How Accurately Can We Predict Eclipses for Algol? (Poster abstract)

NASA Astrophysics Data System (ADS)

Turner, D.

2016-06-01

(Abstract only) beta Persei, or Algol, is a very well known eclipsing binary system consisting of a late B-type dwarf that is regularly eclipsed by a GK subgiant every 2.867 days. Eclipses, which last about 8 hours, are regular enough that predictions for times of minima are published in various places, Sky & Telescope magazine and The Observer's Handbook, for example. But eclipse minimum lasts for less than a half hour, whereas subtle mistakes in the current ephemeris for the star can result in predictions that are off by a few hours or more. The Algol system is fairly complex, with the Algol A and Algol B eclipsing system also orbited by Algol C with an orbital period of nearly 2 years. Added to that are complex long-term O-C variations with a periodicity of almost two centuries that, although suggested by Hoffmeister to be spurious, fit the type of light travel time variations expected for a fourth star also belonging to the system. The AB sub-system also undergoes mass transfer events that add complexities to its O-C behavior. Is it actually possible to predict precise times of eclipse minima for Algol months in advance given such complications, or is it better to encourage ongoing observations of the star so that O-C variations can be tracked in real time?

How Cool was the Eclipse? Atmospheric Measurements and Citizen Science via NASA's GLOBE Observer

NASA Astrophysics Data System (ADS)

Weaver, K. L. K.; Riebeek Kohl, H.

2017-12-01

The solar eclipse of 2017 presented an extraordinary opportunity to engage the public in shared science activity across the entire United States. While a natural focus of the eclipse was on astronomy and heliophysics, there was also an opening for excellent connections to Earth science. Because of the excitement of the event, many people gathered for long periods before and after totality, a perfect opportunity for observations and data collection to explore the impact of the eclipse on the atmosphere. The data was collected via NASA's GLOBE Observer app, a subset of the Global Learning and Observations to Benefit the Environment Program, a citizen science project which has been active for more than 20 years training teachers to collect many different types of environmental science data with their students. GLOBE Observer expands that audience to citizen scientists who might not be connected to a school, but are still interested in collecting data. In addition to the clouds observations that are normally part of GLOBE Observer, a special temporary protocol was added for the eclipse to include air temperature. Both types of measurements were collected at regular intervals for several hours before and after the point of maximum eclipse. By crowdsourcing data from all across the United States, on and off the path of totality, the hope was to be able to see patterns that wouldn't be apparent with fewer data points. In particular, there are few sources of detailed cloud data from the ground, including cloud type as well as overall cloud cover, especially as collected during a unique natural experiment such as an eclipse. This presentation will report preliminary results of the GLOBE Observer eclipse citizen science project, including participation totals and impact, data site distribution, as well as early analyses of both temperature and cloud data.

Strategies for the public communication of eclipses

NASA Astrophysics Data System (ADS)

Bretones, P. S.

2015-03-01

Eclipses are among the celestial events that draw the attention of the public. This paper discusses strategies for using eclipses as public communication opportunities in the media. It discusses the impact of articles written by the author and analysis of published material for 25 observed eclipses over the last 30 years by mass media in the state of São Paulo, Brazil. On each occasion, a standard article was posted on the Internet and sent to newspapers, radio and TV with information, such as: date, time and local circumstances; type of the eclipse; area of visibility; explanation; diagram of the phenomenon, and the Moon's path through Earth's shadow; eclipses in history; techniques of observation; getting photographs; place and event for public observation. Over the years, direct contact was maintained with the media and jounralists by the press offices of the institutions.

SS Bootis - A totally eclipsing binary of the RS CVn type

NASA Technical Reports Server (NTRS)

Vaucher, C. A.; Africano, J. L.; Henry, G. W.; Hall, D. S.; Wilson, J. W.

1983-01-01

Photoelectric photometry gathered for SS Bootis over the 1976-1981 period shows a distortion wave amplitude variation from 0.05 to 0.20 mag, with no apparent pattern. From the rectified light curve, a new time of midprimary eclipse was found to be 2444332.0335 + or - 0.0005 days. Solutions of the primary eclipse data, rectified for star spots as well as for ellipticity and reflection, are presented.

Eclipse prediction on the ancient Greek astronomical calculating machine known as the Antikythera Mechanism.

