussed by two competing hypotheses between the classic model and the planetary migration model. The former suggests that Trojan asteroids are mainly survivors of building blocks of the Jupiter system, while the latter claims that they must be intruders from outer regions after the planetary migration of gas planets settled. This paper outlines scientific objectives of Jupiter Trojan exploration, its mission design and major aspects of the spacecraft system, nature of candidate target asteroids, in-situ observation and lander instruments including optical camera, imaging spectrometer, high-resolution TOF mass spectrometer, and large-area dust counter, together with a strategy of the sample return option from the surface of a Trojan asteroid.

  2. Asteroid mining

    NASA Technical Reports Server (NTRS)

    Gertsch, Richard E.

    1992-01-01

    The earliest studies of asteroid mining proposed retrieving a main belt asteroid. Because of the very long travel times to the main asteroid belt, attention has shifted to the asteroids whose orbits bring them fairly close to the Earth. In these schemes, the asteroids would be bagged and then processed during the return trip, with the asteroid itself providing the reaction mass to propel the mission homeward. A mission to one of these near-Earth asteroids would be shorter, involve less weight, and require a somewhat lower change in velocity. Since these asteroids apparently contain a wide range of potentially useful materials, our study group considered only them. The topics covered include asteroid materials and properties, asteroid mission selection, manned versus automated missions, mining in zero gravity, and a conceptual mining method.

  3. Comet or Asteroid?

    NASA Astrophysics Data System (ADS)

    1997-11-01

    When is a minor object in the solar system a comet? And when is it an asteroid? Until recently, there was little doubt. Any object that was found to display a tail or appeared diffuse was a comet of ice and dust grains, and any that didn't, was an asteroid of solid rock. Moreover, comets normally move in rather elongated orbits, while most asteroids follow near-circular orbits close to the main plane of the solar system in which the major planets move. However, astronomers have recently discovered some `intermediate' objects which seem to possess properties that are typical for both categories. For instance, a strange object (P/1996 N2 - Elst-Pizarro) was found last year at ESO ( ESO Press Photo 36/96 ) which showed a cometary tail, while moving in a typical asteroidal orbit. At about the same time, American scientists found another (1996 PW) that moved in a very elongated comet-type orbit but was completely devoid of a tail. Now, a group of European scientists, by means of observations carried out at the ESO La Silla observatory, have found yet another object that at first appeared to be one more comet/asteroid example. However, continued and more detailed observations aimed at revealing its true nature have shown that it is most probably a comet . Consequently, it has received the provisional cometary designation P/1997 T3 . The Uppsala-DLR Trojan Survey Some time ago, Claes-Ingvar Lagerkvist (Astronomical Observatory, Uppsala, Sweden), in collaboration with Gerhard Hahn, Stefano Mottola, Magnus Lundström and Uri Carsenty (DLR, Institute of Planetary Exploration, Berlin, Germany), started to study the distribution of asteroids near Jupiter. They were particularly interested in those that move in orbits similar to that of Jupiter and which are located `ahead' of Jupiter in the so-called `Jovian L4 Lagrangian point'. Together with those `behind' Jupiter, these asteroids have been given the names of Greek and Trojan Heroes who participated in the famous Trojan war

  4. Asteroid team

    NASA Technical Reports Server (NTRS)

    Matson, D. L.

    1988-01-01

    The purpose of this task is to support asteroid research and the operation of an Asteroid Team within the Earth and Space Sciences Division at the Jet Propulsion Laboratory (JPL). The Asteroid Team carries out original research on asteroids in order to discover, better characterize and define asteroid properties. This information is needed for the planning and design of NASA asteroid flyby and rendezvous missions. The asteroid Team also provides scientific and technical advice to NASA and JPL on asteroid related programs. Work on asteroid classification continued and the discovery of two Earth-approaching M asteroids was published. In the asteroid photometry program researchers obtained N or Q photometry for more than 50 asteroids, including the two M-earth-crossers. Compositional analysis of infrared spectra (0.8 to 2.6 micrometer) of asteroids is continuing. Over the next year the work on asteroid classification and composition will continue with the analysis of the 60 reduced infrared spectra which we now have at hand. The radiometry program will continue with the reduction of the N and Q bandpass data for the 57 asteroids in order to obtain albedos and diameters. This year the emphasis will shift to IRAS follow-up observations; which includes objects not observed by IRAS and objects with poor or peculiar IRAS data. As in previous year, we plan to give top priority to any opportunities for observing near-Earth asteroids and the support (through radiometric lightcurve observations from the IRTF) of any stellar occultations by asteroids for which occultation observation expeditions are fielded. Support of preparing of IRAS data for publication and of D. Matson for his participation in the NASA Planetary Astronomy Management and Operations Working Group will continue.

  5. Trojan horse particle invariance studied with the {sup 6}Li(d,{alpha}){sup 4}He and {sup 7}Li(p,{alpha}){sup 4}He reactions

    SciTech Connect

    Pizzone, R. G.; Spitaleri, C.; Lamia, L.; Cherubini, S.; La Cognata, M.; Puglia, S. M. R.; Rapisarda, G. G.; Romano, S.; Sergi, M. L.; Bertulani, C.; Mukhamedzhanov, A.; Blokhintsev, L.; Burjan, V.; Hons, Z.; Kroha, V.; Mrazek, J.; Piskor, S.; Kiss, G. G.; Li, C.; Tumino, A.

    2011-04-15

    The Trojan horse nucleus invariance for the binary reaction cross section extracted from the Trojan horse reaction was tested using the quasifree {sup 3}He({sup 6}Li,{alpha}{alpha})H and {sup 3}He({sup 7}Li,{alpha}{alpha}){sup 2}H reactions. The cross sections for the {sup 6}Li(d,{alpha}){sup 4}He and {sup 7}Li(p,{alpha}){sup 4}He binary processes were extracted in the framework of the plane wave approximation. They are compared with direct behaviors as well as with cross sections extracted from previous indirect investigations of the same binary reactions using deuteron as the Trojan horse nucleus instead of {sup 3}He. The very good agreement confirms the applicability of the plane wave approximation which suggests the independence of the binary indirect cross section on the chosen Trojan horse nucleus, at least for the investigated cases.

  6. Trojan Horse Method: Recent Experiments

    SciTech Connect

    Cherubini, S.; Spitaleri, C.; Crucilla, V.; Gulino, M.; La Cognata, M.; Lamia, L.; Pizzone, R. G.; Romano, S.; Tudisco, S.; Tumino, A.; Mukhamedzhanov, A.; Trache, L.; Tribble, R.; Rolfs, C.; Typel, S.

    2006-07-12

    The Trojan Horse Method allows for the measurements of cross sections in nuclear reactions between charged particles at astrophysical energies. The basic features of the method are discussed and recent applications are presented.

  7. Sample return from asteroids --- Hayabusa2 and the next

    NASA Astrophysics Data System (ADS)

    Yoshikawa, M.; Kuninaka, H.; Inaba, N.; Tsuda, Y.; Watanabe, S.; Mori, O.; Yano, H.; Nakamura, R.; Kawaguchi, J.

    2014-07-01

    In 2006, a few years before the Earth return of Hayabusa, which is the first asteroid sample-return mission in the world, we started to consider the next asteroid sample-return mission, Hayabusa2. Hayabusa was a mission for engineering, but Hayabusa2 focuses also on the science. The scientific purpose of Hayabusa2 is to learn about the origin and evolution of the solar system, especially, the origin of water and organic matters. It is considered that C-type asteroids contain more organic matters and hydrated minerals than S-type asteroids like Itokawa. Therefore, the C-type asteroid (162173) 1999 JU_3 was selected as the target. From the technological point of view, the purpose of Hayabusa2 is to make a more reliable and robust system for sample-return exploration. The scale of the spacecraft is similar to Hayabusa, but many parts are modified so that we will not have to face the trouble that we experienced in Hayabusa. We will try new things, too. One of them is the impactor, which creates a small crater on the surface of the asteroid. Then, we can sample the sub-surface material as shown in the figure. We are now preparing the spacecraft for launch at the end of 2014. Hayabusa2 will arrive at the asteroid in June 2018. It will stay there for about one and half years. Then, it will leave the asteroid in December 2019, and will come back to the Earth in December 2020 [1]. We have already started to consider the next sample-return mission after Hayabusa2. In this future mission, the target asteroid is a Jupiter Trojan, which is a more primitive asteroid (D/P-type asteroid) than the S-type Itokawa and C-type 1999 JU_3. We use the solar-power-sail technique, which was demonstrated successfully by IKAROS. IKAROS means Interplanetary Kite-craft Accelerated by Radiation Of the Sun, and it was the first interplanetary solar sail in the world. The science purpose of this Jupiter Trojan mission is to study the various kinds of issues related to the planetary formation, such

  8. Trojan Tour and Rendezvous (TTR): A New Frontiers Mission to Explore the Origin and Evolution of the Early Solar System

    NASA Astrophysics Data System (ADS)

    Bell, J. F., III; Olkin, C.; Castillo, J. C.

    2015-12-01

    The orbital properties, compositions, and physical properties of the diverse populations of small outer solar system bodies provide a forensic map of how our solar system formed and evolved. Perhaps the most potentially diagnostic, but least explored, of those populations are the Jupiter Trojan asteroids, which orbit at ~5 AU in the L4 and L5 Lagrange points of Jupiter. More than 6200 Jupiter Trojans are presently known, but these are predicted to be only a small fraction of the 500,000 to 1 million Trojans >1 km in size. The Trojans are hypothesized to be either former Kuiper Belt Objects (KBOs) that were scattered into the inner solar system by early giant planet migration and then trapped in the 1:1 Jupiter mean motion resonance, or bodies formed near 5 AU in a much more quiescent early solar system, and then trapped at L4 and L5. The 2011 Planetary Science Decadal Survey identified important questions about the origin and evolution of the solar system that can be addressed by studying of the Trojan asteroids, including: (a) How did the giant planets and their satellite systems accrete, and is there evidence that they migrated to new orbital positions? (b) What is the relationship between large and small KBOs? Is the small population derived by impact disruption of the large one? (c) What kinds of surface evolution, radiation chemistry, and surface-atmosphere interactions occur on distant icy primitive bodies? And (d) What are the sources of asteroid groups (Trojans and Centaurs) that remain to be explored by spacecraft? The Trojan Tour and Rendezvous (TTR) is a New Frontiers-class mission designed to answer these questions, and to test hypotheses for early giant planet migration and solar system evolution. Via close flybys of a large number of these objects,, and orbital characterization of at least one large Trojan, TTR will enable the first-time exploration of this population. Our primary mission goals are to characterize the overall surface geology

  9. Capture of Asteroids and Transport of Asteroid Materials to Earth

    NASA Astrophysics Data System (ADS)

    Chiu, Hong-Yee; no Team

    2014-01-01

    Recently there has been much discussion on the capture of asteroids or mining the asteroids. While the technology might be years away, in this paper we will discuss an energy efficient method to transport either a small asteroid or materials gathered from asteroids to the Earth. In particular, I will concentrate on a large and nearby asteroid, 8 Flora in the Flora Family. Generally, asteroids are located between 2 to 3 AU (astronomical unit) from the Earth, and in transporting materials from asteroids to the Earth, an energy equivalent of the gravitational potential energy difference between the Earth and the asteroids to the Sun. This amount of potential energy is a sizable fraction of the orbital kinetic energy of the Earth around the Sun. This amount of energy is considerable. In this paper I propose to use the planet Mars as a medium to remove much of the gravitational energy difference. In the case of the asteroid 8 Flora, it is only necessary to decelerate the asteroid mate- rials by a small decrement, of the order of 3 km/sec. This decrement could even be achieved (pending on the availability of technology) by mechanical devices such as catapults on 8 Flora. It is also proposed to separate a pair of contact asteroid binaries by using impulse propulsion, and to propel one component of the separated asteroids to pass by Mars to be decelerated to reach the Earth orbit and captured by the Earth or the Moon. The plausibility of this ambitious project will be discussed. The author is NASA-GSFC Astrophysicist, Retired.

  10. Distortion Effects on Trojan Horse Applications

    NASA Astrophysics Data System (ADS)

    Pizzone, R. G.; Spitaleri, C.; Mukhamedzhanov, A. M.; Blokhintsev, L. D.; Bertulani, C. A.; Irgaziev, B. F.; La Cognata, M.; Lamia, L.; Romano, S.

    2011-05-01

    The widths of the spectator momentum distributions in several nuclei, which have been used as Trojan Horses, have been obtained as a function of the transferred momentum. Applications of Trojan Horse method will also be discussed.

  11. The Trojan Horse method for nuclear astrophysics: Recent results for direct reactions

    SciTech Connect

    Tumino, A.; Gulino, M.; Spitaleri, C.; Cherubini, S.; Romano, S.; Cognata, M. La; Pizzone, R. G.; Rapisarda, G. G.; Lamia, L.

    2014-05-09

    The Trojan Horse method is a powerful indirect technique to determine the astrophysical factor for binary rearrangement processes A+x→b+B at astrophysical energies by measuring the cross section for the Trojan Horse (TH) reaction A+a→B+b+s in quasi free kinematics. The Trojan Horse Method has been successfully applied to many reactions of astrophysical interest, both direct and resonant. In this paper, we will focus on direct sub-processes. The theory of the THM for direct binary reactions will be shortly presented based on a few-body approach that takes into account the off-energy-shell effects and initial and final state interactions. Examples of recent results will be presented to demonstrate how THM works experimentally.

  12. The Trojan Horse method for nuclear astrophysics: Recent results for direct reactions

    NASA Astrophysics Data System (ADS)

    Tumino, A.; Spitaleri, C.; Cherubini, S.; Gulino, M.; La Cognata, M.; Lamia, L.; Pizzone, R. G.; Rapisarda, G. G.; Romano, S.

    2014-05-01

    The Trojan Horse method is a powerful indirect technique to determine the astrophysical factor for binary rearrangement processes A+x→b+B at astrophysical energies by measuring the cross section for the Trojan Horse (TH) reaction A+a→B+b+s in quasi free kinematics. The Trojan Horse Method has been successfully applied to many reactions of astrophysical interest, both direct and resonant. In this paper, we will focus on direct sub-processes. The theory of the THM for direct binary reactions will be shortly presented based on a few-body approach that takes into account the off-energy-shell effects and initial and final state interactions. Examples of recent results will be presented to demonstrate how THM works experimentally.

  13. Trojan horse particle invariance: The impact on nuclear astrophysics

    NASA Astrophysics Data System (ADS)

    Pizzone, R. G.; Spitaleri, C.; Bertulani, C. A.; Mukhamedzhanov, A. M.; Blokhintsev, L. D.; La Cognata, M.; Lamia, L.; Spartá, R.; Tumino, A.

    2014-05-01

    In the current picture of nuclear astrophysics indirect methods and, in particular, the Trojan Horse Method cover a crucial role for the measurement of charged particle induced reactions cross sections of astrophysical interest, in the energy range required by the astrophysical scenarios. To better understand its cornerstones and its applications to physical cases many tests were performed to verify all its properties and the possible future perspectives. The key to the method is the quasi-free break-up and some of its properties will be investigated in the present work. In particular, the Trojan Horse nucleus invariance will be studied and previous studies will be extended to the cases of the binary d(d, p)t and 6Li(d,α)4He reactions, which were tested using different quasi-free break-up's, namely 6Li and 3He. The astrophysical S(E)-factor were then extracted with the Trojan Horse formalism applied to the two different break-up schemes and compared with direct data as well as with previous indirect investigations. The very good agreement confirms the independence of binary indirect cross section on the chosen spectator particle also for these reactions.

  14. Trojan horse particle invariance: The impact on nuclear astrophysics

    SciTech Connect

    Pizzone, R. G.; La Cognata, M.; Spitaleri, C.; Bertulani, C. A.; Mukhamedzhanov, A. M.; Blokhintsev, L. D.; Lamia, L.; Spartá, R.; Tumino, A.

    2014-05-02

    In the current picture of nuclear astrophysics indirect methods and, in particular, the Trojan Horse Method cover a crucial role for the measurement of charged particle induced reactions cross sections of astrophysical interest, in the energy range required by the astrophysical scenarios. To better understand its cornerstones and its applications to physical cases many tests were performed to verify all its properties and the possible future perspectives. The key to the method is the quasi-free break-up and some of its properties will be investigated in the present work. In particular, the Trojan Horse nucleus invariance will be studied and previous studies will be extended to the cases of the binary d(d, p)t and {sup 6}Li(d,α){sup 4}He reactions, which were tested using different quasi-free break-up's, namely {sup 6}Li and {sup 3}He. The astrophysical S(E)-factor were then extracted with the Trojan Horse formalism applied to the two different break-up schemes and compared with direct data as well as with previous indirect investigations. The very good agreement confirms the independence of binary indirect cross section on the chosen spectator particle also for these reactions.

  15. Giga-year evolution of Jupiter Trojans and the asymmetry problem

    NASA Astrophysics Data System (ADS)

    Di Sisto, Romina P.; Ramos, Ximena S.; Beaugé, Cristián

    2014-11-01

    We present a series of numerical integrations of observed and fictitious Jupiter Trojan asteroids, under the gravitational effects of the four outer planets, for time-spans comparable with the age of the Solar System. From these results we calculate the escape rate from each Lagrange point, and construct dynamical maps of "permanence" time in different regions of the phase space. Fictitious asteroids in L4 and L5 show no significant difference, showing almost identical dynamical maps and escape rates. For real Trojans, however, we found that approximately 23% of the members of the leading swarm escaped after 4.5 Gyrs, while this number increased to 28.3% for L5 . This implies that the asymmetry between the two populations increases with time, indicating that it may have been smaller at the time of formation/capture of these asteroids. Nevertheless, the difference in chaotic diffusion cannot, in itself, account for the current observed asymmetry (∼40%), and must be primarily primordial and characteristic of the capture mechanism of the Trojans. Finally, we calculate new proper elements for all the numbered Trojans using the semi-analytical approach of Beaugé and Roig (Beaugé, C., Roig, F.V. [2001]. Icarus, 153, 391-415), and compare the results with the numerical estimations by Brož and Rosehnal (Brož, M., Rosehnal, J. [2011]. Mon. Not. R. Astron. Soc. 414, 565-574). For asteroids that were already numbered in 2011, both methods yield very similar results, while significant differences were found for those bodies that became numbered after 2011.

  16. The Asteroid Impact Mission

    NASA Astrophysics Data System (ADS)

    Carnelli, Ian; Galvez, Andres; Mellab, Karim

    2016-04-01

    The Asteroid Impact Mission (AIM) is a small and innovative mission of opportunity, currently under study at ESA, intending to demonstrate new technologies for future deep-space missions while addressing planetary defense objectives and performing for the first time detailed investigations of a binary asteroid system. It leverages on a unique opportunity provided by asteroid 65803 Didymos, set for an Earth close-encounter in October 2022, to achieve a fast mission return in only two years after launch in October/November 2020. AIM is also ESA's contribution to an international cooperation between ESA and NASA called Asteroid Impact Deflection Assessment (AIDA), consisting of two mission elements: the NASA Double Asteroid Redirection Test (DART) mission and the AIM rendezvous spacecraft. The primary goals of AIDA are to test our ability to perform a spacecraft impact on a near-Earth asteroid and to measure and characterize the deflection caused by the impact. The two mission components of AIDA, DART and AIM, are each independently valuable but when combined they provide a greatly increased scientific return. The DART hypervelocity impact on the secondary asteroid will alter the binary orbit period, which will also be measured by means of lightcurves observations from Earth-based telescopes. AIM instead will perform before and after detailed characterization shedding light on the dependence of the momentum transfer on the asteroid's bulk density, porosity, surface and internal properties. AIM will gather data describing the fragmentation and restructuring processes as well as the ejection of material, and relate them to parameters that can only be available from ground-based observations. Collisional events are of great importance in the formation and evolution of planetary systems, own Solar System and planetary rings. The AIDA scenario will provide a unique opportunity to observe a collision event directly in space, and simultaneously from ground-based optical and

  17. Visual and near-IR spectrophotometry of asteroids

    NASA Technical Reports Server (NTRS)

    Lebofsky, Larry A.

    1991-01-01

    We have been continuing our studies of the spectral properties of dark asteroids in the solar system. From these studies we expect to learn about the distribution of volatile materials, such as water in clay materials (water of hydration) and how the asteroids may relate to the comets. Our most recent work has been concentrating on simultaneous visual and near infrared photometry near Earth, main belt, and trojan asteroids. We have made observations of some unusual asteroids such as Chiron, which has recently shown cometary activity, and 944 Hidalgo, which has a comet-like orbit. We have also begun studies of the small, dark satellites of Mars and Jupiter in order to understand better how they may relate to the steroids. Could they actually be captured asteroids or comets?

  18. AIDA: The Asteroid Impact & Deflection Assessment Mission

    NASA Astrophysics Data System (ADS)

    Galvez, A.; Carnelli, I.; Michel, P.; Cheng, A. F.; Reed, C.; Ulamec, S.; Biele, J.; Abell, P.; Landis, R.

    2013-09-01

    The Asteroid Impact and Deflection Assessment (AIDA) mission, a joint effort of ESA, JHU/APL, NASA, OCA, and DLR, is the first demonstration of asteroid deflection and assessment via kinetic impact. AIDA consists of two independent but mutually supporting mission elements, one of which is the asteroid kinetic impactor and the other is the characterization spacecraft. These two missions are, respectively, JHU/APL's Double Asteroid Redirection Test (DART) and the European Space Agency's Asteroid Investigation Mission (AIM) missions. As in the separate DART and AIM studies, the target of this mission is the binary asteroid [65803] Didymos in October, 2022. For a successful joint mission, one spacecraft, DART, would impact the secondary of the Didymos system while AIM would observe and measure any change in the relative orbit. AIM will be the first probe to characterise a binary asteroid, especially from the dynamical point of view, but also considering its interior and subsurface composition. The mission concept focuses on the monitoring aspects i.e., the capability to determine in-situ the key physical properties of a binary asteroid playing a role in the system's dynamic behavior. DART will be the first ever space mission to deflect the trajectory of an asteroid in a measurable way.- It is expected that the deflection can be measured as a change in the relative orbit period with a precision better than 10%. The joint AIDA mission will return vital data to determine the momentum transfer efficiency of the kinetic impact [1,2].

  19. AIDA: Asteroid Impact & Deflection Assessment

    NASA Astrophysics Data System (ADS)

    Cheng, A. F.; Galvez, A.; Carnelli, I.; Michel, P.; Rivkin, A.; Reed, C.

    2012-12-01

    To protect the Earth from a hazardous asteroid impact, various mitigation methods have been proposed, including deflection of the asteroid by a spacecraft impact. AIDA, consisting of two mission elements, the Double Asteroid Redirection Test (DART) and the Asteroid Impact Monitoring (AIM) mission, is a demonstration of asteroid deflection. To date, there has been no such demonstration, and there is major uncertainty in the result of a spacecraft impact onto an asteroid, that is, the amount of deflection produced by a given momentum input from the impact. This uncertainty is in part due to unknown physical properties of the asteroid surface, such as porosity and strength, and in part due to poorly understood impact physics such that the momentum carried off by ejecta is highly uncertain. A first mission to demonstrate asteroid deflection would not only be a major step towards gaining the capability to mitigate an asteroid hazard, but in addition it would return unique information on an asteroid's strength, other surface properties, and internal structure. This information return would be highly relevant to future human exploration of asteroids. We report initial results of the AIDA joint mission concept study undertaken by the Johns Hopkins Applied Physics Laboratory and ESA with support from NASA centers including Goddard, Johnson and Jet Propulsion Laboratory. For AIDA, the DART spacecraft impactor study is coordinated with an ESA study of the AIM mission, which would rendezvous with the same asteroid to measure effects of the impact. Unlike the previous Don Quijote mission study performed by ESA in 2005-2007, DART envisions an impactor spacecraft to intercept the secondary member of a binary near-Earth asteroid. DART includes ground-based observations to measure the deflection independently of the rendezvous spacecraft observations from AIM, which also measures deflection and provides detailed characterization of the target asteroid. The joint mission AIDA

  20. Trojan search at ESO.

    NASA Astrophysics Data System (ADS)

    Elst, E. W.

    1988-09-01

    Doing minor planet research is sometimes considered a proof of bad taste among astronomers. It is a fact that asteroids, these rocky pieces between the orbits of Mars and Jupiter, have lost much of their interest, now that most of the larger ones have been catalogued: their orbits are weil known, their chemical structure has been studied and their rotation properties investigated. Hence, chasing the smaller kilometer-sized members does not seem a useful occupation. Indeed, why should they be different from the larger ones?

  1. A Trojan Horse in Birmingham

    ERIC Educational Resources Information Center

    Yarker, Patrick

    2014-01-01

    "Trojan Horse" has become journalistic shorthand for an apparent attempt by a small group in East Birmingham to secure control of local non-faith schools and impose policies and practices in keeping with the very conservative (Salafist and Wahhabi) version of Islam which they hold. In this article, Pat Yarker gives an account of two…

  2. The asteroid lightcurve database

    NASA Astrophysics Data System (ADS)

    Warner, Brian D.; Harris, Alan W.; Pravec, Petr

    2009-07-01

    The compilation of a central database for asteroid lightcurve data, i.e., rotation rate and amplitude along with ancillary information such as diameter and albedo (known or estimated), taxonomic class, etc., has been important to statistical studies for several decades. Having such a compilation saves the researcher hours of effort combing through any number of journals, some obvious and some not, to check on prior research. Harris has been compiling such data in the Asteroid Lightcurve Database (LCDB) for more than 25 years with Warner and Pravec assisting the past several years. The main data included in the LCDB are lightcurve rotation periods and amplitudes, color indices, H-G parameters, diameters (actual or derived), basic binary asteroid parameters, and spin axis and shape models. As time permits we are reviewing existing entries to enter data not previously recorded ( e.g., phase angle data). As of 2008 December, data for 3741 asteroids based on more than 10650 separate detail records derived from entries in various journals were included in the LCDB. Of those 3741 asteroids, approximately 3100 have data of sufficient quality for statistical analysis, including 7 that have "dual citizenship" - meaning that they have (or had) asteroid designations as well comet designations. Here we present a discussion of the nature of LCDB data, i.e., which values are actually measured and which are derived. For derived data, we give our justification for specific values. We also present some analysis based on the LCDB data, including new default albedo ( p) and phase slope parameter ( G) values for the primary taxonomic classes and a review of the frequency-diameter distribution of all asteroids as well as some selected subsets. The most recent version of data used in this analysis is available for download from the Collaborative Asteroid Lightcurve Link (CALL) site at http://www.MinorPlanetObserver.com/astlc/default.htm. Other data sets, some only subsets of the full

  3. Asteroid Impact & Deflection Assessment mission: Kinetic impactor

    NASA Astrophysics Data System (ADS)

    Cheng, A. F.; Michel, P.; Jutzi, M.; Rivkin, A. S.; Stickle, A.; Barnouin, O.; Ernst, C.; Atchison, J.; Pravec, P.; Richardson, D. C.

    2016-02-01

    The Asteroid Impact & Deflection Assessment (AIDA) mission will be the first space experiment to demonstrate asteroid impact hazard mitigation by using a kinetic impactor to deflect an asteroid. AIDA is an international cooperation, consisting of two mission elements: the NASA Double Asteroid Redirection Test (DART) mission and the ESA Asteroid Impact Mission (AIM) rendezvous mission. The primary goals of AIDA are (i) to test our ability to perform a spacecraft impact on a potentially hazardous near-Earth asteroid and (ii) to measure and characterize the deflection caused by the impact. The AIDA target will be the binary near-Earth asteroid (65803) Didymos, with the deflection experiment to occur in late September, 2022. The DART impact on the secondary member of the binary at ~7 km/s is expected to alter the binary orbit period by about 4 minutes, assuming a simple transfer of momentum to the target, and this period change will be measured by Earth-based observatories. The AIM spacecraft will characterize the asteroid target and monitor results of the impact in situ at Didymos. The DART mission is a full-scale kinetic impact to deflect a 150 m diameter asteroid, with known impactor conditions and with target physical properties characterized by the AIM mission. Predictions for the momentum transfer efficiency of kinetic impacts are given for several possible target types of different porosities, using Housen and Holsapple (2011) crater scaling model for impact ejecta mass and velocity distributions. Results are compared to numerical simulation results using the Smoothed Particle Hydrodynamics code of Jutzi and Michel (2014) with good agreement. The model also predicts that the ejecta from the DART impact may make Didymos into an active asteroid, forming an ejecta coma that may be observable from Earth-based telescopes. The measurements from AIDA of the momentum transfer from the DART impact, the crater size and morphology, and the evolution of an ejecta coma will

  4. Investigation of asteroids in Pulkovo Observatory

    NASA Astrophysics Data System (ADS)

    Devyatkin, A.; Gorshanov, D.; L'vov, V.; Tsekmeister, S.; Petrova, S.; Martyusheva, A.; Slesarenko, V.; Naumov, K.; Sokova, I.; Sokov, E.; Zinoviev, S.; Karashevich, S.; Ivanov, A.; Lyashenko, A.; Rusov, S.; Kouprianov, V.; Bashakova, E.; Melnikov, A.

    2015-08-01

    Observational Astrometry Laboratory and Ephemeris Provision Sector of Pulkovo Observatory carry out a joint multipurpose research on asteroids belonging to various groups. Astrometric and photometric observations are done using ZA-320M and MTM-500M telescopes located at Pulkovo and in Northern Caucasus mountains, correspondingly. We obtain lightcurves that allow us to determine spin parameters and shapes of asteroids. Their color indices and taxonomy classes are derived from wideband filter observations. Improvement of asteroid orbits is achieved by doing positional measurements. Orbital evolution of asteroids is modelled, taking into account also non-gravity forces, including light pressure and Yarkovsky effect. NEAs, as well as binary asteroids, take an important place in our investigations. Quasi-satellites of Venus, Earth, and Mars are new targets of our research, one of the examples being 2012DA14 that approached Earth in early 2013; many MTM-500M observations of this asteroid were obtained around the date of approach.

  5. Asteroid Motions

    NASA Astrophysics Data System (ADS)

    Sykes, Mary V.; Moynihan, P. Daniel

    1996-12-01

    Equations are derived which describe the apparent motion of an asteroid traveling on an elliptical orbit in geocentric ecliptic coordinates. At opposition, the equations are identical to those derived by Bowellet al. (Bowell, E., B. Skiff, and L. Wasserman 1990. InAsteroids, Comets, Meteors III(C.-I. Lagerkvist, M. Rickman, B. A. Lindblad, and M. Lindgren, Eds.), pp. 19-24. Uppsala Universitet, Uppsala, Sweden). These equations can be an important component in the optimization of search strategies for specific asteroid populations based on their apparent motions relative to other populations when observed away from opposition.

  6. Asteroid taxonomy

    NASA Technical Reports Server (NTRS)

    Tholen, David J.; Barucci, M. Antonietta

    1989-01-01

    The spectral reflectivity of asteroid surfaces over the wavelength range of 0.3 to 1.1 micron can be used to classify these objects into several broad groups with similar spectral characteristics. The three most recently developed taxonomies group the asteroids into 9, 11, or 14 different clases, depending on the technique used to perform the analysis. The distribution of the taxonomic classes shows that darker and redder objects become more dominant at larger heliocentric distances, while the rare asteroid types are found more frequently among the small objects of the planet-crossing population.

  7. Long-Term Evolution of Neptune Trojans

    NASA Astrophysics Data System (ADS)

    Tello, E.; Di Sisto, R. P.; Brunini, A.

    2015-10-01

    Neptune Trojans are objects that share the orbit with the planet Neptune and are in a neighborhood of the Lagrangian points L4 and L5 located 60({°) } "front" and 60({°) } "behind" the planet in its orbit. So far, there have been nine Neptune Trojans discovered. However stability studies indicate that this population should be large. In this work we report the results of numerical simulations of the evolution of fictitious Neptune Trojans, to detect stability and instability areas and also to study the escape of Trojans over the age of the Solar System.

  8. Asteroid resources

    NASA Technical Reports Server (NTRS)

    Lewis, John S.

    1992-01-01

    There are three types of possible asteroidal materials that appear to be attractive for exploitation: (1) volatiles, (2) free metals, and (3) bulk dirt. Because some of the near-Earth asteroids are energetically more accessible than the Moon (require a round-trip total change in velocity less than 9 km/sec, though the trip time would be measured in years not days), such an asteroid might be chosen as the source of any useful material, even if that material was also available on the Moon. Provided that the asteroid was minable, it might therefore be chosen as the source of bulk dirt needed for shielding in low Earth orbit (LEO) or elsewhere in near-Earth space. And the near-Earth asteroids may offer materials that are rare or absent on the surface of the Moon. The relationship between asteroids and meteorites is discussed. A brief overview of the entire range of meteorite compositions, with emphasis on the occurrence of interesting resources is presented. Focus is on materials useful in space, especially volatiles, metals, and raw dirt. Those few materials that may have sufficiently high market value to be worth returning to Earth will be mentioned.

  9. Composition and Degree of Alteration of Dark Asteroids

    NASA Astrophysics Data System (ADS)

    McAdam, Margaret; Sunshine, J. M.; Kelley, M. S.

    2013-10-01

    Spectral classification schemes of asteroids are typically based on visible and near-infrared measurements made from both Earth- and space-based observatories. Some asteroids have spectral features that readily indicate their composition and can be used to relate them to laboratory spectral measurements of meteorites. However, asteroids with characteristically low visible light albedos (e.g. C- and B- types) have few features, if any, in this wavelength region. The absence of strong spectral features makes the determination of surface composition and the connection to meteorite groups difficult. In CM/CI group meteorites, a strong mid-infrared feature at 10-12 μm (1000-800 cm-1) has been found to correlate with composition and degree of alteration (McAdam et al., LPSC, 2013). A similar feature, but weaker in strength, has also been found in the spectra of some dark asteroids. Seven asteroids from the Themis family and Cybele group (C-types) have spectral features that are consistent with iron-rich clays indicating a low degree of alteration. Three Trojan asteroids (D-types) studied do not exhibit this feature, which may suggest a different origin for these bodies. We present the preliminary results from a survey of dark asteroids using archived data from mid-infrared space telescopes. The 10-12-µm (1000-800 cm-1) feature is used to characterize the surface composition of dark asteroids in the context of the alteration trends seen in meteorites.

  10. Studies on solar system dynamics. I - The stability of Saturnian Trojans

    NASA Astrophysics Data System (ADS)

    Innanen, K. A.; Mikkola, S.

    1989-03-01

    Numerical N-body integrations show that there may exist stable 1-1 resonance orbits of minor planets for each of the outer planets from Jupiter to Neptune. In Jupiter's case, these are the Trojan asteroids. Such orbits show no sign of instability, for at least ten million yr. For Saturn, the existence of such orbits is surprising because of the periodic proximity of Jupiter. This case was studied in some detail, and evidence was found of the importance of resonances in the stability of the Saturnian triangular Lagrangian points. The results of the numerical study are discussed, including the possibilities for constructing an analytic theory and what phenomena must be included in the treatment of the problem. The possibilities of observational confirmation of the conclusions are also considered. There is preliminary evidence for similar stability for the Trojan analogs of some of the inner planets.

  11. Finding 'paydirt' on the moon and asteroids

    NASA Technical Reports Server (NTRS)

    Staehle, R. L.

    1983-01-01

    Lunar polar region water ice, the Trojan asteroids of the earth, accessible, volatile substance-rich near-earth asteroids, and lunar gas deposits, are theoretically identified extraterrestrial resources for application to space transportation whose existence and economical exploitability could be confirmed by explorations conducted with relatively simple spacecraft. Any of these resources could improve the economics of interorbit transportation, thereby permitting launch vehicle payloads to be devoted to the transport of revenue-generating or services-providing equipment, rather than to the large propellant volumes required for the placing of large payloads on station. Among the verification missions cited is a simple lunar prospector orbiter, carrying a gamma-ray spectrometer and an electromagnetic sounder, which could ascertain the presence of water ice at the lunar poles.

  12. CHAOTIC CAPTURE OF NEPTUNE TROJANS

    SciTech Connect

    Nesvorny, David; Vokrouhlicky, David

    2009-06-15

    Neptune Trojans (NTs) are swarms of outer solar system objects that lead/trail planet Neptune during its revolutions around the Sun. Observations indicate that NTs form a thick cloud of objects with a population perhaps {approx}10 times more numerous than that of Jupiter Trojans and orbital inclinations reaching {approx}25 deg. The high inclinations of NTs are indicative of capture instead of in situ formation. Here we study a model in which NTs were captured by Neptune during planetary migration when secondary resonances associated with the mean-motion commensurabilities between Uranus and Neptune swept over Neptune's Lagrangian points. This process, known as chaotic capture, is similar to that previously proposed to explain the origin of Jupiter's Trojans. We show that chaotic capture of planetesimals from an {approx}35 Earth-mass planetesimal disk can produce a population of NTs that is at least comparable in number to that inferred from current observations. The large orbital inclinations of NTs are a natural outcome of chaotic capture. To obtain the {approx}4:1 ratio between high- and low-inclination populations suggested by observations, planetary migration into a dynamically excited planetesimal disk may be required. The required stirring could have been induced by Pluto-sized and larger objects that have formed in the disk.

  13. Debris about asteroids: Where and how much?

    NASA Technical Reports Server (NTRS)

    Burns, Joseph A.; Hamilton, Douglas P.

    1992-01-01

    We summarize several recent findings on the size and shape of the region within which material can stably orbit an asteroid. If the asteroid (with assumed density 2.38 g/cu cm) circles the Sun at 2.55 AU, co-planar prograde material will remain trapped whenever started on unperturbed circular orbits at less than about 220 R(sub A) (asteroid radii); co-planar retrograde particles are stable out twice as far. Our 3-D stability surface, which encloses several hundred numerically calculated orbits that start with various inclinations, is shaped like a sphere with its top and bottom sliced off; its dimensions scale like the Hill radius =(mu/3)(exp 1/3)R, where mu is the asteroid-to-solar mass ratio and R is the asteroid's orbital radius. If the asteroid moves along an elliptical orbit, a fairly reliable indicator of the dimensions of the hazard zone is the size of its Hill sphere at the orbit's pericenter. Grains with radii less than a few mm will be lost through the action of radiation forces which can induce escape or cause collisions with the asteroid on times scales of a few years; interplanetary micrometeoroids produce collisional break-up of these particles in approximately 10(exp 4) yrs. The effects of Jupiter and of asteroids that pass close to the target asteroid allow particles to diffuse from the system, again shrinking the hazard zone. None of the considered sources-primordial formation, debris spalled off the asteroid during micrometeoroid impact, captured interplanetary particles, feeder satellites, etc., seem capable of densely populating distant orbits from the asteroid. No certain detections of debris clouds or of binary asteroids have been made. Thus, it seems highly unlikely that a spacecraft fly-by targeted at 100 R(sub A) from the asteroid over its orbital pole would encounter any material.

  14. 5-14 μm Spitzer spectra of Themis family asteroids

    NASA Astrophysics Data System (ADS)

    Licandro, J.; Hargrove, K.; Kelley, M.; Campins, H.; Ziffer, J.; Alí-Lagoa, V.; Fernández, Y.; Rivkin, A.

    2012-01-01

    Context. The Themis collisional family is one of the largest and best established families in the main belt. Composed of primitive asteroids, there is evidence that water is likely present in a large fraction of its members, either in aqueously altered silicates or in water ice reservoirs. The study of the abundance of water in the outer asteroid belt is important as it may be linked to the origin of Earth's water. Studying the Themis family can also help to constrain the compositional and thermal environment in the region of the solar nebula where these asteroids formed. Aims: Our aim is to constrain the composition and thermal properties of the surfaces of several Themis family asteroids. Methods: We present 5-14 μm spectra of 8 Themis family asteroids observed with Spitzer: (222) Lucia, (223) Rosa, (316) Goberta, (383) Janina, (468) Lina, (492) Gismonda, (515) Athalia, and (526) Jena. We determine their diameters, geometric albedos and beaming parameters using the near-Earth asteroid thermal model. Their emissivity spectra are studied in order to determine if they exhibit an emission plateau from 9 to 12 μm which has been observed in other primitive asteroids and attributed to fine-grained silicates (the Si-O stretch fundamental). Results: The derived mean albedo of our sample of Themis family asteroids is bar pV = 0.07 ± 0.02 = 0.07 ± 0.02, and the mean beaming parameter is bar η = 1.05 ± 0.10. The derived bar η value is close to unity, which implies that the infrared beaming is not significant, there is likely little night-side emission from the asteroids, and the thermal inertia is probably low. The emissivity spectra of at least 5 of our 8 asteroids show a 9-12 μm emission plateau with spectral contrast of 2-4%, similar but smaller than that observed in the spectra of Trojan asteroids and cometary dust. The plateau may be due to the surfaces having either small silicate grains embedded in a relatively transparent matrix, or from a very under

  15. Asteroid researches in ASPIN/ISON project

    NASA Astrophysics Data System (ADS)

    Molotov, Igor; Schildknecht, Thomas; Inasaridze, Raguli; Elenin, Leonid; Krugly, Yurij; Rumyantsev, Vasilij; Namkhai, Tungalag; Schmalz, Sergei; Reva, Inna

    2016-07-01

    International Scientific Optical Network (ISON) represents one of largest systems specializing in observation of space objects. The main goal of project is observations of space debris. As an additional task the regular research of asteroids are carried out under ASPIN (Asteroid Search and Photometry Initiative) project. ASPIN is working in three main directions - search of new asteroids and comets with two 40-cm telescopes at New-Mexico (USA) and Siding Spring (Australia), follow up of new NEAs with 40-cm telescope at Khuraltogot (Mongolia) and research of physical properties of asteroids using photometry lightcurves of these celestial bodies. In 2015 it was obtained 278726 measurements and discovered 79 new objects including 7 NEAs (1 PHA) and 2 comets - P/2015 PD229 (ISON-Cameron) and C/2015 X4 (Elenin). Results of follow up observations were included in 68 MPC circulars. 5 campaigns of photometry observations were arranged with participation of 16 telescopes. It were obtained 320 lightcurves for 80 asteroids (including 69 NEAs) - 16 recently discovered objects, 2 Mars-crossers and 14 main-belt asteroids. It was measured or updated rotation periods of 20 NEAs including 9 small objects (˜300 m). 10 asteroids were observed under program of searching of the binary systems. 13 NEAs were observed in support of radar experiments. (1620) Geographos and 138852 (2000 WN10) asteroids were observed to investigated YORP-effect. The obtained results will be presented and perspectives of asteroid researches with ISON telescopes will be discussed.

  16. Asteroids IV

    NASA Astrophysics Data System (ADS)

    Michel, Patrick; DeMeo, Francesca E.; Bottke, William F.

    Asteroids are fascinating worlds. Considered the building blocks of our planets, many of the authors of this book have devoted their scientific careers to exploring them with the tools of our trade: ground- and spacebased observations, in situ space missions, and studies that run the gamut from theoretical modeling efforts to laboratory work. Like fossils for paleontologists, or DNA for geneticists, they allow us to construct a veritable time machine and provide us with tantalizing glimpses of the earliest nature of our solar system. By investigating them, we can probe what our home system was like before life or even the planets existed. The origin and evolution of life on our planet is also intertwined with asteroids in a different way. It is believed that impacts on the primordial Earth may have delivered the basic components for life, with biology favoring attributes that could more easily survive the aftermath of such energetic events. In this fashion, asteroids may have banished many probable avenues for life to relative obscurity. Similarly, they may have also prevented our biosphere from becoming more complex until more recent eras. The full tale of asteroid impacts on the history of our world, and how human life managed to emerge from myriad possibilities, has yet to be fully told. The hazard posed by asteroid impacts to our civilization is low but singular. The design of efficient mitigation strategies strongly relies on asteroid detection by our ground- and spacebased surveys as well as knowledge of their physical properties. A more positive motivation for asteroid discovery is that the proximity of some asteroids to Earth may allow future astronauts to harvest their water and rare mineral resources for use in exploration. A key goal of asteroid science is therefore to learn how humans and robotic probes can interact with asteroids (and extract their materials) in an efficient way. We expect that these adventures may be commonplace in the future

  17. Planetary geology: Impact processes on asteroids

    NASA Technical Reports Server (NTRS)

    Chapman, C. R.; Davis, D. R.; Greenberg, R.; Weidenschilling, S. J.

    1982-01-01

    The fundamental geological and geophysical properties of asteroids were studied by theoretical and simulation studies of their collisional evolution. Numerical simulations incorporating realistic physical models were developed to study the collisional evolution of hypothetical asteroid populations over the age of the solar system. Ideas and models are constrained by the observed distributions of sizes, shapes, and spin rates in the asteroid belt, by properties of Hirayama families, and by experimental studies of cratering and collisional phenomena. It is suggested that many asteroids are gravitationally-bound "rubble piles.' Those that rotate rapidly may have nonspherical quasi-equilibrium shapes, such as ellipsoids or binaries. Through comparison of models with astronomical data, physical properties of these asteroids (including bulk density) are determined, and physical processes that have operated in the solar system in primordial and subsequent epochs are studied.

  18. Olivine Composition of the Mars Trojan 5261 Eureka: Spitzer IRS Data

    NASA Technical Reports Server (NTRS)

    Lim, L. F.; Burt, B. J.; Emery, J. P.; Mueller, M.; Rivkin, A. S.; Trilling, D.

    2011-01-01

    The largest Mars trojan, 5261 Eureka, is one of two prototype "Sa" asteroids in the Bus-Demeo taxonomy. Analysis of its visible/near-IR spectrum led to the conclusion that it might represent either an angritic analog or an olivine-rich composition such as an R chondrite. Spitzer IRS data (5-30 micrometers) have enabled us to resolve this ambiguity. The thermal-IR spectrum exhibits strong olivine reststrahlen features consistent with a composition of approximately equals Fo60-70. Laboratory spectra of R chondrites, brachinites, and chassignites are dominated by similar features.

  19. International CJMT-1 Workshop on Asteroidal Science

    NASA Astrophysics Data System (ADS)

    Ip, Wing-Huen

    2014-03-01

    An international workshop on asteroidal science was held between October 16 and 17, 2012, at the Macau University of Science and Technology gathering together experts on asteroidal study in China, Japan, Macao and Taiwan. For this reason, we have called it CJMT-1 Workshop. Though small in sizes, the asteroids orbiting mainly between the orbit of Mars and of Jupiter have important influence on the evolution of the planetary bodies. Topics ranging from killer asteroids to space resources are frequently mentioned in news reports with prominence similar to the search for water on Mars. This also means that the study of asteroids is very useful in exciting the imagination and interest in science of the general public. Several Asian countries have therefore developed long-term programs integrating ground-based observations and space exploration with Japan being the most advanced and ambitious as demonstrated by the very successful Hayabusa mission to asteroid 25143 Itokawa. In this volume we will find descriptions of the mission planning of Hayabusa II to the C-type near-Earth asteroid, 1999 JU3. Not to be outdone, China's Chang-E 2 spacecraft was re-routed to a flyby encounter with asteroid 4179 Toutatis in December 2012. It is planned that in the next CJMT workshop, we will have the opportunity to learn more about the in-depth data analysis of the Toutatis observations and the progress reports on the Hayabusa II mission which launch date is set to be July 2014. Last but not least, the presentations on the ground-based facilities as described in this volume will pave the way for coordinated observations of asteroidal families and Trojan asteroids - across Asia from Taiwan to Uzbekistan. Such international projects will serve as an important symbol of good will and peaceful cooperation among the key members of this group. Finally, I want to thank the Space Science Institute, Macao University of Science and Technology, for generous support, and its staff members

  20. Trojan Horse Method: Recent Results

    SciTech Connect

    Pizzone, R. G.; Spitaleri, C.

    2008-01-24

    Owing the presence of the Coulomb barrier at astrophysically relevant kinetic energies, it is very difficult, or sometimes impossible to measure astrophysical reaction rates in laboratory. This is why different indirect techniques are being used along with direct measurements. The THM is unique indirect technique allowing one measure astrophysical rearrangement reactions down to astrophysical relevant energies. The basic principle and a review of the main application of the Trojan Horse Method are presented. The applications aiming at the extraction of the bare S{sub b}(E) astrophysical factor and electron screening potentials U{sub e} for several two body processes are discussed.

  1. Trojan Horse particle invariance for 2H(d,p)3H reaction: a detailed study

    NASA Astrophysics Data System (ADS)

    Pizzone, R. G.; Spitaleri, C.; Bertulani, C. A.; Mukhamedzhanov, A. M.; Blokhintsev, L.; La Cognata, M.; Lamia, L.; Rinollo, A.; Spartá, R.; Tumino, A.

    2014-03-01

    In the last decades the Trojan Horse method has played a crucial role for the measurement of several charged particle induced reactions cross sections of astrophysical interest. To better understand its cornerstones and its applications to physical cases many tests were performed to verify all its properties and the possible future perspectives. The Trojan Horse nucleus invariance for the binary d(d,p)t reaction was therefore tested using the quasi free 2H(6Li, pt)4He and 2H(3He,pt)H reactions after 6Li and 3He break-up, respectively. The astrophysical S(E)-factor for the d(d,p)t binary process was then extracted in the framework of the Plane Wave Approximation applied to the two different break-up schemes. The obtained results are compared with direct data as well as with previous indirect investigations. The very good agreement confirms the applicability of the plane wave approximation and suggests the independence of binary indirect cross section on the chosen Trojan Horse nucleus also for the present case.

  2. Asteroid Sample Return Missions of Japan : Past, Present, and Future

    NASA Astrophysics Data System (ADS)

    Yoshikawa, Makoto

    In Japan, sample return mission from asteroids is regarded as one of the most important space missions for both science and engineering. Therefore, we had done Hayabusa mission, which is the first asteroid sample return mission in the world. The second asteroid sample return mission Hayabusa2 is now preparing and it will be launched soon. Hayabusa and Hayabusa2 are very challenging missions, but a much more challenging mission is now under consideration. That is a sample return mission from a Jupiter Trojan asteroid by a solar power sail. In this paper, we report the current status of these three missions. Hayabusa was launched in May 2003, arrived at its target asteroid (25143) Itokawa in September 2005, and came back to the Earth in June 2010. After seven-year space trip, Hayabusa was successful to bring back the surface material of Itokawa, although the amount of the sample was much less than that was expected. We constructed the curation facility in JAXA Sagamihara Campus, and we have picked up about 400 particles from the sample catcher up to now. In 2012 and 2013, we had two international AOs (Announcement of Opportunity) of Itokawa particles, and we distributed the samples to about 30 research groups all over the world. Many results of the sample analysis have already been reported and the analyses are still going on. From a few years before the earth return of Hayabusa, we started considering the next asteroid sample return mission, Hayabusa2. Hayabusa was a mission for engineering, but Hayabusa2 focuses also on the science. The scientific purpose of Hayabusa2 is to know the origin and evolution of the solar system, especially the origin of water and organic matters. It is considered that C-type asteroids contain more organic matters and hydrated minerals than S-type asteroids like Itokawa. Therefore, C-type asteroid (162173) 1999 JU3 was selected as the target. From the technological point of view, the purpose of Hayabusa2 is to make more reliable and

  3. The Asteroid Impact and Deflection Assessment Mission and its Potential Contributions to Human Exploration of Asteroids

    NASA Technical Reports Server (NTRS)

    Abell, Paul A.; Rivkin, Andy S.

    2014-01-01

    The joint ESA and NASA Asteroid Impact and Deflection Assessment (AIDA) mission will directly address aspects of NASA's Asteroid Initiative and will contribute to future human exploration. The NASA Asteroid Initiative is comprised of two major components: the Grand Challenge and the Asteroid Mission. The first component, the Grand Challenge, focuses on protecting Earth's population from asteroid impacts by detecting potentially hazardous objects with enough warning time to either prevent them from impacting the planet, or to implement civil defense procedures. The Asteroid Mission, involves sending astronauts to study and sample a near-Earth asteroid (NEA) prior to conducting exploration missions of the Martian system, which includes Phobos and Deimos. AIDA's primary objective is to demonstrate a kinetic impact deflection and characterize the binary NEA Didymos. The science and technical data obtained from AIDA will aid in the planning of future human exploration missions to NEAs and other small bodies. The dual robotic missions of AIDA, ESA's Asteroid Impact Monitor (AIM) and NASA's Double Asteroid Redirection Test (DART), will provide a great deal of technical and engineering data on spacecraft operations for future human space exploration while conducting in-depth scientific examinations of the binary target Didymos both prior to and after the kinetic impact demonstration. The knowledge gained from this mission will help identify asteroidal physical properties in order to maximize operational efficiency and reduce mission risk for future small body missions. The AIDA data will help fill crucial strategic knowledge gaps concerning asteroid physical characteristics that are relevant for human exploration considerations at similar small body destinations.

  4. Speckle interferometry applied to asteroids and other solar system objects

    NASA Technical Reports Server (NTRS)

    Drummond, J. D.; Hege, E. K.

    1985-01-01

    The application of speckle interferometry to asteroids and other solar system objects is discussed. The assumption of a triaxial ellipsoid rotating about its shortest axis is the standard model. Binary asteroids, 433 Eros, 532 Herculina, 511 Davida, and Pallas are discussed.

  5. Optical Spectroscopy of Unbound Asteroid Pairs

    NASA Astrophysics Data System (ADS)

    Duddy, Samuel; Lowry, S. C.; Christou, A.; Wolters, S. D.; Snodgrass, C.; Fitzsimmons, A.; Deller, J. F.; Hainaut, O. R.; Rozitis, B.; Weissman, P. R.; Green, S. F.

    2012-10-01

    The recently discovered unbound asteroid pairs have been suggested to be the result of the decoupling of binary asteroids formed either through collision processes or, more likely, rotational fission of a rubble-pile asteroid after spin-up (Vokrouhlicky et al. 2008, AJ 136, 280; Pravec et al., 2010, Nature, 466, 1085). Much of the evidence for linkage of the asteroids in each pair relies solely on the backwards integrations of their orbits. We report new results from our continuing spectroscopic survey of the unbound asteroid pairs, including the youngest known pair, (6070) Rhineland - (54827) 2001 NQ8. The survey goal is to determine whether the asteroids in each unbound pair have similar spectra and therefore composition, expected if they have formed from a common parent body. Low-resolution spectroscopy covering the range 0.4-0.95 microns was conducted using the 3.6m ESO NTT+EFOSC2 during 2011-2012 and the 4.2m WHT+ACAM. We have attempted to maintain a high level of consistency between the observations of the components in each pair to ensure that differences in the asteroid spectra are not the result of the observing method or data reduction, but purely caused by compositional differences. Our WHT data indicates that the asteroids of unbound pair 17198 - 229056 exhibit different spectra and have been assigned different taxonomies, A and R respectively. Initial analysis of our data from the NTT suggests that the asteroids in unbound pairs 6070 - 54827 and 38707 - 32957 are likely silicate-dominated asteroids. The components of pair 23998 - 205383 are potentially X-type asteroids. We present final taxonomic classifications and the likelihood of spectral similarity in each pair.

  6. Distortion effects in Trojan Horse applications

    SciTech Connect

    Pizzone, R. G.; La Cognata, M.; Lamia, L.; Mukhamedzhanov, A. M.; Blokhintsev, L. D.; Irgaziev, B.; Bertulani, C. A.; Spitaleri, C.

    2012-11-20

    Deuteron induced quasi-free scattering and reactions have been extensively investigated in the past few decades. This was done not only for nuclear structure and processes study but also for the important astrophysical implication (Trojan Horse Method, THM). In particular the width of the neutron momentum distribution in deuteron will be studied as a function of the transferred momentum. The same will be done for other nuclides of possible use as Trojan Horse particles. Trojan horse method applications will also be discussed because the momentum distribution of the spectator particle inside the Trojan horse nucleus is a necessary input for this method. The impact of the width (FWHM) variation on the extraction of the astrophysical S(E)-factor is discussed.

  7. Updated evidence of the Trojan horse particle invariance for the 2H(d,p)3H reaction

    NASA Astrophysics Data System (ADS)

    Pizzone, R. G.; Spitaleri, C.; Bertulani, C. A.; Mukhamedzhanov, A. M.; Blokhintsev, L.; La Cognata, M.; Lamia, L.; Rinollo, A.; Spartá, R.; Tumino, A.

    2013-02-01

    The Trojan horse nucleus invariance for the binary d(d,p)t reaction was tested by means of an experiment using the quasifree 2H(6Li,pt)4He and 2H(3He,pt)H reactions after 6Li and 3He breakup, respectively. The astrophysical S(E) factor for the d(d,p)t binary process was extracted from the present data in the framework of the plane wave approximation applied to the two different breakup schemes. The obtained results are compared with direct data as well as with previous indirect investigations. The very good agreement confirms the applicability of the plane wave approximation and suggests the independence of the binary indirect cross section on the chosen Trojan horse nucleus also for the present case.

  8. Dexamethasone acetate encapsulation into Trojan particles.

    PubMed

    Gómez-Gaete, Carolina; Fattal, Elias; Silva, Lídia; Besnard, Madeleine; Tsapis, Nicolas

    2008-05-22

    We have combined the therapeutic potential of nanoparticles systems with the ease of manipulation of microparticles by developing a hybrid vector named Trojan particles. We aim to use this new delivery vehicle for intravitreal administration of dexamethasone. Initialy, dexamethasone acetate (DXA) encapsulation into biodegradable poly(d,l-lactide-co-glycolide) (PLGA) nanoparticles was optimized. Then, Trojan particles were formulated by spray drying 1,2-Dipalmitoyl-sn-Glycero-3-Phosphocholine (DPPC), hyaluronic acid (HA) and different concentrations of nanoparticle suspensions. The effect of nanoparticles concentration on Trojan particle physical characteristics was investigated as well as the effect of the spray drying process on nanoparticles size. Finally, DXA in vitro release from nanoparticles and Trojan particles was evaluated under sink condition. SEM and confocal microscopy show that most of Trojan particles are spherical, hollow and possess an irregular surface due to the presence of nanoparticles. Neither Trojan particle tap density nor size distribution are significantly modified as a function of nanoparticles concentration. The mean nanoparticles size increase significantly after spray drying. Finally, the in vitro release of DXA shows that the excipient matrix provides protection to encapsulated nanoparticles by slowing drug release. PMID:18374442

  9. AIDA: Asteroid Impact and Deflection Assessment

    NASA Astrophysics Data System (ADS)

    Michel, Patrick; Cheng, A.; Galvez, A.; Reed, C.; Carnelli, I.; Abell, P.; Ulamec, S.; Rivkin, A.; Biele, J.; Murdoch, N.

    2015-03-01

    AIDA (Asteroid Impact and Deflection Assessment) is a project of a joint mission demonstration of asteroid deflection and characterisation of the kinetic impact effects. It involves the Johns Hopkins Applied Physics Laboratory (with support from members of NASA centers including Goddard Space Flight Center, Johnson Space Center, and the Jet Propulsion Laboratory), and the European Space Agency (with support from members of the french CNRS/Cte dAzur Observatory and the german DLR). This assessment will be done using a binary asteroid target. AIDA consists of two independent but mutually supporting mission concepts, one of which is the asteroid kinetic impactor and the other is the characterisation spacecraft. The objective and status of the project will be presented.

  10. Visible and infrared investigations of planet-crossing asteroids and outer solar system objects

    NASA Technical Reports Server (NTRS)

    Tholen, David J.

    1991-01-01

    The project is supporting lightcurve photometry, colorimetry, thermal radiometry, and astrometry of selected asteroids. Targets include the planet-crossing population, particularly Earth approachers, which are believed to be the immediate source of terrestrial meteorites, future spacecraft targets, and those objects in the outer belt, primarily the Hilda and Trojan populations, that are dynamically isolated from the main asteroid belt. Goals include the determination of population statistics for the planet-crossing objects, the characterization of spacecraft targets to assist in encounter planning and subsequent interpretation of the data, a comparison of the collisional evolution of dynamically isolated Hilda and Trojan populations with the main belt, and the determination of the mechanism driving the activity of the distant object 2060 Chiron.

  11. Asteroid Redirect Mission: Robotic Segment

    NASA Video Gallery

    This concept animation illustrates the robotic segment of NASA's Asteroid Redirect Mission. The Asteroid Redirect Vehicle, powered by solar electric propulsion, travels to a large asteroid to robot...

  12. Chang'e-2 spacecraft observations of asteroid 4179 Toutatis

    NASA Astrophysics Data System (ADS)

    Ji, Jianghui; Jiang, Yun; Zhao, Yuhui; Wang, Su; Yu, Liangliang

    2016-01-01

    On 13 December 2012, Chang'e-2 completed a successful flyby of the near-Earth asteroid 4179 Toutatis at a closest distance of 770 meters from the asteroid's surface. The observations show that Toutatis has an irregular surface and its shape resembles a ginger-root of a smaller lobe (head) and a larger lobe (body). Such bilobate shape is indicative of a contact binary origin for Toutatis. In addition, the high-resolution images better than 3 meters provide a number of new discoveries about this asteroid, such as an 800-meter depression at the end of the large lobe, a sharply perpendicular silhouette near the neck region, boulders, indicating that Toutatis is probably a rubble-pile asteroid. Chang'e-2 observations have significantly revealed new insights into the geological features and the formation and evolution of this asteroid. In final, we brief the future Chinese asteroid mission concept.

  13. Observations of Planet Crossing Asteroids

    NASA Technical Reports Server (NTRS)

    Tholen, David J.; Whiteley, Robert J.; Lambert, Joy; Connelley, Michael; Salyk, Colette

    2002-01-01

    The goals of this research were the physical and dynamical characterization of planet crossing asteroids (Earth crossers, Mars crossers, Centaurs, and Pluto crossers, meaning trans-Neptunian objects), including colorimetry, rotational studies, and astrometry. Highlights are listed as follows: 1) Produced one doctoral dissertation (R. J. Whiteley, A Compositional and Dynamical Survey of the Near-Earth Asteroids). A key result is the fraction of Q-type asteroids among the near-Earth population was found to be about one-third; 2) Had prediscovery image showing the binary nature of trans-Neptunian object 1998 WW31, which is the first TNO to have a satellite found in orbit around it; 3) Discovery of shortest known rotation period for any asteroid (2000 D08, rotation period 78 seconds); it is just one of several fast-rotating small asteroids observed during the course of this project; 4) Discovery of a Centaur asteroid (1998 QM107) with, at the time, the smallest known orbital eccentricity among the Centaurs (0.13) and nearly in a 1:1 resonance with Uranus (semimajor axis of 19.9 AU); 5) Discovery of Apollo-type asteroid 1999 OW3, with a surprisingly bright absolute magnitude of 14.6 (estimated diameter of 4.6 km), brightest Apollo found in that calendar year; 6) Discovery of Aten-type asteroid 2000 SG344, which has the highest cumulative Earth impact probability among the near-Earth asteroids and a very Earth-similar orbit; 7) Instrumental in repairing the orbit of a numbered near-Earth asteroid for which prediscovery observations had been mis-attributed to it (2000 VN2); 8) Second-opposition recovery of 30-meter diameter Apollo-type asteroid 1998 KY26 in early 2002 when it was at a favorable magnitude of 24.8; 9) Primary contributor of astrometric observations of the CONTOUR fragments to the CONTOUR project following the failure of the spacecraft s kick motor; and 10) Development of orbit and ephemeris computation code that handles short observational arcs

  14. Mapping the stability field of Jupiter Trojans

    NASA Technical Reports Server (NTRS)

    Levison, H. F.; Shoemaker, E. M.; Wolfe, R. F.

    1991-01-01

    Jupiter Trojans are a remnant of outer solar system planetesimals captured into stable or quasistable libration about the 1:1 resonance with the mean motion of Jupiter. The observed swarms of Trojans may provide insight into the original mass of condensed solids in the zone from which the Jovian planets accumulated, provided that the mechanisms of capture can be understood. As the first step toward this understanding, the stability field of Trojans were mapped in the coordinate proper eccentricity, e(sub p), and libration amplitude, D. To accomplish this mapping, the orbits of 100 particles with e(sub p) in the range of 0 to 0.8 and D in the range 0 to 140 deg were numerically integrated. Orbits of the Sun, the four Jovian planets, and the massless particles were integrated as a full N-body system, in a barycentric frame using fourth order symplectic scheme.

  15. An intestinal Trojan horse for gene delivery

    NASA Astrophysics Data System (ADS)

    Peng, Haisheng; Wang, Chao; Xu, Xiaoyang; Yu, Chenxu; Wang, Qun

    2015-02-01

    The intestinal epithelium forms an essential element of the mucosal barrier and plays a critical role in the pathophysiological response to different enteric disorders and diseases. As a major enteric dysfunction of the intestinal tract, inflammatory bowel disease is a genetic disease which results from the inappropriate and exaggerated mucosal immune response to the normal constituents in the mucosal microbiota environment. An intestine targeted drug delivery system has unique advantages in the treatment of inflammatory bowel disease. As a new concept in drug delivery, the Trojan horse system with the synergy of nanotechnology and host cells can achieve better therapeutic efficacy in specific diseases. Here, we demonstrated the feasibility of encapsulating DNA-functionalized gold nanoparticles into primary isolated intestinal stem cells to form an intestinal Trojan horse for gene regulation therapy of inflammatory bowel disease. This proof-of-concept intestinal Trojan horse will have a wide variety of applications in the diagnosis and therapy of enteric disorders and diseases.

  16. An intestinal Trojan horse for gene delivery.

    PubMed

    Peng, Haisheng; Wang, Chao; Xu, Xiaoyang; Yu, Chenxu; Wang, Qun

    2015-03-14

    The intestinal epithelium forms an essential element of the mucosal barrier and plays a critical role in the pathophysiological response to different enteric disorders and diseases. As a major enteric dysfunction of the intestinal tract, inflammatory bowel disease is a genetic disease which results from the inappropriate and exaggerated mucosal immune response to the normal constituents in the mucosal microbiota environment. An intestine targeted drug delivery system has unique advantages in the treatment of inflammatory bowel disease. As a new concept in drug delivery, the Trojan horse system with the synergy of nanotechnology and host cells can achieve better therapeutic efficacy in specific diseases. Here, we demonstrated the feasibility of encapsulating DNA-functionalized gold nanoparticles into primary isolated intestinal stem cells to form an intestinal Trojan horse for gene regulation therapy of inflammatory bowel disease. This proof-of-concept intestinal Trojan horse will have a wide variety of applications in the diagnosis and therapy of enteric disorders and diseases. PMID:25619169

  17. Sleeping with an Elephant: Asteroids that Share a Planet's Orbit

    NASA Astrophysics Data System (ADS)

    Wiegert, Paul; Connors, Martin; Brasser, Ramon; Mikkola, Seppo; Stacey, Greg; Innanen, Kimmo

    2005-08-01

    Under special circumstances, relatively small asteroids are able to safely share the orbit of a much larger planet. The best known examples of such "co-orbital" bodies are the Trojan asteroids of Jupiter, over 1700 of which are known to travel either 60 degrees ahead of or behind this giant planet in its orbit. The stability of such configurations might be thought to depend on the asteroid giving the planet a wide berth. In reality, co-orbital asteroids may approach their planet relatively closely, to within a few times its Hill sphere (which is five times the distance to the Moon in the case of the Earth). For many co-orbital bodies such approaches occur rarely or not at all, but recently examples of co-orbital states that become trapped near their planet have been found. Such "quasi-satellites" may remain near their much larger partner for thousands of years, though in actuality they are not true satellites and continue to orbit the Sun. Here we discuss the behaviour of some recently discovered co-orbital asteroids with emphasis on 2004 GU9, recently found to have a long-lived quasi-satellite state relative to the Earth.

  18. Picking Sides: Classifying Jupiter’s Greeks and Trojans

    NASA Astrophysics Data System (ADS)

    Chatelain, Joseph; Henry, Todd J.; French, Linda M.; Trilling, David E.

    2014-11-01

    The L4 and L5 Lagrange points of Jupiter are populated with thousands of known, and possibly hundreds of thousands of unknown, Greek and Trojan Asteroids. As a robust, intermediate population, these objects represent a crucial dynamical group for testing the viability of various Solar System formation models and mechanisms. A detailed examination of these two camps is therefore necessary for fully understanding Solar System formation. We have collected hundreds of visible photometric observations for 110 of the brightest (H ≤ 10.0) members from both camps using several different observatories in both hemispheres in an effort to precisely classify these objects in a way readily comparable both to the Main Belt population as well as to populations of icy bodies further out in the Solar System. Here we present the full results of our photometric survey and analysis. These data also allow for a visible wavelength comparison between the two camps as well a search for a similar visible color bimodality in the populations as has been suggested by some Infrared spectroscopic observations. Ultimately such information will help us better understand this very important group of objects and how they came to reside in their current orbits. This in-turn will provide insight into the very formation of the Solar System.

  19. 5 - 14 μm Spitzer spectra of the Themis and Veritas asteroid families

    NASA Astrophysics Data System (ADS)

    Landsman, Zoe A.; Licandro, Javier; Campins, Humberto; Ziffer, Julie; de Prá, Mario

    2016-01-01

    Spectroscopic studies of primitive asteroid families provide constraints on the composition of the solar nebula and the distribution of volatiles in the asteroid belt. Results from visible and near-infrared spectroscopy show diversity between primitive families. We aim to better constrain the composition of two primitive families with very different ages: Themis (~2.5 Gyr) and Veritas (~8 Myr). We analyzed 5 - 14 μm Spitzer Space Telescope spectra of 11 Themis asteroids and nine Veritas asteroids, for a total of 20 asteroids. We report the presence of a broad 10-μm emission feature, attributed to a layer of fine-grained silicates, in the spectra of all 11 Themis asteroids and six of nine Veritas asteroids in our sample. Spectral contrast in statistically significant detections of the 10-μm feature ranges from 1% ± 0.1% to 8.5% ± 0.9%. Comparison with the spectra of primitive meteorites (McAdam et al. 2015, Icarus, 245, 320) suggests asteroids in both families are similar to meteorites with lower abundances of phyllosilicates. We used the Near-Earth Asteroid Thermal Model to derive diameters, beaming parameters and albedos for our sample. Asteroids in both families have beaming parameters near unity and low to moderate albedos. We find that contrast of the silicate emission feature is not correlated with asteroid diameter; however, higher 10-μm contrast may be associated with flatter spectral slopes in the near-infrared. The spectra of both families are consistent with icy bodies with some amount of fine-grained silicates, but with coarser grains or denser surface structure than Trojan asteroids and comets. The range of spectral contrast of the 10-μm emission feature within each family suggests diversity in regolith porosity and/or grain size.

  20. Binary NEAs Summary V1.0

    NASA Astrophysics Data System (ADS)

    Pravec, P.; Scheirich, P.

    2006-03-01

    This data set includes a summary table of the characteristics of known binary near-Earth asteroids, compiled by Petr Pravec and Petr Scheirich. A list of references to the original observations is also included.

  1. NEOWISE: The distribution of the large primitive asteroids

    NASA Astrophysics Data System (ADS)

    Grav, T.; Mainzer, A.; Bauer, J.; Masiero, J.; Nugent, C.; Stevenson, R.; Sonnett, S.

    2014-07-01

    The Wide-field Infrared Survey Explorer (WISE) is a NASA Medium-class Explorer mission that surveyed the entire sky in four infrared wavelengths at 3.4, 4.6, 12, and 22 microns (denoted W1, W2, W3, and W4, respectively) [1,2]. The solar-system specific portion of the WISE project, known as NEOWISE, collected more than 2 million observations of more than 158,000 asteroids, including near-Earth objects, main-belt asteroids, comets, Hildas, Jovian Trojans, Centaurs, and scattered-disk objects [3]. The methods used for data extraction and thermal modeling have been extensively detailed in [3--6]. The resulting physical properties have been reported in a series of papers [3--13]. In [6] and [9], it was shown that the visible albedo in the V band and the near-infrared albedo in the W1 and W2 bands can be used to taxonomically classify a significant number of the largest members of the Hilda and Jovian Trojan populations (see Figure 1). This allows for the study of the distribution of primitive asteroids in the region between the main asteroid and the giant planets, down to sizes where the populations are completely sampled. Figure 2 shows that for the Hilda population, where the sample is observationally complete to about 40 km, the C/P types dominated over the D types at the larger sizes. However, for the smaller sizes, the D types become significantly more numerous. For the Jovian Trojan population, for which the sample is observationally complete to about 50 km, the D types are slightly more numerous at the largest sizes. As smaller sizes are included, the D types become more dominant, with more than 80 % of the objects larger than 50 km having this taxonomic type. We have now extended the study to include thermal fits and taxonomic classification of the outer main belt, Cybeles, irregular satellites of Jupiter and Saturn, and the Centaur population [13], and will present the results of this work. The distribution of primitive asteroids in the different populations

  2. A SYSTEMATIC SEARCH FOR TROJAN PLANETS IN THE KEPLER DATA

    SciTech Connect

    Janson, Markus

    2013-09-10

    Trojans are circumstellar bodies that reside in characteristic 1:1 orbital resonances with planets. While all the trojans in our solar system are small ({approx}<100 km), stable planet-size trojans may exist in extrasolar planetary systems, and the Kepler telescope constitutes a formidable tool to search for them. Here we report on a systematic search for extrasolar trojan companions to 2244 known Kepler Objects of Interest (KOIs), with epicyclic orbital characteristics similar to those of the Jovian trojan families. No convincing trojan candidates are found, despite a typical sensitivity down to Earth-size objects. This fact, however, cannot be used to stringently exclude the existence of trojans in this size range, since stable trojans need not necessarily share the same orbital plane as the planet, and thus may not transit. Following this reasoning, we note that if Earth-sized trojans exist at all, they are almost certainly both present and in principle detectable in the full set of Kepler data, although a very substantial computational effort would be required to detect them. Additionally, we also note that some of the existing KOIs could in principle be trojans themselves, with a primary planet orbiting outside of the transiting plane. A few examples are given for which this is a readily testable scenario.

  3. Max Wolf's Discovery of Near-Earth Asteroid 887 Alinda

    NASA Astrophysics Data System (ADS)

    Connors, Martin; Mandel, Holger; Demleitner, Markus; Heidelberg Digitized Astronomical Plates Project

    2016-01-01

    Max Wolf, director of the Heidelberg Observatory (Landessternwarte Königsstuhl), was the most prodigious discoverer of asteroids in the early twentieth century. He is now best known for the discovery of the Trojan asteroids associated with Jupiter in 1906, but was a pioneer in the application of photographic techniques to astronomy, particularly for conducting asteroid surveys. His attention to detail and perseverance also led to the discovery of the near-Earth asteroid 887 Alinda, which is the eponym of an orbital class in 3:1 resonance with Jupiter. Alinda class contains several potentially hazardous asteroids, and has been particularly instructive in development of theories of eccentricity increase for resonant asteroids. Alinda was discovered on January 3, 1918, on the very edge of one of two plates taken with the 40 cm aperture Bruce double astrograph. The inability to reduce a long trail going off the plate meant that only one month later could the object again be found with the Bruce telescope, and later observed with the follow-up instrument, the 72 cm aperture Waltz reflector. In what Wolf referred to as "the greatest embarrassment of my life", reflector observations had him conclude that Alinda had a satellite. At a time when plates had to be exposed for several hours, laboriously developed and analyzed, and in the case of high eccentricity objects like Alinda, predicted with inadequate theories, Wolf's persistence allowed it never to be lost. Despite this, its essential resonant nature was not determined until 1969, despite the pioneering work by Brown (1911) on resonance in the asteroid belt and the knowledge dating to the late nineteenth century work of Kirkwood that commensurabilities were important in its structure. The majority of Wolf's plates are available as online scans through the Heidelberg Digitized Astronomical Plates project of the German Astrophysical Virtual Observatory, but the Alinda discovery plate, which was broken, was scanned

  4. Nuclear Astrophysics with the Trojan Horse Method

    NASA Astrophysics Data System (ADS)

    Tumino, A.; Spitaleri, C.; Lamia, L.; Pizzone, R. G.; Cherubini, S.; Gulino, M.; La Cognata, M.; Puglia, S. M. R.; Rapisarda, G. G.; Romano, S.; Sergi, M. L.; Spartá, R.

    2016-01-01

    The Trojan Horse Method (THM) represents the indirect path to determine the bare nucleus astrophysical S(E) factor for reactions between charged particles at astrophysical energies. This is done by measuring the quasi free cross section of a suitable three body process. The basic features of the THM will be presented together with some applications to demonstrate its practical use.

  5. Nuclear astrophysics and the Trojan Horse Method

    NASA Astrophysics Data System (ADS)

    Spitaleri, C.; La Cognata, M.; Lamia, L.; Mukhamedzhanov, A. M.; Pizzone, R. G.

    2016-04-01

    In this review, we discuss the new recent results of the Trojan Horse Method that is used to determine reaction rates for nuclear processes in several astrophysical scenarios. The theory behind this technique is shortly presented. This is followed by an overview of some new experiments that have been carried out using this indirect approach.

  6. Science Education as South Africa's Trojan Horse.

    ERIC Educational Resources Information Center

    Rogan, John M.; Gray, Brian V.

    1999-01-01

    Presents the story of one nongovernmental organization (NGO) and the role it played in reconceptualizing science education in South Africa. Describes the success of the Science Education Project (SEP) in confronting authoritarian practices of government organizations and those within its own ranks. Science education can become the Trojan horse of…

  7. CAPTURE OF TROJANS BY JUMPING JUPITER

    SciTech Connect

    Nesvorny, David; Vokrouhlicky, David; Morbidelli, Alessandro

    2013-05-01

    Jupiter Trojans are thought to be survivors of a much larger population of planetesimals that existed in the planetary region when planets formed. They can provide important constraints on the mass and properties of the planetesimal disk, and its dispersal during planet migration. Here, we tested a possibility that the Trojans were captured during the early dynamical instability among the outer planets (aka the Nice model), when the semimajor axis of Jupiter was changing as a result of scattering encounters with an ice giant. The capture occurs in this model when Jupiter's orbit and its Lagrange points become radially displaced in a scattering event and fall into a region populated by planetesimals (that previously evolved from their natal transplanetary disk to {approx}5 AU during the instability). Our numerical simulations of the new capture model, hereafter jump capture, satisfactorily reproduce the orbital distribution of the Trojans and their total mass. The jump capture is potentially capable of explaining the observed asymmetry in the number of leading and trailing Trojans. We find that the capture probability is (6-8) Multiplication-Sign 10{sup -7} for each particle in the original transplanetary disk, implying that the disk contained (3-4) Multiplication-Sign 10{sup 7} planetesimals with absolute magnitude H < 9 (corresponding to diameter D = 80 km for a 7% albedo). The disk mass inferred from this work, M{sub disk} {approx} 14-28 M{sub Earth}, is consistent with the mass deduced from recent dynamical simulations of the planetary instability.

  8. New K type asteroids

    NASA Technical Reports Server (NTRS)

    Granahan, James C.; Smith, Greg; Bell, Jeffrey F.

    1993-01-01

    Several new K type asteroids were identified during near infrared spectral observations on July 30, 1992 at NASA's infrared telescope facility (IRTF) at Mauna Kea, Hawaii. These K asteroids are 513 Centesima, 633 Zelima, 1129 Neujmina, 1416 Renauxa, 1799 Koussevitzky, and 1883 Rauma. A K asteroid is an asteroid which possesses a S type spectra in visible wavelengths and a C type spectra visible in near-infrared wavelengths. These objects are usually misclassified as S asteroids on the basis of visible spectra alone. This type was first detected by the 52 infrared color asteroid survey also conducted at the IRTF. Our observations utilized a new seven color infrared asteroid filter system which allows near-infrared data to be collected from asteroids as faint as 16th 5 magnitude.

  9. Name That Asteroid!

    NASA Video Gallery

    The OSIRIS-REx Asteroid Sample Return Mission is going to an asteroidto return a sample to Earth. Instead of traveling to asteroid 1999RQ36, the asteroid’s current name, we’re asking youth un...

  10. Physical Diversity of Near-Earth Asteroids from Arecibo Radar Observations

    NASA Astrophysics Data System (ADS)

    Taylor, Patrick A.; Howell, Ellen S.; Nolan, Michael C.; Richardson, James E.; Springmann, Alessondra

    2015-08-01

    Radar observations of near-Earth asteroids have revealed a heterogeneous population with diameters spanning meter to kilometer scales, diverse shapes ranging from simple spheroids to extremely irregular bodies, rotation periods stretching from minutes to weeks, and a spectrum of surface properties. Since 1998, the Arecibo Observatory S-band radar system has detected over 400 near-Earth asteroids. We find the radar-observed near-Earth asteroid population with absolute magnitude H < 21 is not dominated by a single category of basic shape: spheroids, multiple-asteroid systems, double-lobed contact binaries, elongated bodies, or irregularly shaped asteroids. A radar-observed binary fraction of 14% (N = 38; including two triple-asteroid systems) among near-Earth asteroids with H < 21 is in agreement with optical observations, while contact binaries account for a similar fraction (14%; N = 38). At smaller sizes, binaries and contact binaries are much rarer, with only three binaries and one contact binary with H < 21 detected thus far. The spin distribution of near-Earth asteroids estimated from radar matches very well with the spin distribution determined from optical lightcurves, including the well-known spin barrier for bodies with H < 21 and the curious lack of small, slowly rotating bodies with H > 21, despite different biases in these observing techniques. The shape and spin distributions of near-Earth asteroids observed with radar both show a distinct change in the population around H of 21 or 22 (100- to 200-m diameters), possibly indicating fundamental structural changes at this scale. Beyond constraining overall sizes and shapes, radar images as fine as 7.5-m resolution with Arecibo, akin to a low-cost flyby, reveal asteroid surfaces with ridges, concavities, crater-like depressions, angular facets, and boulders, details that constrain regolith properties and affect our understanding of geophysics in microgravity. Furthermore, the integrated surface properties

  11. AIDA: the Asteroid Impact & Deflection Assessment mission

    NASA Astrophysics Data System (ADS)

    Vincent, Jean-Baptiste

    2016-07-01

    The Asteroid Impact & Deflection Assessment (AIDA) mission is a joint cooperation between European and US space agencies that consists of two separate and independent spacecraft that will be launched to a binary asteroid system, the near-Earth asteroid Didymos, to assess the possibility of deflecting an asteroid trajectory by using a kinetic impactor. The European Asteroid Impact Mission (AIM) is under Phase A/B1 study at ESA from March 2015 until summer 2016. AIM is set to rendez-vous with the asteroid system a few months prior to the impact by the US Double Asteroid Redirection Test (DART) spacecraft to fully characterize the smaller of the two binary components. AIM is a unique mission as it will be the first time that a spacecraft will investigate the surface, subsurface, and internal properties of a small binary near Earth asteroid. In addition it will perform various important technology demonstrations that can serve other space missions: AIM will release a set of CubeSats in deep space and a lander on the surface of the smaller asteroid and for the first time, deep-space inter-satellite linking will be demonstrated between the main spacecraft, the CubeSats, and the lander, and data will also be transmitted from interplanetary space to Earth by a laser communication system. The knowledge obtained by this mission will have great implications for our understanding of the history of the Solar System. Small asteroids are believed to result from collisions and other processes (e.g., spinup, shaking) that made them what they are now. Having direct information on their surface and internal properties will allow us to understand how these processes work and transform these small bodies as well as, for this particular case, how a binary system forms. So far, our understanding of the collisional process and the validation of numerical simulations of the impact process rely on impact experiments at laboratory scales. With DART, thanks to the characterization of the

  12. Orbital Evolution of Asteroids

    NASA Astrophysics Data System (ADS)

    Dermott, S. F.; Kehoe, T. J. J.

    2011-10-01

    The synthetic orbital frequencies and eccentricities of main belt asteroids computed by Knezevic and Milani [2] show evidence that the structure of the asteroid belt has been determined by a dense of web of high-order resonances. By examining the orbital frequency distribution at high resolution, we discover a correlation between asteroid number density, mean orbital eccentricity and Lyapunov Characteristic Exponent. In particular, the orbital eccentricities of asteroids trapped in resonance tend to be higher than those of non-resonant asteroids and we argue that this is observational evidence for orbital evolution due to chaotic diffusion.

  13. Lightcurve Analysis of a Magnitude Limited Asteroid Sample

    NASA Astrophysics Data System (ADS)

    Molnar, Lawrence A.; Haegert, Melissa, J.; Beaumont, Christopher N.; Block, Marjorie J.; Brom, Timothy H.; Butler, Andrew R.; Cook, Peter L.; Green, Allyson, G.; Holtrop, Joshua P.; Hoogeboom, Kathleen M.; Kulisek, Jason J.; Lovelace, Jonathan S.; Olivero, Jeffrey S.; Shrestha, Achyut; Taylor, Jessie F.; Todd, Kenneth, D.; Vander Heide, John D.; van Coter, Samuel O.

    2008-03-01

    Synodic rotation periods and amplitudes for twelve main-belt asteroids observed at the Calvin-Rehoboth Observatory are reported: 285 Regina, 939 Isberga, 1104 Syringa, 1206 Numerowia, 1613 Smiley, 1623 Vivian, 1835 Gajdariya, 3013 Dobrovoleva, 3170 Dzhanibekov, 4411 Kochibunkyo, (5854) 1992UP, and (119245) 2001 QD293. The asteroid 939 Isberga is a binary with orbital period 26.8 ± 0.1 h. Together with five asteroids previously measured these constitute a complete magnitude limited sample which can be used to test for bias in the larger catalog of rotation periods.

  14. Study of 2003 YT1 Asteroid

    NASA Astrophysics Data System (ADS)

    Vodniza, A. Q.; Rojas, M.