PubMed

Freeth, Tony

2014-01-01

The ancient Greek astronomical calculating machine, known as the Antikythera Mechanism, predicted eclipses, based on the 223-lunar month Saros cycle. Eclipses are indicated on a four-turn spiral Saros Dial by glyphs, which describe type and time of eclipse and include alphabetical index letters, referring to solar eclipse inscriptions. These include Index Letter Groups, describing shared eclipse characteristics. The grouping and ordering of the index letters, the organization of the inscriptions and the eclipse times have previously been unsolved. A new reading and interpretation of data from the back plate of the Antikythera Mechanism, including the glyphs, the index letters and the eclipse inscriptions, has resulted in substantial changes to previously published work. Based on these new readings, two arithmetical models are presented here that explain the complete eclipse prediction scheme. The first model solves the glyph distribution, the grouping and anomalous ordering of the index letters and the structure of the inscriptions. It also implies the existence of lost lunar eclipse inscriptions. The second model closely matches the glyph times and explains the four-turn spiral of the Saros Dial. Together, these models imply a surprisingly early epoch for the Antikythera Mechanism. The ancient Greeks built a machine that can predict, for many years ahead, not only eclipses but also a remarkable array of their characteristics, such as directions of obscuration, magnitude, colour, angular diameter of the Moon, relationship with the Moon's node and eclipse time. It was not entirely accurate, but it was an astonishing achievement for its era.

Eclipse Prediction on the Ancient Greek Astronomical Calculating Machine Known as the Antikythera Mechanism

PubMed Central

Freeth, Tony

2014-01-01

The ancient Greek astronomical calculating machine, known as the Antikythera Mechanism, predicted eclipses, based on the 223-lunar month Saros cycle. Eclipses are indicated on a four-turn spiral Saros Dial by glyphs, which describe type and time of eclipse and include alphabetical index letters, referring to solar eclipse inscriptions. These include Index Letter Groups, describing shared eclipse characteristics. The grouping and ordering of the index letters, the organization of the inscriptions and the eclipse times have previously been unsolved. A new reading and interpretation of data from the back plate of the Antikythera Mechanism, including the glyphs, the index letters and the eclipse inscriptions, has resulted in substantial changes to previously published work. Based on these new readings, two arithmetical models are presented here that explain the complete eclipse prediction scheme. The first model solves the glyph distribution, the grouping and anomalous ordering of the index letters and the structure of the inscriptions. It also implies the existence of lost lunar eclipse inscriptions. The second model closely matches the glyph times and explains the four-turn spiral of the Saros Dial. Together, these models imply a surprisingly early epoch for the Antikythera Mechanism. The ancient Greeks built a machine that can predict, for many years ahead, not only eclipses but also a remarkable array of their characteristics, such as directions of obscuration, magnitude, colour, angular diameter of the Moon, relationship with the Moon’s node and eclipse time. It was not entirely accurate, but it was an astonishing achievement for its era. PMID:25075747

The O-type eclipsing contact binary LY Aurigae - member of a quadruple system

NASA Astrophysics Data System (ADS)

Mayer, Pavel; Drechsel, Horst; Harmanec, Petr; Yang, Stephenson; Šlechta, Miroslav

2013-11-01

The eclipsing binary LY Aur (O9 II + O9 III) belongs to the rare class of early-type contact systems. We obtained 23 new spectra at the Ondřejov and Dominion Astrophysical Observatories, which were analysed with four older Calar Alto and one ELODIE archive spectra. A new result of this study is that the visual companion of LY Aur - the spectral lines of which are clearly seen in our spectra - is also an SB1 binary having an orbital period of 20.46d, an eccentric orbit, and a radial velocity semi-amplitude of 33 km s-1. The Hα line blend contains an emission component, which shows dependence on the orbital phase of the eclipsing system, with the strongest emission around the secondary eclipse. Revised elements of the eclipsing binary and the orbital solution of the companion binary are determined from our set of spectra and new light-curve solutions of the eclipsing pair. The mass of the primary of 25.5 M⊙ agrees well with its spectral type, whereas the secondary mass of 14 M⊙ is smaller than expected. From an O-C analysis of the minimum times of LY Aur that span more than 40 years, we found that the orbital period is decreasing, indicating the presence of interaction processes. The system is likely in a phase of non-conservative mass exchange. Based on spectral observations collected at the German-Spanish Observatory, Calar Alto, Spain; Dominion Astrophysical Observatory, Canada; Ondřejov Observatory, Czech Republic, and an archival Haute Provence Observatory ELODIE spectrum.

New Light Curves and Analysis of the Overcontact Binaries PP Lac and DK Sge

NASA Astrophysics Data System (ADS)

Sanders, S. J.; Hargis, J. R.; Bradstreet, D. H.