    2011-10-01

    The asteroid 2003 YT1 was at approximately 25 million kilometers from the Earth on May 05-2011 (U.T) [1]. It has an orbital period of 1.17 years and it was estimated to have a size of 2.63 kilometers [2]. From our Observatory, located in Pasto-Colombia, we captured several pictures, videos and astrometry data during three days. Our data was published by the Minor Planet Center (MPC) and also appears at the web page of NEODyS [3]. Our observatory's code at the MPC is "H78". Pictures of the asteroid were captured with the following equipment: 14" LX200 GPS MEADE (f/10 Schmidt-Cassegrain Telescope) and STL-1001 SBIG camera. This asteroid has a rotation period of 2.343 hours [4] and its binary nature was noted by the Modra and Ondrejov Observatories independently [5]. Nolan used radar observations to determine that this is a binary with sizes of approximately 1 and 0.2 km and primary rotation period of P < 2.6 h [6]. The asteroid will be at approximately 0.0348 A.U from the Earth on October 31-2016 and at approximately 0.0113 A.U from the Earth on October 31-2016 [7]. Astrometry was carried out, and we calculated the orbital elements. It was designed a computing program on Visual Basic 6.0. SPACEWEATHER published our video of 2003YT1 on May 5/2011 [8].

  15. 5 - 14 μm Spitzer spectra of primitive asteroid families

    NASA Astrophysics Data System (ADS)

    Landsman, Zoe A.; Licandro, Javier; Campins, Humberto; Ziffer, Julie; de Prá, Mário

    2015-11-01

    Compositional studies of primitive asteroid families provide constraints on the physical and chemical environment of the solar nebula and the evolution of the asteroid belt. Spectroscopic studies in the visible and near-infrared have shown spectral diversity between primitive families. Our goal is to better constrain the composition of two primitive families with very different ages: Themis (~2.5 Gyr) and Veritas (~8 Myr). We analyzed 5 - 14 μm Spitzer Space Telescope spectra of a total of 18 asteroids, nine from each family. We report the presence of a broad 10-μm emission feature, attributed to a layer of fine-grained silicates, in the spectra of all nine Themis asteroids and six of nine Veritas asteroids in our sample. Spectral contrast in statistically significant detections of the 10-μm feature ranges from 1% ± 0.1% to 8.5% ± 0.9%. Comparison with the spectra of primitive meteorites (McAdam et al. 2015, Icarus, 245, 320) suggests asteroids in both families are similar to meteorites with lower abundances of phyllosilicates. We used the Near-Earth Asteroid Thermal Model to derive diameters, beaming parameters and albedos for our sample. Asteroids in both families have beaming parameters near unity and geometric albedos in the range 0.06 ± 0.01 to 0.14 ± 0.02. We find that contrast of the silicate emission feature is not correlated with asteroid diameter; however, higher 10-μm contrast may be associated with flatter spectral slopes in the near-infrared. The spectra of both families suggest icy bodies with some amount of fine-grained silicates, but with coarser grains or denser surface structure than Trojan asteroids and comets.

  16. The Trojan Horse Method in Nuclear Astrophysics

    SciTech Connect

    Spitaleri, C.

    2010-11-24

    The Trojan Horse Method allows for the measurements of cross section in nuclear reaction between charged particles at astrophysical energies. The basic features of the method are discussed in the non resonant reactions case. A review of applications aimed to extract the bare nucleus astrophysical S{sub b}(E) factor for two body processes are presented. The information on electron screening potential U{sub e} were obtained from comparison with direct experiments of fusion reactions.

  17. High surface porosity as the origin of emissivity features in asteroid spectra

    NASA Astrophysics Data System (ADS)

    Vernazza, P.; Delbo, M.; King, P. L.; Izawa, M. R. M.; Olofsson, J.; Lamy, P.; Cipriani, F.; Binzel, R. P.; Marchis, F.; Merín, B.; Tamanai, A.

    2012-11-01

    Emission features in the mid-IR domain (7-25 μm) are quite ubiquitous among large asteroids and therefore offer the potential to uncover their surface composition. However, when comparing these spectra with the actual laboratory spectra of both minerals and meteorites, they do not necessarily match. Here, and in a companion paper by King et al. (in preparation, 2012), we show that by modifying the sample preparation - typically by suspending meteorite and/or mineral powder (<30 μm) in IR-transparent KBr (potassium bromide) powder - we are able to reproduce the spectral behavior of those main-belt asteroids with emissivity features. This resulting good match between KBr-diluted meteorite spectra and asteroid spectra suggests an important surface porosity (>90%) for the first millimeter for our asteroid sample. It therefore appears that mid-IR emission spectra of asteroids do not only carry information about their surface composition but they can also help us constraining their surface structure (under-dense versus compact surface structure), as suggested by Emery et al. (Emery, J.P., Cruikshank, D.P., van Cleve, J. [2006]. Icarus 182, 496-512) in the case of the Jupiter Trojans. The large surface porosity inferred from the mid-IR spectra of certain asteroids is also implied by two other independent measurements, namely their thermal inertia and their radar albedo. We further clarified how much compositional information can be retrieved from the mid-IR range by focusing our analysis on a single object, 624 Hektor. We showed that the mid-IR range provides critical constraints (i) on its origin and of that of the red Trojans that we locate in the formation regions of the comets, and (ii) on the primordial composition of the dust present in the outer region (>10 AU) of the Solar System’s protoplanetary disk. Future investigations should focus on finding the mechanism responsible for creating such high surface porosity.

  18. The asteroids. [review

    NASA Technical Reports Server (NTRS)

    Chapman, C. R.; Hartmann, W. K.; Williams, J. G.

    1978-01-01

    The asteroids are small rocky bodies that orbit in modestly eccentric and inclined orbits, mainly between the orbits of Mars and Jupiter. With the comets, they are the only known population of residual planetesimals from the earliest epochs of solar system history. The observational characteristics of asteroids are discussed, taking into account aspects of photometry, rotations, masses and densities, spectrophotometry and surface compositions, surface textures and regoliths, size distribution, and erosion and fragmentation occurring as a result of interasteroidal collisions. Questions of dynamics and orbital evolution are investigated and ramifications for planetary evolution are explored. Attention is given to asteroids as planetesimals, aspects of early orbital evolution, the geochemical evolution of asteroids, commensurabilities and Kirkwood gaps, secular resonances, the material transport from the asteroid belt, Poisson's theorem, planetary masses, catalogs and selection effects, families, and Apollo, Amor, and Mars-crossing asteroids.

  19. Asteroid exploration and utilization

    NASA Technical Reports Server (NTRS)

    Radovich, Brian M.; Carlson, Alan E.; Date, Medha D.; Duarte, Manny G.; Erian, Neil F.; Gafka, George K.; Kappler, Peter H.; Patano, Scott J.; Perez, Martin; Ponce, Edgar

    1992-01-01

    The Earth is nearing depletion of its natural resources at a time when human beings are rapidly expanding the frontiers of space. The resources possessed by asteroids have enormous potential for aiding and enhancing human space exploration as well as life on Earth. Project STONER (Systematic Transfer of Near Earth Resources) is based on mining an asteroid and transporting raw materials back to Earth. The asteroid explorer/sample return mission is designed in the context of both scenarios and is the first phase of a long range plan for humans to utilize asteroid resources. Project STONER is divided into two parts: asteroid selection and explorer spacecraft design. The spacecraft design team is responsible for the selection and integration of the subsystems: GNC, communications, automation, propulsion, power, structures, thermal systems, scientific instruments, and mechanisms used on the surface to retrieve and store asteroid regolith. The sample return mission scenario consists of eight primary phases that are critical to the mission.

  20. Cratering on Asteroids

    NASA Astrophysics Data System (ADS)

    Marchi, S.; Chapman, C. R.; Barnouin, O. S.; Richardson, J. E.; Vincent, J.-B.

    Impact craters are a ubiquitous feature of asteroid surfaces. On a local scale, small craters puncture the surface in a way similar to that observed on terrestrial planets and the Moon. At the opposite extreme, larger craters often approach the physical size of asteroids, thus globally affecting their shapes and surface properties. Crater measurements are a powerful means of investigation. Crater spatial and size distributions inform us of fundamental processes, such as asteroid collisional history. A paucity of craters, sometimes observed, may be diagnostic of mechanisms of erasure that are unique on low-gravity asteroids. Byproducts of impacts, such as ridges, troughs, and blocks, inform us of the bulk structure. In this chapter we review the major properties of crater populations on asteroids visited by spacecraft. In doing so we provide key examples to illustrate how craters affect the overall shape and can be used to constrain asteroid surface ages, bulk properties, and impact-driven surface evolution.

  1. Witnessing Extrasolar Asteroid Destruction?

    NASA Astrophysics Data System (ADS)

    Xu, Siyi; Jura, Michael; Su, Kate; Meng, Huan

    2014-11-01

    40 white dwarfs with excess infrared radiation due to a circumstellar dust disk from tidally disrupted asteroids have been identified. Recently, we identified one dusty white dwarf whose infrared fluxes have been increasing since May 2014. Very likely, it is caused by a recent tidal disruption event of extrasolar asteroid. We propose DDT to follow it up in a timely manner because the flare could dissipate very soon. This proposal provides a unique opportunity to study the destruction of an extrasolar asteroid.

  2. The Calar Alto Serendipitous Asteroid Discovery and Observation program --- CASADO

    NASA Astrophysics Data System (ADS)

    Hellmich, S.; Debschütz, L.; Hafemeister, L.; Gerull, O.; Proffe, G.; Mottola, S.; Hahn, G.

    2014-07-01

    In the past years much effort was put into programs for asteroid discovery. Large-scale programs like LINEAR[1] and Catalina Sky Survey were introduced and powerful telescopes like Pan-STARRS[3] were built only for the purpose of finding asteroids, to name just a few. Thus, the rate of asteroid discoveries literally exploded. Although by far the largest number of observations is done by the big surveys also smaller observation programs can provide valuable data. Telescopes, whether they hunt asteroids or do other tasks, image them all the time. By searching the images for serendipitously observed asteroids one can contribute to refine orbits of already known asteroids, find new objects and sometimes even determine basic physical properties which are unknown for most of the known asteroids. In October 2012 we started CASADO, a program for secondary usage of the data collected within a long term observation program carried out at the 1.23m telescope at Calar Alto. The telescope is equipped with a 4k by 4k CCD covering a field of view of about 22 by 22 arcmin. We use the telescope for 100 nights per year mainly for photometric observations of Jupiter Trojans[4] but also main-belt objects, satellites of Jupiter and comets are sometimes observed. In a typical observation campaign, we focus on about 15 to 20 minor bodies of which we repetitively observe 10 to 15 during a single night. To search the fields for serendipitously-observed objects we implemented a semi-automated software which performs the astrometric calibration, searches the images for moving objects, identifies already known asteroids and prepares MPC reports. By calculating preliminary orbital elements for the newly-discovered objects using OpenOrb[2] we are also able to compute ephemeris and reliably link the observations of these objects over multiple nights. Not only do we process the images of ongoing campaigns, but also went back in time to July 2011. While the astrometry of the objects which have

  3. An overview of the asteroids

    NASA Technical Reports Server (NTRS)

    Binzel, Richard P.

    1989-01-01

    An introductory overview of the field of asteroid science is presented, with emphasis placed on the accomplishments of the 1980s. Following the survey of known asteroids, attention is given to the observations of asteroids with the IRAS. Particular consideration is given to the origin and evolution of asteroids and their interrelations. Possible future directions of asteroid research are discussed together with the potential of the Hubble Space Telescope for providing new data on asteroid surface chemistry, geology, structure, and morphology.

  4. Asteroid radar astrometry

    NASA Technical Reports Server (NTRS)

    Ostro, S. J.; Jurgens, R. F.; Rosema, K. D.; Winkler, R.; Yeomans, D. K.; Campbell, D. B.; Chandler, J. F.; Shapiro, I. I.; Hine, A. A.; Velez, R.

    1991-01-01

    Measurements of time delay and Doppler frequency are reported for asteroid-radar echoes obtained at Arecibo and Goldstone during 1980-1990. Radar astrometry is presented for 23 near-earth asteroids and three mainbelt asteroids. These measurements, which are orthogonal to optical, angular-position measurements, and typically have a fractional precision between 10 to the -5th and 10 to the -8th, permit significant improvement in estimates of orbits and hence in the accuracy of prediction ephemerides. Estimates are also reported of radar cross-section and circular polarization ratio for all asteroids observed astrometrically during 1980-1990.

  5. Physical properties of asteroids

    NASA Technical Reports Server (NTRS)

    Veeder, Glenn J.

    1988-01-01

    Infrared photometry at 1.2, 1.6 and 2.2 micrometer provides a relatively rapid and accurate method for the classification of asteroids and is important for comparison with laboratory measurements of meteorites and other possible compositional analogues. Extension beyond the visual is espicially useful for minerals which have strong characteristic infrared colors such as olivine in the A class asteroids. Radiometry at long infrared wavelengths is important for deriving basic physical parameters (via thermal models) such as size and albedo which in turn enables the conversion of relative colors to absolute reflectances. In particular, albedos are the only way to distinguish among the otherwise ambiguous E, M and P classes of asteroids. Infrared observations of 15 asteroids were made at the NASA infrared Telescope Facility (IRTF) on Mauna Kea in 1987. Researchers completed the analysis of 22 Aten, Apollo and Amor asteroids. Results include albedos and diameters for these objects as well as the identification of the first known class M and Class E near-Earth asteroids. The standard thermal model appears to be inadequate for some of these small asteroids because of their coarse regolith, so researchers constructed a rotating thermal model for such asteroids. They have identified a subtle systematic difference between the sub-populations of large and small IRAS asteroids as well as several anomalous objects.

  6. Asteroid and comet surfaces

    NASA Technical Reports Server (NTRS)

    Mcfadden, Lucy-Ann

    1988-01-01

    Photometric and spectrophotometric studies of asteroids and comets are in progress to address questions about the mineralogical relationship between asteroids near the 3:1 Kirkwood gap and ordinary chondrite meteorites and between cometary nuclei and the surface of asteroids. Progress was made on a method to convert the measured excess UV flux in the spectrum of 2201 Oljato to column abundance of OH and CN. Spectral reflectance measurements of large asteroids near the 3:1 Kirkwood gap, which is expected to be the source of ordinary chondrite meteorites, were briefly examined and show no spectral signatures that are characteristic of ordinary chondrite meteorite powders measured in the lab.

  7. Science case for the Asteroid Impact Mission (AIM): A component of the Asteroid Impact & Deflection Assessment (AIDA) mission

    NASA Astrophysics Data System (ADS)

    Michel, Patrick; Cheng, A.; Küppers, M.; Pravec, P.; Blum, J.; Delbo, M.; Green, S. F.; Rosenblatt, P.; Tsiganis, K.; Vincent, J. B.; Biele, J.; Ciarletti, V.; Hérique, A.; Ulamec, S.; Carnelli, I.; Galvez, A.; Benner, L.; Naidu, S. P.; Barnouin, O. S.; Richardson, D. C.; Rivkin, A.; Scheirich, P.; Moskovitz, N.; Thirouin, A.; Schwartz, S. R.; Campo Bagatin, A.; Yu, Y.

    2016-06-01

    The Asteroid Impact & Deflection Assessment (AIDA) mission is a joint cooperation between European and US space agencies that consists of two separate and independent spacecraft that will be launched to a binary asteroid system, the near-Earth asteroid Didymos, to test the kinetic impactor technique to deflect an asteroid. The European Asteroid Impact Mission (AIM) is set to rendezvous with the asteroid system to fully characterize the smaller of the two binary components a few months prior to the impact by the US Double Asteroid Redirection Test (DART) spacecraft. AIM is a unique mission as it will be the first time that a spacecraft will investigate the surface, subsurface, and internal properties of a small binary near-Earth asteroid. In addition it will perform various important technology demonstrations that can serve other space missions. The knowledge obtained by this mission will have great implications for our understanding of the history of the Solar System. Having direct information on the surface and internal properties of small asteroids will allow us to understand how the various processes they undergo work and transform these small bodies as well as, for this particular case, how a binary system forms. Making these measurements from up close and comparing them with ground-based data from telescopes will also allow us to calibrate remote observations and improve our data interpretation of other systems. With DART, thanks to the characterization of the target by AIM, the mission will be the first fully documented impact experiment at asteroid scale, which will include the characterization of the target's properties and the outcome of the impact. AIDA will thus offer a great opportunity to test and refine our understanding and models at the actual scale of an asteroid, and to check whether the current extrapolations of material strength from laboratory-scale targets to the scale of AIDA's target are valid. Moreover, it will offer a first check of the

  8. Asteroid selection for mission opportunities

    NASA Technical Reports Server (NTRS)

    Chapman, C. R.; Stone, C. A.

    1972-01-01

    A study to assess the present state of knowledge of asteroids as well as the rate of change of that knowledge to better identify the mission and target priorities for advanced planning of asteroidal flights in the 1980's is presented. Topics discussed include; the present state of asteroid knowledge, the scientific goals and priorities attached to asteroid exploration, the anticipated advances in knowledge over the current decade, asteroid mission consideration, and asteroid selection. Data sheets for 118 asteroids are contained. These are asteroids for which some data is available over and above orbital parameters and magnitude.

  9. The GTC mid-infrared spectroscopic program of primitive outer-belt asteroids

    NASA Astrophysics Data System (ADS)

    Licandro, J.; Alvarez-Iglesias, C. Carlos; Cabrera-Lavers, A.; Ali-Lagoa, V.; Pinilla-Alonso, N.; Campins, H.; de Leon, J.; Kelley, M.

    2014-07-01

    Asteroids in the outer edge of the asteroid belt (Cybeles, Hildas, and Jupiter Trojans) may provide a number of clues to the origin and evolution of the asteroid belt and the formation of our planetary system. They have a pristine composition, experienced little heating and may contain a significant fraction of ice in their interiors. The origin of these populations is still under debate. Levison et al. (2009) suggested that a large fraction of these bodies are transneptunian objects (TNOs) moved to these resonances in an early epoch of the Solar System called the ''Late Heavy Bombardment'' (LHB). To compare the physical properties of these asteroid populations with TNOs and comets is thus a strong test of dynamical models. In mid 2013, we started a mid-infrared photometric and spectroscopic program in the N-band using the CANARICAM camera-spectrograph at the 10.4-m GTC telescope at the ''Roque de los Muchachos'' Obserbatory (Canary Islands, Spain). We aim to study the surface composition and key properties such as radius, albedo, and thermal inertia based on their low-resolution 8--13-micron spectra and N-band photometry. We already obtained the spectra of 5 objects, that of (225) Henrieta is shown as an example in the Figure. The three published spectra of Trojan asteroids (Emery et al. 2006) and of (65) Cybele (Licandro et al. 2011) exhibit clear emissivity features from which the compositional and physical properties can be inferred. The spectra of these objects strongly resemble one another, presenting an emission plateau due to silicates at about 9.1-11.5 microns (the Si-O stretch fundamental). Fine-grained silicates in a very porous (fairly castle) structure, and no other mineral group (Emery et al. 2006, Vernazza et al. 2012), reproduce the major features of the Trojans and Cybele asteroid spectra. In this work, we present the preliminary results of our observational program including the N-band spectra, size, and albedo of the already observed 5 asteroids

  10. Radar characterization of asteroids and comets

    NASA Astrophysics Data System (ADS)

    Howell, E.; Taylor, P.; Nolan, M.; Springmann, A.; Benner, L.; Brozovic, M.; Giorgini, J.; Busch, M.; Margot, J.; Naidu, S.; Magri, C.; Shepard, M.

    2014-07-01

    Radar observations are one of the few ground-based techniques that reveal shapes and surface details of asteroids and comets. Since 1998, over 400 asteroids and 15 comets have been detected by radar at either the Arecibo Observatory, the Goldstone Solar System Radar, or both. With resolution as fine as 7.5 m at Arecibo and 3.75 m at Goldstone for the highest signal-to-noise (SNR) observations, the images show a variety of shapes. Nearly 60 percent of near-Earth asteroids (NEAs) detected are of high-enough SNR or have enough time coverage to at least categorize the shape. At least 35 percent of the NEAs are spheroidal, including the 15 percent that are binary or multiple systems. These NEAs, with diameters less than a few kilometers, must have little or no internal strength, in order to have a spheroidal shape. Contact binary, or two-lobed objects, where the lobes are nearly the same size, may also be strengthless. NEA contact binaries may have formed by being spun up, but then failing to form a stable binary system. Few cometary nuclei have been imaged using radar, but several of those also seem to have a contact binary, or two-lobed structure. 103P/Hartley~2, and 8P/Tuttle both have nearly equal lobes joined by a narrow waist [1,2]. The very slow rotation rates of comet nuclei compared to most asteroids suggests that they may not share a common formation mechanism. Radar measurements also give an instantaneous measure of the line-of-sight velocity of the asteroid limb, which is proportional to the rotation rate for an equatorial view. NEAs with H>21 (diameter smaller than 150--300 m) frequently have rotation rates well beyond the spin limit for a strengthless body. However, not all small asteroids are rotating at very rapid rates. Lightcurve measurements become difficult for very small asteroids, which are not observable for long periods of time and have rapidly changing viewing geometries. Radar measurements of the rotation rates, while affected by projection

  11. Asteroids and Amateur Astronomers.

    ERIC Educational Resources Information Center

    Gunter, Jay U.

    1985-01-01

    Traces asteroid discoveries by amateurs from the 19th century to the present. The importance and necessity of amateur work are noted, especially with reference to observing and documenting occultations (one object passes directly in front of another which is farther away). Suggestions are made for viewing asteroids as a hobby. (DH)

  12. A Triple Asteroid System

    NASA Astrophysics Data System (ADS)

    2005-09-01

    One of the thousands of minor planets orbiting the Sun has been found to have its own mini planetary system. Astronomer Franck Marchis (University of California, Berkeley) and his colleagues at the Observatoire de Paris have discovered the first triple asteroid system - two small asteroids orbiting a larger one known since 1866 as 87 Sylvia.

  13. The Double Asteroid Redirection Test in the AIDA Project

    NASA Astrophysics Data System (ADS)

    Cheng, Andrew; Rivkin, Andrew; Michel, Patrick

    2016-04-01

    The Asteroid Impact & Deflection Assessment (AIDA) mission will be the first space experiment to demonstrate asteroid impact hazard mitigation by using a kinetic impactor. AIDA is a joint ESA-NASA cooperative project, that includes the ESA Asteroid Impact Mission (AIM) rendezvous mission and the NASA Double Asteroid Redirection Test (DART) mission. The AIDA target is the near-Earth binary asteroid 65803 Didymos, which will make an unusually close approach to Earth in October, 2022. The ~300-kg DART spacecraft is designed to impact the Didymos secondary at 7 km/s and demonstrate the ability to modify its trajectory through momentum transfer. DART and AIM are currently Phase A studies supported by NASA and ESA respectively. The primary goals of AIDA are (1) perform a full-scale demonstration of the spacecraft kinetic impact technique for deflection of an asteroid, by targeting an object larger than ~100 m and large enough to qualify as a Potentially Hazardous Asteroid; (2) measure the resulting asteroid deflection, by targeting the secondary member of a binary NEO and measuring the period change of the binary orbit; (3) understand the hyper-velocity collision effects on an asteroid, including the long-term dynamics of impact ejecta; and validate models for momentum transfer in asteroid impacts, based on measured physical properties of the asteroid surface and sub-surface. The primary DART objectives are to demonstrate a hyper-velocity impact on the Didymos moon and to determine the resulting deflection from ground-based observatories. The DART impact on the Didymos secondary will cause a measurable change in the orbital period of the binary. Supporting Earth-based optical and radar observations and numerical simulation studies are an integral part of the DART mission. The baseline DART mission launches in December, 2020 to impact the Didymos secondary in September, 2022. There are multiple launch opportunities for DART leading to impact around the 2022 Didymos close

  14. Serendipitous Observations of Asteroids by the K2 Mission

    NASA Astrophysics Data System (ADS)

    Barentsen, Geert

    2015-11-01

    The K2 mission is using the unique assets of the Kepler space telescope to perform long-baseline, high-cadence, high-precision photometry of targets selected by the community. Unlike the original Kepler mission, the loss of two reaction wheels requires K2 to point near the ecliptic plane. As a result, thousands of faint asteroids can be seen to pass through the target pixel masks that are downlinked to earth after each ~75-day observing campaign. I will show how these serendipitous observations of asteroids can be used to obtain lightcurves for faint (V>18) objects which are otherwise challenging to target from the ground. In particular, I will demonstrate that the data are well-suited to identify small asteroids with rotation periods near or below the ~2 hour "spin barrier". I will also highlight the K2 data of other solar system bodies, including the comets, trans-Neptunian objects and Jupiter trojans for which dedicated pixel masks have been (or will be) downlinked. Owing to its ecliptic pointing and 1.4-meter diameter mirror, K2 is offering unique time-series photometry of small solar system bodies at a precision which is unlikely to be rivaled by the future, smaller-aperture photometric missions such as TESS and PLATO.

  15. Polarimetric properties of asteroids

    NASA Astrophysics Data System (ADS)

    Shestopalov, D. I.; Golubeva, L. F.

    2015-11-01

    Quite frequently astronomic polarimetric observations of different celestial bodies do not guarantee a proper phase angle coverage that is required for estimating all of the attributes of their polarization phase curves with a high accuracy. To approximate the phase dependences of polarization observed for particulate surfaces, we use a simple empiric formula recently suggested by Shestopalov (2004). The efficiency of the approximating function in a wide range of phase angles is illustrated with the use of the results of polarimetric measurements of lunar areas, lunar samples, and near-Earth asteroids. For asteroids of various types, we can reproduce their negative polarization branches with adequate accuracy and roughly estimate a probable value of the maximum polarization degree at an appropriate phase angle. From the polarimetric database available at NASA PDS [Asteroid Polarimetric Database V7.0 (2012)] we calculated the main parameters of 153 polarimetric curves of asteroids in various spectral bands with the accuracy comparable to the observation errors. One more purpose of our analysis was to find correlations between the polarimetric and photometric properties of asteroids. For C-, M-, S-, E-type asteroids, the characteristics of the negative branch of polarization curves turned out to correlate closely with the phase coefficient of the photometric function of asteroids and the photometric roughness of asteroid surfaces. This implies that the complex geometry of the surface microrelief affects the polarization properties of asteroids. In particular, the data scattering around regression lines on the plots of the albedo versus the depth of negative polarization branch and the slope of the polarimetric function at inversion angle strongly depends on the differences in the photometric roughness of asteroid surfaces.

  16. 313 new asteroid rotation periods from Palomar Transient Factory observations

    SciTech Connect

    Chang, Chan-Kao; Ip, Wing-Huen; Lin, Hsing-Wen; Cheng, Yu-Chi; Ngeow, Chow-Choong; Yang, Ting-Chang; Waszczak, Adam; Kulkarni, Shrinivas R.; Levitan, David; Sesar, Branimir; Prince, Thomas A.; Laher, Russ; Surace, Jason

    2014-06-10

    A new asteroid rotation period survey has been carried out by using the Palomar Transient Factory (PTF). Twelve consecutive PTF fields, which covered an area of 87 deg{sup 2} in the ecliptic plane, were observed in the R band with a cadence of ∼20 minutes during 2013 February 15-18. We detected 2500 known asteroids with a diameter range of 0.5 km ≤D ≤ 200 km. Of these, 313 objects had highly reliable rotation periods and exhibited the 'spin barrier' at ∼2 hr. In contrast to the flat spin-rate distribution of the asteroids with 3 km ≤D ≤ 15 km shown by Pravec et al., our results deviated somewhat from a Maxwellian distribution and showed a decrease at the spin rate greater than 5 rev day{sup –1}. One superfast rotator candidate and two possible binary asteroids were also found in this work.

  17. Sizes, Shapes, and Satellites of Asteroids from Occultations

    NASA Astrophysics Data System (ADS)

    Dunham, David W.; Herald, David; Preston, Steve; Timerson, Brad; Maley, Paul; Frappa, Eric; Hayamizu, Tsutomu; Talbot, John; Poro, Atila

    2016-01-01

    For 40 years, the sizes and shapes of many dozens of asteroids have been determined from observations of asteroidal occultations, and over a thousand high-precision positions of the asteroids relative to stars have been measured. Some of the first evidence for satellites of asteroids was obtained from the early efforts; now, the orbits and sizes of some satellites discovered by other means have been refined from occultation observations. Also, several close binary stars have been discovered, and the angular diameters of some stars have been measured from analysis of these observations. The International Occultation Timing Association (IOTA) coordinates this activity worldwide, from predicting and publicizing the events, to accurately timing the occultations from as many stations as possible, and publishing and archiving the observations.

  18. Neptune trojan formation during planetary instability and migration

    NASA Astrophysics Data System (ADS)

    Gomes, R.; Nesvorný, D.

    2016-08-01

    Aims: We investigate the process of Neptune trojan capture and permanence in resonance up to the present time based on a planetary instability migration model. Methods: We do a numerical simulation of the migration of the giant planets in a planetesimal disk. Several planetesimals became trapped in coorbital resonance with Neptune, but no trojan survived to the end of the integration at 4.5 Gy. We increased the statistics by running synthetic integrations with cloned particles from the original integration and keeping the same migration rates of the planets. Results: For the synthetic integrations, Neptune trojans survived to the end of the simulations. The total mass that corresponds to these surviving trojans is about 1.6 × 10-4 Earth mass and the distributions of eccentricities, inclinations, and libration amplitudes are respectively 0.007-0.173, 4.9°-32.9°, and 6.9°-64.3°. In a specific run where Neptune to Uranus mean motion ratio reached 1.963 and decreased to its present value (1.961), many more trojans escaped the coorbital resonance with Neptune and in the end there was an equivalent mass of 5 × 10-5 Earth mass of Neptune trojans. Conclusions: The simulations yielded Neptune trojans that match the orbital distribution of real Neptune trojans quite well. Since planetary migration in an instability model shows the possibility that in the past Neptune was a little farther from the Sun than it is today, it is reasonable to consider this possibility to explain the relatively low mass of Neptune trojans.

  19. The Trojan Horse Method in nuclear astrophysics

    SciTech Connect

    Spitaleri, C.; Mukhamedzhanov, A. M.; Blokhintsev, L. D.; Cognata, M. La; Pizzone, R. G.; Tumino, A.

    2011-12-15

    The study of energy production and nucleosynthesis in stars requires an increasingly precise knowledge of the nuclear reaction rates at the energies of interest. To overcome the experimental difficulties arising from the small cross sections at those energies and from the presence of the electron screening, the Trojan Horse Method has been introduced. The method provides a valid alternative path to measure unscreened low-energy cross sections of reactions between charged particles, and to retrieve information on the electron screening potential when ultra-low energy direct measurements are available.

  20. The Strength of Rubble Pile Asteroids

    NASA Astrophysics Data System (ADS)

    Scheeres, D. J.; Sanchez, P.

    2012-12-01

    throughout rubble pile asteroids similar to Itokawa. This has important consequences for the strength of a rubble pile due to natural cohesion forces that are known to be present for such small grains, as evidenced by terrestrial experience. We calculate and simulate the effect of these forces for the strength of a rubble pile constituted of larger boulders embedded in a matrix of finer grains. This simple model predicts a yield strength that varies inversely with the mean particle size, and provides sufficient strength to a rubble pile to account for many of the fast spinning bodies seen in the population. If rubble pile asteroids are strengthened through cohesion between dust fines, there are several implications that can be tested and compared against the existing asteroid data. These involve the observed size cutoff for binary asteroids, the presence of rapidly rotating tumbling asteroids, and other features in the data. We present these tests and evaluate whether this model is consistent with them. Finally, based on the theoretical work behind this research we propose a reinterpretation of the spin limit for asteroids with size between 0.5 - 10 km in terms of mechanics models of strength and failure, predicting a larger mean density than the currently derived ~ 2.1 g/cm^3 limit.

  1. The Double Asteroid Redirection Test in the AIDA Mission

    NASA Astrophysics Data System (ADS)

    Cheng, Andrew; Reed, Cheryl; Rivkin, Andrew

    2016-07-01

    The Asteroid Impact & Deflection Assessment (AIDA) mission will be the first space experiment to demonstrate asteroid impact hazard mitigation by using a kinetic impactor. AIDA is a joint ESA-NASA cooperative project, consisting of the ESA Asteroid Impact Mission (AIM) rendezvous mission and the NASA Double Asteroid Redirection Test (DART) mission. The AIDA target is the near-Earth binary asteroid 65803 Didymos, which will make an unusually close approach to Earth in October, 2022. The DART spacecraft is designed to impact the Didymos secondary at 7 km/s and demonstrate the ability to modify its trajectory through momentum transfer. DART and AIM are currently Phase A studies supported by NASA and ESA respectively. The primary goals of AIDA are (1) perform a full-scale demonstration of the spacecraft kinetic impact technique for deflection of an asteroid; (2) measure the resulting asteroid deflection, by targeting the secondary member of a binary NEO and measuring the resulting changes of the binary orbit; and (3) study hyper-velocity collision effects on an asteroid, validating models for momentum transfer in asteroid impacts based on measured physical properties of the asteroid surface and sub-surface, and including long-term dynamics of impact ejecta. The primary DART objectives are to demonstrate a hyper-velocity impact on the Didymos moon and to determine the resulting deflection from ground-based observations. The DART impact on the Didymos secondary will change the orbital period of the binary which can be measured by supporting Earth-based optical and radar observations. The baseline DART mission launches in December, 2020 to impact the Didymos secondary in September,2022. There are multiple launch opportunities for DART leading to impact around the 2022 Didymos close approach to Earth. The AIM spacecraft will be launched in Dec. 2020 and arrive at Didymos in spring, 2022, several months before the DART impact. AIM will characterize the Didymos binary system

  2. Koronis binaries and the role of families in binary frequency

    NASA Astrophysics Data System (ADS)

    Merline, W. J.; Tamblyn, P. M.; Nesvorny, D.; Durda, D. D.; Chapman, C. R.; Dumas, C.; Owen, W. M.; Storrs, A. D.; Close, L. M.; Menard, F.

    2005-08-01

    Our ground-based adaptive optics observations of many larger Koronis members show no binaries, while our HST survey of smaller Koronis members (say smaller than 10 km) shows a surprising 20% binary fraction. Admittedly, this is from small-number statistics, but we nonetheless calculate a 99% confidence that the binary fraction is different from the 2% we observe among the larger (over 20km) main belt asteroids as a whole. In addition, we estimate that among the two young families (Karin and Veritas) that we surveyed for binaries in our HST Cy 13 program, the binary fraction appears to be less than 5%. These young families both have significantly smaller progenitors than the Koronis family. We have speculated that progenitor size may be a more important factor than age in determination of binary frequency. But here we suggest an alternative idea, that the binary fraction may be more related to what part of the family's size distribution is sampled. Our HST program targeted objects of the same physical sizes, but was clearly sampling further down the size distribution (to smaller sizes, relative to the largest remnant) in the Koronis sample than was the case for Karin and Veritas, which we sampled mostly at the larger sizes, relatively. Our SPH collision models are estimating the typical size-frequency distributions to be expected from catastrophic and non-catastrophic impact events. But they are also appear to be showing that the largest fragments from a collision are less likely to form binaries (as co-orbiting ejecta pairs) than are the smaller fragments. Thus, it might be expected that we would have found fewer binaries among Karin and Veritas than among the Koronis sample. In fact, models of the Karin breakup show binary formation to be unlikely in the size range measured. It some might be tempted to tie the small end of the main-belt binary population to the binaries seen among the NEAs (also small and also showing about 20% fraction), given the 20% fraction

  3. Nocardia asteroides keratitis.

    PubMed Central

    Hirst, L W; Harrison, G K; Merz, W G; Stark, W J

    1979-01-01

    Nocardia asteroides has been reported as the cause of keratitis in only 7 cases and of other ocular disease in another 12 cases. We report a case of N. asteroides keratitis that presented 3 weeks after rural trauma and progressed despite trials of appropriate antibiotics. Seven weeks after the origianl injury a successful conjunctival flap was placed over the cornea. The morphology and the sensitivity testing of N. asteroides to antibiotics appears necessary before reliable information can be obtained for clinical use. Moreover, our case did not show the relatively benign course of other reported cases of nocardia keratitis. Images PMID:380634

  4. Radar Investigations of Asteroids

    NASA Technical Reports Server (NTRS)

    Ostro, S. J.

    1984-01-01

    Radar investigations of asteroids, including observations during 1984 to 1985 of at least 8 potential targets and continued analyses of radar data obtained during 1980 to 1984 for 30 other asteroids is proposed. The primary scientific objectives include estimation of echo strength, polarization, spectral shape, spectral bandwidth, and Doppler shift. These measurements yield estimates of target size, shape, and spin vector; place constraints on topography, morphology, density, and composition of the planetary surface; yield refined estimates of target orbital parameters; and reveals the presence of asteroidal satellites.

  5. Applied Astronomy: Asteroid Prospecting

    NASA Astrophysics Data System (ADS)

    Elvis, M.

    2013-09-01

    In the age of asteroid mining the ability to find promising ore-bearing bodies will be valuable. This will give rise to a new discipline- "Applied Astronomy". Just as most geologists work in industry, not in academia, the same will be true of astronomers. Just how rare or common ore-rich asteroids are likely to be, and the skills needed to assay their value, are discussed here, with an emphasis on remote - telescopic - methods. Also considered are the resources needed to conduct extensive surveys of asteroids for prospecting purposes, and the cost and timescale involved. The longer-term need for applied astronomers is also covered.

  6. The absence of satellites of asteroids

    NASA Astrophysics Data System (ADS)

    Gehrels, T.; Drummond, J. D.; Levenson, N. A.

    1987-05-01

    A CCD-imaging survey was made for satellites of minor planets at distances of about 0.1 to 7 arcmin from 1 Ceres, 2 Pallas, 4 Vesta, 6 Hebe, 7 Iris, 8 Flora, 15 Eunomia, 29 Amphitrite, 41 Daphne, and 44 Nysa, with cursory inspection of 192 Nausikaa. Satellites larger than 3 km were not found in this work, nor in previous photographic surveys. Not finding them appears to be consistent with theoretical studies of collisions in the asteroid belt by several authors. The satellites would have to be larger than at least 30 km to be collisionally stable. Taking tidal stability into account, it is concluded that the only possible satellites for main-belt asteroids are near-contact binaries. The only other rare possibility for a satellite might be a piece of debris from a recent collision.

  7. Creation, detection, and evolution of Jupiter Trojan families

    NASA Astrophysics Data System (ADS)

    Karlsson, O.

    2011-07-01

    An investigation is carried out looking at correlations between the orbital elements of collisional targets and projectiles, estimating the number of interlopers in Trojan collisional families, and at the possibility of determining the ages of the Jupiter Trojan families by orbital integration. Real Trojans are integrated and close encounters are recorded in order to evaluate collisional circumstances between Trojans. Fictitious collisional families are created and integrated for 10 MJyr (million Julian years) forward in time and back again to the time of the collision in order to check the performance of the integrator, and the behaviour of the fictitious collisional fragments. Proper elements are calculated for the detection of family clustering using the hierarchically clustering method.

  8. 12. TROJAN MILL, INTERIOR SHOWING PRIMARY MILL No. 1 (MONADNOCK ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    12. TROJAN MILL, INTERIOR SHOWING PRIMARY MILL No. 1 (MONADNOCK CHILEAN) FROM EAST, c. 1912. ELEVATOR No. 1 ADJACENT TO MILL. CREDIT WR. - Bald Mountain Gold Mill, Nevada Gulch at head of False Bottom Creek, Lead, Lawrence County, SD

  9. 9. TROJAN MILL, EXTERIOR FROM NORTHWEST, c. 191828. WINTER SNOW ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    9. TROJAN MILL, EXTERIOR FROM NORTHWEST, c. 1918-28. WINTER SNOW SHOWS LINE OF CRUDE ORE BIN STAIR. CREDIT JW. - Bald Mountain Gold Mill, Nevada Gulch at head of False Bottom Creek, Lead, Lawrence County, SD

  10. Karin cluster formation by asteroid impact

    NASA Astrophysics Data System (ADS)

    Nesvorný, David; Enke, Brian L.; Bottke, William F.; Durda, Daniel D.; Asphaug, Erik; Richardson, Derek C.

    2006-08-01

    Insights into collisional physics may be obtained by studying the asteroid belt, where large-scale collisions produced groups of asteroid fragments with similar orbits and spectra known as the asteroid families. Here we describe our initial study of the Karin cluster, a small asteroid family that formed 5.8±0.2 Myr ago in the outer main belt. The Karin cluster is an ideal 'natural laboratory' for testing the codes used to simulate large-scale collisions because the observed fragments produced by the 5.8-Ma collision suffered apparently only limited dynamical and collisional erosion. To date, we have performed more than 100 hydrocode simulations of impacts with non-rotating monolithic parent bodies. We found good fits to the size-frequency distribution of the observed fragments in the Karin cluster and to the ejection speeds inferred from their orbits. These results suggest that the Karin cluster was formed by a disruption of an ≈33-km-diameter asteroid, which represents a much larger parent body mass than previously estimated. The mass ratio between the parent body and the largest surviving fragment, (832) Karin, is ≈0.15-0.2, corresponding to a highly catastrophic event. Most of the parent body material was ejected as fragments ranging in size from yet-to-be-discovered sub-km members of the Karin cluster to dust grains. The impactor was ≈5.8 km across. We found that the ejections speeds of smaller fragments produced by the collision were larger than those of the larger fragments. The mean ejection speeds of >3-km-diameter fragments were ≈10 ms. The model and observed ejection velocity fields have different morphologies perhaps pointing to a problem with our modeling and/or assumptions. We estimate that ˜5% of the large asteroid fragments created by the collision should have satellites detectable by direct imaging (separations larger than 0.1 arcsec). We also predict a large number of ejecta binary systems with tight orbits. These binaries, located in the

  11. Hilda Asteroid Colors: Insight into Giant Planet Migration?

    NASA Astrophysics Data System (ADS)

    Sharkey, Benjamin; Ryan, Erin L.; Woodward, Charles E.; Noll, Keith S.

    2016-01-01

    The Hilda asteroids are a unique population of small bodies that are locked in a 3:2 mean motion resonance with Jupiter. Unlike other resonances in the asteroid belt, the 3:2 is a stable resonance at 3.95 AU. Objects at this resonance have stable orbits for at least 2 GYr and, more likely, for the age of the Solar System. In an instantaneous top down view of the solar system, the Hildas approximately trace a triangle with over-densities of asteroids near the L3, L4 and L5 Jovian Lagrange points. This configuration is cited as evidence that Jupiter migrated inwards by ~0.4 AU. Stable Hilda orbits have mean eccentricities of 0.16 with typical perihelia of 3.15 AU. These latter properties, in terms of observability and accessibility to spacecraft, are a major advantage that distinguishes the Hildas from other populations of potential scientific interest such as the Jovian Trojans. The Outer Main Belt (OMB) also has many objects that may have originated in the outer protoplanetary disk (OPD). However, the OMB appears to be more mixed with objects from elsewhere in the Main Belt and enjoys only a small advantage in terms of brightness for a given diameter and albedo. The intrinsic collisional probability for objects in the Hilda population is also a factor of 3 to 5 less than the collisional probabilities for Trojan and OMB populations. Thus, the Hildas likely represent a significant population of objects unaltered due to collisional processing. Here we discuss findings of our ongoing NASA Planetary Astronomy program to obtain Sloan optical (g' r' i' z') colors of Hilda-group asteroids. The loci of these colors are compared to the Kuiper Belt populations to test post-formation migration effects of the giant planets in our solar system on the small body population. In part, this work was conducted as part of a University of Minnesota Undergraduate Research Scholarship, and is supported by NASA PAST Award NNX13AJ11G.