2004-12-01

As a by-product of the ongoing work with the Catalog and AtLas of Eclipsing Binaries database (CALEB; Bradstreet et al. 2004), several hundred eclipsing binary systems have been identified that have either unpublished or poor quality light curves. We present new V & Rc light curves for the overcontact systems PP Lac and DK Sge, both chosen because their deep eclipses (peak-to-peak amplitudes of nearly 0.7 mag) help constrain the light curve modelling. Data were obtained using the 41-cm telescope at the Eastern University Observatory equipped with an SBIG ST-10XME CCD. PP Lac (P= 0.40116 d) is a W-type contact binary with only one previously published light curve (Dumont & Maraziti 1990), but the data are sparse and almost non-existent at primary eclipse. Modelling of these data gave varying results; the published mass ratios differ by nearly 0.3. Our data confirms the noted differing eclipse depths but we find the primary eclipse to be total. We present a new light curve solution using Binary Maker 3 (Bradstreet & Steelman 2002) and Wilson-Devinney, finding the mass ratio to be well-constrained by the duration of total eclipse. A period study will be presented using previously existing and newly derived times of minimum light. DK Sge (P=0.62182 d) appears to be an A-type contact binary with no published light curve. The eclipses are partial, with the primary eclipse being deeper by about 0.08 mag. The maxima show evidence of a slight asymmetry, although the light curve appears to be repeatable over the 1 month of observations. We present the first light curve solution using Binary Maker 3 and Wilson-Devinney, but have limited mass ratio constraints due to the absence of radial velocity data. A period study will be presented using previously existing and newly derived times of minimum light.

A NEW CLASS OF NASCENT ECLIPSING BINARIES WITH EXTREME MASS RATIOS

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

Moe, Maxwell; Stefano, Rosanne Di, E-mail: mmoe@cfa.harvard.edu

2015-03-10

Early B-type main-sequence (MS) stars (M {sub 1} ≈ 5-16 M {sub ☉}) with closely orbiting low-mass stellar companions (q = M {sub 2}/M {sub 1} < 0.25) can evolve to produce Type Ia supernovae, low-mass X-ray binaries, and millisecond pulsars. However, the formation mechanism and intrinsic frequency of such close extreme mass-ratio binaries have been debated, especially considering none have hitherto been detected. Utilizing observations of the Large Magellanic Cloud galaxy conducted by the Optical Gravitational Lensing Experiment, we have discovered a new class of eclipsing binaries in which a luminous B-type MS star irradiates a closely orbiting low-massmore » pre-MS companion that has not yet fully formed. The primordial pre-MS companions have large radii and discernibly reflect much of the light they intercept from the B-type MS primaries (ΔI {sub refl} ≈ 0.02-0.14 mag). For the 18 definitive MS + pre-MS eclipsing binaries in our sample with good model fits to the observed light-curves, we measure short orbital periods P = 3.0-8.5 days, young ages τ ≈ 0.6-8 Myr, and small secondary masses M {sub 2} ≈ 0.8-2.4 M {sub ☉} (q ≈ 0.07-0.36). The majority of these nascent eclipsing binaries are still associated with stellar nurseries, e.g., the system with the deepest eclipse ΔI {sub 1} = 2.8 mag and youngest age τ = 0.6 ± 0.4 Myr is embedded in the bright H II region 30 Doradus. After correcting for selection effects, we find that (2.0 ± 0.6)% of B-type MS stars have companions with short orbital periods P = 3.0-8.5 days and extreme mass ratios q ≈ 0.06-0.25. This is ≈10 times greater than that observed for solar-type MS primaries. We discuss how these new eclipsing binaries provide invaluable insights, diagnostics, and challenges for the formation and evolution of stars, binaries, and H II regions.« less

Two-Color V and R CCD Photometry of the SW Sex-Type Eclipsing Cataclysmic Variable V1315 Aql

NASA Astrophysics Data System (ADS)

Andronov, I. L.; Baklanov, A. V.; Burwitz, V.

2005-08-01

The V-R color index shows a complicated behaviour during the eclipse, being largest at the brightness minimum, but showing asymmetric minima at phases -0.07 and +0.13. The hump at the light curve occurs after the eclipse, contrary to systems with the "hot spot". The phases of minima in V and R are 0.0092(17) and 0.0062(17), respectively, for the mean date JD=2453202.

A hot companion to Mu Sagittarii - An opportunity to sound the atmosphere of a B8 Ia supergiant

NASA Technical Reports Server (NTRS)

Polidan, R. S.; Plavec, M. J.

1984-01-01

It is argued that the bright supergiant star Mu Sagittarii is accompanied by a smaller and hotter star, of spectral type approximately B1.5 V. The single-line radial-velocity curve of the B8 star leads to a fairly large mass function, f(m) = 2.64 solar masses, implying that the companion should have at least 50 percent of the mass of the visible star. Older optical observations indicated the presence of a shallow eclipse at the time of the conjunction with the supergiant behind the companion. Since the Copernicus, IUE, and Voyager observations show that the companion is the hotter component, that eclipse must have been the secondary eclipse (if it was an eclipse at all). A deeper, primary eclipse has been predicted by Plavec in 1978. It was indeed observed as a marked decrease of the far-ultraviolet flux from the system both with the Copernicus and the IUE satellites. The presence of a hotter but smaller component in Mu Sagittarii offers a unique opportunity to study the outer atmospheric layers of a supergiant which is of a much earlier spectral type than the supergiants in the Zeta Aurigae systems.

Full Phase Multi-Band Study of Eclipsing Binaries 1SWASP J061850.43+220511.9 and 2MASSJ07095549+3643564

NASA Astrophysics Data System (ADS)

Terheide, Rachel; Zhang, Liyun; Han, Xianming; Lu, Hongpeng

2018-01-01

We present full-phase VRI-band light curves for eclipsing binary 1SWASP J061850.43+220511.9, and full-phase BVRI-band light curves for eclipsing binary 2MASS J07095549+3643564. The observations were conducted using the 0.94-m Holcomb Observatory telescope located on Butler University Campus in Indianapolis, Indiana, and the 0.6-m SARA telescope located at the Cerro Tololo Inter-American Observatory in Chile. We obtained key system parameters for both eclipsing binaries. For 1SWASP J061850.43+220511.9, the period is 0.21482 ±0.00053 days compared to 0.21439 days from an older study (Lohr et. al), the system mass ratio is found as 2.50 and the system is classified as EW type. Similarly, for 2MASS J07095549+3643564, we obtained a linear ephemeris and a physical model for the first time. We found its period to be 0.22297 ±0.00032 days, as compared to 0.446092 days and 0.11152 days from previous research (Drake et. al 2014, Hartman et. al 2011). 2MASS J07095549+3643564 is classified as a W Uma type eclipsing binary.

Deep reconditioning of batteries during DSCS 3 flight operations

NASA Technical Reports Server (NTRS)

Thierfelder, H. E.; Stearns, R. J.; Jones, P. W.

1985-01-01

Deep reconditioning of batteries is defined as discharge below the 1.0 volt/cell level to a value of about 1.0 volt/battery. This type of reconditioning was investigated for use on the Defense Satellite Communications System (DSCS) spacecraft, and has been used during the first year of orbital operation. Prior to launch of the spacecraft, the deep reconditioning was used during the battery life test, which has now complete fourteen eclipse periods. Reconditioning was performed prior to each eclipse period of the life test, and is scheduled to be used prior to each eclipse period in orbit. The battery data for discharge and recharge is presented for one of the life test reconditioning cycles, and for each of the three batteries during the reconditioning cycles between eclipse period no.1 and eclipse period no.2 in Earth orbit.

Discovery of Eclipses from the Accreting Millisecond X-Ray Pulsar Swift J1749.4-2807

NASA Technical Reports Server (NTRS)

Markwardt, C. B.; Stromhmayer, T. E.

2010-01-01

We report the discovery of X-ray eclipses in the recently discovered accreting millisecond X-ray pulsar SWIFT J1749.4-2807. This is the first detection of X-ray eclipses in a system of this type and should enable a precise neutron star mass measurement once the companion star is identified and studied. We present a combined pulse and eclipse timing solution that enables tight constraints on the orbital parameters and inclination and shows that the companion mass is in the range 0.6-0.8 solar mass for a likely range of neutron star masses, and that it is larger than a main-sequence star of the same mass. We observed two individual eclipse egresses and a single ingress. Our timing model shows that the eclipse features are symmetric about the time of 90 longitude from the ascending node, as expected. Our eclipse timing solution gives an eclipse duration (from the mid-points of ingress to egress) of 2172+/-13 s. This represents 6.85% of the 8.82 hr orbital period. This system also presents a potential measurement of "Shapiro" delay due to general relativity; through this technique alone, we set an upper limit to the companion mass of 2.2 Solar mass .

A model of V356 Sagittarii. [eclipsing binary star

NASA Technical Reports Server (NTRS)

Wilson, R. E.; Caldwell, C. N.

1978-01-01

It is pointed out that V356 Sgr is an abnormal member of the Algol class of binaries. According to Popper (1955), the primary component is of spectral type B3V and is rotating rapidly, while the secondary is of type A2II and is rotating at least approximately in synchronism with the orbital motion. The system is either semidetached or quite near to being semidetached. The main anomalies are related to the ratio of eclipse depths, the very small reflection effect of the light curves, differences between the duration of the primary and the secondary eclipse, and the unusual characteristics of the primary eclipse. It is concluded that the lack of agreement between theory and observation can be due only to an important attribute of the binary which has not yet been incorporated into the theory. The peculiarities can most reasonably be explained in terms of a geometrically and optically thick disk which surrounds the primary component.

High-resolution IUE observations of the 1981 eclipse of 32 CYG

NASA Technical Reports Server (NTRS)

Reimers, D.; Che, A.; Hempe, K.

1981-01-01

32 Cyg shows a spectacular pure emission line spectrum during eclipse. Six weeks later, most lines, which were observed in emission during eclipse, are seen as P Cygni type profiles with strong absorption components. The lines are formed through line scattering of B star light in the extended atmosphere (wind) of the K supergiant. During eclipse, the emission parts of the P Cyg lines remain visible since the size of the line scattering sphere around the B star is larger than the red giant. Other emission lines are formed in a shock front near the B star (CIV, SiIV, FeIII) and possibly in an accretion disk. The strong FeII UV Mult. 191 lambda lambda 1785-88 A is shown to be formed through optical pumping via FeII UV Mult. 9 photons. The phase dependence of the P Cyg type profiles is modelled by means of line transfer calculations in nonspherical, 3-dimensional geometry with velocity fields.