  12. IRAS asteroid families

    NASA Technical Reports Server (NTRS)

    Veeder, G. J.; Williams, J. G.; Tedesco, E. F.; Matson, D. L.

    1991-01-01

    The Infrared Astronomical Satellite (IRAS) sampled the entire asteroid population at wavelengths from 12 to 100 microns during its 1983 all sky survey. The IRAS Minor Planet Survey (IMPS) includes updated results for more recently numbered as well as other additional asteroids with reliable orbital elements. Albedos and diameters were derived from the observed thermal emission and assumed absolute visual magnitudes and then entered into the IMPS database at the Infrared Processing and Analysis Center (IPAC) for members of the Themis, Eos, Koronis and Maria asteroid families and compared with their visual colors. The IMPS results for the small (down to about 20 km) asteroids within these major families confirm trends previously noted for their larger members. Each of these dynamical families which are defined by their similar proper elements appears to have homogeneous physical properties.

  13. Dawn: mission to asteroids

    NASA Video Gallery

    NASA’s Dawn spacecraft is the first to orbit an object in the main asteroid belt. Join NASA scientist and program manager Tony Carro and find out what NASA is hoping to learn from these big rocks.

  14. Tiny Asteroid Approaches Earth

    NASA Video Gallery

    On Oct. 15, 2010, NASA astronomer Rob Suggs captured this view of the tiny asteroid 2010 TG19 as it made its way among the stars of the constellation Pegasus. It will continue to approach during th...

  15. Physical properties of asteroids

    NASA Technical Reports Server (NTRS)

    Veeder, G. J.

    1986-01-01

    The physical properties of asteroids were studied by telescopic observations and laboratory and theoretical work. Spectrophotometry from 0.3 to 1.1 microns and 1.2, 1.6 and 2.2 micron photometry allow spectral-compositional classification of asteroids. Based on laboratory data and telescopic observations, it was found that infrared measurements at 1.2, 1.6 and 2.2 microns provide a relatively rapid and accurate method for the classification of minor planets and are important in comparing asteroids with meteorites. This technique was proven and employed in an expanded survey of Apollo-Amor-Aten and other unusual asteroids recently scanned by IRAS.

  16. Asteroid Photometry: Tricky Business

    NASA Astrophysics Data System (ADS)

    Menke, J.

    2005-05-01

    Two nagging issues (among others) that tend to afflict asteroid photometrists (and others) are (1) concerns about just what a Flat is doing (and whether it makes things better or worse), and (2) how to handle those pesky stars that keep jumping into the path of the asteroid as it cruises across the field of view (FOV) using StarZap, a program written to subtract the offending stars. We'll discuss experiments done to get a handle on these two issues.

  17. Asteroid Evolution: Role of geotechnical properties

    NASA Astrophysics Data System (ADS)

    Sanchez Lana, Diego P.

    2015-08-01

    Over the last decade of Planetary research, the scientific community has made many advances in their understanding of the evolution of asteroids in the Solar System. One particular area of fruitful study started with the bold idea that these small planetary bodies could be gravitational aggregates and initially motivated by several different observations and early simulations.If we start with the idea that asteroids are aggregates of different sized components, and not singular monolithic bodies, it is possible to study them with some of the tools that have been used in the fields of Soil Mechanics and Granular Dynamics. In them, parameters such as porosity, cohesive and tensile strength, angles of friction and repose, particle size distributions, stress states, heterogeneity and yield criteria among others, determine how these granular systems will react when subjected to different, changing, external factors. These external factors are believed to have produced and shaped the asteroids that now exist around us and include solar photon momentum, gravitational tides, micro- and macro-impacts and internal energy dissipation.In this presentation we will review what is known about the surface and interiors of rubble pile asteroids, how different theoretical, experimental and simulation tools have been used to study them, how space mission and ground-based observations have shaped our understanding of their physical reality, and what we expect to learn from future missions. The talk will also touch on some of the latest findings obtained by different groups. In particular we will discuss the rotational evolution of self-gravitating aggregates under the influence of the YORP effect and how their angles of friction, tensile strength, porosity, internal structure and density give rise to different disruption modes and the role they play in the formation of asteroids pairs, tumblers and binary systems.

  18. Regolith Levitation on Small Fast Rotating Asteroids

    NASA Astrophysics Data System (ADS)

    Campo Bagatin, Adriano; Moreno, Fernando; Molina, Antonio

    2014-11-01

    A number of NEAs larger than few hundred meters are found with relatively high spin rates (from ~2.2 to less than 4 hr, depending on composition). On those bodies, local acceleration near their equator may be directed outwards, as in the case of the primaries of binary asteroids Didymos and 1996 FG3. They both are potential targets of future space missions. What are the effects of high spin states on regolith material at low asteroidal latitudes?NEAs come from the asteroid belt and are believed to be mostly gravitational aggregates at D > 0.5 - 1 km due to their former collisional evolution history (Campo Bagatin et al, 2001). Once in the inner Solar System, NEAs may undergo spin up evolution through YORP causing their components to disperse, shed mass or fission and eventually form binary, multiple systems or asteroid pairs (Walsh et al, 2008, Jacobson and Scheers, 2010, Pravec et al, 2009 and 2010). The end state of those events is often an object spinning above any Chandrasekhar stability limit, kept together by friction (Holsapple, 2007) and sometimes characterized by an equatorial “bulge”, as shown by radar images (Ostro et al, 2006).The centrifugal force acting on surface particles at equatorial latitudes may overcome the gravitational pull of the asteroid itself, and particles may leave its suface. Centrifugal is an apparent contact force, and as soon as particles lift off they mainly move under the gravitational field of the asteroid and the satellite, they may levitate for some time, land on the surface and repeat this cycle over and over. We are studying the motion of particles in the 1 μm to 10 cm range in the non-inertial reference frame of the rotating primary, accounting for centrifugal and Coriolis apparent forces as well as the gravitational fields of the primary, the secondary, the Sun and the radiation forces by the Sun itself. The main features of this effect are presented in the case of Didymos and 1996 FG3.

  19. Effect of Non-Sphericity of Gravitational Field of the Asteroid on the its Satellites Orbits Evolution

    NASA Astrophysics Data System (ADS)

    Troianskyi, V. V.

    Lately it has become possible to sufficiently precise definition of the physical and geometric characteristics of asteroid systems using radar observations (http://echo.jpl.nasa.gov/˜lance/binary.neas.html), which allowed calculating the asymmetry of the massive component of double and multiple asteroids for studying the dynamics of motion of their satellites.

  20. Asteroids: A History

    NASA Astrophysics Data System (ADS)

    Britt, Dan

    I finished reading Curtis Peebles' book Asteroids: A History with mixed emotions, but overall I was very disappointed. I enjoyed, with some reservations, the first few chapters, which describe the early days of asteroid astronomy. One thing that makes asteroid science enjoyable today is the rich collection of interesting and eccentric characters that share this profession.The 19th and early 20th centuries were no different. The story of these dedicated and sometimes strange individuals makes for lively reading. There was Hermann Goldschmidt, a German-born artist living over the Café Procope in Paris. In 1852, he caught the asteroid bug after attending a public lecture on astronomy, bought a telescope, and over the next 9 years discovered 14 asteroids by observing out of his apartment window with a 2-inch telescope! In those days, before astronomical photography, observers searched for asteroids by hand-drawing the starfield as seen through the telescope and then comparing it with another hand-drawn starfield done hours or nights later. Keen eyesight, steady hands, and the ability to draw accurately in the dark—and cold—were major advantages.

  1. Where Did Ceres Accrete - In Situ in the Asteroid Belt, Among the Giant Planets, or in the Primordial Transneptunian Belt?

    NASA Astrophysics Data System (ADS)

    McKinnon, William B.

    2012-10-01

    Ceres appears to be in rotational hydrostatic equilibrium and its density implies a substantial water ice fraction (20±5% by mass). Thermal evolution arguments strongly favor an icy outer shell as opposed to bound water throughout (Castillo-Rogez et al., Icarus 2001). Such iciness is unusually large for asteroids (or meteorites) as we know them. If Ceres formed in situ, this could be consistent with temporal evolution of the nebular snow-line across the asteroidal zone; icy planetesimals from further out could also contribute, prior to Jupiter formation. In the “grand tack” elaboration of the Nice model, Jupiter and Saturn undergo a two-stage, inward-then-outward, migration (Walsh et al., Nature 2011). Because Jupiter reverses migration direction close in, the primordial asteroid belt is emptied and then repopulated with bodies from both the inner and outer solar system. At Ceres’ position the majority of icy, outer solar system bodies derive from between the giant planets (out to 8 AU in the initial configuration). This new asteroid belt is predicted to be highly dynamically agitated, however, which may not be consistent with 39Ar/40Ar age constraints from meteorites. In the Nice model proper, KBOs/comets are embedded in large numbers into the jovian Trojan clouds and the outer asteroid belt (>2.6 AU) (Levison et al., Nature 2009). Although the model embedded cometary population does not include large bodies (>180 km diameter), the size-frequency distribution can be extended according to various proposed population indices. Without violating the Trojan population constraint, I find that embedding and retaining large (500-to-1000 km diameter) KBOs in the outer asteroid belt generally cannot be statistically ruled out at the 2σ level (though the original steep differential power-law index of Levison et al., -6.5, is not consistent with an embedded Ceres). Chemical and isotopic measurements (especially D/H) will be important future tests of Ceres

  2. Hilda Asteroid Compositions as an Observational Test of Giant Planet Migration Models

    NASA Astrophysics Data System (ADS)

    Ryan, Erin L.; Woodward, Charles E.; Sharkey, Benjamin; Noll, Keith S.

    2015-11-01

    Multiple lines of evidence indicate that planetary migration is a key part of the evolution of planetary systems. Planetary migration models of the solar system suggest that the Jupiter Trojan and Hilda stable resonances were repopulated during giant planet migration. We have completed a 4-year, multi-epoch photomteric multi-color survey of Hilda asteroids in order to determine individual object composition. The colors of ~500 Hildas are now known, a factor of 3 increase in objects with determined compositions compared to the start of our observations. We report the results of our survey in the context of the predictions from current dynamical migration models, identify the model inconsistent with the compositional results, and address future observational data that is required in addition to Hilda asteroid compositions to validate the Nice and Grand Tack models.This work supported by the University of Minnesota Undergraduate Research Scholarship Program and NASA Planetary Astronomy Grant NNX13AJ11G.

  3. Nuclear Astrophysics with the Trojan Horse Method

    NASA Astrophysics Data System (ADS)

    Spitaleri, Claudio

    2015-04-01

    In stars nuclear reactions take place at physical conditions that make very hard their measurements in terrestrial laboratories. Indeed in astrophysical environments nuclear reactions between charged nuclei occur at energies much lower than the Coulomb barrier and the corresponding cross section values lie in the nano or picobarn regime, that makes their experimental determination extremely difficult. This is due to the very small barrier Coulomb penetration factor, which produces an exponential fall off of the cross section as a function of energy. Additionally, the presence of the electron screening needs to be properly taken into account when dealing with cross section measurements at low-energies. The Trojan Horse Method (THM) represents an independent experimental technique, allowing one to measure astrophysical S(E)-factor bared from both Coulomb penetration and electron screening effects. The main advantages and the most recent results are here shown and discussed.

  4. Probable Disastrous Consequences of Collision Between Unknown Small (100 m) Asteroids with Known (Approximately 1 km) Near Earth Orbiting (NEO) Asteroids

    NASA Technical Reports Server (NTRS)

    Smalley, Larry

    2003-01-01

    The long-term stability of the Solar System is not well understood. Ironically its stability is taken for granted even though our knowledge of all the constituents [comets, asteroids. (The Asteroid Belt between Mars and Jupiter, Trojan Asteroids, Kuiper belt, Ort Cloud), planetoids, planets, moons, etc], and its long-term dynamics cannot be easily computed. At best one might say that the solar system is chaotic, but much of the time it seems to exists near a quasi-stationary state. An asteroid that passes near the Earth regularly returns with clock-like precision. Taking into account every known detail of its path through the solar system, its orbit is calculated forward thousands of years with no untoward calamity on the horizon. And then one day, this passive visitor slams into the Earth during a sunny afternoon picnic! Can this happen? Unfortunately, this is a real possibility in the ordinary history of the solar system. In fact our knowledge of the solar system in the small is sketchy, as will be pointed out. Events, which lie outside our awareness, can precipitate disasters that we may perceive when it's too late to launch effective counter measures. In this work, one such scenario is described and the direct consequences for the Earth are calculated.

  5. Radar Observations of Near-Earth and Main-Belt Asteroids

    NASA Astrophysics Data System (ADS)

    Benner, L. A. M.; Busch, M. W.; Giorgini, J. D.; Taylor, P. A.; Margot, J.-L.

    Radar is a very powerful technique for characterizing near-Earth and main-belt asteroids and for improving their orbits. This results from radar's ability to spatially resolve objects that often cannot be resolved at comparable resolutions by other groundbased techniques. Radar has revealed binary and contact binary objects, at least two triple systems, non-principal-axis rotators, objects whose radar reflectivity and circular polarization ratio have longitudinal variation, irregularly shaped near-Earth asteroids, objects with metallic compositions, objects with rubble-pile structures, and detailed radar images of main-belt asteroids that reveal complicated surfaces and substantial topographic relief. This chapter concentrates on the most significant advances in the field since publication of the radar chapter by Ostro et al. (2002) in Asteroids III. Detailed descriptions of asteroid radar observing techniques and terminology have appeared in Ostro (1993) and Ostro et al. (2002) (Asteroids III), so we refer readers to those papers for background information. This chapter emphasizes the first ground-truth tests of asteroid shape models by spacecraft encounters, population trends among near-Earth and main-belt asteroids, results for selected objects, new observing techniques, improved capabilities at radar telescopes, and improvements in three-dimensional shape modeling. We conclude with a discussion of future prospects.

  6. An Experimental Path to Constraining the Origins of the Jupiter Trojans Using Observations, Theoretical Predictions, and Laboratory Simulants

    NASA Astrophysics Data System (ADS)

    Blacksberg, Jordana; Eiler, John; Brown, Mike; Ehlmann, Bethany; Hand, Kevin; Hodyss, Robert; Mahjoub, Ahmed; Poston, Michael; Liu, Yang; Choukroun, Mathieu; Carey, Elizabeth; Wong, Ian

    2014-11-01

    Hypotheses based on recent dynamical models (e.g. the Nice Model) shape our current understanding of solar system evolution, suggesting radical rearrangement in the first hundreds of millions of years of its history, changing the orbital distances of Jupiter, Saturn, and a large number of small bodies. The goal of this work is to build a methodology to concretely tie individual solar system bodies to dynamical models using observables, providing evidence for their origins and evolutionary pathways. Ultimately, one could imagine identifying a set of chemical or mineralogical signatures that could quantitatively and predictably measure the radial distance at which icy and rocky bodies first accreted. The target of the work presented here is the Jupiter Trojan asteroids, predicted by the Nice Model to have initially formed in the Kuiper belt and later been scattered inward to co-orbit with Jupiter. Here we present our strategy which is fourfold: (1) Generate predictions about the mineralogical, chemical, and isotopic compositions of materials accreted in the early solar system as a function of distance from the Sun. (2) Use temperature and irradiation to simulate evolutionary processing of ices and silicates, and measure the alteration in spectral properties from the UV to mid-IR. (3) Characterize simulants to search for potential fingerprints of origin and processing pathways, and (4) Use telescopic observations to increase our knowledge of the Trojan asteroids, collecting data on populations and using spectroscopy to constrain their compositions. In addition to the overall strategy, we will present preliminary results on compositional modeling, observations, and the synthesis, processing, and characterization of laboratory simulants including ices and silicates. This work has been supported by the Keck Institute for Space Studies (KISS). The research described here was carried out at the Jet Propulsion Laboratory, Caltech, under a contract with the National

  7. Standard Asteroid Photometric Catalogue

    NASA Astrophysics Data System (ADS)

    Piironen, J.; Lagerkvist, C.-I.; Torppa, J.; Kaasalainen, M.; Warner, B.

    2001-12-01

    The Asteroid Photometric Catalogue (APC) is now in its fifth update with over 8600 lightcurves of more than 1000 asteroids in the database. The APC also has references of over one thousand lightcurves not in digital format. The catalogue has been published by Uppsala University Observatory and is distributed by request (contact: classe@astro.uu.se). The new update also includes a list of known asteroid rotational periods and a CD-ROM containing all the existing digital data in the APC. The total number of observed lightcurves is growing rapidly, not the least because of the new state-of-the-art equipment and growing interest among amateur astronomers. The photometric database is now so large that the present format must be altered to facilitate a user-friendly on-line service for the down- and uploading of data. We are proposing (and have started to construct) a new Internet-based Standard Asteroid Photometric Catalogue (SAPC). The website is planned to open during the first half of the year 2002. In addition to the data files, the site would contain the index and guide to the catalogue, a web-form for reporting observations, and some general observing guidelines (e.g., on filters, timing, etc.). There would also be a list of asteroids for which more observations are needed, together with recommended observing periods. This would be accompanied by an up-to-date collection of physical asteroid models based on photometric data, as well as links to observer network pages and other sites that work in collaboration with the catalogue project. Our aim is to develop this site into a global standard service used by everyone involved in asteroid photometry.

  8. M-class Asteroids: Soft Rock, Heavy Metal, Or None Of That Jazz?

    NASA Astrophysics Data System (ADS)

    Rivkin, Andrew S.

    2008-09-01

    M-class asteroids in the Tholen taxonomy have featureless spectra in the 0.3-1.0 micrometer region and moderate albedos. Taxonomic studies using reflectance spectra have long associated M-class asteroids with iron meteorites. Dozens of parent bodies are required by cosmochemists in order to generate the diversity seen in the iron meteorite population, representing both the disrupted cores of differentiated parent bodies as well as objects with more exotic histories. Unfortunately, the featureless spectrum of iron-nickel metal in the visible and near-IR can be matched by other mineralogies unrelated to iron meteorites. For instance, the primitive enstatite chondrites are also matches to M asteroids (Burbine et al. 2002). The past 20 years have led to increased recognition that the M asteroid class includes a diverse set of objects. Polarimetric, spectral, and radar observations in the 1980s and 1990s showed that at least some M asteroids were not iron-meteorite-like. In particular, observations by Jones et al. (1990), Rivkin et al. (1995), and Rivkin et al. (2000) found several M asteroids with absorptions near 3 micrometers, interpreted as hydrated minerals. This led to the proposal to separate those asteroids with bands into a new W class. Since 2000, new observations have been made by various workers in the near and mid-IR from the ground and with Spitzer. An increase in the sample size of radar-detected asteroids has provided additional insight into M and W asteroids. New meteorite classes have been delimited and characterized, some of which are of direct relevance to the M asteroid population. Discoveries of binary M-class asteroids have allowed densities to be measured Finally, the Rosetta spacecraft will fly by the M (W) asteroid 21 Lutetia in 2010. I will discuss the M/W asteroid class in the context of all of these new data. Thanks to the NASA PAST and PGG programs.

  9. Asteroid selection for mission opportunities. Appendix: Asteroid data sheets

    NASA Technical Reports Server (NTRS)

    1972-01-01

    The characteristics of asteroids selected as possible space mission objectives are presented. The asteroids are described according to: (1) magnitude, (2) spectral reflectivity; (3) phase factors, (4) polarization, (5) light curve, and (6) physical parameters. The data are tabulated on specific formats for each asteroid considered.

  10. NASA Radar Images Asteroid Toutatis

    NASA Video Gallery

    This 64-frame movie of asteroid Toutatis was generated from data by Goldstone's Solar System Radar on Dec. 12 and 13, 2012. In the movie clips, the rotation of the asteroid appears faster than it o...

  11. Asteroid Redirect Mission: Crew Segment

    NASA Video Gallery

    NASA announced the next step in the plan to retrieve an asteroid boulder from a near-Earth asteroid and redirect it into a stable orbit around the moon to carry out human exploration missions, all ...

  12. (25884) 2000 SQ4: A New Hungaria Binary?

    NASA Astrophysics Data System (ADS)

    Warner, Brian D.; Brinsfield, James W.; Vilagi, Jozef, Kornos, Leos; Harris, Alan W.

    2012-07-01

    CCD photometry observations of the Hungaria asteroid (25884) 2000 SQ4 were made at the Palmer Divide and Via Capote Observatories in 2011 November. This asteroid is of particular interest since it is part of an "asteroid pair", one of two asteroids believed to have once been a single object. Such pairs are believed to have been created due to fission after YORP spin up followed by the prompt ejection of the smaller body instead of it becoming a satellite. The two asteroids now occupy almost identical heliocentric orbits but do not circle one another. Analysis of the observations gives strong indications that 2000 SQ4 is a binary. If true, this would be the second member of an asteroid pair to have been found to have its own satellite.

  13. Geography of the asteroid belt

    NASA Technical Reports Server (NTRS)

    Zellner, B. H.

    1978-01-01

    The CSM classification serves as the starting point on the geography of the asteroid belt. Raw data on asteroid types are corrected for observational biases (against dark objects, for instance) to derive the distribution of types throughout the belt. Recent work on family members indicates that dynamical families have a true physical relationship, presumably indicating common origin in the breakup of a parent asteroid.

  14. Physical properties of small B-type asteroids from SDSS and WISE data

    NASA Astrophysics Data System (ADS)

    Ali-Lagoa, V.; Licandro, J.; Delbo, M.; Gil-Hutton, R.; Cañada-Assandri, M.; de Leon, J.; Pinilla-Alonso, N.; Campins, H.

    2014-07-01

    In this work, we study the physical properties from WISE data (Wright et al. 2010, Mainzer et al. 2011, Masiero et al. 2011) of a list of asteroids whose Sloan Digital Sky Survey (SDSS) data are compatible with those of B types in terms of their negative visible slopes (see, for example, de Leon et al. 2012). This allows us to extend to smaller-sized objects the study of spectroscopic B-types carried out by Ali-Lagoa et al. (2013), where we concluded that the members of the Pallas collisional family (PCF) have significantly different geometric albedos than the rest of the B types. Grav et al. (2012) pointed out that, even though the small-end members of the Jupiter Trojans appear to have higher geometric visible albedos than their larger counterparts (see their Figure 3), this is actually an artifact caused by the natural spread of the errors of the smaller objects and that there is no strong trend between size and albedo for the Jupiter Trojans. This motivates us to examine --- in a different context, since we are not proposing an albedo-size dependency --- the possibility that the abovementioned difference between the PCF and the rest of spectroscopic B types may also be caused by the former being smaller than the latter, which would introduce potential biases and/or result from larger relative errors in the values of the geometric albedo, since it is derived from poorer-quality asteroid absolute magnitudes and best-fit radiometric diameters.

  15. The active asteroids

    NASA Astrophysics Data System (ADS)

    Jewitt, D.

    2014-07-01

    Active asteroids simultaneously possess the orbits of main-belt asteroids and the physical appearances of comets; they show transient dust comae and solar-radiation pressure-swept tails. Apart from the shear surprise at finding such strange objects in the asteroid belt, the active asteroids are scientifically interesting for several reasons. Although we are limited to scarcely more than a dozen examples, the active asteroids already reveal the distinct action of different physical processes, each previously unobserved and carrying big-picture importance for understanding the solar system. 1. IMPACT. An unambiguous asteroid-asteroid impact was observed in 2010, when a 30-m scale body struck 100-km diameter (596) Scheila. Direct observations of impacts hold scientific importance both by sampling this natural process at full scale (compared with laboratory impacts conducted at tiny scales) and because impact statistics will allow us to assess the erosion rate in the asteroid belt and the contribution of asteroid dust to the interplanetary medium. 2. CRITICAL ROTATION. Several objects have been observed in which the best explanation seems to lie with spin-up to critical periods, presumably (but not certainly) caused by YORP. Examples of both likely mass-shedding (P/2010 A2, P/2013 P5) and full break-up (P/2013 R3, shown below) exist. It has been suggested that, at sub-kilometer sizes, spin-up disruption rates may surpass impact disruption rates. Future observations will show whether or not this is true, and may ultimately lead to an improved understanding of the physics of break-up. 3. THERMAL DISINTEGRATION. Geminid parent (3200) Phaethon shows on-going mass-loss at perihelion, driven by the 1000-K surface temperatures found there. The mechanisms appear to be some combination of thermal fracture and desiccation stress. 4. SUBLIMATION. Two objects have shown repeated activity that appears to be correlated with position in the orbit. The best example is 133P, which has

  16. Asteroid dynamics with GAIA

    NASA Astrophysics Data System (ADS)

    Delbo, Marco; Tanga, Paolo; Mignard, Francois; Carry, Benoit; Dell'Oro, Aldo; Hestroffer, Daniel; Granvik, Mikael; Muinonen, Karri; Pauwels, Thierry; Petit, Jean-Marc; Thuillot, William

    2015-08-01

    The astrometric mission Gaia of the European Space Agency (ESA) was launched in December 2013 and started the scientific phase of its 5-years-long, whole-sky survey in July 2014. Gaia characterise all astrophysical sources with V<=20, by measuring their position, motion and spectral properties. The high-precision astrometry (~25 micro-arcsec at V=15) is the unbeatable science driver of Gaia, promising a revolution in astrophysics, with the first data release in 2016.Solar system objects are serendipitously observed in the visible light by Gaia wide-field telescopes, with these observations providing astrometry and colour photometry for ~250,000 asteroids.Here, we report on the analysis of Gaia observations performed by the Data Processing and Analysis Consortium (DPAC). Regarding astrometry, the most important products are epoch positions of minor bodies and the stellar catalogue that will be used to improve the orbits of virtually all observed solar system bodies.We will detail how, from measurements of the orbital gravitational perturbations on small asteroids that have close encounters with more massive ones, Gaia data will allow the determination of the masses of about 150 of the largets asteroids, with important repercussion on dynamical and physical models of our solar system.Furthermore, Gaia is observing several near-Earth asteroids. For those with the longest arc, Gaia observations could help the detection of the drift in orbital semi-major axis due to the Yarkovsky effect. Beyond the Gaia observations themselves, one of the most important improvements for solar system science will be the Gaia stellar catalogue. This will allow recalibrating all astrometric (and photometric) measurements of solar system minor bodies obtained so far, with important improvements in the measurements of drift of the orbital semi-major axes of asteroids, in the modelling of the spreading of asteroid families, and in the ephemeris of the planets.

  17. Manuel's asteroid disruption technique

    PubMed Central

    John, Manuel; Ipe, Abraham; Jacob, Ivan

    2015-01-01

    A seventy-year-old male presented with dense asteroid hyalosis in both eyes. He had undergone cataract extraction in one eye 3 years ago, and the other eye had immature cataract. Both the autorefractor and dilated streak retinoscopy did not give readings and subjective visual improvement could not be achieved. Immediately following YAG posterior capsulotomy and anterior vitreous asteroid disruption, the vision improved to 20/20 with recordable auto refractor and streak retinoscopy values. Our initial experience indicates that the treatment is simple, safe and effective but needs controlled and prospective studies to confirm its long-term safety. PMID:23571244

  18. Asteroid Control and Resource Utilization

    NASA Astrophysics Data System (ADS)

    Paterson, G.; Radice, G.; Sanchez, J.-P.

    Asteroids are materials rich small solar system bodies which are prime candidates for rendezvous and mining. Up until now much attention has been focused on methods of destroying or deflecting potentially hazardous asteroids from colliding with the Earth. Recently however the concept of asteroid capture has been suggested whereby the asteroid is returned to an orbit close to the Earth before mining can begin. This paper aims to provide a comprehensive introduction to the field for new researchers and to put forward a number of novel strategies for asteroid control.

  19. Asteroid science by Gaia

    NASA Astrophysics Data System (ADS)

    Muinonen, Karri; Cellino, Alberto; Dell Oro, Aldo; Tanga, Paolo; Delbo, Marco; Mignard, Francois; Thuillot, William; Berthier, Jerome; Carry, Benoit; Hestroffer, Daniel; Granvik, Mikael; Fedorets, Grigori

    2016-07-01

    Since the start of its regular observing program in summer 2014, the Gaia mission has carried out systematic photometric, spectrometric, and astrometric observations of asteroids. In total, the unique capabilities of Gaia allow for the collection of an extensive and homogeneous data set of some 350,000 asteroids down to the limiting magnitude of G = 20.7 mag. The Gaia performance remains excellent over the entire available brightness range. Starting from 2003, a working group of European asteroid scientists has explored the main capabilities of the mission, defining the expected scientific impact on Solar System science. These results have served as a basis for developing the Gaia data reduction pipeline, within the framework of the Data Processing and Analysis Consortium (DPAC). We describe the distribution of the existing and forecoming Gaia observations in space and time for different categories of objects. We illustrate the peculiar properties of each single observation, as these properties will affect the subsequent exploitation of the mission data. We will review the expected performances of Gaia, basically as a function of magnitude and proper motion of the sources. We will further focus on the areas that will benefit from complementary observational campaigns to improve the scientific return of the mission, and on the involvement of the planetary science community as a whole in the exploitation of the Gaia survey. We will thus describe the current and future opportunities for ground-based observers and forthcoming changes brought by Gaia in some observational approaches, such as stellar occultations by transneptunian objects and asteroids. We will show first results from the daily, short-term processing of Gaia data, all the way from the onboard data acquisition to the ground-based processing. We illustrate the tools developed to compute predictions of asteroid observations, we discuss the procedures implemented by the daily processing, and we illustrate

  20. Genetic drift. Descent, lineage, and pedigree of the Trojans in Homer's Iliad.

    PubMed

    Bazopoulou-Kyrkanidou, Euterpe

    2007-12-15

    Homer's Iliad, is an epic poem that describes the last 70 days of the Trojan War, which was waged against the city of Troy by the Achaeans. Here, the descent, lineage, and the pedigree of the Trojans are presented. In the Illiad, they are said to have originated from Zeus. Beginning with him, the Trojan pedigree comprised 17 men in 8 generations with Dardanus, founder of Dardania in the second generation; Tros, King of the Trojans in the fourth generation; and the two heroes Hector and Aeneas in the eighth generation. In the seventh generation, Priam, as King of the Trojans, had a huge family, including 50 sons: 19 children with his wife Hecabe, other sons with many different wives, and some daughters as well. Hector, the first born, became leader of the Trojans. Hector's brother, Paris, in abducting Helen of Sparta, the wife of King Menelaus, caused the Trojan War to break out. PMID:17985360

  1. CHAOTIC ZONES AROUND GRAVITATING BINARIES

    SciTech Connect

    Shevchenko, Ivan I.

    2015-01-20

    The extent of the continuous zone of chaotic orbits of a small-mass tertiary around a system of two gravitationally bound primaries of comparable masses (a binary star, a binary black hole, a binary asteroid, etc.) is estimated analytically, as a function of the tertiary's orbital eccentricity. The separatrix map theory is used to demonstrate that the central continuous chaos zone emerges (above a threshold in the primaries' mass ratio) due to overlapping of the orbital resonances corresponding to the integer ratios p:1 between the tertiary and the central binary periods. In this zone, the unlimited chaotic orbital diffusion of the tertiary takes place, up to its ejection from the system. The primaries' mass ratio, above which such a chaotic zone is universally present at all initial eccentricities of the tertiary, is estimated. The diversity of the observed orbital configurations of biplanetary and circumbinary exosystems is shown to be in accord with the existence of the primaries' mass parameter threshold.

  2. Characteristics of Known Triple Asteroid Systems in the Main Belt

    NASA Astrophysics Data System (ADS)

    Marchis, Franck; Berthier, J.; Burns, K. J.; Descamps, P.; Durech, J.; Emery, J. P.; Enriquez, J. E.; Lainey, V.; Reiss, A. E.; Vachier, F.

    2010-10-01

    Since the discovery of "Sylvia Remus II” [1], around the binary asteroid (87) Sylvia [2] using the VLT/NACO instrument, the number of known triple systems increased significantly. Using the same instrument, a second moonlet was discovered around the binary (45) Eugenia [3] in 2007 [4]. Using an improved W.M. Keck II AO system, [5] announced the discovery of two 3 & 5-km moons orbiting the M-type asteroid (216) Kleopatra and more recently, [6] revealed the presence of two tiny 4-km moons around the C-type (93) Minerva. 3749 Balam is a different triple asteroid system whose existence was suggested by combining lightcurves and AO observations [7]. The properties of these triple systems have been derived individually and published recently [1, 8,9,10]. We will review and contrast their characteristics, including the orbital parameters of the satellite orbits, the size and shape of the primary and the satellites, their taxonomic classes, their bulk densities, and their ages. The goal of this study is to uncover clues concerning the formation and evolution of these mini-planetary systems. The National Science Foundation supported this research under award number AAG-0807468. 1. Marchis et al. Nature 2005 2. Brown et al., IAU 7588, 2001 3. Merline et al. Nature 401, 1999 4. Marchis et al. IAU 1073, 2007 5. Marchis et al. IAU 8980, 2008 6. Marchis et al., IAU 9069, 2009 7. Marchis et al., IAU 8928, 2008 8. Marchis et al., A Dynamical Solution of the Triple Asteroid System (45) Eugenia , Icarus in press, 2010 9. Descamps et al, Triplicity and Physical Characteristics of Asteroid 216 Kleopatra Icarus, in revision, 2010 10. Marchis et al., Triplicity and Physical Characteristics of the main-belt Asteroid (93) Minerva, Icarus submitted 2010

  3. 5426 Sharp: A Probable Hungaria Binary

    NASA Astrophysics Data System (ADS)

    Warner, Brian D.; Benishek, Vladimir; Ferrero, Andrea

    2015-07-01

    Initial CCD photometry observations of the Hungaria asteroid 5426 Sharp in 2014 December and 2015 January at the Center of Solar System Studies-Palmer Divide Station in Landers, CA, showed attenuations from the general lightcurve, indicating the possibility of the asteroid being a binary system. The secondary period was almost exactly an Earth day, prompting a collaboration to be formed with observers in Europe, which eventually allowed establishing two periods: P1 = 4.5609 ± 0.0003 h, A1 = 0.18 ± 0.01 mag and P2 = 24.22 ± 0.02 h, A2 = 0.08 ± 0.01 mag. No mutual events, i.e., occultations and/or eclipses, were seen, therefore the asteroid is considered a probable and not confirmed binary

  4. Size and Shape from Stellar Occultation Observations of the Double Jupiter Trojan Patroclus and Menoetius

    NASA Astrophysics Data System (ADS)

    Buie, Marc W.; Olkin, Catherine B.; Merline, William J.; Walsh, Kevin J.; Levison, Harold F.; Timerson, Brad; Herald, Dave; Owen, William M., Jr.; Abramson, Harry B.; Abramson, Katherine J.; Breit, Derek C.; Caton, D. B.; Conard, Steve J.; Croom, Mark A.; Dunford, R. W.; Dunford, J. A.; Dunham, David W.; Ellington, Chad K.; Liu, Yanzhe; Maley, Paul D.; Olsen, Aart M.; Preston, Steve; Royer, Ronald; Scheck, Andrew E.; Sherrod, Clay; Sherrod, Lowell; Swift, Theodore J.; Taylor, Lawrence W., III; Venable, Roger

    2015-03-01

    We present results of a stellar occultation by the Jupiter Trojan asteroid Patroclus and its nearly equal size moon, Menoetius. The geocentric mid-time of the event was 2013 October 21 06:43:02 UT. Eleven sites out of 36 successfully recorded an occultation. Seven chords across Patroclus yielded an elliptical limb fit of 124.6 by 98.2 km. There were six chords across Menoetius that yielded an elliptical limb fit of 117.2 by 93.0 km. There were three sites that got chords on both objects. At the time of the occultation we measured a separation of 664.6 km (0.247 arcsec) and a position angle for Menoetius of 265.°7 measured eastward from J2000 north. Combining this occultation data with previous light curve data, the axial ratios of both objects are 1.3 : 1.21 : 1, indicative of a mostly oblate ellipsoid with a slight asymmetry in its equatorial projection. The oblate shape is not an equilibrium shape for the current rotation period, but would be if it were rotating with an ˜8 h period. This faster period is consistent with a pre-evolved state of the system with an orbital separation that is 50% smaller. Our best estimate of the system density is 0.88 g cm-3.

  5. Herschel observations of the Marco Polo-R asteroid 175706 (1996 FG3).

    NASA Astrophysics Data System (ADS)

    O'Rourke, L.; Barucci, A.; Gònzalez-Garcìa, B.; Dotto, E.; Küppers, M.

    2012-09-01

    Background: The Marco Polo-R mission has been selected for the assessment study phase of the ESA M3 missions. This ESA-led sample return mission to the binary asteroid 1996 FG3 (launch window between 2020 and 2024) is proposed with a design that allows it to fit within the pre-defined cost cap of a M-class mission. The binary nature of the target will allow more precise measurements of mass, gravity, and density than for a single object, as well as additional insights into the geology and geophysics of the system. The asteroid has been classified by Binzel et al. [1] as a C-type. It is considered to be a typical example of a primitive object [2]. Dynamically, this is an Apollo asteroid with semimajor axis a of 1.054 AU, eccentricity e of 0.35, and and inclination i of 1.98 degrees. Measurements of the albedo derived from thermal infrared observations give a value of pV = 0.042 (+0.035 -0.017), and a combined diameter of D = 1.84 (+0.56 -0.47) km [3]. The Herschel observations : The MACH-11 (Measurements of 11 Asteroids & Comets) Programme observed this binary asteroid in two occasions in November of 2012. The observations performed had a duration of 0.6 hours with the asteroid pair moving rapidly at 6'/hr thus making removal of the background quite straightforward. The observations were performed in two observing blocks; the first block consisted of a 2 repetition blue/red map, the second block consisted of a 2 repetition green/red map, with the intention to observe the target at different phase angles. Our Results : Our measurements will serve to update the known radiometric properties for this binary asteroid through their inclusion into a thermophysical model (TPM) [4] which has been validated against a large database of asteroids including targets of other spacecraft mission e.g. Lutetia [5], Itokawa [6]. Using existing sets of published thermal observations (Spitzer, TNG NICS), combined with our Herschel observations, applied within this thermophysical model

  6. Asteroid Lightcurve Photometry

    NASA Astrophysics Data System (ADS)

    Harris, A. W.

    2004-05-01

    With the advent of modestly priced CCD cameras and computer controller and reduction software, amateurs can now do photometry on fainter targets than was possible even from large observatories only a decade or so ago. This has led to an explosion of lightcurve data that in turn has yielded rich results. We now have rotation periods for more than 1500 asteroids, extending down to objects only tens of meters in diameter, and well determined shapes and pole orientations of more than 100 objects. Among smaller asteroids, the dispersion in rotation rates ranges from minutes to months, with the slower ones mostly "tumbling," or in states of non-principal axis rotation. The fastest ones must be monolithic, as centrifugal force exceeds their gravity. But among those larger than a few hundred meters diameter, there is a "rotation barrier" at the rate where gravity and centrifugal force match, suggesting that most asteroids this large or larger are "rubble piles." The broad dispersion in spin rates, almost a bimodal distribution, has long been a mystery, but now appears likely to be due to thermal radiation torques from the randomly asymmetric shapes of small asteroids. This is a major paradigm shift from the past, where mutual collisions were considered to be the dominant (or only) evolutionary process affecting spins. Amateur observations have already contributed a great deal leading to this new view, and much remains to be done, providing abundant opportunities for amateur-professional collaborations.

  7. Physics of Asteroids

    NASA Astrophysics Data System (ADS)

    Albrecht, Rudolf

    1990-12-01

    The puropse of these observations is to obtain high resolution images of the asteroid Ceres with the present HST. All information given in the general form text pertains to pre-spherical aberration; observations as described there (DECON and ROT) will be carried out in Cy 9.

  8. THE ACTIVE ASTEROIDS

    SciTech Connect

    Jewitt, David

    2012-03-15

    Some asteroids eject dust, unexpectedly producing transient, comet-like comae and tails. First ascribed to the sublimation of near-surface water ice, mass-losing asteroids (also called 'main-belt comets') can in fact be driven by a surprising diversity of mechanisms. In this paper, we consider 11 dynamical asteroids losing mass, in nine of which the ejected material is spatially resolved. We address mechanisms for producing mass loss including rotational instability, impact ejection, electrostatic repulsion, radiation pressure sweeping, dehydration stresses, and thermal fracture, in addition to the sublimation of ice. In two objects (133P and 238P) the repetitive nature of the observed activity leaves ice sublimation as the only reasonable explanation, while in a third ((596) Scheila), a recent impact is the cause. Another impact may account for activity in P/2010 A2, but this tiny object can also be explained as having shed mass after reaching rotational instability. Mass loss from (3200) Phaethon is probably due to cracking or dehydration at extreme ({approx}1000 K) perihelion temperatures, perhaps aided by radiation pressure sweeping. For the other bodies, the mass-loss mechanisms remain unidentified, pending the acquisition of more and better data. While the active asteroid sample size remains small, the evidence for an astonishing diversity of mass-loss processes in these bodies is clear.

  9. Asteroids, Comets, Meteors 1991

    NASA Technical Reports Server (NTRS)

    Harris, Alan W. (Editor); Bowell, Edward (Editor)

    1992-01-01

    Papers from the conference are presented and cover the following topics with respect to asteroids, comets, and/or meteors: interplanetary dust, cometary atmospheres, atmospheric composition, comet tails, astronomical photometry, chemical composition, meteoroid showers, cometary nuclei, orbital resonance, orbital mechanics, emission spectra, radio astronomy, astronomical spectroscopy, photodissociation, micrometeoroids, cosmochemistry, and interstellar chemistry.

  10. Asteroidal and planetary analysis

    NASA Technical Reports Server (NTRS)

    Hartmann, W. K.

    1975-01-01

    Photometric, spectrophotometric, and radiometric investigations of asteroids and planets are reported. Profiles of the planetary disk were used to study the physical structure of the Uranus atmosphere, and thermal and photographic properties of Saturn rings were theoretically modelled. Ground-based Mars observations were made for long-term comparison with Mariner 9 results.

  11. The Binary Nature of 8077 Hoyle

    NASA Astrophysics Data System (ADS)

    Klinglesmith, Daniel A.; Hendrickx, Sebastian

    2016-07-01

    Analysis of CCD photometric observations of 8077 Hoyle shows that it is a binary asteroid with a synodic period for the primary of 2.746 ± 0.001 h and an orbital period of 53.862 ± 0.026 h. The amplitude of the primary lightcurve is 0.18 mag.