From YY Boo (eclipsing binary) via J1407 (ringed companion) to WD 1145+017 (white dwarf with debris disk) (Abstract)

NASA Astrophysics Data System (ADS)

Hambsch, F.-J.

2018-06-01

(Abstract only) Several years ago by accident I observed YY Boo outside of an eclipse and was very surprised to see a short term periodic variation of about 0.1 mag. That was completely unexpected and it initiated an international campaign by amateurs to identify the cause of these variations. It turned out that YY Boo showed a pulsation period of about 88 min in addition to being an Algol type eclipsing binary. Hence it turned out that YY Boo has become a new member of a class of pulsating eclipsing binary systems with, at that time, the second largest amplitude after BO Her.

V571 Lyr is a Multiple System (Abstract)

NASA Astrophysics Data System (ADS)

Billings, G.

2016-12-01

(Abstract only) V571 Lyr (GSC 3116-1047) was discovered by the ROTSE survey to be an EA-type eclipsing binary with 1.25-day period. Primary and secondary eclipses are very similar, with depth V = 0.58 magnitude. In 2000, the then-active AAVSO "EB Team" started observing it, to refine the period estimate. A few eclipses were readily found, and a revised period computed. Subsequent eclipses diverged from the revised linear ephemeris by more than the expected amount of error, so observations were continued. Now, more than 100 time-of-minimum observations, over 15 years, clearly show that V571 Lyr is a triple system, with a third-body orbital period of 5.013 ± 0.008 years, and eccentricity of 0.74 ± 0.03. Our orbit fit also yields a period for the close pair, of 1.252 596 66(6) days. After removing the third-body light-time effect, the eclipse-time residuals still show larger than expected scatter, and possibly non-randomness, perhaps due to significant starspots and/or additional bodies in the system. The color of the system is B-V = 0.52 ± 0.01, corresponding to spectral type F7V, and we obtained a spectrum that we classify as F7V ± 2. The mass function computed from the fitted third-body orbit yields a minimum mass of 1.0 ± 0.1 Msolar, corresponding to a spectral range of F9V to G5V for the third star. We assume the two stars of the close pair are very similar, so the remaining light in eclipses (59%) is consistent with total eclipses and 3rd light from a star slightly dimmer than each of the pair.

MM Herculis - An eclipsing binary of the RS CVn

NASA Technical Reports Server (NTRS)

Sowell, J. R.; Hall, D. S.; Henry, G. W.; Burke, E. W., Jr.; Milone, E. F.

1983-01-01

V, B and U differential photoelectric photometry has been obtained for the RS Canum Venaticorum-class eclipsing binary star MM Her, with the light outside the eclipse being Fourier-analyzed to study wave migration and amplitude. These, together with the mean light level of the system, have been monitored from 1976 through 1980. Observations within the eclipse have revealed eclipses to be partial, rather than total as previously thought. The geometric elements of the presently rectified light curve are forced on the pre-1980 light curves and found to be compatible. With these elements, and previously obtained double line radial velocity curves, new absolute dimensions of 1.18 solar masses and 1.58 solar radii are calculated for the hotter star and 1.27 solar masses and 2.83 solar radii for the cooler star. The plotting of color indices on the color-color curve indicates G2V and K2IV spectral types.

1H 1752 + 081: An eclipsing cataclysmic variable with a small accretion disk

NASA Technical Reports Server (NTRS)

Silber, Andrew D.; Remillard, Ronald A.; Horne, Keith; Bradt, Hale V.

1994-01-01

We announce the discovery of an eclipsing nova-like cataclysmic variable (CV) as the optical counterpart to the HEAO 1 X-ray source 1H1752 + 081. This CV has an orbital period of 1.882801 hr, a high equivalent width of H-beta, and an average m(sub v) of 16.4 out of the eclipse. A geometric model is constructed from observations of the eclipse ingress and egress in many optical bandpasses. The broad-band emission originates primarily in two regions; the disk/accretion stream 'hot spot' and a compact central component, which may be a spot on the white dwarf surface, the entire white dwarf surface or the boundary layer between the accretion disk and the white dwarf surface. Based on the durations and offsets of the two eclipses we determined the mass ratio q = 2.5 +/- 0.6 and the angle of inclination i = 77 deg +/- 2 deg. If the central component is the entire white dwarf surface the masses of the stars are M(sub 1) = 0.80 +/- 0.06 solar masses and M(sub 2) = 0.32 +/- 0.06 solar masses. The disk is faint and small (R(sub D) = 0.25 +/- 0.05 r(sub L1), where r(sub L1) is the distance from the primary to the L(sub 1) point), compared to other eclipsing CVs. The small disk may result from the removal of angular momentum from the accretion disk by the magnetic field of the white dwarf; this CV may be a DQ Her type with a slowly rotating white dwarf. The emission-line velocities do not show the 'Z-wave' expected from the eclipse of a Keplerian accretion disk, nor do they have the correct phasing to originate near the white dwarf. The most likely origin of the line emission is the hot spot. The secondary star is visible at wavelengths greater than or equal to 6000 A during eclipse. We estimate a spectral type approximately M6 which, together with the observed m(sub 1) = 16.94 during eclipse, results in a distance estimate of 150 +/- 27 pc.

Low-radio-frequency eclipses of the redback pulsar J2215+5135 observed in the image plane with LOFAR.

PubMed

Broderick, J W; Fender, R P; Breton, R P; Stewart, A J; Rowlinson, A; Swinbank, J D; Hessels, J W T; Staley, T D; van der Horst, A J; Bell, M E; Carbone, D; Cendes, Y; Corbel, S; Eislöffel, J; Falcke, H; Grießmeier, J-M; Hassall, T E; Jonker, P; Kramer, M; Kuniyoshi, M; Law, C J; Markoff, S; Molenaar, G J; Pietka, M; Scheers, L H A; Serylak, M; Stappers, B W; Ter Veen, S; van Leeuwen, J; Wijers, R A M J; Wijnands, R; Wise, M W; Zarka, P

2016-07-01

The eclipses of certain types of binary millisecond pulsars (i.e. 'black widows' and 'redbacks') are often studied using high-time-resolution, 'beamformed' radio observations. However, they may also be detected in images generated from interferometric data. As part of a larger imaging project to characterize the variable and transient sky at radio frequencies <200 MHz, we have blindly detected the redback system PSR J2215+5135 as a variable source of interest with the Low-Frequency Array (LOFAR). Using observations with cadences of two weeks - six months, we find preliminary evidence that the eclipse duration is frequency dependent (∝ν -0.4 ), such that the pulsar is eclipsed for longer at lower frequencies, in broad agreement with beamformed studies of other similar sources. Furthermore, the detection of the eclipses in imaging data suggests an eclipsing medium that absorbs the pulsed emission, rather than scattering it. Our study is also a demonstration of the prospects of finding pulsars in wide-field imaging surveys with the current generation of low-frequency radio telescopes.

Measuring the Number of M Dwarfs per M Dwarf Using Kepler Eclipsing Binaries

NASA Astrophysics Data System (ADS)

Shan, Yutong; Johnson, John A.; Morton, Timothy D.

2015-11-01

We measure the binarity of detached M dwarfs in the Kepler field with orbital periods in the range of 1-90 days. Kepler’s photometric precision and nearly continuous monitoring of stellar targets over time baselines ranging from 3 months to 4 years make its detection efficiency for eclipsing binaries nearly complete over this period range and for all radius ratios. Our investigation employs a statistical framework akin to that used for inferring planetary occurrence rates from planetary transits. The obvious simplification is that eclipsing binaries have a vastly improved detection efficiency that is limited chiefly by their geometric probabilities to eclipse. For the M-dwarf sample observed by the Kepler Mission, the fractional incidence of eclipsing binaries implies that there are {0.11}-0.04+0.02 close stellar companions per apparently single M dwarf. Our measured binarity is higher than previous inferences of the occurrence rate of close binaries via radial velocity techniques, at roughly the 2σ level. This study represents the first use of eclipsing binary detections from a high quality transiting planet mission to infer binary statistics. Application of this statistical framework to the eclipsing binaries discovered by future transit surveys will establish better constraints on short-period M+M binary rate, as well as binarity measurements for stars of other spectral types.

Tidal Synchronization and Differential Rotation of Kepler Eclipsing Binaries

NASA Astrophysics Data System (ADS)

Lurie, John C.; Vyhmeister, Karl; Hawley, Suzanne L.; Adilia, Jamel; Chen, Andrea; Davenport, James R. A.; Jurić, Mario; Puig-Holzman, Michael; Weisenburger, Kolby L.

2017-12-01

Few observational constraints exist for the tidal synchronization rate of late-type stars, despite its fundamental role in binary evolution. We visually inspected the light curves of 2278 eclipsing binaries (EBs) from the Kepler Eclipsing Binary Catalog to identify those with starspot modulations, as well as other types of out-of-eclipse variability. We report rotation periods for 816 EBs with starspot modulations, and find that 79% of EBs with orbital periods of less than 10 days are synchronized. However, a population of short-period EBs exists, with rotation periods typically 13% slower than synchronous, which we attribute to the differential rotation of high-latitude starspots. At 10 days, there is a transition from predominantly circular, synchronized EBs to predominantly eccentric, pseudosynchronized EBs. This transition period is in good agreement with the predicted and observed circularization period for Milky Way field binaries. At orbital periods greater than about 30 days, the amount of tidal synchronization decreases. We also report 12 previously unidentified candidate δ Scuti and γ Doradus pulsators, as well as a candidate RS CVn system with an evolved primary that exhibits starspot occultations. For short-period contact binaries, we observe a period-color relation and compare it to previous studies. As a whole, these results represent the largest homogeneous study of tidal synchronization of late-type stars.