  12. A Geophysical Laboratory for Rubble Pile Asteroids: The BASiX Mission

    NASA Astrophysics Data System (ADS)

    Scheeres, Daniel J.; Chesley, Steven; Anderson, Robert C.

    2014-11-01

    Small rubble pile asteroids exhibit a diverse range of evolutionary behaviors and morphologies, driven by an array of poorly understood geophysical effects. The complex ways that these bodies evolve belies their simple structure: gravitational aggregates of shattered primitive bodies. Their evolution can be dramatic, such as seen in the active asteroids P/2013 P5 and P/2013 R3, or may be subtly masked, such as in the tide-BYORP equilibria of singly-synchronous binary asteroids. Their evolutionary outcomes can defy the imagination, such as asteroid 1950 DA which is spinning faster than its gravitational attraction yet is held together by weak van der Waals forces (Rozitis et al. 2014), or present us with profound mysteries, such as how the Almahata Sitta meteorite could be comprised of such diverse components. Beyond these motivations, the study of rubble pile asteroid geophysics can shed insight into any solar system environment where gravitational aggregates interact in a micro-gravity setting, ranging from the protoplanetary disc to planetary ring systems. The broad study of the geophysics of aggregates in such micro-gravity environments is becoming both a unifying theme and emerging field of study. Out of the many diverse and complex forms that rubble pile asteroids take on, the study of NEA binary asteroids can in particular be used to expose the geophysics of micro-gravity aggregates. Binaries are an expression of micro-gravity geophysics due to the manner in which they form and their continuing evolution. Due to our ability to visit, probe and interact with NEA, we can also turn them into geophysical laboratories. This talk will introduce the science of the Binary Asteroid in-situ Explorer (BASiX) Discovery mission, which proposes to turn the primitive C-Type binary asteroid (175706) 1996 FG3 into such a geophysical laboratory. Exploring this body enables us to probe a broad range of rubble pile asteroid properties: internal tidal dissipation (through FG3

  13. Primordial nucleosynthesis revisited via Trojan Horse Results

    NASA Astrophysics Data System (ADS)

    Pizzone, R. G.; Spartá, R.; Bertulani, C.; Spitaleri, C.; La Cognata, M.; Lamia, L.; Mukhamedzhanov, A.; Tumino, A.

    2016-05-01

    Big Bang Nucleosynthesis (BBN) requires several nuclear physics inputs and nuclear reaction rates. An up-to-date compilation of direct cross sections of d(d,p)t, d(d,n)3He and 3He(d,p)4He reactions is given, being these ones among the most uncertain bare-nucleus cross sections. An intense experimental effort has been carried on in the last decade to apply the Trojan Horse Method (THM) to study reactions of relevance for the BBN and measure their astrophysical S(E)-factor. The reaction rates and the relative error for the four reactions of interest are then numerically calculated in the temperature ranges of relevance for BBN (0.01

  14. Asteroid Kinetic Impactor Missions

    NASA Astrophysics Data System (ADS)

    Chesley, Steven

    2015-08-01

    Asteroid impact missions can be carried out as a relatively low-cost add-ons to most asteroid rendezvous missions and such impact experiments have tremendous potential, both scientifically and in the arena of planetary defense.The science returns from an impactor demonstration begin with the documentation of the global effects of the impact, such as changes in orbit and rotation state, the creation and dissipation of an ejecta plume and debris disk, and morphological changes across the body due to the transmission of seismic waves, which might induce landslides and toppling of boulders, etc. At a local level, an inspection of the impact crater and ejecta blanket reveals critical material strength information, as well as spectral differences between the surface and subsurface material.From the planetary defense perspective, an impact demonstration will prove humankind’s capacity to alter the orbit of a potentially threatening asteroid. This technological leap comes in two parts. First, terminal guidance systems that can deliver an impactor with small errors relative to the ~100-200 meter size of a likely impactor have yet to be demonstrated in a deep space environment. Second, the response of an asteroid to such an impact is only understood theoretically due to the potentially significant dependence on the momentum carried by escaping ejecta, which would tend to enhance the deflection by tens of percent and perhaps as much as a factor of a few. A lack of validated understanding of momentum enhancement is a significant obstacle in properly sizing a real-world impactor deflection mission.This presentation will describe the drivers for asteroid impact demonstrations and cover the range of such concepts, starting with ESA’s pioneering Don Quijote mission concept and leading to a brief description of concepts under study at the present time, including the OSIRIS-REx/ISIS, BASiX/KIX and AIM/DART (AIDA) concepts.

  15. Asteroid (90) Antiope: Another icy member of the Themis family?

    NASA Astrophysics Data System (ADS)

    Hargrove, Kelsey D.; Emery, Joshua P.; Campins, Humberto; Kelley, Michael S. P.

    2015-07-01

    Many members of the Themis family show evidence of hydration in the form of oxidized iron in phyllosilicates (Florczak, M. et al. [1999]. Astron. Astrophys. Suppl. Ser. 134, 463-471), and OH-bearing minerals (Takir, D., Emery, J.P. [2012]. Icarus 219, 641-654). The largest member, (24) Themis, has H2O ice covering its surface (Campins, H. et al. [2010]. Nature 464, 1320-1321; Rivkin, A.S., Emery, J.P. [2010]. Nature 464, 1322-1323). We have investigated the second largest Themis-family asteroid, (90) Antiope, which Castillo-Rogez and Schmidt (Castillo-Rogez, J.C., Schmidt, B.E. [2010]. Geophys. Res. Lett. 37, L10202) predict to have a composition that includes water ice and organics. We obtained 2-4-μm spectroscopy of (90) Antiope in 2006 and 2008, and we find an absorption in the 3-μm region clearly present in our 2008 spectrum and likely in our 2006 spectrum. Both spectra have rounded, bowl-shaped absorptions consistent with those ascribed to water ice as in the spectrum of Asteroid (24) Themis. We also present and compare Spitzer 8-12-μm mid-infrared spectra of (24) Themis and (90) Antiope. We find that (90) Antiope is lacking a "fairy castle" dusty surface, which is in contrast to (24) Themis, other Themis family members (Licandro, J. et al. [2012]. Astron. Astrophys. 537, A73), and Jupiter Trojans (e.g. Emery, J.P., Cruikshank, D.P., Van Cleve, J. [2006]. Icarus 182, 496-512). We conclude that the surface structure of (90) Antiope is most similar to Cybele Asteroid (121) Hermione (Hargrove, K.D. et al. [2012]. Icarus 221, 453-455).

  16. (3749) BALAM: A VERY YOUNG MULTIPLE ASTEROID SYSTEM

    SciTech Connect

    Vokrouhlicky, David

    2009-11-20

    Binaries and multiple systems among small bodies in the solar system have received wide attention over the past decade. This is because their observations provide a wealth of data otherwise inaccessible for single objects. We use numerical integration to prove that the multiple asteroid system (3749) Balam is very young, in contrast to its previously assumed age of 0.5-1 Gyr related to the formation of the Flora family. This work is enabled by a fortuitous discovery of a paired component to (3749) Balam. We first show that the proximity of the (3749) Balam and 2009 BR60 orbits is not a statistical fluke of otherwise quasi-uniform distribution. Numerical integrations then strengthen the case and allow us to prove that 2009 BR60 separated from the Balam system less than a million years ago. This is the first time the age of a binary asteroid can be estimated with such accuracy.

  17. Spacecraft exploration of asteroids - The 1988 perspective

    NASA Technical Reports Server (NTRS)

    Veverka, J.; Langevin, Y.; Farquhar, R.; Fulchignoni, M.

    1989-01-01

    Planned and proposed missions to study asteroids are examined. The history of asteroid studies in the 1980s is reviewed, including the proposed Mainbelt Asteroid Orbiter/Flyby mission. Main-belt asteroid flyby missions are discussed, including the Galileo, Cassini, and Comet Rendezvous Asteroid Flyby mission. Also, consideration is given to proposed missions to near-earth asteroids, the Vesta mission to perform in situ studies on two large asteroids, the Piazzi mission to flyby an Apollo-Amor-Aten asteroid using a Giotto-derived spacecraft, and the possibility of a Japanese asteroid flyby mission.

  18. On The Possibility Of Large KBOs Being Injected Into The Outer Asteroid Belt

    NASA Astrophysics Data System (ADS)

    McKinnon, William B.

    2008-09-01

    In the "Nice model,” an enormous quantity of KBOs are injected into the outer asteroid belt, >2.6 AU (Levison et al., submitted). Most are dynamically lost or collisionally destroyed, yet the remnant of this embedded population may be the source of the D-type asteroids. This raises the issue of whether larger KBOs were also embedded, and what they would look like today (and can we tell?). It is interesting to note that Ceres, the largest asteroid, is not that different from what we imagine dwarf planet KBOs to be like: differentiated, ice-rich (0.72-0.77 anhydrous rock by mass), and possessing unusual surface chemistry. In Levison et al., large KBOs are not considered; the embedded distribution is truncated at 200-km diameter, and the large (bright) end of the size-frequency distribution follows a very steep power-law slope (at least -6.4 differential). This is done, apparently, in order prevent the Trojan population from acquiring large members. If we extend this distribution to larger sizes, using the observed power-law slope of the bright end of today's Kuiper belt (about -4.5; Petit et al., in "The Solar System Beyond Neptune"), the probability of the outer asteroid belt acquiring a "Ceres” is a few percent; if the steep power-law component of Levison et al. is adjusted to the arguably more correct value, this probability rises to 10%. Large embedded asteroids are immune to collisional destruction, but they are subject to dynamical ejection. The probability of Ceres being a refugee from the Kuiper belt would appear to be small, but perhaps it was not as easily ejected as its much smaller D-type brethren. Regardless, its survival in the extreme collisional environment implied above implies bulk ice loss. The probability that one or more of the largest surviving asteroids came from the Kuiper belt should not be discounted.

  19. ASTROMETRIC MASSES OF 26 ASTEROIDS AND OBSERVATIONS ON ASTEROID POROSITY

    SciTech Connect

    Baer, James; Chesley, Steven R.; Matson, Robert D. E-mail: steve.chesley@jpl.nasa.gov

    2011-05-15

    As an application of our recent observational error model, we present the astrometric masses of 26 main-belt asteroids. We also present an integrated ephemeris of 300 large asteroids, which was used in the mass determination algorithm to model significant perturbations from the rest of the main belt. After combining our mass estimates with those of other authors, we study the bulk porosities of over 50 main-belt asteroids and observe that asteroids as large as 300 km in diameter may be loose aggregates. This finding may place specific constraints on models of main-belt collisional evolution. Additionally, we observe that C-group asteroids tend to have significantly higher macroporosity than S-group asteroids.

  20. A path to asteroid bulk densities: Simultaneous size and shape optimization from optical lightcurves and Keck disk-resolved data

    NASA Astrophysics Data System (ADS)

    Hanus, Josef; Viikinkoski, Matti; Marchis, Franck; Durech, Josef

    2015-11-01

    A reliable bulk density of an asteroid can be determined from the knowledge of its volume and mass. This quantity provides hints on the internal structure of asteroids and their origin. We compute volume of several asteroids by scaling sizes of their 3D shape models to fit the disk-resolved images, which are available in the Keck Observatory Archive (KOA) and the Virtual Observatory Binary Asteroids Database (VOBAD). The size of an asteroid is optimized together with its shape by the All-Data Asteroid Modelling inversion algorithm (ADAM, Viikinkoski et al., 2015, A&A, 576, A8), while the spin state of the original convex shape model from the DAMIT database is only used as an initial guess for the modeling. Updated sets of optical lightcurves are usually employed. Thereafter, we combine obtained volume with mass estimates available in the literature and derive bulk densities for tens of asteroids with a typical accuracy of 20-50%.On top of that, we also provide a list of asteroids, for which (i) there are already mass estimates with reported uncertainties better than 20% or their masses will be most likely determined in the future from Gaia astrometric observations, and (ii) their 3D shape models are currently unknown. Additional optical lightcurves are necessary in order to determine convex shape models of these asteroids. Our web page (https://asteroid-obs.oca.eu/foswiki/bin/view/Main/Photometry) contains additional information about this observation campaign.

  1. Multiple origins of asteroid pairs

    NASA Astrophysics Data System (ADS)

    Jacobson, Seth A.

    2016-01-01

    Rotationally fissioned asteroids produce unbound asteroid pairs that have very similar heliocentric orbits. Backward integration of their current heliocentric orbits provides an age of closest proximity that can be used to date the rotational fission event. Most asteroid pairs follow a predicted theoretical relationship between the primary spin period and the mass ratio of the two pair members that is a direct consequence of the YORP-induced rotational fission hypothesis. If the progenitor asteroid has strength, asteroid pairs may have higher mass ratios or faster rotating primaries. However, the process of secondary fission leaves the originally predicted trend unaltered. We also describe the characteristics of pair members produced by four alternative routes from a rotational fission event to an asteroid pair. Unlike direct formation from the event itself, the age of closest proximity of these pairs cannot generally be used to date the rotational fission event since considerable time may have passed.

  2. Physical properties of asteroid families

    NASA Astrophysics Data System (ADS)

    Masiero, J.; DeMeo, F.; Kasuga, T.; Parker, A.

    2014-07-01

    Asteroid families are created when a parent body undergoes a cratering or collisional disruption event, forming a population of smaller asteroids that initially have orbital elements similar to the parent. Members of asteroid families should also show a compositional similarity indicative of their lineage. This can be observed by comparing colors, spectra, and albedos of family members to each other and to the background population, and can be used to improve family associations by rejecting background objects and extending the search space. In this talk, we review the new data that has become available over the last decade from large-scale surveys of asteroid physical properties, recent work using these datasets to investigate family properties, and how this wealth of information has expanded our understanding of the formation and evolution of asteroid families. This work will be detailed in an upcoming chapter of the ''Asteroids IV'' book in 2015.

  3. Ultraviolet reflectance properties of asteroids

    NASA Astrophysics Data System (ADS)

    Butterworth, P. S.; Meadows, A. J.

    1985-05-01

    An analysis of the UV spectra of 28 asteroids obtained with the Internal Ultraviolet Explorer (IUE) satellite is presented. The spectra lie within the range 2100-3200 A. The results are examined in terms of both asteroid classification and of current ideas concerning the surface mineralogy of asteroids. For all the asteroids examined, UV reflectivity declines approximately linearly toward shorter wavelengths. In general, the same taxonomic groups are seen in the UV as in the visible and IR, although there is some evidence for asteroids with anomalous UV properties and for UV subclasses within the S class. No mineral absorption features are reported of strength similar to the strongest features in the visible and IR regions, but a number of shallow absorptions do occur and may provide valuable information on the surface composition of many asteroids.

  4. Planet-crossing asteroid survey

    NASA Technical Reports Server (NTRS)

    Wilder, P. D.

    1984-01-01

    The planet-crossing asteroid survey was begun in 1973 in order to study those asteroids which may intersect the orbits of the inner planets. Throughout the history of the survey, many of the various classes of asteroids were investigated. The near-Earth objects including the Apollo, Amor, and Aten families were studied in addition to asteroids whose orbits cross that of Mars, and some objects which are generally confined to the main belt. Observing was done on the 18 inch Schmidt telescope at the Palomar Mtn. Observatory. Typically, two consecutive photographs of a favorable field are taken. The exposure times of the films are usually twenty minutes and ten minutes, respectively. The telescope is guided at sidereal rate, so that asteroids will leave short trailed images. The films are then scanned for trails. By comparing the two films, the direction and approximate rate of motion of an asteroid may be determined.

  5. Asteroid Polarimetric Database V5.0

    NASA Astrophysics Data System (ADS)

    Lupishko, D.

    2006-07-01

    The Asteroid Polarimetric Database (APD) is a collection of asteroid polarimetry results compiled by D.F. Lupishko of Karazin Kharkiv National University, Ukraine. It is intended to include most asteroid polarimetry available through March 21, 2006.

  6. Asteroid Polarimetric Database V8.0

    NASA Astrophysics Data System (ADS)

    Lupishko, D.

    2014-07-01

    The Asteroid Polarimetric Database (APD) is a collection of asteroid polarimetry results compiled by D.F. Lupishko of Karazin Kharkiv National University, Ukraine. It is intended to include most asteroid polarimetry available through Feb. 10, 2014.

  7. ASTER: A Brazilian Mission to an Asteroid.

    NASA Astrophysics Data System (ADS)

    Winter, O. C.; Macau, E. E. N.; de Campos Velho, H.; Carruba, V.

    2012-05-01

    The first Brazilian mission to an asteroid is being planned. The target is the asteroid 2001 SN263, which has a NEA orbit of class AMOR. The mission is scheduled to be launched in 2015, reaching the asteroid in 2019.

  8. ASPIN: Research project on near-Earth asteroid photometry in frame of the ISON optical network

    NASA Astrophysics Data System (ADS)

    Molotov, Igor; Inasaridze, Raguli; Elenin, Leonid; Krugly, Yurij; Rumyantsev, Vasilij; Namkhai, Tungalag; Schmalz, Sergei; Tsogt-Ochir, Shijirbayar

    International Scientific Optical Network (ISON) represents one of largest systems specializing in observation of space objects. The main goal of project is observations of space debris. As an additional task the regular photometry of near-Earth asteroids (NEAs) is carried out using the network’s telescopes with apertures from 0.4 m up to 2.6 m (ASPIN project - Asteroid Search and Photometry Initiative). The photometry is aimed at getting lightcurves of asteroids for solving different tasks concerning with physical properties of these celestial bodies. The lightcurves have been obtained with a typical photometric accuracy of 0.01-0.03 mag. The main purpose of the observations is to study characteristics of asteroids such as rotation period, size and shape of the body, surface composition and other. It is expected to detect an influence of the YORP effect. Special attention is paid to the detection of binary asteroids. During 2013 the photometric observations have been carried out at 12 observatories during more than 250 nights which have been allowed to obtain the data on 40 NEAs as well as 15 main-belt asteroids. In result the rotation periods have been determined for 8 NEAs in the first time and refined for 10 NEAs. Two binary systems were discovered. Lightcurves of 11 main-belt asteroids with diameters less than 10 km (binary systems or members of small clusters) were obtained. Several of the observed asteroids were radar targets - between them the NEA (367943) Duende (or 2012 DA14), which was approached to the Earth in day of falling the Chelyabinsk meteor on February 23, 2013. The obtained results will be presented and perspectives of NEA photometry with ISON telescopes will be discussed.

  9. Coding as a Trojan Horse for Mathematics Education Reform

    ERIC Educational Resources Information Center

    Gadanidis, George

    2015-01-01

    The history of mathematics educational reform is replete with innovations taken up enthusiastically by early adopters without significant transfer to other classrooms. This paper explores the coupling of coding and mathematics education to create the possibility that coding may serve as a Trojan Horse for mathematics education reform. That is,…

  10. 10. TROJAN MILL, EXTERIOR FROM EAST, c. 191928. ADDITION TO ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    10. TROJAN MILL, EXTERIOR FROM EAST, c. 1919-28. ADDITION TO THE EAST END OF MILLING FLOOR VISIBLE WITH TRAM ENTRY DOOR. ALSO SEEN ARE THE ADDITIONS FOR MILL SOLUTION TANKS AND THE EAST SIDE OF SAMPLING ROOMS. CREDIT JW. - Bald Mountain Gold Mill, Nevada Gulch at head of False Bottom Creek, Lead, Lawrence County, SD

  11. 6. TROJAN MILL, PRIMARY THICKENER No. 1 FROM WEST, c. ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    6. TROJAN MILL, PRIMARY THICKENER No. 1 FROM WEST, c. 1914. TANK COMPLETED PRIOR TO ADDITION OF ENCLOSURE. ADDITION FOR BARREN SOLUTION TANK JUST VISIBLE BETWEEN THICKENER AND CRUSHED ORE BIN. CREDIT WR. - Bald Mountain Gold Mill, Nevada Gulch at head of False Bottom Creek, Lead, Lawrence County, SD

  12. 5. TROJAN MILL, PRIMARY THICKENER No. 1 FROM WEST, c. ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    5. TROJAN MILL, PRIMARY THICKENER No. 1 FROM WEST, c. 1914. TANK BARREL IS COMPLETE, BUT ADDITION ENCLOSURE NOT YET BEGUN. SAMPLING ADDITION SOUTH OF CRUSHED ORE BIN (CHANGE OF SIDING COLOR SHOWN AS COMPLETE. ROCK BIN VISIBLE ON FAR RIGHT. CREDIT WR. - Bald Mountain Gold Mill, Nevada Gulch at head of False Bottom Creek, Lead, Lawrence County, SD

  13. 13. TROJAN MILL, INTERIOR SHOWING PRIMARY MILL No. 1 (ALLIS ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    13. TROJAN MILL, INTERIOR SHOWING PRIMARY MILL No. 1 (ALLIS CHALMERS BALL MILL) FROM EAST, c. 1919. ELECTRIC MOTOR AND DRIVE SHAFT CLEARLY VISIBLE. CREDIT WR. - Bald Mountain Gold Mill, Nevada Gulch at head of False Bottom Creek, Lead, Lawrence County, SD

  14. Asteroid Ida Rotation Sequence

    NASA Technical Reports Server (NTRS)

    1994-01-01

    This montage of 14 images (the time order is right to left, bottom to top) shows Ida as it appeared in the field of view of Galileo's camera on August 28, 1993. Asteroid Ida rotates once every 4 hours, 39 minutes and clockwise when viewed from above the north pole; these images cover about one Ida 'day.' This sequence has been used to create a 3-D model that shows Ida to be almost croissant shaped. The earliest view (lower right) was taken from a range of 240,000 kilometers (150,000 miles), 5.4 hours before closest approach. The asteroid Ida draws its name from mythology, in which the Greek god Zeus was raised by the nymph Ida.

  15. Modeling of Fragmentation of Asteroids

    NASA Technical Reports Server (NTRS)

    Agrawal, Parul; Prabhu, Dinesh K.; Carlozzi, Alexander; Hart, Kenneth; Bryson, Katie; Sears, Derek

    2015-01-01

    The objective of this study is to understand fragmentation and fracture of a given asteroid and mechanisms of break-up. The focus of the present work is to develop modeling techniques for stony asteroids in 10m-100m range to answer two questions: 1) What is the role of material makeup of an asteroid in the stress distribution? 2)How is stress distribution altered in the presence of pre-existing defects?

  16. Silicates in Alien Asteroids

    NASA Technical Reports Server (NTRS)

    2009-01-01

    This plot of data from NASA's Spitzer Space Telescopes shows that asteroid dust around a dead 'white dwarf' star contains silicates a common mineral on Earth. The data were taken primarily by Spitzer's infrared spectrograph, an instrument that breaks light apart into its basic constituents. The yellow dots show averaged data from the spectrograph, while the orange triangles show older data from Spitzer's infrared array camera. The white dwarf is called GD 40.

  17. Asteroids, Comets, Meteors 2014

    NASA Astrophysics Data System (ADS)

    Muinonen, K.; Penttilä, A.; Granvik, M.; Virkki, A.; Fedorets, G.; Wilkman, O.; Kohout, T.

    2014-08-01

    Asteroids, Comets, Meteors focuses on the research of small Solar System bodies. Small bodies are the key to understanding the formation and evolution of the Solar System, carrying signals from pre-solar times. Understanding the evolution of the Solar System helps unveil the evolution of extrasolar planetary systems. Societally, small bodies will be important future resources of minerals. The near-Earth population of small bodies continues to pose an impact hazard, whether it be small pieces of falling meteorites or larger asteroids or cometary nuclei capable of causing global environmental effects. The conference series entitled ''Asteroids, Comets, Meteors'' constitutes the leading international series in the field of small Solar System bodies. The first three conferences took place in Uppsala, Sweden in 1983, 1985, and 1989. The conference is now returning to Nordic countries after a quarter of a century. After the Uppsala conferences, the conference has taken place in Flagstaff, Arizona, U.S.A. in 1991, Belgirate, Italy in 1993, Paris, France in 1996, Ithaca, New York, U.S.A. in 1999, in Berlin, Germany in 2002, in Rio de Janeiro, Brazil in 2005, in Baltimore, Maryland, U.S.A. in 2008, and in Niigata, Japan in 2012. ACM in Helsinki, Finland in 2014 will be the 12th conference in the series.

  18. Near Earth asteroid rendezvous

    NASA Technical Reports Server (NTRS)

    1992-01-01

    The Spacecraft Design Course is the capstone design class for the M.S. in astronautics at the Naval Postgraduate School. The Fall 92 class designed a spacecraft for the Near Earth Asteroid Rendezvous Mission (NEAR). The NEAR mission uses a robotic spacecraft to conduct up-close reconnaissance of a near-earth asteroid. Such a mission will provide information on Solar System formation and possible space resources. The spacecraft is intended to complete a NEAR mission as a relatively low-budget program while striving to gather as much information about the target asteroid as possible. A complete mission analysis and detailed spacecraft design were completed. Mission analysis includes orbit comparison and selection, payload and telemetry requirements, spacecraft configuration, and launch vehicle selection. Spacecraft design includes all major subsystems: structure, electrical power, attitude control, propulsion, payload integration, and thermal control. The resulting spacecraft demonstrates the possibility to meet the NEAR mission requirements using existing technology, 'off-the-shelf' components, and a relatively low-cost launch vehicle.

  19. Scientific mission to asteroid Phaethon

    NASA Astrophysics Data System (ADS)

    Padevet, V.; Lala, P.; Bumba, V.

    1986-10-01

    The asteroid 3200 Phaethon (previously 1983 TB) is being suggested for direct research by interplanetary probe. The asteroid, in an Apollo-type orbit, coincides with Geminid meteor stream and is so far the only body known to have features of an asteroid as well as a comet. A special program has been prepared for a desk computer to analyze interplanetary orbits with which the asteroid could be reached by the year 2000. Direct trajectories as well as trajectories with a gravitational maneuver near Venus have been tested.

  20. Photometry of Karin family asteroids

    NASA Astrophysics Data System (ADS)

    Hahn, G.; Mottola, S.; Sen, A. K.; Harris, A. W.; Kührt, E.; Mueller, M.

    2006-12-01

    We have performed photometric observations in the V-band of two asteroids belonging to the Karin asteroid family, (11728) Einer and (93690) 2000 VE21 , using the 2-m Himalayan Chandra Telescope, Hanle and 2k ×4k pixels CCD imager. We obtained measurements during two nights (November 25 and 26, 2005) which enabled information on the rotational periods and the lightcurve amplitudes of the asteroids to be derived. In addition, we derived the absolute magnitudes H, improving previously published values. These observations were performed to complement the IR observations obtained for a set of Karin family asteroids with the Spitzer space telescope.

  1. Roles of Shape and Internal Structure in Rotational Disruption of Asteroids

    NASA Astrophysics Data System (ADS)

    Hirabayashi, Masatoshi; Scheeres, Daniel Jay

    2015-08-01

    An active research area over the last decade has been to explore configuration changes of rubble pile asteroids due to rotationally induced disruption, initially driven by the remarkable fact that there is a spin period threshold of 2 hr for asteroids larger than a few hundred meters in size. Several different disruption modes due to rapid rotation can be identified, as surface shedding, fission and failure of the internal structure. Relevant to these discussions are many observations of asteroid shapes that have revealed a diversity of forms such as oblate spheroids with equatorial ridges, strongly elongated shapes and contact binaries, to say nothing of multi-body systems. With consideration that rotationally induced deformation is one of the primary drivers of asteroid evolution, we have been developing two techniques for investigating the structure of asteroids, while accounting for their internal mechanical properties through plastic theory. The first technique developed is an analytical model based on limit analysis, which provides rigorous bounds on the asteroid mechanical properties for their shapes to remain stable. The second technique applies finite element model analysis that accounts for plastic deformation. Combining these models, we have explored the correlation between unique shape features and failure modes. First, we have been able to show that contact binary asteroids preferentially fail at their narrow necks at a relatively slow spin period, due to stress concentration. Second, applying these techniques to the breakup event of active asteroid P/2013 R3, we have been able to develop explicit constraints on the cohesion within rubble pile asteroids. Third, by probing the effect of inhomogeneous material properties, we have been able to develop conditions for whether an oblate body will fail internally or through surface shedding. These different failure modes can be tested by measuring the density distribution within a rubble pile body through

  2. Trojan Tour Enabled by Solar Electric Based Mission Architecture

    NASA Astrophysics Data System (ADS)

    Smith, David B.; Klaus, K.; Behrens, J.; Bingaman, G.; Elsperman, M.; Horsewood, J.

    2013-10-01

    Introduction: A Trojan Tour and Rendezvous mission was one of the missions recommended by the most recent Planetary Science Decadal Survey. To the greatest extent possible, we will utilize this concept as a basis for re-examining the feasibility of a Solar Electric Propulsion (SEP) mission using a Boeing bus and Advanced Modular Power System (AMPS) solar power generation. The concept study for the Decadal survey concluded that s SEP mission is not viable because of low solar intensity levels. Mission Overview: With the advent of the new high power solar array technology, SEP missions to the outer planets become viable. The mission objective is 1143 Odysseus, a Trojan within the Trojan cloud, consistent with the Decadal Survey. Our mission analysis using SEP yielded a 6 year travel time. The Decadal mission concept uses REP (Radioisotope Electric Propulsion) mission objective. For comparison, the REP mission concept flight time was 8 years. For the purposes of our study, the science payload instruments, data rates, mass and power requirements are identical to the Trojan Decadal study. Our investments focus on innovative lightweight structures, advanced solar array deployment systems, high voltage power systems, and high efficiency solar cells. Summary/Conclusion: By using advanced, high power generation solar arrays, SEP becomes a viable alternative for Jupiter system missions. We show that a SEP mission reduces the flight time to the Trojans by 2.5 years. We also show that a proven commercial bus can provide the necessary pointing accuracy and stability required for the Decadal mission concept and its science instrument suite.

  3. Reconstructing the spin distributions of main-belt asteroids

    NASA Astrophysics Data System (ADS)

    Holsapple, K.

    2014-07-01

    spin. There are reasonable parameter choices that result in the average equilibrium curve consistent with the average spins, and with the resulting distributions centered along that curve. Then there is also a ''maximum equilibrium spin curve'' defined as the maximum possible spin an asteroid can attain, again as a function of asteroid size. That bounds the upper limit of asteroid spins, and has a downward power slope of 0.65. The fact that the maximum equilibrium curve intersection with the gravity limit curve occurs right at the 10 km upper bound of the data for binary asteroids strongly suggests that it is collision spin-up and not YORP that creates the spins that result in binaries. Finally, a single large impact into an asteroid with a pre-existing average spin can easily reduce its spin to near zero. That may explain the excess of slow spinners (as compared to Maxwellian) for the spin distributions of the asteroids with diameters larger than 10 km. These results and others will be presented at the conference.

  4. Rotational properties of asteroids: CCD observations of nine small asteroids

    NASA Astrophysics Data System (ADS)

    Birlan, M.; Barucci, M. A.; Angeli, C. A.; Doressoundiram, A.; De Sanctis, M. C.

    1996-06-01

    The observational programme on small asteroids (diameter less than about 50 km) is continued to enlarge the available dataset of small asteroids. The results are presented of CCD observations of nine small asteroids ( D≤23 km), performed in France with the 1.2 m telescope at Haute Provence Observatory and with the 2 m telescope at Pic du Midi Observatory. A total of 27 single night lightcurves for nine asteroids were obtained. All the objects were observed for the first time and rotational periods have been determined for all of the observed asteroids: 1992 Galvarino ( Psyn = 7 h.004), 2419 Moldavia ( Psyn = 2 h.412), 2921 Sophocles ( Psyn = 4 h.778), 3247 Di Martino ( Psyn = 5 h.445), 3623 Chaplin ( Psyn = 8 h.361), 3986 Rozhkovskij ( Psyn = 4 h.26), 4436 1983 EX ( Psyn = 6 h.656), 5046 1981 DQ ( Psyn = 6 h.050) and 1992 YG3 ( Psyn = 8 h.91).

  5. A Mobile Asteroid Surface Scout for the AIDA Mission

    NASA Astrophysics Data System (ADS)

    Ho, Tra Mi; Lange, Caroline; Grimm, Christian; Thimo Grundmann, Jan; Rößler, Johannes; Schröder, Silvio; Skoczylas, Thomas; Ziach, Christian; Biele, Jens; Cozzoni, Barbara; Krause, Christian; Küchemann, Oliver; Maibaum, Michael; Ulamec, Stephan; Lange, Michael; Mierheim, Olaf; Maier, Maximilian; Herique, Alain; Mascot Study Team

    2016-04-01

    The Asteroid Impact Deflection, AIDA, mission is composed of a kinetic impactor, DART and an observer, the Asteroid Impact Monitor, AIM, carrying among other payload a surface package, MASCOT2 (MSC2). Its proposed concept is based on the MASCOT lander onboard the HAYABUSA2 Mission (JAXA) to near-Earth asteroid (162173) Ryugu. MASCOT is a compact platform ('shoe box size') carrying a suite of 4 scientific instruments and has a landed mass of ~10kg. Equipped with a mobility mechanism, the MASCOT lander is able to upright and relocate on the targeted asteroid; thus providing in-situ data at more than one site. In the context of the AIDA Mission, the MASCOT2 lander would be carried by the AIM spacecraft and delivered onto Didymoon, the secondary object in the (65803) Didymos binary near-Earth asteroid system. Since the mission objectives of the AIM mission within the joint AIDA mission concept differ from JAXA's sample return mission HAYABUSA2, several design changes need to be studied and implemented. To support one of the prime objectives of the AIM mission, the characterization of the bulk physical properties of Didymoon, the main scientific payload of MSC2 is a low-frequency radar (LFR) to investigate the internal structure of the asteroid moon. Since the total science payload on MASCOT2 is limited to approximately 2.3 kg, the mass remaining for a suite of other experiments is in the range of 0.1 to 0.5 kg per instrument. Further requirements have a significant impact on the MSC2 design which will be presented. Among these are the much longer required operational lifetime than for MASCOT on HAYABUSA2, and different conditions on the target body such as an extremely low gravity due to its small size of Ø_[Didymoon] ~ 150m.

  6. The deployment of scientific packages to asteroid surfaces

    NASA Astrophysics Data System (ADS)

    Tardivel, Simon Charles Vincent

    A strategy for the deployment of landers to asteroid surfaces is described. The landing pods are scientific packages with no guidance, navigation and control system, and no specific landing apparatus, so as to minimize onboard platform and maximize payload. The landers are jettisoned from a main spacecraft at high altitude over the target. They impact its surface, bouncing multiple times before finally coming to rest. The amended gravity field of an asteroid is described in general and regions favorable to a deployment are found close to saddle equilibrium points. For elongated bodies and for binary systems, a linearization shows that a branch of the unstable manifold intersects the surface of the body; the strategy then consists of choosing initial conditions that will express this branch. For quasi-axisymmetric bodies, the initial velocity of the lander is increased to guarantee an impact. The efficacy of the strategy is numerically verified. A model of the asteroid surface and of the interaction between the pod and this surface is detailed. The asteroid surface is represented with three layers. The asteroid is first modeled using a mesh of triangular facets that can represent its global shape down to the presence of large boulders (greater than 1m). The presence of smaller rocks is accounted for via a stochastic model that generates random collisions with rocks, at impact with the surface or during lasting contact motion (rolling). Finally the interaction with the regolith is handled with a model of contact dynamics, including surface forces and torques (reaction, friction and rolling resistance). The rolling resistance force and torques experienced on regolith are defined and justified. Their coefficients are measured by experiments and explained by theory and finite-element simulations. Practical mission case studies are presented and discussed, for asteroid Itokawa, 1999 JU3, 1999 KW4 Alpha and Beta.

  7. Stability of binaries. Part II: Rubble-pile binaries

    NASA Astrophysics Data System (ADS)

    Sharma, Ishan

    2016-10-01

    We consider the stability of the binary asteroids whose members are granular aggregates held together by self-gravity alone. A binary is said to be stable whenever both its members are orbitally and structurally stable to both orbital and structural perturbations. To this end, we extend the stability analysis of Sharma (Sharma [2015] Icarus, 258, 438-453), that is applicable to binaries with rigid members, to the case of binary systems with rubble members. We employ volume averaging (Sharma et al. [2009] Icarus, 200, 304-322), which was inspired by past work on elastic/fluid, rotating and gravitating ellipsoids. This technique has shown promise when applied to rubble-pile ellipsoids, but requires further work to settle some of its underlying assumptions. The stability test is finally applied to some suspected binary systems, viz., 216 Kleopatra, 624 Hektor and 90 Antiope. We also see that equilibrated binaries that are close to mobilizing their maximum friction can sustain only a narrow range of shapes and, generally, congruent shapes are preferred.

  8. Matching asteroid population characteristics with a model constructed from the YORP-induced rotational fission hypothesis

    NASA Astrophysics Data System (ADS)

    Jacobson, Seth A.; Marzari, Francesco; Rossi, Alessandro; Scheeres, Daniel J.

    2016-10-01

    From the results of a comprehensive asteroid population evolution model, we conclude that the YORP-induced rotational fission hypothesis is consistent with the observed population statistics of small asteroids in the main belt including binaries and contact binaries. These conclusions rest on the asteroid rotation model of Marzari et al. ([2011]Icarus, 214, 622-631), which incorporates both the YORP effect and collisional evolution. This work adds to that model the rotational fission hypothesis, described in detail within, and the binary evolution model of Jacobson et al. ([2011a] Icarus, 214, 161-178) and Jacobson et al. ([2011b] The Astrophysical Journal Letters, 736, L19). Our complete asteroid population evolution model is highly constrained by these and other previous works, and therefore it has only two significant free parameters: the ratio of low to high mass ratio binaries formed after rotational fission events and the mean strength of the binary YORP (BYORP) effect. We successfully reproduce characteristic statistics of the small asteroid population: the binary fraction, the fast binary fraction, steady-state mass ratio fraction and the contact binary fraction. We find that in order for the model to best match observations, rotational fission produces high mass ratio (> 0.2) binary components with four to eight times the frequency as low mass ratio (<0.2) components, where the mass ratio is the mass of the secondary component divided by the mass of the primary component. This is consistent with post-rotational fission binary system mass ratio being drawn from either a flat or a positive and shallow distribution, since the high mass ratio bin is four times the size of the low mass ratio bin; this is in contrast to the observed steady-state binary mass ratio, which has a negative and steep distribution. This can be understood in the context of the BYORP-tidal equilibrium hypothesis, which predicts that low mass ratio binaries survive for a significantly

  9. Asteroids: Does Space Weathering Matter?

    NASA Technical Reports Server (NTRS)

    Gaffey, Michael J.

    2001-01-01

    The interpretive calibrations and methodologies used to extract mineralogy from asteroidal spectra appear to remain valid until the space weathering process is advanced to a degree which appears to be rare or absent on asteroid surfaces. Additional information is contained in the original extended abstract.

  10. Modeling Asteroid Spin-up with Cohesion

    NASA Astrophysics Data System (ADS)

    Walsh, Kevin J.; Richardson, D. C.; Michel, P.

    2008-09-01

    Recent work has shown that the gradual spin-up of cohesionless gravitational aggregates produces a wide range of outcomes depending on the specific configuration of the body, such as particle size distribution. One important outcome is the creation of binary asteroids, which requires bodies that can maintain spherical/oblate shapes as the body is spun to rapid rotation (Walsh et al., 2008, Nature, 454, 188-191). Our recent work includes a similar model which also models cohesion within the gravitational aggregate by way of a spring-like restoring force between neighboring particles that vanishes under high strain. We will present early results of gradual spin-up tests on gravitational aggregates covering a large range of starting conditions including the initial body shape and size, as well as varying configurations for the cohesion properties. These results will be compared to previous spin-up work as well as analytical theory. KJW and PM had the support of the French Programme National de Planétologie and the ACT Team of ESA and Ariadna Study 07/4111"Asteroid Rotational Fragmentation". KJW is also supported by the Henri Poincaré fellowship at the Observatoire de la Côte d'Azur, Nice, France, and Rotary International -- District 1730. DCR acknowledges support from the National Science Foundation under grant AST0708110 and the National Aeronautics and Space Administration under Grant No. NNX08AM39G.

  11. Penetrometry on an asteroid

    NASA Astrophysics Data System (ADS)

    Paton, M.; Green, S.; Ball, A.; Zarnecki, J.

    2014-07-01

    An end-of-mission landing on a near-Earth asteroid (like the NEAR landing on Eros) offers the opportunity to make dynamic force measurements followed by extended thermal investigations of the subsurface using simple sensors housed inside or outside of a penetrometer fixed to the spacecraft body. Such measurements could provide useful information on the microstructural and thermal properties of the regolith [1,2]. The high mass (about 100 kg) and low landing speed (< 2 m s^{-1}) of the spacecraft will provide enough momentum to push a penetrometer into an asteroid regolith. To simulate the impact under the low gravity of the asteroid, where the strength of the material would dominate the impact dynamics, it is desirable to remove the effect of Earth's gravity from both the target and the penetrometer/spacecraft. A low speed, high momentum, penetrometer test rig, built at The Open University [3] effectively removes the gravitational force acting on the landing penetrometer/spacecraft, but not the target. This enables tests to be conducted with regolith analogues of lower strength than would otherwise be possible if the acceleration due to gravity was acting on the landing spacecraft. The rig has been used for conducting penetrometry [4] and thermal experiments [2] in a variety of planetary regolith analogues. Here we examine the advantages and disadvantages of using a small penetrometer that can easily penetrate the surface. We also examine the advantages and disadvantages of using a large, wide penetrometer, that could possibly decelerate the spacecraft before its base impacts the surface and compacts the regolith beneath it. Laboratory tests comparing the two penetrometers are presented with some realistic calculations for simulating a spacecraft landing with a non-zero horizontal speed.

  12. Migration of Asteroidal Dust

    NASA Technical Reports Server (NTRS)

    Ipatov, S. I.; Mather, J. C.

    2003-01-01

    Using the Bulirsh Stoer method of integration, we investigated the migration of dust particles under the gravitational influence of all planets, radiation pressure, Poynting Robertson drag and solar wind drag for equal to 0.01, 0.05, 0.1, 0.25, and 0.4. For silicate particles such values of correspond to diameters equal to about 40, 9, 4, 2, and 1 microns, respectively [1]. The relative error per integration step was taken to be less than 10sup-8. Initial orbits of the particles were close to the orbits of the first numbered mainbelt asteroids.

  13. Asteroids and andesites.

    PubMed

    Arculus, Richard; Campbell, Ian H; McLennan, Scott M; Taylor, Stuart Ross

    2009-05-28

    The production of terrestrial andesites in subduction zones is well established. Day et al. describe two examples of meteorites (GRA 06128 and GRA 06129) that they claim to represent "an entirely new mode of generation of andesite crust compositions" on asteroids; this suggestion has wide implications for the generation of andesitic planetary crusts in general. However, here we show that compositional data, particularly for the rare-earth elements (REEs) and other lithophile elements, presented in their paper do not substantiate this claim. We conclude that existing mechanisms for andesite generation do not need revision. PMID:19478728

  14. Asteroid Impact Mission (aim) & Deflection Assessment: AN Opportunity to Understand Impact Dynamics and Modelling

    NASA Astrophysics Data System (ADS)

    Galvez, A.; Carnelli, I.; Fontaine, M.; Corral Van Damme, C.

    2012-09-01

    ESA's Future Preparation and Strategic Studies Office has carried out the Asteroid Impact Mission (AIM) study with the objective of defining an affordable and fully independent mission element that ESA could contribute to an Asteroid Impact Deflection Assessment campaign (AIDA), a joint effort of ESA, JHU/APL, NASA, OCA and DLR. The mission design foresees two independent spacecraft, one impactor (DART) and one rendezvous probe (AIM). The target of this mission is the binary asteroid system (65803) Didymos (1996 GT): one spacecraft, DART, would impact the secondary of the Didymos binary system while AIM would observe and measure any the change in the relative orbit. For this joint project, the timing of the experiment is set (maximum proximity of the target to Earth allowing for ground-based characterisation of the experiment) but the spacecraft are still able to pursue their missions fully independently. This paper describes in particular the AIM rendezvous mission concept.

  15. Discovery of a Satellite around a Near-Earth Asteroid

    NASA Astrophysics Data System (ADS)

    1997-07-01

    the data necessary for these determinations, observations will be continued during the present period of good visibility that lasts until September-October 1997. For this reason the discoverers have initiated an international observation campaign devoted to the study of this intriguing object and now involving astronomers from many countries. How common are such satellites? Satellites in orbit around small bodies in the solar system - asteroids and cometary nuclei - have been predicted on theoretical grounds for a long time, even though there is no consensus among planetary scientists about the actual numbers of such systems. Hints about the existence of asteroid satellites also come from the presence of double impact craters on the Moon and other planetary surfaces. This suggests that the projectiles forming these craters were `double' asteroids. Moreover, measurements obtained when an asteroid passes in front of a relatively bright star (a so-called `occultation') have on a few occasions shown features which could be interpreted as due to the presence of a satellite. However, because of the difficult nature of such measurements, it has never been possible to draw unambiguous conclusions. The existence of double asteroids was invoked earlier by Petr Pravec and Gerhard Hahn to explain the unusual features observed in the lightcurves of two other Earth-approaching asteroids 1991 VH and 1994 AW1 . In the case of Dionysus , however, it is possible to predict eclipse events and to confirm them by subsequent measurements. There is therefore mounting evidence that asteroid binary systems might be comparatively common. Observational programmes like the present one by the DLR and Ondrejov groups will help to verify this possibility. Where to find additional information Detailed and up-to-date information about (3671) Dionysus can be found in the Web at the following URL: http://earn.dlr.de/dionysus. Notes: [1] This institute and its parent organisation are known in Germany as

  16. Asteroid Size-Frequency Distribution (The ISO Deep Asteroid Survey)

    NASA Technical Reports Server (NTRS)

    Tedesco, Edward F.

    2001-01-01

    A total of six deep exposures (using AOT CAM01 with a 6" PFOV) through the ISOCAM LW10 filter (IRAS Band 1, i.e., 12 micro-m) were obtained on an approximately 15 arcminute square field centered on the ecliptic plane. Point sources were extracted using the technique described by Desert, et al. Two known asteroids appear in these frames and 20 sources moving with velocities appropriate for main belt asteroids are present. Most of the asteroids detected have flux densities less than 1 mJy, i.e., between 150 and 350 times fainter than any of the asteroids observed by Infrared Astronomy Satellite (IRAS). These data provide the first direct measurement of the 12 micro-m sky-plane density for asteroids on the ecliptic equator. The median zodiacal foreground, as measured by ISOCAM during this survey, is found to be 22.1 +/- 1.5 mJy per pixel, i.e., 26.2 +/- 1.7 MJy/sr. The results presented here imply that the actual number of kilometer-sized asteroids is significantly greater than previously believed and in reasonable agreement with the Statistical Asteroid Model.

  17. Multiple asteroid systems: Dimensions and thermal properties from Spitzer Space Telescope and ground-based observations

    NASA Astrophysics Data System (ADS)

    Marchis, F.; Enriquez, J. E.; Emery, J. P.; Mueller, M.; Baek, M.; Pollock, J.; Assafin, M.; Vieira Martins, R.; Berthier, J.; Vachier, F.; Cruikshank, D. P.; Lim, L. F.; Reichart, D. E.; Ivarsen, K. M.; Haislip, J. B.; LaCluyze, A. P.

    2012-11-01

    We collected mid-IR spectra from 5.2 to 38 μm using the Spitzer Space Telescope Infrared Spectrograph of 28 asteroids representative of all established types of binary groups. Photometric lightcurves were also obtained for 14 of them during the Spitzer observations to provide the context of the observations and reliable estimates of their absolute magnitudes. The extracted mid-IR spectra were analyzed using a modified standard thermal model (STM) and a thermophysical model (TPM) that takes into account the shape and geometry of the large primary at the time of the Spitzer observation. We derived a reliable estimate of the size, albedo, and beaming factor for each of these asteroids, representing three main taxonomic groups: C, S, and X. For large (volume-equivalent system diameter Deq > 130 km) binary asteroids, the TPM analysis indicates a low thermal inertia (Γ ⩽ ∼100 J s-1/2 K-1 m-2) and their emissivity spectra display strong mineral features, implying that they are covered with a thick layer of thermally insulating regolith. The smaller (surface-equivalent system diameter Deff < 17 km) asteroids also show some emission lines of minerals, but they are significantly weaker, consistent with regoliths with coarser grains, than those of the large binary asteroids. The average bulk densities of these multiple asteroids vary from 0.7-1.7 g/cm3 (P-, C-type) to ∼2 g/cm3 (S-type). The highest density is estimated for the M-type (22) Kalliope (3.2 ± 0.9 g/cm3). The spectral energy distributions (SEDs) and emissivity spectra, made available as a supplement document, could help to constrain the surface compositions of these asteroids.

  18. Multiple Asteroid Systems: Dimensions and Thermal Properties from Spitzer Space Telescope and Ground-based Observations

    NASA Technical Reports Server (NTRS)

    Marchis, F.; Enriquez, J. E.; Emery, J. P.; Mueller, M.; Baek, M.; Pollock, J.; Assafin, M.; Matins, R. Vieira; Berthier, J.; Vachier, F.; Cruikshank, D. P.; Lim, L. F.; Reichart, D. E.; Ivarsen, K. M.; Haislip, J. B.; LaCluyze, A. P.

    2012-01-01

    We collected mid-IR spectra from 5.2 to 38 microns using the Spitzer Space Telescope Infrared Spectrograph of 28 asteroids representative of all established types of binary groups. Photometric light curves were also obtained for 14 of them during the Spitzer observations to provide the context of the observations and reliable estimates of their absolute magnitudes. The extracted mid-IR spectra were analyzed using a modified standard thermal model (STM) and a thermophysical model (TPM) that takes into account the shape and geometry of the large primary at the time of the Spitzer observation. We derived a reliable estimate of the size, albedo, and beaming factor for each of these asteroids, representing three main taxonomic groups: C, S, and X. For large (volume-equivalent system diameter Deq > 130 km) binary asteroids, the TPM analysis indicates a low thermal inertia (Lambda < or = approx.100 J/1/2 s/K/sq m2) and their emissivity spectra display strong mineral features, implying that they are covered with a thick layer of thermally insulating regolith. The smaller (surface-equivalent system diameter Deff < 17 km) asteroids also show some emission lines of minerals, but they are significantly weaker, consistent with regoliths with coarser grains, than those of the large binary asteroids. The average bulk densities of these multiple asteroids vary from 0.7-1.7 g/cu cm (P-, C-type) to approx. 2 g/cu cm (S-type). The highest density is estimated for the M-type (22) Kalliope (3.2 +/- 0.9 g/cu cm). The spectral energy distributions (SEDs) and emissivity spectra, made available as a supplement document, could help to constrain the surface compositions of these asteroids.

  19. Modeling Momentum Transfer from Kinetic Impacts: Implications for Redirecting Asteroids

    SciTech Connect

    Stickle, A. M.; Atchison, J. A.; Barnouin, O. S.; Cheng, A. F.; Crawford, D. A.; Ernst, C. M.; Fletcher, Z.; Rivkin, A. S.

    2015-05-19

    Kinetic impactors are one way to deflect a potentially hazardous object headed for Earth. The Asteroid Impact and Deflection Assessment (AIDA) mission is designed to test the effectiveness of this approach and is a joint effort between NASA and ESA. The NASA-led portion is the Double Asteroid Redirect Test (DART) and is composed of a ~300-kg spacecraft designed to impact the moon of the binary system 65803 Didymos. The deflection of the moon will be measured by the ESA-led Asteroid Impact Mission (AIM) (which will characterize the moon) and from ground-based observations. Because the material properties and internal structure of the target are poorly constrained, however, analytical models and numerical simulations must be used to understand the range of potential outcomes. Here, we describe a modeling effort combining analytical models and CTH simulations to determine possible outcomes of the DART impact. We examine a wide parameter space and provide predictions for crater size, ejecta mass, and momentum transfer following the impact into the moon of the Didymos system. For impacts into “realistic” asteroid types, these models produce craters with diameters on the order of 10 m, an imparted Δv of 0.5–2 mm/s and a momentum enhancement of 1.07 to 5 for a highly porous aggregate to a fully dense rock.

  20. Modeling Momentum Transfer from Kinetic Impacts: Implications for Redirecting Asteroids

    DOE PAGESBeta

    Stickle, A. M.; Atchison, J. A.; Barnouin, O. S.; Cheng, A. F.; Crawford, D. A.; Ernst, C. M.; Fletcher, Z.; Rivkin, A. S.

    2015-05-19

    Kinetic impactors are one way to deflect a potentially hazardous object headed for Earth. The Asteroid Impact and Deflection Assessment (AIDA) mission is designed to test the effectiveness of this approach and is a joint effort between NASA and ESA. The NASA-led portion is the Double Asteroid Redirect Test (DART) and is composed of a ~300-kg spacecraft designed to impact the moon of the binary system 65803 Didymos. The deflection of the moon will be measured by the ESA-led Asteroid Impact Mission (AIM) (which will characterize the moon) and from ground-based observations. Because the material properties and internal structure ofmore » the target are poorly constrained, however, analytical models and numerical simulations must be used to understand the range of potential outcomes. Here, we describe a modeling effort combining analytical models and CTH simulations to determine possible outcomes of the DART impact. We examine a wide parameter space and provide predictions for crater size, ejecta mass, and momentum transfer following the impact into the moon of the Didymos system. For impacts into “realistic” asteroid types, these models produce craters with diameters on the order of 10 m, an imparted Δv of 0.5–2 mm/s and a momentum enhancement of 1.07 to 5 for a highly porous aggregate to a fully dense rock.« less

  1. Active Near Earth Asteroids

    NASA Astrophysics Data System (ADS)

    Jenniskens, Peter

    2015-08-01

    Past activity from Near Earth Asteroids is recorded in the meteoroid streams that cause our meteor showers. Automated meteoroid orbit surveys by photographic, low-light video, specular radar, and head-echo radar reflections are providing the first maps of meteor shower activity at different particle sizes. There are distinct differences in particle size distributions among streams. The underlaying mechanisms that created these streams are illuminated: fragmentation from spin-up or thermal stresses, meteoroid ejection by water vapor drag, and ejection of icy particles by CO and CO2 sublimation. The distribution of the meteoroid orbital elements probe the subsequent evolution by planetary perturbations and sample the range of dynamical processes to which Near Earth Asteroids are exposed. The non-stream "sporadic" meteors probe early stages in the evolution from meteoroid streams into the zodiacal dust cloud. We see that the lifetime of large meteoroids is generally not limited by collisions. Results obtained by the CAMS video survey of meteoroid orbits are compared to those from other orbit surveys. Since October 2010, over 200,000 meteoroid orbits have been measured. First results from an expansion into the southern hemisphere are also presented, as are first results from the measurement of main element compositions. Among the many streams detected so far, the Geminid and Sextantid showers stand out by having a relatively high particle density and derive from parent bodies that appear to have originated in the main belt.

  2. Asteroid Surface Geophysics

    NASA Astrophysics Data System (ADS)

    Murdoch, N.; Sánchez, P.; Schwartz, S. R.; Miyamoto, H.

    The regolith-covered surfaces of asteroids preserve records of geophysical processes that have occurred both at their surfaces and sometimes also in their interiors. As a result of the unique microgravity environment that these bodies possess, a complex and varied geophysics has given birth to fascinating features that we are just now beginning to understand. The processes that formed such features were first hypothesized through detailed spacecraft observations and have been further studied using theoretical, numerical, and experimental methods that often combine several scientific disciplines. These multiple approaches are now merging toward a further understanding of the geophysical states of the surfaces of asteroids. In this chapter we provide a concise summary of what the scientific community has learned so far about the surfaces of these small planetary bodies and the processes that have shaped them. We also discuss the state of the art in terms of experimental techniques and numerical simulations that are currently being used to investigate regolith processes occurring on small-body surfaces and that are contributing to the interpretation of observations and the design of future space missions.

  3. Trojan-horse attacks on quantum-key-distribution systems

    SciTech Connect

    Gisin, N.; Fasel, S.; Kraus, B.; Zbinden, H.; Ribordy, G.

    2006-02-15

    General Trojan-horse attacks on quantum-key-distribution systems, i.e., attacks on Alice or Bob's system via the quantum channel, are analyzed. We illustrate the power of such attacks with today's technology and conclude that all systems must implement active counter measures. In particular, all systems must include an auxiliary detector that monitors any incoming light. We show that such counter measures can be efficient, provided that enough additional privacy amplification is applied to the data. We present a practical way to reduce the maximal information gain that an adversary can gain using Trojan-horse attacks. This does reduce the security analysis of the two-way plug-and-play implementation to those of the standard one-way systems.

  4. A Trojan horse mechanism of bacterial pathogenesis against nematodes

    PubMed Central

    Niu, Qiuhong; Huang, Xiaowei; Zhang, Lin; Xu, Jianping; Yang, Dongmei; Wei, Kangbi; Niu, Xuemei; An, Zhiqiang; Bennett, Joan Wennstrom; Zou, Chenggang; Yang, Jinkui; Zhang, Ke-Qin

    2010-01-01

    Understanding the mechanisms of host–pathogen interaction can provide crucial information for successfully manipulating their relationships. Because of its genetic background and practical advantages over vertebrate model systems, the nematode Caenorhabditis elegans model has become an attractive host for studying microbial pathogenesis. Here we report a “Trojan horse” mechanism of bacterial pathogenesis against nematodes. We show that the bacterium Bacillus nematocida B16 lures nematodes by emitting potent volatile organic compounds that are much more attractive to worms than those from ordinary dietary bacteria. Seventeen B. nematocida-attractant volatile organic compounds are identified, and seven are individually confirmed to lure nematodes. Once the bacteria enter the intestine of nematodes, they secrete two proteases with broad substrate ranges but preferentially target essential intestinal proteins, leading to nematode death. This Trojan horse pattern of bacterium–nematode interaction enriches our understanding of microbial pathogenesis. PMID:20733068

  5. Scientific experimentation afforded by the International Asteroid Mission

    NASA Astrophysics Data System (ADS)

    The International Asteroid Mission (IAM) affords scientists the opportunity to perform interesting and important experimentations. This opportunity is not sufficient in its own right to mandate inclusion of science into the mission. Certain scientific experimentations are essential to the success of the mission, and are the driving force behind the inclusion of science. Instrument designs incorporate the need for direct contribution to the success of the mining mission. Examples of these applications include the search for additional candidate asteroids, especially at the Earth-Sun Trojan points, with an infrared telescope facility; a gamma ray burst detector provides the crew with real-time notification of potentially harmful solar-flare activity; and a materials processing laboratory provides information on the porosity, composition, and crystalline structure of samples to optimize the mining operations in addition to yielding great insight into the history and formation of the solar-system. Instrument designs have emphasized the use of off-the-shelf hardware, demonstrated technologies. Their scientific value is derived from the location on an interplanetary platform, not necessarily advancements in technology or detection methods. Instrumentation will be delivered to the IAM project after completion of a thorough certification program. The program will include qualification, acceptance, performance, thermal balance, thermal vacuum, vibration, electromagnetic susceptibility and compatibility, and calibration testing. After delivery to the assembly-site in low-Earth orbit, an additional series of functional and compatibility tests will be required prior to initiation of the mission. The scientific instrumentation proposed for the IAM consists of experiments using a Gamma Ray Burst Detector, a Infrared Observatory, a Materials Processing Facility, Long-Wavelength Radar, Seismic Measurement Devices, Cosmic Ray Detectors, Interplanetary Plasma Measurements, a Solar

  6. Trojan horse attacks on counterfactual quantum key distribution

    NASA Astrophysics Data System (ADS)

    Yang, Xiuqing; Wei, Kejin; Ma, Haiqiang; Sun, Shihai; Du, Yungang; Wu, Lingan

    2016-04-01

    There has been much interest in "counterfactual quantum cryptography" (T.-G. Noh, 2009 [10]). It seems that the counterfactual quantum key distribution protocol without any photon carrier through the quantum channel provides practical security advantages. However, we show that it is easy to break counterfactual quantum key distribution systems in practical situations. We introduce the two types of Trojan horse attacks that are available for the two-way protocol and become possible for practical counterfactual systems with our eavesdropping schemes.

  7. Compositional studies of primitive asteroids

    NASA Technical Reports Server (NTRS)

    Vilas, F.

    1988-01-01

    The composition of primitive asteroids and their relationship to satellites in the solar system will be studied by analyzing existing narrowband charge coupled device (CCD) reflectance spectra, acquiring additional spectra of asteroids and small satellites in the 0.5 to 1.0 micrometer spectral range, and exploring possibilities for obtaining compositional information in the blue-UV spectral region. Comparison with laboratory spectra of terrestrial chlorites and serpentines (phyllosilicates) and the clay minerals found in carbonaceous chondrite meteorites will continue. During 1987, narrowband CCD reflectance spectra of 17 additional asteroids were acquired. These spectra and spectra of 34 other asteroids have been used primarily for two studies: weak absorption features similar to those due to Fe2(+) and Fe2(+) - Fe3(+) transitions in iron oxides f ound in terrestrial chlorites and serpentines and carbonaceous chondrites have been identified in some primitive asteroid spectra. There is a first indication that asteroids grouped by heliocentric distance show similar weak absorption features. Nonparametric statistics are being applied to test the hypothesis of discrete remnants of a gradation in composition of outer-belt asteroids.

  8. Studies of asteroids and comets

    NASA Technical Reports Server (NTRS)

    Bowell, E. L. G.; Lumme, K.; Wasserman, L. C.; Kreidl, T. J. N.; Bus, S. J.; Skiff, B. A.

    1986-01-01

    About 3000 accurate positions of asteroids and comets were measured concentrating particularly on close-Earth approachers, but also targeting asteroids in need for follow-up observations because of unusual orbital characteristics or poor observational history. In 1985, 36 of the discoveries were numbered. Very accurate + or - 0.1 arcsec?) positional measurements were made of P/Halley on four nights in November and December 1985 in support of Giotto mission navigation. The asteroid orbit files were maintained, and ephemeris data for observational planning were supplied to colleagues worldwide. Considerable progress was made in understanding how information on asteroid shapes, surface albedo variegation, and rotational states can be derived from lightcurve and phase curve data. The analytical formulation was completed of a new asteroid magnitude system for the International Astronomical Union; the system was adopted at the New Delhi General Assembly by IAU Commission 20. Photographic photometry of about 10000 images of faint asteroids observed during the course of the United Kingdom Schmidt-CalTech Asteroid Survey in 1981 was continued, completing the microdensitometric scanning and all process of software development for data handling.

  9. Asteroid Size-Frequency Distribution

    NASA Technical Reports Server (NTRS)

    Tedesco, Edward F.

    2001-01-01

    A total of six deep exposures (using AOT CAM01 with a 6 inch PFOV) through the ISOCAM LW10 filter (IRAS Band 1, i.e. 12 micron) were obtained on an approximately 15 arcminute square field centered on the ecliptic plane. Point sources were extracted using the technique described. Two known asteroids appear in these frames and 20 sources moving with velocities appropriate for main belt asteroids are present. Most of the asteroids detected have flux densities less than 1 mJy, i,e., between 150 and 350 times fainter than any of the asteroids observed by IRAS. These data provide the first direct measurement of the 12 pm sky-plane density for asteroids on the ecliptic equator. The median zodiacal foreground, as measured by ISOCAM during this survey, is found to be 22.1 +/- 1.5 mJy per pixel, i.e., 26.2 +/- 1.7 MJy/sr. The results presented here imply that the actual number of kilometer-sized asteroids is significantly greater than previously believed and in reasonable agreement with the Statistical Asteroid Model.

  10. Radiometry of near-earth asteroids

    NASA Technical Reports Server (NTRS)

    Veeder, G. J.; Hanner, M. S.; Matson, D. L.; Tedesco, E. F.; Lebofsky, L. A.

    1989-01-01

    Infrared photometry is reported for 22 Aten, Apollo, and Amor asteroids. Thermal models are used to derive the corresponding radiometric albedos and diameters. Several of these asteroids appear to have surfaces of relatively high thermal inertia due to the exposure of bare rock or a coarse regolith. The Apollo asteroid 3103, 1982 BB, is recognized as class E. The Jupiter-crossing Amor asteroid 3552, 1983 SA, is confirmed as class D, but low albedos remain rare for near-earth asteroids.

  11. Beyond injection: Trojan horse underdense photocathode plasma wakefield acceleration

    SciTech Connect

    Hidding, B.; Rosenzweig, J. B.; Xi, Y.; O'Shea, B.; Andonian, G.; Schiller, D.; Barber, S.; Williams, O.; Pretzler, G.; Koenigstein, T.; Kleeschulte, F.; Hogan, M. J.; Litos, M.; Corde, S.; White, W. W.; Muggli, P.; Bruhwiler, D. L.; Lotov, K.

    2012-12-21

    An overview on the underlying principles of the hybrid plasma wakefield acceleration scheme dubbed 'Trojan Horse' acceleration is given. The concept is based on laser-controlled release of electrons directly into a particle-beam-driven plasma blowout, paving the way for controlled, shapeable electron bunches with ultralow emittance and ultrahigh brightness. Combining the virtues of a low-ionization-threshold underdense photocathode with the GV/m-scale electric fields of a practically dephasing-free beam-driven plasma blowout, this constitutes a 4th generation electron acceleration scheme. It is applicable as a beam brightness transformer for electron bunches from LWFA and PWFA systems alike. At FACET, the proof-of-concept experiment 'E-210: Trojan Horse Plasma Wakefield Acceleration' has recently been approved and is in preparation. At the same time, various LWFA facilities are currently considered to host experiments aiming at stabilizing and boosting the electron bunch output quality via a trojan horse afterburner stage. Since normalized emittance and brightness can be improved by many orders of magnitude, the scheme is an ideal candidate for light sources such as free-electron-lasers and those based on Thomson scattering and betatron radiation alike.

  12. Beyond injection: Trojan horse underdense photocathode plasma wakefield acceleration

    NASA Astrophysics Data System (ADS)

    Hidding, B.; Rosenzweig, J. B.; Xi, Y.; O'Shea, B.; Andonian, G.; Schiller, D.; Barber, S.; Williams, O.; Pretzler, G.; Königstein, T.; Kleeschulte, F.; Hogan, M. J.; Litos, M.; Corde, S.; White, W. W.; Muggli, P.; Bruhwiler, D. L.; Lotov, K.

    2012-12-01

    An overview on the underlying principles of the hybrid plasma wakefield acceleration scheme dubbed "Trojan Horse" acceleration is given. The concept is based on laser-controlled release of electrons directly into a particle-beam-driven plasma blowout, paving the way for controlled, shapeable electron bunches with ultralow emittance and ultrahigh brightness. Combining the virtues of a low-ionization-threshold underdense photocathode with the GV/m-scale electric fields of a practically dephasing-free beam-driven plasma blowout, this constitutes a 4th generation electron acceleration scheme. It is applicable as a beam brightness transformer for electron bunches from LWFA and PWFA systems alike. At FACET, the proof-of-concept experiment "E-210: Trojan Horse Plasma Wakefield Acceleration" has recently been approved and is in preparation. At the same time, various LWFA facilities are currently considered to host experiments aiming at stabilizing and boosting the electron bunch output quality via a trojan horse afterburner stage. Since normalized emittance and brightness can be improved by many orders of magnitude, the scheme is an ideal candidate for light sources such as free-electron-lasers and those based on Thomson scattering and betatron radiation alike.

  13. Distribution of spin axes and senses of rotation for 20 large asteroids

    NASA Astrophysics Data System (ADS)

    Magnusson, P.

    1986-10-01

    Various methods for pole determinations are examined. Previous data on the pole determination problem are reviewed. The principles and procedures of the amplitude-magnitude method which is based on a triaxial ellipsoidal model, and the epoch method which is based on the features of an observed light curves are described. It is observed that the amplitude-magnitude method provides good resolution in one-dimension and the epoch method is utilized to distinguish between prograde and retrograde senses of rotation. The data reveal that a combination of these methods is necessary to accurately predict spin axes and senses of rotation. A combination of the two methods is applied to the pole determinations for 20 main belt Trojan asteroids; the derived pole determinations are presented.

  14. HUBBLE: ON THE ASTEROID TRAIL

    NASA Technical Reports Server (NTRS)

    2002-01-01

    Astronomers Karl Stapelfeldt and Robin Evans have tracked down about 100 small asteroids by hunting through more than 28,000 archival images taken by the Hubble Space Telescope's Wide Field and Planetary Camera 2. Here is a sample of what they have found: four archival images that show the curved trails left by asteroids. [Top left]: Hubble captured a bright asteroid, with a visual magnitude of 18.7, roaming in the constellation Centaurus. Background stars are shown in white, while the asteroid trail is depicted in blue at top center. The trail has a length of 19 arc seconds. This asteroid has a diameter of one and one-quarter miles (2 kilometers), and was located 87 million miles from Earth and 156 million miles from the sun. Numerous orange and blue specks in this image and the following two images were created by cosmic rays, energetic subatomic particles that struck the camera's detector. [Top right]: Here is an asteroid with a visual magnitude of 21.8 passing a galaxy in the constellation Leo. The trail is seen in two consecutive exposures, the first shown in blue and the second in red. This asteroid has a diameter of half a mile (0.8 kilometers), and was located 188 million miles from Earth and 233 million miles from the sun. [Lower left]: This asteroid in the constellation Taurus has a visual magnitude of 23, and is one of the faintest seen so far in the Hubble archive. It moves from upper right to lower left in two consecutive exposures; the first trail is shown in blue and the second in red. Because of the asteroid's relatively straight trail, astronomers could not accurately determine its distance. The estimated diameter is half a mile (0.8 kilometers) at an Earth distance of 205 million miles and a sun distance of 298 million miles. [Lower right]: This is a broken asteroid trail crossing the outer regions of galaxy NGC 4548 in Coma Berenices. Five trail segments (shown in white) were extracted from individual exposures and added to a cleaned color image

  15. Recent astrophysical applications of the Trojan Horse Method to nuclear astrophysics

    SciTech Connect

    Spitaleri, C.; Cherubini, S.; Crucilla, V.; Gulino, M.; La Cognata, M.; Lamia, L.; Pizzone, R. G.; Puglia, S. M. R.; Rapisarda, G. G.; Romano, S.; Sergi, M. L.; Tumino, A.; Fu, C.; Tribble, R.; Banu, A.; Al-Abdullah, T.; Goldberg, V.; Mukhamedzhanov, A.; Tabacaru, G.; Trache, L.

    2008-05-21

    The Trojan Horse Method (THM) is an unique indirect technique allowing to measure astrophysical rearrangement reactions down to astrophysical relevant energies. The basic principle and a review of the recent applications of the Trojan Horse Method are presented. The applications aiming to the extraction of the bare astrophysical S{sub b}(E) for some two-body processes are discussed.

  16. Images of an Activated Asteroid

    NASA Astrophysics Data System (ADS)

    Kohler, Susanna

    2016-08-01

    In late April of this year, asteroid P/2016 G1 (PANSTARRS) was discovered streaking through space, a tail of dust extending behind it. What caused this asteroids dust activity?Asteroid or Comet?Images of asteroid P/2016 G1 at three different times: late April, late May, and mid June. The arrow in the center panel points out an asymmetric feature that can be explained if the asteroid initially ejected material in a single direction, perhaps due to an impact. [Moreno et al. 2016]Asteroid P/2016 G1 is an interesting case: though it has the orbital elements of a main-belt asteroid it orbits at just under three times the EarthSun distance, with an eccentricity of e ~ 0.21 its appearance is closer to that of a comet, with a dust tail extending 20 behind it.To better understand the nature and cause of this unusual asteroids activity, a team led by Fernando Moreno (Institute of Astrophysics of Andalusia, in Spain) performed deep observations of P/2016 G1 shortly after its discovery. The team used the 10.4-meter Great Canary Telescope to image the asteroid over the span of roughly a month and a half.A Closer Look at P/2016 G1P/2016 G1 lies in the inner region of the main asteroid belt, so it is unlikely to have any ices that suddenly sublimated, causing the outburst. Instead, Moreno and collaborators suggest that the asteroids tail may have been caused by an impact that disrupted the parent body.To test this idea, the team used computer simulations to model their observations of P/2016 G1s dust tail. Based on their models, they demonstrate that the asteroid was likely activated on February 10 2016 roughly 350 days before it reached perihelion in its orbit and its activity was a short-duration event, lasting only ~24 days. The teams models indicate that over these 24 days, the asteroid lost around 20 million kilograms of dust, and at its maximum activity level, it was ejecting around 8 kg/s!Comparison of the observation from late May (panel a) and two models: one in which

  17. Internal structures of asteroids and comets: Beyond spherical cows

    NASA Astrophysics Data System (ADS)

    Campo~Bagatin, A.; Alemañ, R.; Richardson, D.

    2014-07-01

    The internal structure of asteroids and comets is fundamentally unknown due to difficulties in sounding their interiors. The measurements carried out by space probes and the observations of binary asteroids (optical and radar) have provided good estimates of the masses of a few asteroids. From their sizes and shape models, estimates of their bulk densities are derived. Such bulk densities are usually smaller than the values corresponding to typical densities of meteorites with compositions matching surface spectroscopical observations of those asteroids, raising doubts about the actual composition of their interiors [1]. Similar arguments --- but with much larger uncertainties --- hold for comets. One interpretation of such low bulk densities is that part of the volume is occupied by voids in between the coherent components forming their global structures, qualifying them as gravitational aggregates (also, ''rubble piles''). The origin of such bodies is likely to be related to former catastrophic disruptions or to the original planetesimal accumulation process. Moreover, numerical simulations of the collisional evolution of the asteroid belt predict that most of the bodies between some hundreds of meters and about 100 km should be gravitational aggregates [2]. The situation is a little fuzzier in the case of comets. In this research, we try to reproduce the internal structure of some of the asteroids with best known physical characteristics (mass, size, rotation state) going beyond the simulation of components by just spheres. We perform numerical simulations that produce irregularly shaped (roughly 3-axial) asteroid components. Simulations are performed using the code PKDGRAV [3,4] with the new soft-sphere implementation [5] that manages the N-body gravitational problem and accounts for collisions between components and for friction between them. In order to mimic non-spherical shapes, groups of spherical particles --- the basic elements of the PKDGRAV code

  18. Trojans and Plutinos as probes of planet building

    NASA Astrophysics Data System (ADS)

    Alexandersen, Mike; Gladman, B.; Kavelaars, J. J.; Petit, J.; Gwyn, S.; Greenstreet, S.

    2013-10-01

    Planetesimals formed during planet formation are the building blocks of giant planet cores; some are preserved as large trans-neptunian objects (TNOs). Previous work has shown steep power-law distributions for TNOs of diameters > 100 km. Recent results claim a dramatic roll-over or divot in the size distribution of Neptunian Trojans and scattering TNOs, with a significant lack of intermediate-size D<100 km planetesimals. One theoretical explanation for this is that planetesimals were born big, skipping the intermediate sizes, contrary to the classical understanding of planetesimal formation. Exploration of the TNO size distribution requires more precisely calibrated detections in order to improve statistics on these results. We have searched a 32 sq.deg. area near RA=2 hr to a r-band limiting magnitude of m_r=24.6 using the Canada-France-Hawaii Telescope. This coverage was near the Neptunian L4 region to maximise our detection rate, as this is where Trojans reside and where Plutinos (and several other resonant populations) come to perihelion. Our program successfully detected, tracked and characterized 77 TNOs and Centaurs for up to 17 months, giving us the high-quality orbits needed for precise modelling. Among our detections were one Uranian Trojan (see Alexandersen et al. 2013 & abstract by Greenstreet et al.), two Neptunian Trojans, 18 Plutinos and many other resonant objects. This meticulously calibrated survey and the high-quality orbits obtained for the detected objects allow us to create and test models of TNO size and orbital distributions. We test these models using a survey simulator, which simulates the detectability of model objects, accounting for the constraints and biases of our survey. Thus, we set precise constraints on the size and orbital distributions of the Neptunian Trojans, Plutinos and other resonant populations. We show that the Plutino inclination distribution is dynamically colder than found by the Canada-France Ecliptic Plane Survey. We

  19. A Statistical Search for a Population of Exo-Trojans in the Kepler Data Set

    NASA Astrophysics Data System (ADS)

    Hippke, Michael; Angerhausen, Daniel

    2015-09-01

    Trojans are small bodies in planetary Lagrangian points. In our solar system, Jupiter has the largest number of such companions. Their existence is assumed for exoplanetary systems as well, but none have been found so far. We present an analysis by super-stacking ∼4 × 103 Kepler planets with a total of ∼9 × 104 transits, searching for an average Trojan transit dip. Our results give an upper limit to the average Trojan transiting area (per planet) that corresponds to one body of radius \\lt 460 {km} with 2σ confidence. We find a significant Trojan-like signal in a sub-sample for planets with more (or larger) Trojans for periods >60 days. Our tentative results can and should be checked with improved data from future missions like PLATO 2.0, and can guide planetary formation theories.

  20. Structural Stability of Asteroids

    NASA Astrophysics Data System (ADS)

    Hirabayashi, Toshi

    This thesis develops a technique for analyzing the internal structure of an irregularly shaped asteroid. This research focuses on asteroid (216) Kleopatra, a few-hundred-kilometer-sized main belt asteroid spinning about its maximum moment of inertia axis with a rotation period of 5.385 hours, to motivate the techniques. While Ostro et al. [117] reported its dog bone-like shape, estimation of its size has been actively discussed. There are at least three different size estimates: Ostro et al., Descamps et al., and Marchis et al. Descamps et al. reported that (216) Kleopatra has satellites and obtained the mass of this object. This research consists of determination of possible failure modes of (216) Kleopatra and its subsequent detailed stress analysis, with each part including an estimation of the internal structure. The first part of this thesis considers the failure mode of Kleopatra and evaluates the size from it. Possible failure modes are modeled as either material shedding from the surface or plastic failure of the internal structure. The surface shedding condition is met when a zero-velocity curve with the same energy level as one of the dynamical equilibrium points attaches to the surface at the slowest spin period, while the plastic failure condition is characterized by extending the theorem by Holsapple (2008) that the yield condition of the averaged stress over the whole volume is identical to an upper bound for global failure. The prime result shows that while surface shedding does not occur at the current spin period and thus cannot result in the formation of the satellites, the neck may be situated near its plastic deformation state. From the failure condition, we also find that the size estimated by Descamps et al. (2011) is the most structurally stable. The second part of this thesis discusses finite element analyses with an assumption of an elastic-perfectly plastic material and a non-associated flow rule. The yield condition is modeled as the

  1. Radar investigation of asteroids

    NASA Technical Reports Server (NTRS)

    Ostro, S. J.

    1982-01-01

    The dual polarization CW radar system which permits simultaneous reception in the same rotational sense of circular polarization as transmitted (i.e., the "SC" sense) and in the opposite ("OC") sense, was used to observe five previously unobserved asteroids: 2 Pallas, 8 Flora, 22 Kalliope, 132 Aethra, and 471 Papagena. Echoes from Pallas and Flora were easily detected in the OC sense on each of several nights. Weighted mean echo power spectra also show marginally significant responses in the SC sense. An approximately 4.5 standard deviation signal was obtained for Aethra. The Doppler shift of the peak is about 10 Hz higher than that predicted from the a priori trial ephemeris. Calculations are performed to determine whether this frequency offset can be reconciled dynamically with optical positions reported for Aethra.

  2. Asteroids to Quasars

    NASA Astrophysics Data System (ADS)

    Lugger, Phyllis M.

    2004-12-01

    Asteroid dedication; William Liller: Biographical Sketch; William Liller: Autobiographical Meanderings; Preface; List of Participants; Conference Photo; Part I. 1. Solar System Astronomy: Asteroids Joseph Veverka; 2. Sixteen years of stellar occultations James Elliott; 3. Comets to Quasars: Surface photometry from standard stars and the morphology of the galaxy-quasar interface Peter Usher; 4. Observing Solar Eclipses Jay Pasachoff; Part II. 5. Planetary Nebulae: new insights and opportunities Lawrence Aller; 6. Studies of planetary nebulae at radio wavelengths Yervant Terzian; 7. Optical identifications of compact galactic X-ray sources: Liller Lore Jonathan Grindlay; 8. Ages of globular clusters derived from BVRI CCD photometry Gonzalo Alcaino; 9. Stellar spectrum synthesis Jun Jugaku; 10. Mass exchange and stellar abundance anomalies Benjamin Peery; Part III. Extragalactic Astronomy: 11. The M31 globular cluster system John Huchra; 12. Spiral structure and star formation in galaxies Debra Elmegreen; 13. The discovery of hot coronae around early type galaxies William Forman and Christine Jones; 14. The morphology of clusters of galaxies, the formation efficiency of galaxies and the origin of the intracluster medium Christine Jones and William Forman; 15. Testing models for the dynamical evolution of clusters of galaxies Phyllis Lugger; 16. What is in the X-ray sky? Rudolph Schild; 17. Einstein deep surveys Stephen Murray, Christine Jones and William Forman; Part IV. History, Lore and Archaeoastronomy: 18. Robert Wheeler Willson: His Life and Legacy Barbara Welther; 19. The great mnemonics contest Owen Gingerich; 20. Hetu'u Rapanui: The archaeoastronomy of Easter Island William Liller; Indexes; Names; Objects; Subjects.

  3. Lightcurve Analysis of Six Asteroids

    NASA Astrophysics Data System (ADS)

    Garceràn, Alfonso Carreño; Macias, Amadeo Aznar; Mansego, Enrique Arce; Rodriguez, Pedro Brines; de Haro, Juan Lozano

    2015-10-01

    Photometric observations of six asteroids were made from 2015 March to May. We report the results of our lightcurve analysis for 425 Cornelia, 625 Xenia, 664 Judith, 785 Bredichina, 910 Anneliese, and 1831 Nicholson.

  4. Camping Out On An Asteroid

    NASA Video Gallery

    An astronaut and a geologist recently spent three days camping out as though they were on an asteroid. They were inside NASA's Space Exploration Vehicle prototype, flying it virtually in a digital ...

  5. Asteroid 433 Eros Approaches Earth

    NASA Video Gallery

    Asteroid 433 Eros made a close approach to Earth the morning of January 31st coming within 0.17 AU (15 million miles) of our planet. In this set of images taken that morning, the bright moving dot ...

  6. Asteroid Lightcurves from Estcorn Observatory

    NASA Astrophysics Data System (ADS)

    Klinglesmith, Daniel A., III; Hendrickx, Sebastian; Madden, Karl; Montgomery, Samuel

    2016-07-01

    We obtained lightcurves and amplitudes for 17 asteroids, 8 of which had unknown or poorly determined periods. The other 9 have known lightcurves at several oppositions and so are candidates for spin/shape analysis.

  7. Solar wind tans young asteroids

    NASA Astrophysics Data System (ADS)

    2009-04-01

    A new study published in Nature this week reveals that asteroid surfaces age and redden much faster than previously thought -- in less than a million years, the blink of an eye for an asteroid. This study has finally confirmed that the solar wind is the most likely cause of very rapid space weathering in asteroids. This fundamental result will help astronomers relate the appearance of an asteroid to its actual history and identify any after effects of a catastrophic impact with another asteroid. ESO PR Photo 16a/09 Young Asteroids Look Old "Asteroids seem to get a ‘sun tan' very quickly," says lead author Pierre Vernazza. "But not, as for people, from an overdose of the Sun's ultraviolet radiation, but from the effects of its powerful wind." It has long been known that asteroid surfaces alter in appearance with time -- the observed asteroids are much redder than the interior of meteorites found on Earth [1] -- but the actual processes of this "space weathering" and the timescales involved were controversial. Thanks to observations of different families of asteroids [2] using ESO's New Technology Telescope at La Silla and the Very Large Telescope at Paranal, as well as telescopes in Spain and Hawaii, Vernazza's team have now solved the puzzle. When two asteroids collide, they create a family of fragments with "fresh" surfaces. The astronomers found that these newly exposed surfaces are quickly altered and change colour in less than a million years -- a very short time compared to the age of the Solar System. "The charged, fast moving particles in the solar wind damage the asteroid's surface at an amazing rate [3]", says Vernazza. Unlike human skin, which is damaged and aged by repeated overexposure to sunlight, it is, perhaps rather surprisingly, the first moments of exposure (on the timescale considered) -- the first million years -- that causes most of the aging in asteroids. By studying different families of asteroids, the team has also shown that an asteroid

  8. The intrinsic Neptune Trojan orbit distribution: Implications for the primordial disk and planet migration

    NASA Astrophysics Data System (ADS)

    Parker, Alex H.

    2015-02-01

    The present-day orbit distribution of the Neptune Trojans is a powerful probe of the dynamical environment of the outer Solar System during the late stages of planet migration. In this work, I conservatively debias the inclination, eccentricity, and libration amplitude distributions of the Neptune Trojans by reducing a priori unknown discovery and follow-up survey properties to nuisance parameters and using a likelihood-free Bayesian rejection sampler for parameter estimation. Using this survey-agnostic approach, I confirm that the Neptune Trojans are a dynamically excited population: at >95% confidence, the Neptune Trojans' inclination width must be σi>11° . For comparison and motivation purposes, I also model the Jupiter Trojan orbit distributions in the same basis and produce new estimates of their parameters (Jupiter Trojan σi=14.4° ±0.5° , σL11=11.8° ±0.5° , and σe=0.061±0.002 ). The debiased inclination, libration amplitude, and eccentricity distributions of the Neptune Trojans are nominally very similar to those of the Jupiter Trojans. I use these new constraints to inform a suite of simulations of Neptune Trojan capture by an eccentric, rapidly-migrating Neptune from an initially dynamically-hot disk. These simulations demonstrate that if migration and eccentricity-damping timescales were short (τa≲ 10 Myr, τe≲ 1 Myr), the disk that Neptune migrated into must have been pre-heated (prior to Neptune's appearance) to a width comparable to the Neptune Trojans' extant width to produce a captured population with an inclination distribution width consistent with that of the observed population.