Long-term eclipse timing of white dwarf binaries: an observational hint of a magnetic mechanism at work

NASA Astrophysics Data System (ADS)

Bours, M. C. P.; Marsh, T. R.; Parsons, S. G.; Dhillon, V. S.; Ashley, R. P.; Bento, J. P.; Breedt, E.; Butterley, T.; Caceres, C.; Chote, P.; Copperwheat, C. M.; Hardy, L. K.; Hermes, J. J.; Irawati, P.; Kerry, P.; Kilkenny, D.; Littlefair, S. P.; McAllister, M. J.; Rattanasoon, S.; Sahman, D. I.; Vučković, M.; Wilson, R. W.

2016-08-01

We present a long-term programme for timing the eclipses of white dwarfs in close binaries to measure apparent and/or real variations in their orbital periods. Our programme includes 67 close binaries, both detached and semi-detached and with M-dwarfs, K-dwarfs, brown dwarfs or white dwarfs secondaries. In total, we have observed more than 650 white dwarf eclipses. We use this sample to search for orbital period variations and aim to identify the underlying cause of these variations. We find that the probability of observing orbital period variations increases significantly with the observational baseline. In particular, all binaries with baselines exceeding 10 yr, with secondaries of spectral type K2 - M5.5, show variations in the eclipse arrival times that in most cases amount to several minutes. In addition, among those with baselines shorter than 10 yr, binaries with late spectral type (>M6), brown dwarf or white dwarf secondaries appear to show no orbital period variations. This is in agreement with the so-called Applegate mechanism, which proposes that magnetic cycles in the secondary stars can drive variability in the binary orbits. We also present new eclipse times of NN Ser, which are still compatible with the previously published circumbinary planetary system model, although only with the addition of a quadratic term to the ephemeris. Finally, we conclude that we are limited by the relatively short observational baseline for many of the binaries in the eclipse timing programme, and therefore cannot yet draw robust conclusions about the cause of orbital period variations in evolved, white dwarf binaries.

The Search for Bright Variable Stars in Open Cluster NGC 6819.

NASA Astrophysics Data System (ADS)

Talamantes, Antonio; Sandquist, E. L.

2009-01-01

During this research period data was taken for seven nights at the 1m telescope at Mt. Laguna Observatory for the open cluster NGC 6819. For four of the nights data was taken using a V-band filter. For the three nights remaining nights the data was taken using an R-band filter. Photometry was done using the ISIS image subtraction package. Six new variable stars were located using these techniques. These variable types include a pulsating variable, five detached eclipsing binaries. Of the detached eclipsing binaries, three are near the cluster turnoff and two in the blue straggler region(and one of these has total eclipses). Nine previously known variables(six contact binaries, two detached eclipsing binaries and one near-contact binary) were also studied.

Observation and Analysis of Secondary Eclipses of WASP-32b

NASA Astrophysics Data System (ADS)

Garland, Justin; Harrington, Joesph; Cubillos, Patricio; Blecic, Jasmina; Foster, Andrew S.; Bowman, Matthew O.; Maxted, Pierre F. L.

2014-11-01

We report two Spitzer secondary eclipses of the exoplanet WASP-32b. Discovered by Maxted et al. (2010), this hot-Jupiter planet has a mass of 3.6 +/- 0.07 Mj, a radius of 1.18 +/- 0.07 Rj, and an orbital period of 2.71865 +/- 0.00008 days around a G-type star. We observed two secondary eclipses in the 3.6 micron and 4.5 micron channels using the Spitzer Space Telescope in 2010 as a part of the Spitzer Exoplanet Target of Opportunity program (program 60003). We present eclipse-depth measurements, estimates of infrared brightness temperatures, and refinements of orbital parameters for WASP-32b from our eclipse measurements as well as amatuer and professional data. Spitzer is operated by the Jet Propulsion Laboratory, California Institute of Technology, under a contract with NASA. This work was supported by NASA Planetary Atmospheres grant NNX12AI69G and NASA Astrophysics Data Analysis Program grant NNX13AF38G. JB holds a NASA Earth and Space Science Fellowship.

Transits, Spots, and Eclipses: The Sunís Role in Pedagogy and Outreach (Abstract)

NASA Astrophysics Data System (ADS)

Larsen, K.