  9. Asteroid candidates for mass determination

    NASA Astrophysics Data System (ADS)

    Galád, A.

    2001-04-01

    The first 9511 numbered asteroids are studied in terms of their mutual closest approaches and encounter velocities during the period from November 6, 1967, to September 13, 2023. Several large asteroids (diameter 200 km and above) were (will be) encountered by smaller counterparts within a distance of 0.0200 AU. Thus, they are possible candidates for mass determination by the astrometrical method. Similarly, the search for effective perturbers is extended to even smaller asteroids for the much closer separation distance of 0.0020 AU and below. Only the simplified method for evaluation of observable effects on a perturbed body is used. Asteroid masses alone are not computed here. But a stronger criterion to reveal pairs for this purpose in comparison to some specially devoted papers should compensate for the difference and act as a reliable test. The best candidates for mass determination at present are asteroids (1), (2), (4), (10), (11), (24), (52) and (65). This list may be extended by at least (29) in the next 5 years and by many others in the next two decades. Several other strong perturbers from the last three decades are not included in the list, while there is still only a limited number of (or no) precise and reliable observations of perturbed asteroids before a close encounter. It seems that a perturbation by (10) is at least as effective as that by (2) and could be included in asteroid orbit determination in the future. Except for their bulk density determinations (knowing the size), the masses of perturbers could occasionally be used to improve the precision of the computed orbit for perturbed large-numbered and unnumbered asteroids as well.

  10. Asteroid Ida and Its Moon

    NASA Technical Reports Server (NTRS)

    1994-01-01

    This is the first full picture showing both asteroid 243 Ida and its newly discovered moon to be transmitted to Earth from the National Aeronautics and Space Administration's (NASA's) Galileo spacecraft--the first conclusive evidence that natural satellites of asteroids exist. Ida, the large object, is about 56 kilometers (35 miles) long. Ida's natural satellite is the small object to the right. This portrait was taken by Galileo's charge-coupled device (CCD) camera on August 28, 1993, about 14 minutes before the Jupiter-bound spacecraft's closest approach to the asteroid, from a range of 10,870 kilometers (6,755 miles). Ida is a heavily cratered, irregularly shaped asteroid in the main asteroid belt between Mars and Jupiter--the 243rd asteroid to be discovered since the first was found at the beginning of the 19th century. Ida is a member of a group of asteroids called the Koronis family. The small satellite, which is about 1.5 kilometers (1 mile) across in this view, has yet to be given a name by astronomers. It has been provisionally designated '1993 (243) 1' by the International Astronomical Union. ('1993' denotes the year the picture was taken, '243' the asteroid number and '1' the fact that it is the first moon of Ida to be found.) Although appearing to be 'next' to Ida, the satellite is actually in the foreground, slightly closer to the spacecraft than Ida is. Combining this image with data from Galileo's near-infrared mapping spectrometer, the science team estimates that the satellite is about 100 kilometers (60 miles) away from the center of Ida. This image, which was taken through a green filter, is one of a six-frame series using different color filters. The spatial resolution in this image is about 100 meters (330 feet) per pixel.

  11. Surface heterogeneity of small asteroids

    NASA Astrophysics Data System (ADS)

    Sasaki, Sho

    A rubble pile model of asteroid origin would predict averaged rather homogeneous surface of an asteroid. Previous spacecraft observations (mostly S-type asteroids) did not show large color/albedo variation on the surface. Vesta would be exceptional since HST observation suggested that its surface should be heterogeneous due to the impact excavation of the interior. As for a young asteroid (832) Karin (age being 5Ma), Sasaki et al. (2004) detected variation of infrared spectra which could be explained by the difference of the space weathering degree. They discussed the possibility of the survival of the old surface. However, the variation was not confirmed by later observation (Chapman et al., 2007; Vernazza et al., 2007). Recent observation of a small (550m) asteroid Itokawa by Hayabusa spacecraft revealed that Itokawa is heterogeneous in color and albedo although the overall rocky structure is considered as a rubble pile (Saito et al., 2006). The color difference can be explained by the difference of weathering degree (Ishiguro et al., 2008). The heterogeneity could be explained by mass movement caused by rapid rotation from YORP effect (Scheeres et al., 2007) or seismic shaking (Sasaki, 2006). Probably small silicate asteroids without significant regolith could have heterogeneous in color and albedo. On large asteroids (˜ a few 10km), regolith reaccumulation should have covered the underlying heterogeneity. References: Chapman, C. R. et al (2007) Icarus, 191, 323-329 Ishiguro, M. et al. (2008) MAPS, in press. Saito, J. et al. (2006) Science, 312, 1341-1344 Sasaki, S. (2006) in Spacecraft Reconnaissance of Asteroid and Comet Interiors Sasaki, T. et al (2004) Astrophys. J. 615, L161-L164 Scheeres, D. J. (2007) Icarus 188, 425-429 Vernazza, P. et al. (2007) Icarus 191, 330-336.

  12. Near-Earth Asteroid Returned Sample (NEARS)

    NASA Technical Reports Server (NTRS)

    Shoemaker, Eugene M.; Cheng, Andrew F.

    1994-01-01

    The concept of the Near-Earth Asteroid Returned Sample (NEARS) mission is to return to Earth 10-100 g from each of four to six sites on a near-Earth asteroid and to perform global characterization of the asteroid and measure mass, volume, and density to ten percent. The target asteroid for the mission is 4660 Nereus, probably a primitive C-type asteroid, with the alternate target being 1989ML, an extremely accessible asteroid of unknown type. Launch dates will be 1998, 2000, 2002, and 2004 on the Delta II-7925 launch vehicle. The mission objectives are three-fold. (1) Provide first direct and detailed petrological, chemical, age, and isotopic characterization of a near-Earth asteroid and relate it to terrestrial, lunar, and meteoritic materials. (2) Sample the asteroid regolith and characterize any exotic fragments. (3) Identify heterogeneity in the asteroid's isotopic properties, age, and elemental chemistry.

  13. Binary Plutinos

    NASA Astrophysics Data System (ADS)

    Noll, Keith S.

    2015-08-01

    The Pluto-Charon binary was the first trans-neptunian binary to be identified in 1978. Pluto-Charon is a true binary with both components orbiting a barycenter located between them. The Pluto system is also the first, and to date only, known binary with a satellite system consisting of four small satellites in near-resonant orbits around the common center of mass. Seven other Plutinos, objects in 3:2 mean motion resonance with Neptune, have orbital companions including 2004 KB19 reported here for the first time. Compared to the Cold Classical population, the Plutinos differ in the frequency of binaries, the relative sizes of the components, and their inclination distribution. These differences point to distinct dynamical histories and binary formation processes encountered by Plutinos.

  14. A new method based on the subpixel Gaussian model for accurate estimation of asteroid coordinates

    NASA Astrophysics Data System (ADS)

    Savanevych, V. E.; Briukhovetskyi, O. B.; Sokovikova, N. S.; Bezkrovny, M. M.; Vavilova, I. B.; Ivashchenko, Yu. M.; Elenin, L. V.; Khlamov, S. V.; Movsesian, Ia. S.; Dashkova, A. M.; Pogorelov, A. V.

    2015-08-01

    We describe a new iteration method to estimate asteroid coordinates, based on a subpixel Gaussian model of the discrete object image. The method operates by continuous parameters (asteroid coordinates) in a discrete observational space (the set of pixel potentials) of the CCD frame. In this model, the kind of coordinate distribution of the photons hitting a pixel of the CCD frame is known a priori, while the associated parameters are determined from a real digital object image. The method that is developed, which is flexible in adapting to any form of object image, has a high measurement accuracy along with a low calculating complexity, due to the maximum-likelihood procedure that is implemented to obtain the best fit instead of a least-squares method and Levenberg-Marquardt algorithm for minimization of the quadratic form. Since 2010, the method has been tested as the basis of our Collection Light Technology (COLITEC) software, which has been installed at several observatories across the world with the aim of the automatic discovery of asteroids and comets in sets of CCD frames. As a result, four comets (C/2010 X1 (Elenin), P/2011 NO1(Elenin), C/2012 S1 (ISON) and P/2013 V3 (Nevski)) as well as more than 1500 small Solar system bodies (including five near-Earth objects (NEOs), 21 Trojan asteroids of Jupiter and one Centaur object) have been discovered. We discuss these results, which allowed us to compare the accuracy parameters of the new method and confirm its efficiency. In 2014, the COLITEC software was recommended to all members of the Gaia-FUN-SSO network for analysing observations as a tool to detect faint moving objects in frames.

  15. Future Small Body Exploration after the Investigation of Asteroid Itokawa by Remote Sensing and Returned Sample Analyses

    NASA Astrophysics Data System (ADS)

    Yano, Hajime

    2015-03-01

    the endeavor. JAXAfs solar power sail mission aims for eventual rendezvous with Jovian Trojan asteroids, reservoir of D/P-type asteroids as either leftovers of Jupiter system formation or the second generation intruders from the Kuiper belt regions.

  16. Sizes, Shapes, and Satellites of Asteroids from Occultations

    NASA Astrophysics Data System (ADS)

    Waring Dunham, David; Herald, David Russell; Preston, Steve; Timerson, Bradley; Maley, Paul; Frappa, Eric; Hayamizu, Tsutomu; Talbot, John; Poro, Atila

    2015-08-01

    For 40 years, the sizes and shapes of dozens of asteroids have been determined from observations of asteroidal occultations. Some of the first evidence for satellites of asteroids was obtained from the early efforts; now, the orbits and sizes of some satellites discovered by other means have been refined from occultation observations. Also, several close binary stars have been discovered, and the angular diameters of some stars have been measured from analysis of these observations. The International Occultation Timing Association (IOTA) coordinates this activity worldwide, from predicting and publicizing the events, to accurately timing the occultations from as many stations as possible, and publishing and archiving the observations.The release of the Hipparcos and Tycho catalogs in 1997, from ESA’s Hipparcos space mission, revolutionized asteroidal occultation work, increasing the routine accuracy of the predictions and the annual number of observations by an order of magnitude. IOTA developed an efficient procedure for predicting the occultations using a combination of new star catalogs, based on Hipparcos and new star catalogs, generated mainly at the U. S. Naval Observatory (USNO), and new observations of asteroids relative to the improved astrometric nets mainly from USNO’s Flagstaff Astrometric Scanning Transit Telescope and JPL’s Table Mountain Observatory. In addition, many IOTA observers now use inexpensive low-light-level video cameras and specially built GPS video time inserters to accurately time the events. This automation has also allowed some observers to deploy multiple remote video stations across occultation paths. Then, one observer can record several “chords” across the asteroid. The cameras are sensitive enough that easily-hidden telescopes, many of which can be packed in standard air travel suitcases, can be used for many of the predicted occultations. IOTA’s network of regional coordinators collect and reduce the observations

  17. Lightcurve Analysis of the Hungaria Asteroid 30935 Davasobel

    NASA Astrophysics Data System (ADS)

    Benishek, Vladimir; Warner, Brian D.

    2015-07-01

    After a single night of observations at the Sopot Astronomical Observatory on 2014 Dec 31, there were possible indications of an attenuation that would indicate that the asteroid was binary. A collaboration was formed by the authors to obtain data from well-separated locations in case the potential satellite had an orbital period commensurate with an Earth day. The final data set contained no significant secondary period and led to a single period solution of P = 3.9769 ± 0.0005 h, A = 0.60 ± 0.03 mag.

  18. Radar Imaging of Asteroids

    NASA Astrophysics Data System (ADS)

    Ostro, S. J.

    1996-09-01

    Measurements of the distribution of echo power in time delay (range) and Doppler frequency (line-of-sight velocity) can synthesize images of near-Earth and main-belt asteroids (NEAs and MBAs) that traverse the detectability windows of groundbased radar telescopes. Under ideal circumstances, current radar waveforms can achieve decameter surface resolution. The number of useful pixels obtainable in an imaging data set is of the same order as the signal-to-noise ratio, SNR, of an optimally filtered, weighted sum of all the data. (SNR increases as the square root of the integration time.) The upgraded Arecibo telescope which is about to become operational, should be able to achieve single-date SNRs {\\underline>} (20,100) for an average of (35,5) MBAs per year and single-date SNRs {\\underline>} (20,100,1000) for an average of (10,6,2) of the currently catalogued NEAs per year; optical surveying of the NEA population could increase the frequency of opportunities by an order of magnitude. The strongest imaging opportunities predicted for Arecibo between now and the end of 1997 include (the peak SNR/date is in parentheses): 9 Metis (110), 27 Euterpe (170), 80 Sappho (100), 139 Juewa (140), 144 Vibilia (140), 253 Mathilde (100), 2102 Tantalus (570), 3671 Dionysus (170), 3908 1980PA (4400), 4179 Toutatis (16000), 4197 1982TA (1200), 1991VK (700), and 1994PC1 (7400). A delay-Doppler image projects the echo power distribution onto the target's apparent equatorial plane. One cannot know a priori whether one or two (or more) points on the asteroid contributed power to a given pixel, so accurate interpretation of delay-Doppler images requires modeling (Hudson, 1993, Remote Sensing Rev. 8, 195-203). Inversion of an imaging sequence with enough orientational coverage can remove "north/south" ambiguities and can provide estimates of the target's three-dimensional shape, spin state, radar scattering properties, and delay-Doppler trajectory (e.g., Ostro et al. 1995, Science 270, 80

  19. Potential Biases In Future Asteroid Lightcurve Surveys

    NASA Astrophysics Data System (ADS)

    Warner, Brian D.; Harris, A. W.

    2010-10-01

    A goal of recent and upcoming surveys is securing a large number of asteroid rotation periods via lightcurves. While a worthwhile effort, the "shotgun” approach being applied in many cases may not add significant new information about rotation rates and be biased against critical types of objects: fast/slow rotators, binary and multiple asteroids, and tumblers. We examined different observing strategies to determine the success rate for finding the correct period and how they might be biased against critical objects by generating 11,000 synthetic lightcurves combined into 2,500 composite curves covering a range of periods from 0.3 to 400 hours and amplitudes from 0.1 to 2.0 magnitudes and included random noise. These lightcurves were "sampled” to approximate existing and planned strategies. As with studies by Mann et al. and Masiero et al., we found a high success rate with lightcurves of relatively short periods and moderate to high amplitudes - P ≤ 8 h, A ≥ 0.3 mag - especially if "success” included finding a period that was 0.5x or 2.0x the true period. On the other hand, many lightcurves of low amplitude and long period - P ≥ 24 h, A ≤ 0.1 mag - were initially found to have periods of P ≤ 1 h which, if adopted, would badly skew rotational statistics. Overall, we found that relying on minimum of data, even if obtained over one more weeks, did not produce a significant percentage of statistically useful periods and there was a strong potential for biases against critical types of objects. A better method to advance our understanding of rotation rate and evolution and the underlying causes appears to be to concentrate on a more limited number of objects and follow each one until a reasonable solution is found.

  20. Asteroid Exploration and Exploitation

    NASA Technical Reports Server (NTRS)

    Lewis, John S.

    2006-01-01

    John S. Lewis is Professor of Planetary Sciences and Co-Director of the Space Engineering Research Center at the University of Arizona. He was previously a Professor of Planetary Sciences at MIT and Visiting Professor at the California Institute of Technology. Most recently, he was a Visiting Professor at Tsinghua University in Beijing for the 2005-2006 academic year. His research interests are related to the application of chemistry to astronomical problems, including the origin of the Solar System, the evolution of planetary atmospheres, the origin of organic matter in planetary environments, the chemical structure and history of icy satellites, the hazards of comet and asteroid bombardment of Earth, and the extraction, processing, and use of the energy and material resources of nearby space. He has served as member or Chairman of a wide variety of NASA and NAS advisory committees and review panels. He has written 17 books, including undergraduate and graduate level texts and popular science books, and has authored over 150 scientific publications.

  1. A hitchhiker’s guide to the Trojan Horse Method

    NASA Astrophysics Data System (ADS)

    Pizzone, R. G.; Spitaleri, C.; Cherubini, S.; D’Agata, G.; Guardo, G. L.; Gulino, M.; La Cognata, M.; Lamia, L.; Puglia, S. M. R.; Rapisarda, G. G.; Romano, S.; Sergi, M. L.; Spartá, R.; Tumino, A.

    2016-04-01

    Owing the presence of the Coulomb barrier at astrophysically relevant kinetic energies, it is very difficult, or sometimes impossible to measure astrophysical reaction rates in laboratory. This is why different indirect techniques are being used along with direct measurements. The THM is unique indirect technique allowing one measure astrophysical rearrangement reactions down to astrophysical relevant energies. The basic principle and a review of the main application of the Trojan Horse Method are presented. A step-by-step approach will be adopted in order to describe the features usually unknown to non-experts.

  2. 7. TROJAN MILL, EXTERIOR FROM NORTHWEST, c. 191828. ADDITIONS FOR ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    7. TROJAN MILL, EXTERIOR FROM NORTHWEST, c. 1918-28. ADDITIONS FOR PRIMARY THICKENERS No. 1 AND No. 2, SECONDARY THICKENERS No. 1, No. 2, AND No. 3, AGITATORS, AIR COMPRESSOR, AND PORTLAND FILTERS ARE SHOWN COMPLETE. STAIR ON NORTH SIDE OF CRUDE ORE BINS IS PRESENT AS IS THE LIME BIN ADJACENT TO THE WEST CRUDE ORE BIN, AND THE SNOW SHED ADDED OVER THE TRAMLINE SERVING THE EAST AND WEST CRUDE ORE BINS. ALSO PRESENT IS THE BABBITT HOUSE AND ROCK BIN. CREDIT JW. - Bald Mountain Gold Mill, Nevada Gulch at head of False Bottom Creek, Lead, Lawrence County, SD

  3. 4. TROJAN MILL, DETAIL OF CRUDE ORE BINS FROM NORTH, ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    4. TROJAN MILL, DETAIL OF CRUDE ORE BINS FROM NORTH, c. 1912. SHOWS TIMBER FRAMING UNDER CONSTRUCTION FOR EAST AND WEST CRUDE ORE BINS AT PREVIOUS LOCATION OF CRUSHER HOUSE, AND SNOW SHED PRESENT OVER SOUTH CRUDE ORE BIN WITH PHASE CHANGE IN SNOW SHED CONSTRUCTION INDICATED AT EAST END OF EAST CRUDE ORE BIN. THIS PHOTOGRAPH IS THE FIRST IMAGE OF THE MACHINE SHOP, UPPER LEFT CORNER. CREDIT JW. - Bald Mountain Gold Mill, Nevada Gulch at head of False Bottom Creek, Lead, Lawrence County, SD

  4. Asteroid Redirect Mission: Boulder Collection Concept

    NASA Video Gallery

    This animation illustrates one of two robotic mission concepts under consideration for NASA's Asteroid Redirect Mission. In this concept, the Asteroid Redirect Vehicle descends to the surface of a ...

  5. Asteroid Redirect Mission: EVA and Sample Collection

    NASA Technical Reports Server (NTRS)

    Abell, Paul; Stich, Steve

    2015-01-01

    Asteroid Redirect Mission (ARM) Overview (1) Notional Development Schedule, (2) ARV Crewed Mission Accommodations; Asteroid Redirect Crewed Mission (ARCM) Mission Summary; ARCM Accomplishments; Sample collection/curation plan (1) CAPTEM Requirements; SBAG Engagement Plan

  6. WISE Finds Fewer Asteroids near Earth

    NASA Video Gallery

    New observations by NASA's Wide-field Infrared Survey Explorer, orWISE, show there are significantly fewer near-Earth asteroids in themid-size range than previously thought.› Asteroid and Come...

  7. Excluding interlopers from asteroid families

    NASA Astrophysics Data System (ADS)

    Novakovic, B.; Radovic, V.

    2014-07-01

    Introduction: Asteroid families are believed to have originated from catastrophic collisions among asteroids. They are a very important subject of Solar System investigation, because practically any research topic carried out in asteroid-related science sooner or later encounters problems pertaining to asteroid families. One basic problem encountered when dealing with families is to determine reliably the list of its members, i.e. to reduce the number of interlopers as much as possible. This is an important problem, because many conclusions derived from analyses of the physical properties of family members must be necessarily based on firm and well established membership. However, as the number of known asteroids increases fast it becomes more and more difficult to obtain robust list of members of an asteroid family. To cope with these challenges we are proposing a new approach that may help to significantly reduce presence of interlopers among the family members. This method should be particularly useful once additional information become available, including primarily spectro-photometric data. This is exactly the kind of information that will be provided by Gaia. Metodology: Families (and their members) have been commonly identified by analysing the distribution of asteroids in the space of proper orbital elements, using the Hierarchical Clustering Method (HCM) [1]. A well-known drawback of the HCM based on the single linkage rule is the so-called chaining phenomenon: first concentrations naturally tend to incorporate nearby groups, forming a kind of 'chain'. Thus, any family membership obtained by the pure HCM must unavoidably include some interlopers. The method we are proposing here could be used to identify these interlopers, with its main advantage being an ability to significantly reduce the chaining effect. The method consists of three main steps. First we determine an asteroid family members by applying the HCM to the catalogue of proper elements obtained

  8. Asteroidal Occultation Silhouettes Combined with Asteroid Models Derived by Lightcurve Inversion

    NASA Astrophysics Data System (ADS)

    Durech, Josef; Kaasalainen, M.; Herald, D.; Dunham, D.; Timerson, B.; Hanus, J.; Frappa, E.; Talbot, J.; Hayamizu, T.; Warner, B. D.; Pilcher, F.; Galad, A.

    2010-10-01

    Asteroid sizes can be directly measured by observing occultations of stars by asteroids. When there are enough observations across the path of the shadow, the asteroid's projected silhouette can be reconstructed. We present our analysis of occultation data we combined with convex asteroid models. Asteroid shape models derived from photometry by the lightcurve inversion method enabled us to compute the orientation of an asteroid for the time of occultation. By scaling the shape models to fit the occultation chords, we determined the asteroid sizes with a relative accuracy of typically 10%. We combined shape and spin state models of 44 asteroids (14 of them were new or updated models) with the available occultation data to derive asteroid effective diameters. In many cases, occultations allowed us to reject one of two possible pole solutions that were derived from photometry. Our results demonstrate the possibility of deriving unique physical models of asteroids by combining shape models obtained from lightcurve inversion with occultation timings.

  9. New Horizons Tracks an Asteroid

    NASA Technical Reports Server (NTRS)

    2007-01-01

    The two 'spots' in this image are a composite of two images of asteroid 2002 JF56 taken on June 11 and June 12, 2006, with the Multispectral Visible Imaging Camera (MVIC) component of the New Horizons Ralph imager. In the bottom image, taken when the asteroid was about 3.36 million kilometers (2.1 million miles) away from the spacecraft, 2002 JF56 appears like a dim star. At top, taken at a distance of about 1.34 million kilometers (833,000 miles), the object is more than a factor of six brighter. The best current, estimated diameter of the asteroid is approximately 2.5 kilometers.

    The asteroid observation was a chance for the New Horizons team to test the spacecraft's ability to track a rapidly moving object. On June 13 New Horizons came to within about 102,000 kilometers of the small asteroid, when the spacecraft was nearly 368 million kilometers (228 million miles) from the Sun and about 273 million kilometers (170 million miles) from Earth.

  10. Asteroid shape modelling with ADAM

    NASA Astrophysics Data System (ADS)

    Viikinkoski, Matti; Kaasalainen, Mikko; Durech, Josef

    2015-08-01

    Technological advancements have made it possible to obtain highly detailed images of asteroids, yet 3-D shape reconstruction remains a challenge. Shape inversion is an ill-posed inverse problem as systematic errors, shadowing effects due to non-convex features, and the limitations of the imaging systems render the direct inversion impossible. Moreover, the coverage of one observation session alone is seldom sufficient for 3-D reconstruction, necessitating a method for the integration of widely different, complementary data sources into a coherent shape solution.We present a new 3-D shape reconstruction method for asteroid models. ADAM, an acronym for all-data asteroid modelling, is a general procedure for combining disk-resolved observational data into a shape model. ADAM handles all disk-resolved data in a uniform manner via 2-D Fourier Transform. Almost all disk-resolved data sources are supported: adaptive optics and other images, range-Doppler radar data, and thermal infrared interferometry.As case studies, we examine the shape of (41) Daphne using the adaptive optics images and photometry, and create a model of the asteroid 2000 ET70 from the range-Doppler radar images. Finally, we combine ALMA science verification data, adaptive optics images, occultations, and lightcurve data to study the shape of the large main-belt asteroid (3) Juno.

  11. The compositional distribution of asteroids

    NASA Astrophysics Data System (ADS)

    DeMeo, F.; Carry, B.; Alexander, C.; Walsh, K.; Chapman, C.

    2014-07-01

    Each compositional class of asteroid is a relic of the temperature and composition conditions in which it formed. The current distribution reveals the history of the Solar System, and each body acts as a marker of any mixing that occurred since formation. The remnant of a primordial temperature gradient, seen as transition from the S class to C class dominating in different regions of the asteroid belt has been a paradigm for three decades [1-4]. Today, we are armed with major advancements from the past decade that have revolutionized the field of asteroids in areas such as discovery, physical characterization, and dynamical models. A new and more detailed compositional map [5,6] created with data from the Sloan Digital Sky Survey [7] allows us to re-examine compositional trends in the main asteroid belt and what the physical and dynamical implications might be. This talk is related to recent work from DeMeo & Carry 2013, 2014 [5,6] and an upcoming chapter of the "Asteroids IV" book in 2015.

  12. Accessibility of near-Earth asteroids, 1990

    NASA Technical Reports Server (NTRS)

    Hulkower, Neal D.; Child, Jack B.

    1991-01-01

    Previous research which analyzed the accessibility of all known near-Earth asteroids is updated. Since then, many new near-Earth asteroids have been discovered, and 1928 DB, the most accessible asteroid at that time, has been recovered. Many of these recently discovered near-Earth asteroids have promising orbital characteristics. In addition to accessibility (as defined by minimum global delta v), ideal rendezvous opportunities are identified.

  13. Rotational properties of small asteroids: Photoelectric observations of 16 asteroids

    NASA Astrophysics Data System (ADS)

    Barucci, M. A.; di Martino, M.; Dotto, E.; Fulchignoni, M.; Rotundi, A.; Burchi, R.

    1994-06-01

    Continuing the observational program started in 1984 on small asteroids (diameter smaller than bout 50 km), we present the results of photometric observations performed with a 1-m telescope at the European Southern Observatory (ESO). A total of 56 single-night lightcurves for 16 asteroids were obtained. All the objects were observed for the first time and the rotational periods have been determined for 11. For 655 Briseis, 823 Sisigambis, 847 Agnia, 1591 Baize, and 3237 Victorplatt the complete rotational phase was not covered and in some cases only an indication of the rotational period has been possible.

  14. Asteroid Polarimetric Database V6.0

    NASA Astrophysics Data System (ADS)

    Lupishko, D. F.; Vasilyev, S. V.

    2008-07-01

    The Asteroid Polarimetric Database (APD) is a collection of asteroid polarimetry results compiled by D.F. Lupishko and S.V. Vasiliev of Karazin Kharkiv National University, Ukraine. It is intended to include most asteroid polarimetry available through January 22, 2008.

  15. Asteroid Polarimetric Database V7.0

    NASA Astrophysics Data System (ADS)

    Lupishko, D. F.; Vasilyev, S. V.

    2012-06-01

    The Asteroid Polarimetric Database (APD) is a collection of asteroid polarimetry results compiled by D.F. Lupishko and S.V. Vasiliev of Karazin Kharkiv National University, Ukraine. It is intended to include most asteroid polarimetry available through March 7, 2012.

  16. Reflectance spectroscopy and asteroid surface mineralogy

    NASA Technical Reports Server (NTRS)

    Gaffey, Michael J.; Bell, Jeffrey F.; Cruikshank, Dale P.

    1989-01-01

    Information available from reflectance spectroscopy on the surface mineralogy of asteroids is discussed. Current spectral interpretive procedures used in the investigations of asteroid mineralogy are described. Present understanding of the nature and history of asteroids is discussed together with some still unresolved issues such as the source of ordinary chondrites.

  17. Recent Arecibo Radar Observations of Main-Belt Asteroids.

    NASA Astrophysics Data System (ADS)

    Shepard, Michael K.; Howell, Ellen; Nolan, Michael; Taylor, Patrick; Springmann, Alessondra; Giorgini, Jon; Benner, Lance; Magri, Christopher

    2014-11-01

    We recently observed main-belt asteroids 12 Victoria (Tholen S-class, Bus L-class), 246 Asporina (A-class), and 2035 Stearns with the S-band (12 cm) Arecibo radar. Signal-to-noise ratios for Asporina and Stearns were only strong enough for continuous-wave (CW) analysis. Signal-to-noise ratios for Victoria were high enough for delay-Doppler imaging. Stearns exhibited a high radar polarization ratio of unity, higher than any other main-belt E-class, but similar to near-Earth E-class asteroids [Benner et al. Icarus 198, 294-304, 2008; Shepard et al. Icarus 215, 547-551, 2011]. The A-class asteroids show spectral absorption features consistent with olivine and have been suggested as the source of pallasite meteorites or the rare brachinites [Cruikshank and Hartmann, Science 223, 281-283, 1984]. The radar cross-section measured for Asporina leads to a radar albedo estimate of 0.11, suggesting a low near-surface bulk density, and by inference, a low metal content. This suggests that the brachinites are a better analog for Asporina than the iron-rich pallasites. Victoria has been observed by radar in the past and the continuous-wave echoes suggest it has a large concavity or is a contact binary [Mitchell et al. Icarus 118, 105-131, 1995]. Our new imaging observations should determine which is more likely.

  18. Lowell Observatory Near-Earth Asteroid Photometric Survey (NEAPS) - 2009 January through 2009 June

    NASA Astrophysics Data System (ADS)

    Koehn, Bruce W.; Bowell, Edward G.; Skiff, Brian A.; Sanborn, Jason J.; McLelland, Kyle P.; Pravec, Petr; Warner, Brian D.

    2014-10-01

    We report the results of the Lowell Observatory Near- Earth Asteroid Photometric Survey (NEAPS) for the period between 2009-01-01 and 2009-06-30. During this period, we obtained our first photometric data for 40 asteroids including 433 Eros, 1943 Anteros, 3554 Amun, 5011 Ptah, (5604) 1992 FE, 5620 Jasonwheeler, (5693) 1993 EA, (8566) 1996 EN, (14402) 1991 DB, (16834) 1997 WU22, (22753) 1998 WT, (35107) 1991 VH, (52768) 1998 OR2, (68350) 2001 MK3, (85867) 1999 BY9, (138883) 2000 YL29, (141052) 2001 XR1, (143651) 2003 QO104, (154244) 2002 KL6, 161989 Cacus, (162385) 2000 BM19, (163758) 2003 OS13, (175706) 1996 FG3, (194386) 2001 VG5, (203217) 2001 FX9, (207945) 1991 JW, (208023) 1999 AQ10, (212546) 2006 SV19, (256412) 2007 BT2, 2001 FE90, 2004 LV3, 2005 BC, 2005 SG19, 2008 QT3, 2008 WL60, 2009 DE47, 2009 DO111, 2009 EP2, 2009 FD, and 2009 JM2. We also report our analysis of 5261 Eureka, a Mars Trojan.

  19. Physical Parameters of Asteroids Estimated from the WISE 3 Band Data and NEOWISE Post-Cryogenic Survey

    NASA Astrophysics Data System (ADS)

    Mainzer, A.; Grav, T.; Masiero, J.; Bauer, J.; Cutri, R.; McMillan, R.; Nugent, C. R.; Tholen, D.; Wright, E. L.

    2012-12-01

    Enhancements to the science data processing pipeline of NASA's Wide-field Infrared Explorer (WISE) mission, collectively known as NEOWISE, resulted in the detection of >158,000 minor planets in four infrared wavelengths during the fully cryogenic portion of the mission. Following the depletion of its cryogen, NASA's Planetary Science Directorate funded a four month extension to complete the survey of the inner edge of the Main Asteroid Belt and to detect and discover near-Earth objects (NEOs). This extended survey phase, known as the NEOWISE Post-Cryogenic Survey, resulted in the detection of 6500 large Main Belt asteroids and 86 NEOs in its 3.4 and 4.6 $ um channels. During the Post-Cryogenic Survey, NEOWISE discovered and detected a number of asteroids co-orbital with the Earth and Mars, including the first known Earth Trojan. We present preliminary thermal fits for these and other NEOs detected during the 3-Band Cryogenic and Post-Cryogenic Surveys.

  20. PHYSICAL PARAMETERS OF ASTEROIDS ESTIMATED FROM THE WISE 3-BAND DATA AND NEOWISE POST-CRYOGENIC SURVEY

    SciTech Connect

    Mainzer, A.; Masiero, J.; Bauer, J.; Grav, T.; Cutri, R. M.; McMillan, R. S.; Nugent, C. R.; Tholen, D.; Walker, R.; Wright, E. L.

    2012-11-20

    Enhancements to the science data processing pipeline of NASA's Wide-field Infrared Survey Explorer (WISE) mission, collectively known as NEOWISE, resulted in the detection of >158,000 minor planets in four infrared wavelengths during the fully cryogenic portion of the mission. Following the depletion of its cryogen, NASA's Planetary Science Directorate funded a four-month extension to complete the survey of the inner edge of the Main Asteroid Belt and to detect and discover near-Earth objects (NEOs). This extended survey phase, known as the NEOWISE Post-Cryogenic Survey, resulted in the detection of {approx}6500 large Main Belt asteroids and 86 NEOs in its 3.4 and 4.6 {mu}m channels. During the Post-Cryogenic Survey, NEOWISE discovered and detected a number of asteroids co-orbital with the Earth and Mars, including the first known Earth Trojan. We present preliminary thermal fits for these and other NEOs detected during the 3-Band Cryogenic and Post-Cryogenic Surveys.

  1. Asteroid Return Mission Feasibility Study

    NASA Technical Reports Server (NTRS)

    Brophy, John R.; Gershman, Robert; Landau, Damon; Polk, James; Porter, Chris; Yeomans, Don; Allen, Carlton; Williams, Willie; Asphaug, Erik

    2011-01-01

    This paper describes an investigation into the technological feasibility of finding, characterizing, robotically capturing, and returning an entire Near-Earth Asteroid (NEA) to the International Space Station (ISS) for scientific investigation, evaluation of its resource potential, determination of its internal structure and other aspects important for planetary defense activities, and to serve as a testbed for human operations in the vicinity of an asteroid. Reasonable projections suggest that several dozen candidates NEAs in the size range of interest (approximately 2-m diameter) will be known before the end of the decade from which a suitable target could be selected. The conceptual mission objective is to return an approximately 10,000-kg asteroid to the ISS in a total flight time of approximately 5 years using a single Evolved Expendable Launch Vehicle. Preliminary calculations indicate that this could be accomplished using a solar electric propulsion (SEP) system with high-power Hall thrusters and a maximum power into the propulsion system of approximately 40 kW. The SEP system would be used to provide all of the post-launch delta V. The asteroid would have an unrestricted Earth return Planetary Protection categorization, and would be curated at the ISS where numerous scientific and resource utilization experiments would be conducted. Asteroid material brought to the ground would be curated at the NASA Johnson Space Center. This preliminary study identified several areas where additional work is required, but no show stoppers were identified for the approach that would return an entire 10,000-kg asteroid to the ISS in a mission that could be launched by the end of this decade.

  2. Rosetta visits asteroid (21)Lutetia

    NASA Astrophysics Data System (ADS)

    Accomazzo, A.; Ferri, P.; Hubault, A.; Lodiot, S.; Pellon-Bailon, J. L.; Porta, R.

    2012-03-01

    The International Rosetta Mission, cornerstone of the European Space Agency Scientific Programme, was launched on 2nd March 2004 to its 10 years journey to comet Churyumov-Gerasimenko. Rosetta will reach the comet in summer 2014, orbit it for about 1.5 years down to distances of a few Kilometres and deliver the Lander Philae onto its surface. After its successful asteroid fly-by in September 2008, Rosetta came back to Earth, for the final gravity acceleration towards its longest heliocentric orbit, up to a distance of 5.3 AU. It is during this phase that Rosetta crossed for the second time the main asteroids belt and performed a close encounter with asteroid (21)Lutetia on the 10th of July 2010 at a distance of ca. 3160 km and a relative velocity of 15 km/s. The payload complement of the spacecraft was activated to perform highly valuable scientific observations. The approach phase to the celestial body required a careful and accurate optical navigation campaign that will prove to be useful also for the comet approach phase. The experience gained with first asteroid flyby in 2008 was fed back into the operations definition and preparation for this highly critical phase; this concerns in particular the operations of the navigation camera for the close-loop autonomous asteroid tracking and of the main scientific camera for high resolution imaging. It was shortly after the flyby that Rosetta became the solar-powered spacecraft to have flown furthest from the Sun (>2.72 AU). This paper presents the activities carried out and planned for the definition, preparation and implementation of the asteroid flyby mission operations, including the test campaign conducted to improve the performance of the spacecraft and payload compared to the previous flyby. The results of the flyby itself are presented, with the operations implemented, the achieved performance and the lessons learned.

  3. Binary stars.

    PubMed

    Paczynacuteski, B

    1984-07-20

    Most stars in the solar neighborhood are either double or multiple systems. They provide a unique opportunity to measure stellar masses and radii and to study many interesting and important phenomena. The best candidates for black holes are compact massive components of two x-ray binaries: Cygnus X-1 and LMC X-3. The binary radio pulsar PSR 1913 + 16 provides the best available evidence for gravitational radiation. Accretion disks and jets observed in close binaries offer a very good testing ground for models of active galactic nuclei and quasars. PMID:17749544

  4. Lightcurve Results for Eleven Asteroids

    NASA Astrophysics Data System (ADS)

    Gartrelle, Gordon M.

    2012-04-01

    Differential photometry techniques were used to develop lightcurves, rotation periods and amplitudes for eleven main-belt asteroids: 833 Monica, 962 Aslog, 1020 Arcadia, 1082 Pirola, 1097 Vicia, 1122 Lugduna, 1145 Robelmonte, 1253 Frisia, 1256 Normannia, 1525 Savolinna, and 2324 Janice. Ground-based observations from Badlands Observatory (BLO) in Quinn, SD, as well as the University of North Dakota Observatory (UND) in Grand Forks, ND, provided the data for the project. A search of the asteroid lightcurve database (LCDB) did not reveal any previously reported results for seven of the eleven targets in this study.

  5. Photoelectric photometry of 14 asteroids

    NASA Astrophysics Data System (ADS)

    di Martino, M.; Cacciatori, S.

    1984-10-01

    Results of observations of 14 asteroids are reported; all of them, except 181 Eucharis, have been previously observed at least once. V photoelectric lightcurves were obtained from September 1982 to June 1983 at the Astronomical Observatory of Torino and at the Astrophysical Observatory of Catania. Part of this program aims to obtain complete lightcurves and, when possible, phasecurve information and to determine amplitudes and V magnitudes at different longitudes for a selected group of asteroids, in order to enlarge the set of known rotational axis directions.

  6. New observations of (4179) Toutatis from the Chang'e-2 flyby mission and future Chinese missions to asteroids

    NASA Astrophysics Data System (ADS)

    Ji, J.

    2014-07-01

    Primitive asteroids are remnant building blocks in the Solar System formation. They provide key clues for us to reach in-depth understanding of the process of planetary formation, the complex environment of early Solar nebula, and even the occurrence of life on the Earth. On 13 December 2012, Chang'e-2 completed a successful flyby of the near-Earth asteroid (4179) Toutatis at a closest distance of 770 meters from the asteroid's surface. The observations show that Toutatis has an irregular surface and its shape resembles a ginger-root with a smaller lobe (head) and a larger lobe (body). Such bifurcated configuration is indicative of a contact binary origin for Toutatis. In addition, the images with a 3-m resolution or higher provide a number of new discoveries about this asteroid, such as an 800-meter basin at the end of the large lobe, a sharply perpendicular silhouette near the neck region, and direct evidence of boulders and regolith, indicating that Toutatis is probably a rubble-pile asteroid. The Chang'e-2 observations have provided significant new insights into the geological features and the formation and evolution of this asteroid. Moreover, a conceptual introduction to future Chinese missions to asteroids, such as the major scientific objectives, scientific payloads, and potential targets, will be briefly given. The proposed mission will benefit a lot from potential international collaboration in the future.

  7. Planetary and asteroid missions. Getting there: Anchoring spacecraft to asteroids

    NASA Technical Reports Server (NTRS)

    Meyer, Rudolf X.; Melko, Joseph P.

    1993-01-01

    In this hardware project, the students developed ideas for attaching objects to the surface of small moons or asteroids. A device was designed, and built in the university machine shop, that uses a projectile shot into concrete, thereby attaching a model spacecraft to the landing site.

  8. Astrometric Masses of 21 Asteroids, and an Integrated Asteroid Ephemeris

    NASA Astrophysics Data System (ADS)

    Baer, James J.; Chesley, S. R.

    2007-07-01

    We apply the technique of astrometric mass determination to measure the masses of 21 main-belt asteroids; the masses of 6 Hebe (7.59 +/- 1.42 x 10-12 SM), 9 Metis (1.03 +/- 0.24 x 10-11 SM), 17 Thetis (6.17 +/- 0.64 x 10-13 SM), 19 Fortuna (5.41 +/- 0.76 x 10-12 SM), and 189 Phthia (1.87 +/- 0.64 x 10-14 SM) appear to be new. The resulting bulk porosities of 11 Parthenope (12%) and 16 Psyche (45%) are smaller than previous values; while the bulk porosities of 52 Europa (41%) and 189 Phthia (64%) are significant. The variations in density within the C- and S-classes are consistent with either heteorogenous mineralogical compositions within each class, significant variations in porosity, or both. To accurately model the forces on these asteroids during the mass determination process, we created an integrated ephemeris of the 300 large asteroids used in preparing the DE-405 planetary ephemeris; this new BC-405 integrated asteroid ephemeris also appears useful in other high-accuracy applications.

  9. Depletion of the Outer Asteroid Belt

    NASA Technical Reports Server (NTRS)

    Liou, Jer-Chyi; Malhotra, Renu

    1997-01-01

    During the early history of the solar system, it is likely that the outer planets changed their distance from the sun, and hence, their influence on the asteroid belt evolved with time. The gravitational influence of Jupiter and Saturn on the orbital evolution of asteroids in the outer asteroid belt was calculated. The results show that the sweeping of mean motion resonances associated with planetary migration efficiently destabilizes orbits in the outer asteroid belt on a time scale of 10 million years. This mechanism provides an explanation for the observed depletion of asteroids in that region.

  10. Volcanism on differentiated asteroids (Invited)

    NASA Astrophysics Data System (ADS)

    Wilson, L.

    2013-12-01

    The Dawn spacecraft's investigation of 4 Vesta, best-preserved of the early-forming differentiated asteroids, prompts a reappraisal of factors controlling igneous activity on such bodies. Analogy with melt transfer in zones of partial melting on Earth implies that silicate melts moved efficiently within asteroid mantles in complex networks of veins and dikes, so that only a few percent of the mantle consisted of melt at any one time. Thus even in cases where large amounts of mantle melting occurred, the melts did not remain in the mantle to form "magma oceans", but instead migrated to shallow depths. The link between magma flow rate and the stresses needed to keep fractures open and allow flow fast enough to avoid excessive cooling implies that only within asteroids with radii more than ~190-250 km would continuous magma flow from mantle to surface be possible. In all smaller asteroids (including Vesta) magma must have accumulated in sills at the base of the lithosphere (the conductively controlled ~10 km thick thermal boundary layer) or in crustal magma reservoirs near its base. Magma would then have erupted intermittently to the surface from these steadily replenished reservoirs. The average rates of eruption to the surface (or shallow intrusion) should balance the magma production rate, but since magma could accumulate and erupt intermittently from these reservoirs, the instantaneous eruption rates could be hundreds to thousands of cubic m/s, comparable to historic basaltic eruption rates on Earth and very much greater than the average mantle melting rate. The absence of asteroid atmospheres makes explosive eruptions likely even if magmas are volatile-poor. On asteroids with radii less than ~100 km, gases and sub-mm pyroclastic melt droplets would have had speeds exceeding the escape speed assuming a few hundred ppm volatiles, and only cm sized or larger clasts would have been retained. On larger bodies almost all pyroclasts will have returned to the surface

  11. AsteroidZoo: A New Zooniverse project to detect asteroids and improve asteroid detection algorithms

    NASA Astrophysics Data System (ADS)

    Beasley, M.; Lewicki, C. A.; Smith, A.; Lintott, C.; Christensen, E.

    2013-12-01

    We present a new citizen science project: AsteroidZoo. A collaboration between Planetary Resources, Inc., the Zooniverse Team, and the Catalina Sky Survey, we will bring the science of asteroid identification to the citizen scientist. Volunteer astronomers have proved to be a critical asset in identification and characterization of asteroids, especially potentially hazardous objects. These contributions, to date, have required that the volunteer possess a moderate telescope and the ability and willingness to be responsive to observing requests. Our new project will use data collected by the Catalina Sky Survey (CSS), currently the most productive asteroid survey, to be used by anyone with sufficient interest and an internet connection. As previous work by the Zooniverse has demonstrated, the capability of the citizen scientist is superb at classification of objects. Even the best automated searches require human intervention to identify new objects. These searches are optimized to reduce false positive rates and to prevent a single operator from being overloaded with requests. With access to the large number of people in Zooniverse, we will be able to avoid that problem and instead work to produce a complete detection list. Each frame from CSS will be searched in detail, generating a large number of new detections. We will be able to evaluate the completeness of the CSS data set and potentially provide improvements to the automated pipeline. The data corpus produced by AsteroidZoo will be used as a training environment for machine learning challenges in the future. Our goals include a more complete asteroid detection algorithm and a minimum computation program that skims the cream of the data suitable for implemention on small spacecraft. Our goal is to have the site become live in the Fall 2013.

  12. Combining asteroid models derived by lightcurve inversion with asteroidal occultation silhouettes

    NASA Astrophysics Data System (ADS)

    Ďurech, Josef; Kaasalainen, Mikko; Herald, David; Dunham, David; Timerson, Brad; Hanuš, Josef; Frappa, Eric; Talbot, John; Hayamizu, Tsutomu; Warner, Brian D.; Pilcher, Frederick; Galád, Adrián

    2011-08-01

    Asteroid sizes can be directly measured by observing occultations of stars by asteroids. When there are enough observations across the path of the shadow, the asteroid's projected silhouette can be reconstructed. Asteroid shape models derived from photometry by the lightcurve inversion method enable us to predict the orientation of an asteroid for the time of occultation. By scaling the shape model to fit the occultation chords, we can determine the asteroid size with a relative accuracy of typically ˜10%. We combine shape and spin state models of 44 asteroids (14 of them are new or updated models) with the available occultation data to derive asteroid effective diameters. In many cases, occultations allow us to reject one of two possible pole solutions that were derived from photometry. We show that by combining results obtained from lightcurve inversion with occultation timings, we can obtain unique physical models of asteroids.

  13. Workshop on Oxygen in Asteroids and Meteorites

    NASA Technical Reports Server (NTRS)

    2005-01-01

    Contents include the following: Constraints on the detection of solar nebula's oxidation state through asteroid observation. Oxidation/Reduction Processes in Primitive Achondrites. Low-Temperature Chemical Processing on Asteroids. On the Formation Location of Asteroids and Meteorites. The Spectral Properties of Angritic Basalts. Correlation Between Chemical and Oxygen Isotopic Compositions in Chondrites. Effect of In-Situ Aqueous Alteration on Thermal Model Heat Budgets. Oxidation-Reduction in Meteorites: The Case of High-Ni Irons. Ureilite Atmospherics: Coming up for Air on a Parent Body. High Temperature Effects Including Oxygen Fugacity, in Pre-Planetary and Planetary Meteorites and Asteroids. Oxygen Isotopic Variation of Asteroidal Materials. High-Temperature Chemical Processing on Asteroids: An Oxygen Isotope Perspective. Oxygen Isotopes and Origin of Opaque Assemblages from the Ningqiang Carbonaceous Chondrite. Water Distribution in the Asteroid Belt. Comparative Planetary Mineralogy: V Systematics in Planetary Pyroxenes and fo 2 Estimates for Basalts from Vesta.

  14. The Main-belt Asteroid and NEO Tour with Imaging and Spectroscopy (MANTIS)

    NASA Astrophysics Data System (ADS)

    Rivkin, A.; Cohen, B. A.; Barnouin, O. S.; Chabot, N. L.; Ernst, C. M.; Klima, R. L.; Helbert, J.; Sternovsky, Z.

    2015-12-01

    The asteroids preserve information from the earliest times in solar system history, with compositions in the population reflecting the material in the solar nebula and experiencing a wide range of temperatures. Today they experience ongoing processes, some of which are shared with larger bodies but some of which are unique to their size regime. They are critical to humanity's future as potential threats, resource sites, and targets for human visitation. However, over twenty years since the first spacecraft encounters with asteroids, they remain poorly understood. The mission we propose here, the Main-belt Asteroid and NEO Tour with Imaging and Spectroscopy (MANTIS), explores the diversity of asteroids to understand our solar system's past history, its present processes, and future opportunities and hazards. MANTIS addresses many of NASA's highest priorities as laid out in its 2014 Science Plan and provides additional benefit to the Planetary Defense and Human Exploration communities via a low-risk, cost-effective tour of the near-Earth and inner asteroid belt. MANTIS visits the materials that witnessed solar system formation and its earliest history, addressing the NASA goal of exploring and observing the objects in the solar system to understand how they formed and evolve. MANTIS measures OH, water, and organic materials via several complementary techniques, visiting and sampling objects known to have hydrated minerals and addressing the NASA goal of improving our understanding of the origin and evolution of life on Earth. MANTIS studies the geology and geophysics of nine diverse asteroids, with compositions ranging from water-rich to metallic, representatives of both binary and non-binary asteroids, and sizes covering over two orders of magnitude, providing unique information about the chemical and physical processes shaping the asteroids, addressing the NASA goal of advancing the understanding of how the chemical and physical processes in our solar system

  15. NASA's Asteroid Redirect Mission (ARM)

    NASA Astrophysics Data System (ADS)

    Abell, Paul; Mazanek, Dan; Reeves, David; Naasz, Bo; Cichy, Benjamin

    2015-11-01

    The National Aeronautics and Space Administration (NASA) is developing a robotic mission to visit a large near-Earth asteroid (NEA), collect a multi-ton boulder from its surface, and redirect it into a stable orbit around the Moon. Once returned to cislunar space in the mid-2020s, astronauts will explore the boulder and return to Earth with samples. This Asteroid Redirect Mission (ARM) is part of NASA’s plan to advance the technologies, capabilities, and spaceflight experience needed for a human mission to the Martian system in the 2030s. Subsequent human and robotic missions to the asteroidal material would also be facilitated by its return to cislunar space. Although ARM is primarily a capability demonstration mission (i.e., technologies and associated operations), there exist significant opportunities to advance our knowledge of small bodies in the synergistic areas of science, planetary defense, asteroidal resources and in-situ resource utilization (ISRU), and capability and technology demonstrations. In order to maximize the knowledge return from the mission, NASA is organizing an ARM Investigation Team, which is being preceded by the Formulation Assessment and Support Team. These teams will be comprised of scientists, technologists, and other qualified and interested individuals to help plan the implementation and execution of ARM. An overview of robotic and crewed segments of ARM, including the mission requirements, NEA targets, and mission operations, will be provided along with a discussion of the potential opportunities associated with the mission.

  16. The Asteroid Redirect Mission (ARM)

    NASA Technical Reports Server (NTRS)

    Abell, Paul

    2015-01-01

    The National Aeronautics and Space Administration (NASA) is developing a robotic mission to visit a large near-Earth asteroid (NEA), collect a multi-ton boulder from its surface, and redirect it into a stable orbit around the Moon. Once returned to cislunar space in the mid-2020s, astronauts will explore the boulder and return to Earth with samples. This Asteroid Redirect Mission (ARM) is part of NASA's plan to advance the technologies, capabilities, and spaceflight experience needed for a human mission to the Martian system in the 2030s. Subsequent human and robotic missions to the asteroidal material would also be facilitated by its return to cislunar space. Although ARM is primarily a capability demonstration mission (i.e., technologies and associated operations), there exist significant opportunities to advance our knowledge of small bodies in the synergistic areas of science, planetary defense, asteroidal resources and in-situ resource utilization (ISRU), and capability and technology demonstrations. In order to maximize the knowledge return from the mission, NASA is organizing an ARM Investigation Team, which is being preceded by the Formulation Assessment and Support Team. These teams will be comprised of scientists, technologists, and other qualified and interested individuals to help plan the implementation and execution of ARM. An overview of robotic and crewed segments of ARM, including the mission requirements, NEA targets, and mission operations, will be provided along with a discussion of the potential opportunities associated with the mission.

  17. System-level protection and hardware Trojan detection using weighted voting.

    PubMed

    Amin, Hany A M; Alkabani, Yousra; Selim, Gamal M I

    2014-07-01

    The problem of hardware Trojans is becoming more serious especially with the widespread of fabless design houses and design reuse. Hardware Trojans can be embedded on chip during manufacturing or in third party intellectual property cores (IPs) during the design process. Recent research is performed to detect Trojans embedded at manufacturing time by comparing the suspected chip with a golden chip that is fully trusted. However, Trojan detection in third party IP cores is more challenging than other logic modules especially that there is no golden chip. This paper proposes a new methodology to detect/prevent hardware Trojans in third party IP cores. The method works by gradually building trust in suspected IP cores by comparing the outputs of different untrusted implementations of the same IP core. Simulation results show that our method achieves higher probability of Trojan detection over a naive implementation of simple voting on the output of different IP cores. In addition, experimental results show that the proposed method requires less hardware overhead when compared with a simple voting technique achieving the same degree of security. PMID:25685518

  18. The differing magnitude distributions of the two Jupiter Trojan color populations

    SciTech Connect

    Wong, Ian; Brown, Michael E.; Emery, Joshua P.

    2014-12-01

    The Jupiter Trojans are a significant population of minor bodies in the middle solar system that have garnered substantial interest in recent years. Several spectroscopic studies of these objects have revealed notable bimodalities with respect to near-infrared spectra, infrared albedo, and color, which suggest the existence of two distinct groups among the Trojan population. In this paper, we analyze the magnitude distributions of these two groups, which we refer to as the red and less red color populations. By compiling spectral and photometric data from several previous works, we show that the observed bimodalities are self-consistent and categorize 221 of the 842 Trojans with absolute magnitudes in the range H<12.3 into the two color populations. We demonstrate that the magnitude distributions of the two color populations are distinct to a high confidence level (>95%) and fit them individually to a broken power law, with special attention given to evaluating and correcting for incompleteness in the Trojan catalog as well as incompleteness in our categorization of objects. A comparison of the best-fit curves shows that the faint-end power-law slopes are markedly different for the two color populations, which indicates that the red and less red Trojans likely formed in different locations. We propose a few hypotheses for the origin and evolution of the Trojan population based on the analyzed data.

  19. Abundant Clinopyroxene On The S Asteroids And Implications For Meteorites And Asteroid History And The Asteroid-meteorite Relationship

    NASA Astrophysics Data System (ADS)

    Gietzen, Katherine M.; Lacy, C. H.; Sears, D. W.

    2007-10-01

    Abundant clinopyroxene on the S asteroids and implications for meteorites and asteroid history and the asteroid-meteorite relationship Abstract We have obtained spectra for 25 asteroids in the range 0.8 - 2.5 μm using the NASA IRTF, of which eight were S asteroids. Analysis of their spectra using the Modified Gaussian Model of Sunshine and Pieters (1993) suggests that six of the eight contain significant amounts of pyroxene in the clinorhombic form (CPX), as opposed to the more common orthopyroxene, (OPX). Our pyroxene-rich targets were Hebe (%CPX = 50%), Melponeme (63%), Urda (43%), Ganymed (41%), 1999 JV3 (55%), 1999 CU3 (61%). Clinopyroxene is the low temperature form of pyroxene and is an important diagnostic feature of the primitive (least metamorphosed) ordinary chondrites. Clinopyroxene is also the form of pyroxene associated with igneous meteorites and two V asteroids in our database also contain considerable clinopyroxenes 2003 YQ 117 (50%) and 2002 QF15 (55%). Primitive and igneous meteorites are well-known and widely studied, but numerically they are very rare. The presence of this mineral phase on the surfaces of asteroids therefore has major implications for both asteroid history and the asteroid-meteorite connection. First, the abundance of CPX on the surface of S asteroids implies either that (1) they are covered with unmetamorphosed material, consistent with an onion skin model in which metamorphism is caused by internal heating and the level of metamorphism experienced by the asteroid decreases with increasing distance from the center, or (2) they are covered with igneous material. Second, the abundance of CPX on the surface of S asteroids is consistent with them not being related to ordinary chondrites, most of which are highly metamorphosed and contain only orthopyroxene (OPX). Space weathering is therefore not the reason for the spectral mismatch between S asteroids and ordinary chondrites.

  20. Survey Simulations of a New Near-Earth Asteroid Detection System

    NASA Astrophysics Data System (ADS)

    Mainzer, A.; Grav, T.; Bauer, J.; Conrow, T.; Cutri, R. M.; Dailey, J.; Fowler, J.; Giorgini, J.; Jarrett, T.; Masiero, J.; Spahr, T.; Statler, T.; Wright, E. L.

    2015-05-01

    We have carried out simulations to predict the performance of a new space-based telescopic survey operating at thermal infrared wavelengths that seeks to discover and characterize a large fraction of the potentially hazardous near-Earth asteroid (NEA) population. Two potential architectures for the survey were considered: one located at the Earth–Sun L1 Lagrange point, and one in a Venus-trailing orbit. A sample cadence was formulated and tested, allowing for the self-follow-up necessary for objects discovered in the daytime sky on Earth. Synthetic populations of NEAs with sizes as small as 140 m in effective spherical diameter were simulated using recent determinations of their physical and orbital properties. Estimates of the instrumental sensitivity, integration times, and slew speeds were included for both architectures assuming the properties of newly developed large-format 10 μm HgCdTe detector arrays capable of operating at ∼35 K. Our simulation included the creation of a preliminary version of a moving object processing pipeline suitable for operating on the trial cadence. We tested this pipeline on a simulated sky populated with astrophysical sources such as stars and galaxies extrapolated from Spitzer Space Telescope and Wide-field Infrared Explorer data, the catalog of known minor planets (including Main Belt asteroids, comets, Jovian Trojans, planets, etc.), and the synthetic NEA model. Trial orbits were computed for simulated position-time pairs extracted from the synthetic surveys to verify that the tested cadence would result in orbits suitable for recovering objects at a later time. Our results indicate that the Earth–Sun L1 and Venus-trailing surveys achieve similar levels of integral completeness for potentially hazardous asteroids larger than 140 m; placing the telescope in an interior orbit does not yield an improvement in discovery rates. This work serves as a necessary first step for the detailed planning of a next-generation NEA survey.

  1. Survey Simulations of a New Near-Earth Asteroid Detection System

    NASA Astrophysics Data System (ADS)

    Mainzer, A.; Grav, T.; Bauer, J.; Conrow, T.; Cutri, R. M.; Dailey, J.; Fowler, J.; Giorgini, J.; Jarrett, T.; Masiero, J.; Spahr, T.; Statler, T.; Wright, E. L.

    2015-05-01

    We have carried out simulations to predict the performance of a new space-based telescopic survey operating at thermal infrared wavelengths that seeks to discover and characterize a large fraction of the potentially hazardous near-Earth asteroid (NEA) population. Two potential architectures for the survey were considered: one located at the Earth-Sun L1 Lagrange point, and one in a Venus-trailing orbit. A sample cadence was formulated and tested, allowing for the self-follow-up necessary for objects discovered in the daytime sky on Earth. Synthetic populations of NEAs with sizes as small as 140 m in effective spherical diameter were simulated using recent determinations of their physical and orbital properties. Estimates of the instrumental sensitivity, integration times, and slew speeds were included for both architectures assuming the properties of newly developed large-format 10 μm HgCdTe detector arrays capable of operating at ˜35 K. Our simulation included the creation of a preliminary version of a moving object processing pipeline suitable for operating on the trial cadence. We tested this pipeline on a simulated sky populated with astrophysical sources such as stars and galaxies extrapolated from Spitzer Space Telescope and Wide-field Infrared Explorer data, the catalog of known minor planets (including Main Belt asteroids, comets, Jovian Trojans, planets, etc.), and the synthetic NEA model. Trial orbits were computed for simulated position-time pairs extracted from the synthetic surveys to verify that the tested cadence would result in orbits suitable for recovering objects at a later time. Our results indicate that the Earth-Sun L1 and Venus-trailing surveys achieve similar levels of integral completeness for potentially hazardous asteroids larger than 140 m; placing the telescope in an interior orbit does not yield an improvement in discovery rates. This work serves as a necessary first step for the detailed planning of a next-generation NEA survey.

  2. The Asteroid Redirect Mission (ARM)

    NASA Astrophysics Data System (ADS)

    Abell, Paul; Gates, Michele; Johnson, Lindley; Chodas, Paul; Mazanek, Dan; Reeves, David; Ticker, Ronald

    2016-07-01

    To achieve its long-term goal of sending humans to Mars, the National Aeronautics and Space Administration (NASA) plans to proceed in a series of incrementally more complex human spaceflight missions. Today, human flight experience extends only to Low-Earth Orbit (LEO), and should problems arise during a mission, the crew can return to Earth in a matter of minutes to hours. The next logical step for human spaceflight is to gain flight experience in the vicinity of the Moon. These cis-lunar missions provide a "proving ground" for the testing of systems and operations while still accommodating an emergency return path to the Earth that would last only several days. Cis-lunar mission experience will be essential for more ambitious human missions beyond the Earth-Moon system, which will require weeks, months, or even years of transit time. In addition, NASA has been given a Grand Challenge to find all asteroid threats to human populations and know what to do about them. Obtaining knowledge of asteroid physical properties combined with performing technology demonstrations for planetary defense provide much needed information to address the issue of future asteroid impacts on Earth. Hence the combined objectives of human exploration and planetary defense give a rationale for the Asteroid Re-direct Mission (ARM). Mission Description: NASA's ARM consists of two mission segments: 1) the Asteroid Redirect Robotic Mission (ARRM), the first robotic mission to visit a large (greater than ~100 m diameter) near-Earth asteroid (NEA), collect a multi-ton boulder from its surface along with regolith samples, demonstrate a planetary defense technique, and return the asteroidal material to a stable orbit around the Moon; and 2) the Asteroid Redirect Crewed Mission (ARCM), in which astronauts will take the Orion capsule to rendezvous and dock with the robotic vehicle, conduct multiple extravehicular activities to explore the boulder, and return to Earth with samples. NASA's proposed

  3. Asteroid magnitudes, UBV colors, and IRAS albedos and diameters

    NASA Technical Reports Server (NTRS)

    Tedesco, Edward F.

    1989-01-01

    This paper lists absolute magnitudes and slope parameters for known asteroids numbered through 3318. The values presented are those used in reducing asteroid IR flux data obtained with the IRAS. U-B colors are given for 938 asteroids, and B-V colors are given for 945 asteroids. The IRAS albedos and diameters are tabulated for 1790 asteroids.

  4. The Formation of Asteroid Satellites in Catastrophic Impacts: Results from Numerical Simulations

    NASA Technical Reports Server (NTRS)

    Durda, D. D.; Bottke, W. F., Jr.; Enke, B. L.; Asphaug, E.; Richardson, D. C.; Leinhardt, Z. M.

    2003-01-01

    We have performed new simulations of the formation of asteroid satellites by collisions, using a combination of hydrodynamical and gravitational dynamical codes. This initial work shows that both small satellites and ejected, co-orbiting pairs are produced most favorably by moderate-energy collisions at more direct, rather than oblique, impact angles. Simulations so far seem to be able to produce systems qualitatively similar to known binaries. Asteroid satellites provide vital clues that can help us understand the physics of hypervelocity impacts, the dominant geologic process affecting large main belt asteroids. Moreover, models of satellite formation may provide constraints on the internal structures of asteroids beyond those possible from observations of satellite orbital properties alone. It is probable that most observed main-belt asteroid satellites are by-products of cratering and/or catastrophic disruption events. Several possible formation mechanisms related to collisions have been identified: (i) mutual capture following catastrophic disruption, (ii) rotational fission due to glancing impact and spin-up, and (iii) re-accretion in orbit of ejecta from large, non-catastrophic impacts. Here we present results from a systematic investigation directed toward mapping out the parameter space of the first and third of these three collisional mechanisms.

  5. Asteroid exploration and utilization: The Hawking explorer

    NASA Technical Reports Server (NTRS)

    Carlson, Alan; Date, Medha; Duarte, Manny; Erian, Neil; Gafka, George; Kappler, Peter; Patano, Scott; Perez, Martin; Ponce, Edgar; Radovich, Brian

    1991-01-01

    The Earth is nearing depletion of its natural resources at a time when human beings are rapidly expanding the frontiers of space. The resources which may exist on asteroids could have enormous potential for aiding and enhancing human space exploration as well as life on Earth. With the possibly limitless opportunities that exist, it is clear that asteroids are the next step for human existence in space. This report comprises the efforts of NEW WORLDS, Inc. to develop a comprehensive design for an asteroid exploration/sample return mission. This mission is a precursor to proof-of-concept missions that will investigate the validity of mining and materials processing on an asteroid. Project STONER (Systematic Transfer of Near Earth Resources) is based on two utilization scenarios: (1) moving an asteroid to an advantageous location for use by Earth; and (2) mining an asteroids and transporting raw materials back to Earth. The asteroid explorer/sample return mission is designed in the context of both scenarios and is the first phase of a long range plane for humans to utilize asteroid resources. The report concentrates specifically on the selection of the most promising asteroids for exploration and the development of an exploration scenario. Future utilization as well as subsystem requirements of an asteroid sample return probe are also addressed.

  6. Asteroid Detection with the Space Surveillance Telescope

    NASA Astrophysics Data System (ADS)

    Woods, D.; Shah, R.; Johnson, J.; Pearce, E.; Lambour, R.; Faccenda, W.

    2013-09-01

    The Space Surveillance Telescope (SST) is a 3.5 m wide field-of-view system developed for DARPA by MIT Lincoln Laboratory to advance the nation's capabilities in space situational awareness. In addition to the national interest in identifying and cataloging man-made space objects, there is a growing concern for near-Earth asteroid identification and tracking. MIT is developing a program to detect near-Earth asteroids, as an extension of the Lincoln Near-Earth Asteroid Research (LINEAR) survey, to identify potentially hazardous near-Earth objects, and to extend the catalog of known asteroids to smaller sizes (< 140 m). MIT believes SST's capability to detect asteroids on size scales as small as 5-10 m is well suited to provide NASA with a sample of small asteroids of interest for its proposed mission to send astronauts to near-Earth asteroids as a stepping-stone to further manned exploration of the Solar System. The Keck Institute for Space Studies (Brophy et al. 2012), studied the feasibility of asteroid capture into lunar orbit as a destination for additional investigation. A major requirement of such an effort is the development of a sample of suitable asteroids, a job that SST is uniquely able to achieve by means of its capacity for search rate and sensitivity. The SST also brings the capability of high speed photometry at rates of 100 Hz to 1 kHz; we present initial observations of asteroids using the photometers.

  7. Big bang nucleosynthesis revisited via Trojan Horse method measurements

    SciTech Connect

    Pizzone, R. G.; Spartá, R.; Spitaleri, C.; La Cognata, M.; Tumino, A.; Bertulani, C. A.; Lalmansingh, J.; Lamia, L.; Mukhamedzhanov, A.

    2014-05-10

    Nuclear reaction rates are among the most important input for understanding primordial nucleosynthesis and, therefore, for a quantitative description of the early universe. An up-to-date compilation of direct cross-sections of {sup 2}H(d, p){sup 3}H, {sup 2}H(d, n){sup 3}He, {sup 7}Li(p, α){sup 4}He, and {sup 3}He(d, p){sup 4}He reactions is given. These are among the most uncertain cross-sections used and input for big bang nucleosynthesis calculations. Their measurements through the Trojan Horse method are also reviewed and compared with direct data. The reaction rates and the corresponding recommended errors in this work were used as input for primordial nucleosynthesis calculations to evaluate their impact on the {sup 2}H, {sup 3,4}He, and {sup 7}Li primordial abundances, which are then compared with observations.

  8. Applications of the Trojan Horse method in nuclear astrophysics

    SciTech Connect

    Spitaleri, Claudio

    2015-02-24

    The study of the energy production in stars and related nucleosyntesis processes requires increasingly precise knowledge of the nuclear reaction cross section and reaction rates at interaction energy. In order to overcome the experimental difficulties, arising from small cross-sections involved in charge particle induced reactions at astrophysical energies, and from the presence of electron screening, it was necessary to introduce indirect methods. Trough these methods it is possible to measure cross sections at very small energies and retrieve information on electron screening effect when ultra-low energy direct measurements are available. The Trojan Horse Method (THM) represents the indirect technique to determine the bare nucleus astrophysical S-factor for reactions between charged particles at astrophysical energies. The basic theory of the THM is discussed in the case of non-resonant.

  9. Applications of the Trojan Horse method in nuclear astrophysics

    NASA Astrophysics Data System (ADS)

    Spitaleri, Claudio

    2015-02-01

    The study of the energy production in stars and related nucleosyntesis processes requires increasingly precise knowledge of the nuclear reaction cross section and reaction rates at interaction energy. In order to overcome the experimental difficulties, arising from small cross-sections involved in charge particle induced reactions at astrophysical energies, and from the presence of electron screening, it was necessary to introduce indirect methods. Trough these methods it is possible to measure cross sections at very small energies and retrieve information on electron screening effect when ultra-low energy direct measurements are available. The Trojan Horse Method (THM) represents the indirect technique to determine the bare nucleus astrophysical S-factor for reactions between charged particles at astrophysical energies. The basic theory of the THM is discussed in the case of non-resonant.

  10. Big Bang Nucleosynthesis Revisited via Trojan Horse Method Measurements

    NASA Astrophysics Data System (ADS)

    Pizzone, R. G.; Spartá, R.; Bertulani, C. A.; Spitaleri, C.; La Cognata, M.; Lalmansingh, J.; Lamia, L.; Mukhamedzhanov, A.; Tumino, A.

    2014-05-01

    Nuclear reaction rates are among the most important input for understanding primordial nucleosynthesis and, therefore, for a quantitative description of the early universe. An up-to-date compilation of direct cross-sections of 2H(d, p)3H, 2H(d, n)3He, 7Li(p, α)4He, and 3He(d, p)4He reactions is given. These are among the most uncertain cross-sections used and input for big bang nucleosynthesis calculations. Their measurements through the Trojan Horse method are also reviewed and compared with direct data. The reaction rates and the corresponding recommended errors in this work were used as input for primordial nucleosynthesis calculations to evaluate their impact on the 2H, 3, 4He, and 7Li primordial abundances, which are then compared with observations.

  11. Trojan Horse Method: recent results in nuclear astrophysics

    NASA Astrophysics Data System (ADS)

    Spitaleri, C.; Lamia, L.; Gimenez Del Santo, M.; Burjan, V.; Carlin, N.; Li, Chengbo; Cherubini, S.; Crucilla, V.; Gulino, M.; Hons, Z.; Kroha, V.; Irgaziev, B.; La Cognata, M.; Mrazek, J.; Mukhamedzhanov, M.; Munhoz, M. G.; Palmerini, S.; Pizzone, R. G.; Puglia, M. R.; Rapisarda, G. G.; Romano, S.; Sergi, L.; Zhou, Shu-Hua; Somorjai, E.; Souza, F. A.; Tabacaru, G.; Szanto de Toledo, A.; Tumino, A.; Wen, Qungang; Wakabayashi, Y.; Yamaguchi, H.

    2015-07-01

    The accurate knowledge of thermonuclear reaction rates is important in understanding the energy generation, the neutrinos luminosity and the synthesis of elements in stars. The physical conditions under which the majority of astrophysical reactions proceed in stellar environments make it difficult or impossible to measure them under the same conditions in the laboratory. That is why different indirect techniques are being used along with direct measurements. The Trojan Horse Method (THM) is introduced as an independent technique to obtain the bare nucleus astrophysical S(E)-factor. As examples the results of recent the application of THM to the 2H(11B, σ08Be)n and 2H(10B, σ07Be)n reactions are presented.

  12. Near Earth Asteroid Characteristics for Asteroid Threat Assessment

    NASA Astrophysics Data System (ADS)

    Dotson, J.; Wooden, D. H.; Bryson, K.; Ostrowski, D. R.

    2015-12-01

    Information about the physical characteristics of Near Earth Asteroids (NEAs) is needed to model behavior during atmospheric entry, to assess the risk of an impact, and to model possible mitigation techniques. The intrinsic properties of interest to entry and mitigation modelers, however, rarely are directly measureable. Instead we measure other properties and infer the intrinsic physical properties, so determining the complete set of characteristics of interest is far from straightforward. In addition, for the majority of NEAs, only the basic measurements exist so often properties must be inferred from statistics of the population of more completely characterized objects. We will provide an assessment of the current state of knowledge about the physical characteristics of importance to asteroid threat assessment. In addition, an ongoing effort to collate NEA characteristics into a readily accessible database for use by the planetary defense community will be discussed.

  13. Designing Asteroid Impact Scenario Trajectories

    NASA Astrophysics Data System (ADS)

    Chodas, Paul

    2016-05-01

    In order to study some of the technical and geopolitical issues of dealing with an asteroid on impact trajectory, a number of hypothetical impact scenarios have been presented over the last ten years or so. These have been used, for example, at several of the Planetary Defense Conferences (PDCs), as well as in tabletop exercises with the Federal Emergency Management Agency (FEMA), along with other government agencies. The exercise at the 2015 PDC involved most of the attendees, consisted of seven distinct steps (“injects”), and with all the presentations and discussions, took up nearly 10 hours of conference time. The trajectory for the PDC15 scenario was entirely realistic, and was posted ahead of the meeting. It was made available in the NEO Program’s Horizons ephemeris service so that users could , for example, design their own deflection missions. The simulated asteroid and trajectory had to meet numerous very exacting requirements: becoming observable on the very first day of the conference, yet remaining very difficult to observe for the following 7 years, and far enough away from Earth that it was out of reach of radar until just before impact. It had to be undetectable in the past, and yet provide multiple perihelion opportunities for deflection in the future. It had to impact in a very specific region of the Earth, a specific number of years after discovery. When observations of the asteroid are simulated to generate an uncertainty region, that entire region must impact the Earth along an axis that cuts across specific regions of the Earth, the “risk corridor”. This is important because asteroid deflections generally move an asteroid impact point along this corridor. One scenario had a requirement that the asteroid pass through a keyhole several years before impact. The PDC15 scenario had an additional constraint that multiple simulated kinetic impactor missions altered the trajectory at a deflection point midway between discovery and impact

  14. The Asteroid 2000 ET70

    NASA Astrophysics Data System (ADS)

    Vodniza, Alberto Q.; Pereira, M. R.

    2012-10-01

    The asteroid 2000 ET70 (162421) was discovered by Lincoln Laboratory ETS (LINEAR) in New Mexico on March 8, 2000. Whiteley (2001) classified 2000 ET70 as an X-type object: This asteroid belongs to an ambiguous group that includes objects that are large and dark, metallic.The composition of this asteroid is unknown.The asteroid was at 0.0454430 U.A from the Earth on February 19.85956 (2012) and it will be at approximately 0.1503270 A.U from the Earth on August 21.07061 (2012).The asteroid 2000 ET70 was studied by radar in Arecibo and Goldstone. Shantanu Naidu and Jean-Luc Margot studied this object by Arecibo radar (Feb 13-2012) and they suggest that 2000 ET70 is roughly 1.5 km in diameter and that it has a period of rotation of about 9.5 hours. It has an orbital period of 0.92 years.From our Observatory, located in Pasto-Colombia, we captured several pictures, videos and astrometry data during three days. Our data was published by the Minor Planet Center (MPC) and also appears at the web page of NEODyS. Our observatory’s code at the MPC is “H78”. Pictures of the asteroid were captured with the following equipment: 14” LX200 GPS MEADE (f/10 Schmidt-Cassegrain Telescope) and STL-1001 SBIG camera.Astrometry was carried out, and we calculated the orbital elements. We obtained the following orbital parameters: eccentricity = 0.1243231, semi-major axis = 0.94541495 A.U, orbital inclination = 22.32919 deg, longitude of the ascending node = 331.05007 deg, argument of perihelion = 45.20913 deg, orbital period = 0.92 years (335.76 days), mean motion = 1.07218658 deg/d, perihelion distance = 0.82787796 A.U, aphelion distance = 1.06295195 A.U. The parameters were calculated based on 71 observations (2012 Mar. 1-7) with mean residual = 0.262 arcseconds.

  15. The Asteroid 1998 QE2

    NASA Astrophysics Data System (ADS)

    Vodniza, Alberto Q.; Pereira, M. R.; Arecibo Observatory Team; JPL Target Asteroids Team

    2013-10-01

    This big asteroid was at 5.8 millions of kilometers from the Earth on May 31 (2013) and it has a diameter of 2.7 km. The radar images obtained by JPL showed that the period of rotation around its axis is close to five hours. Hills. K (2013) reported that the period is of 5.281 +/- 0.002 hours. On June 4 the team of Goldstone-Arecibo found a period of 4.75 +/- 0.01 hours. We also contributed with the light and phase curves to estimate the period by means of the telescope (with red filter). The radar imagery (JPL and Arecibo) revealed that 1998 QE2 has a moon, and we captured a mutual event (eclipse). From our Observatory, located in Pasto-Colombia, we captured several pictures, videos and astrometry data during several days. Our data was published by the Minor Planet Center (MPC) and also appears at the web page of NEODyS. The pictures of the asteroid were captured with the following equipment: CGE PRO 1400 CELESTRON (f/11 Schmidt-Cassegrain Telescope) and STL-1001 SBIG camera. We obtained the light curve of the body. Astrometry was carried out, and we calculated the orbital elements. We obtained the following orbital parameters: eccentricity = 0.5692181, semi-major axis = 2.41104631 A.U, orbital inclination = 12.82771 deg, longitude of the ascending node = 250.16876 deg, argument of perihelion = 345.61328 deg, mean motion = 0.26326658 deg/d, perihelion distance = 1.03863508 A.U, aphelion distance = 3.78345755 A.U. The asteroid has an orbital period of 3.74 years The parameters were calculated based on 191 observations (2013 May: 17-24) with mean residual = 0.162 arcseconds. A video of the asteroid from our Observatory was published on the main page of the “SPACEWEATHER” web: http://www.spaceweather.com/archive.php?view=1&day=21&month=05&year=2013 Note: The autors would like to thank to: Dr. Alessondra Springmann (Arecibo Observatory), Dr. Petr Pravec (Czech Republic), Dr. Lance Benner (JPL), Dr. Carl Hergenrother (Target Asteroids Team), and Dr. Dolores Hill

  16. MarcoPolo-R near earth asteroid sample return mission

    NASA Astrophysics Data System (ADS)

    Barucci, Maria Antonietta; Cheng, A. F.; Michel, P.; Benner, L. A. M.; Binzel, R. P.; Bland, P. A.; Böhnhardt, H.; Brucato, J. R.; Campo Bagatin, A.; Cerroni, P.; Dotto, E.; Fitzsimmons, A.; Franchi, I. A.; Green, S. F.; Lara, L.-M.; Licandro, J.; Marty, B.; Muinonen, K.; Nathues, A.; Oberst, J.; Rivkin, A. S.; Robert, F.; Saladino, R.; Trigo-Rodriguez, J. M.; Ulamec, S.; Zolensky, M.

    2012-04-01

    MarcoPolo-R is a sample return mission to a primitive Near-Earth Asteroid (NEA) proposed in collaboration with NASA. It will rendezvous with a primitive NEA, scientifically characterize it at multiple scales, and return a unique sample to Earth unaltered by the atmospheric entry process or terrestrial weathering. MarcoPolo-R will return bulk samples (up to 2 kg) from an organic-rich binary asteroid to Earth for laboratory analyses, allowing us to: explore the origin of planetary materials and initial stages of habitable planet formation; identify and characterize the organics and volatiles in a primitive asteroid; understand the unique geomorphology, dynamics and evolution of a binary NEA. This project is based on the previous Marco Polo mission study, which was selected for the Assessment Phase of the first round of Cosmic Vision. Its scientific rationale was highly ranked by ESA committees and it was not selected only because the estimated cost was higher than the allotted amount for an M class mission. The cost of MarcoPolo-R will be reduced to within the ESA medium mission budget by collaboration with APL (John Hopkins University) and JPL in the NASA program for coordination with ESA's Cosmic Vision Call. The baseline target is a binary asteroid (175706) 1996 FG3, which offers a very efficient operational and technical mission profile. A binary target also provides enhanced science return. The choice of this target will allow new investigations to be performed more easily than at a single object, and also enables investigations of the fascinating geology and geophysics of asteroids that are impossible at a single object. Several launch windows have been identified in the time-span 2020-2024. A number of other possible primitive single targets of high scientific interest have been identified covering a wide range of possible launch dates. The baseline mission scenario of MarcoPolo-R to 1996 FG3 is as follows: a single primary spacecraft provided by ESA, carrying

  17. Two cubesat mission to study the Didymos asteroid system

    NASA Astrophysics Data System (ADS)

    Wahlund, J.-E.; Vinterhav, E.; Trigo-Rodríguez, J. M.; Hallmann, M.; Barabash, S.; Ivchenko, N.

    2015-10-01

    record the impact event from a closer vantage point than the main spacecraft. The two CubeSats are equipped with relative navigation systems capable of estimating the spacecraft position relative to the asteroids and propulsion system that allow them to operate close to the asteroid bodies. The two CubeSats will rely on mapping data relayed via the AIM main spacecraft but operate autonomously and individually based on schedules and navigation maps uploaded from ground. AIDA's target is the binary Apollo asteroid 65803 Didymos that is also catalogued as Potentially Hazardous Asteroid (PHA) because it experiences close approaches to Earth. Didymos' primary has a diameter of ˜800 meters and the secondary is ˜150 m across. Both bodies are separated about 1.1 km [3]. The rotation period and asymmetry of the secondary object is unknown, and it might be tidally locked to the larger primary body. At least the primary body is expected to be associated with ordinary chondrite material, consisting mostly of silicates, and metal, but the earlier made Xk classification suggested a rubble-pile type with large amount of volatile content. The secondary companion spectral class is unknown, but the total mass of the system suggests that the secondary companion could be of similar class. Detailed empirical information on the physical properties of the Didymos asteroid system, in particular the magnetic field, the (mineralogical) surface composition, the internal composition via the bulk density, the ages of surface units through crater counts and other morphological surface features is valuable in order to make progress in the asteroid field of science. Furthermore, the periodic effect of such a close dynamic system in the presence and temporal displacement of the surface regolith is EPSC Abstracts Vol. 10, EPSC2015-698, 2015 European Planetary Science Congress 2015 c Author(s) 2015 EPSC European Planetary Science Congress unknown, and could be followed using close-up video systems

  18. The Asteroid Redirect Mission (ARM)

    NASA Astrophysics Data System (ADS)

    Abell, Paul; Gates, Michele; Johnson, Lindley; Chodas, Paul; Mazanek, Dan; Reeves, David; Ticker, Ronald

    2016-07-01

    To achieve its long-term goal of sending humans to Mars, the National Aeronautics and Space Administration (NASA) plans to proceed in a series of incrementally more complex human spaceflight missions. Today, human flight experience extends only to Low-Earth Orbit (LEO), and should problems arise during a mission, the crew can return to Earth in a matter of minutes to hours. The next logical step for human spaceflight is to gain flight experience in the vicinity of the Moon. These cis-lunar missions provide a "proving ground" for the testing of systems and operations while still accommodating an emergency return path to the Earth that would last only several days. Cis-lunar mission experience will be essential for more ambitious human missions beyond the Earth-Moon system, which will require weeks, months, or even years of transit time. In addition, NASA has been given a Grand Challenge to find all asteroid threats to human populations and know what to do about them. Obtaining knowledge of asteroid physical properties combined with performing technology demonstrations for planetary defense provide much needed information to address the issue of future asteroid impacts on Earth. Hence the combined objectives of human exploration and planetary defense give a rationale for the Asteroid Re-direct Mission (ARM). Mission Description: NASA's ARM consists of two mission segments: 1) the Asteroid Redirect Robotic Mission (ARRM), the first robotic mission to visit a large (greater than ~100 m diameter) near-Earth asteroid (NEA), collect a multi-ton boulder from its surface along with regolith samples, demonstrate a planetary defense technique, and return the asteroidal material to a stable orbit around the Moon; and 2) the Asteroid Redirect Crewed Mission (ARCM), in which astronauts will take the Orion capsule to rendezvous and dock with the robotic vehicle, conduct multiple extravehicular activities to explore the boulder, and return to Earth with samples. NASA's proposed

  19. Earth-crossing asteroids - New discoveries

    NASA Technical Reports Server (NTRS)

    Helin, E. F.

    1982-01-01

    An earth-crossing asteroid is an asteroid whose orbit will intersect the orbit of the earth as a result of secular perturbations. Ast