2018-06-01

(Abstract only) While most people observe variable stars at night, the observers of the AAVSO Solar Section make a single observation per day, but only if it is sunny, because our variable is the Sun itself. While the Sun can play an important role in astronomy outreach and pedagogy in general, as demonstrated by the recent 2017 eclipse, it can also serve as an ambassador for variable stars. This talk will examine how our sun can be used as a tool to explain several types of variable star behaviors, including transits, spots, and eclipses.

Plans to Observe the 2017 Total Solar Eclipse from near the Path Edges

NASA Astrophysics Data System (ADS)

Waring Dunham, David; Nugent, Richard; Guhl, Konrad; Bode, Hans-Joachim

2015-08-01

The August 21st, 2017 solar eclipse provides a good opportunity, to time the totality contacts, other Baily’s bead phenomena, and observe other dynamic edge phenomena, from locations near the edges of the path of totality. A good network of roads and generally favorable weather prospects means that more observers will likely be able to deploy more equipment than during most previous eclipses. The value of contact and Baily’s bead timings of total solar eclipses, for determining solar diameter and intensity variations, was described in an earlier presentation in Focus Meeting 13. This presentation will concentrate on how observations of different types that have been used during past eclipses can be made by different observers, to obtain better information about the accuracy of the different types of observations for determining the mean solar diameter, and the systematic differences between them. A problem has been that the few observers who have attempted recording Baily’s beads from path edge locations have wanted to use the latest technology, to try to record the observations better, rather than try to make the observations in the same ways that were used for many past eclipses. Several observers trying different techniques at the same location, and doing that at several locations at different places along the path, is needed. Past techniques that we would like to compare include direct visual observation (but keeping eye safety in mind); visual observation of telescopically projected images; direct filtered video telescopic observations; and recording the flash spectrum. There are several towns that straddle the path edges. The International Occultation Timing Association would like to mobilize people in those towns to observe the eclipse from many places, to say whether or not the eclipse happened, and if it did, time it. A suitable cell phone app could be designed to report observations, including the observer’s location, as was attempted for an occultation of Regulus by the asteroid Erigone in the northeastern USA in 2014, but which unfortunately was clouded out everywhere.

Probing the mysteries of the X-ray binary 4U 1210-64 with ASM, PCA, MAXI, BAT, and Suzaku

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

Coley, Joel B.; Corbet, Robin H. D.; Mukai, Koji

2014-10-01

4U 1210-64 has been postulated to be a high-mass X-ray binary powered by the Be mechanism. X-ray observations with Suzaku, the ISS Monitor of All-sky X-ray Image (MAXI), and the Rossi X-ray Timing Explorer Proportional Counter Array (PCA) and All Sky Monitor (ASM) provide detailed temporal and spectral information on this poorly understood source. Long-term ASM and MAXI observations show distinct high and low states and the presence of a 6.7101 ± 0.0005 day modulation, interpreted as the orbital period. Folded light curves reveal a sharp dip, interpreted as an eclipse. To determine the nature of the mass donor, themore » predicted eclipse half-angle was calculated as a function of inclination angle for several stellar spectral types. The eclipse half-angle is not consistent with a mass donor of spectral type B5 V; however, stars with spectral types B0 V or B0-5 III are possible. The best-fit spectral model consists of a power law with index Γ = 1.85{sub −0.05}{sup +0.04} and a high-energy cutoff at 5.5 ± 0.2 keV modified by an absorber that fully covers the source as well as partially covering absorption. Emission lines from S XVI Kα, Fe Kα, Fe XXV Kα, and Fe XXVI Kα were observed in the Suzaku spectra. Out of eclipse, the Fe Kα line flux was strongly correlated with unabsorbed continuum flux, indicating that the Fe I emission is the result of fluorescence of cold dense material near the compact object. The Fe I feature is not detected during eclipse, further supporting an origin close to the compact object.« less

Low-mass Pre-He White Dwarf Stars in Kepler Eclipsing Binaries with Multi-periodic Pulsations

NASA Astrophysics Data System (ADS)

Zhang, X. B.; Fu, J. N.; Liu, N.; Luo, C. Q.; Ren, A. B.

2017-12-01

We report the discovery of two thermally bloated low-mass pre-He white dwarfs (WDs) in two eclipsing binaries, KIC 10989032 and KIC 8087799. Based on the Kepler long-cadence photometry, we determined comprehensive photometric solutions of the two binary systems. The light curve analysis reveals that KIC 10989032 is a partially eclipsed detached binary system containing a probable low-mass WD with the temperature of about 10,300 K. Having a WD with the temperature of about 13,300, KKIC 8087799 is typical of an EL CVn system. By utilizing radial velocity measurements available for the A-type primary star of KIC 10989032, the mass and radius of the WD component are determined to be 0.24+/- 0.02 {M}⊙ and 0.50+/- 0.01 {R}⊙ , respectively. The values of mass and radius of the WD in KIC 8087799 are estimated as 0.16 ± 0.02 M ⊙ and 0.21 ± 0.01 R ⊙, respectively, according to the effective temperature and mean density of the A-type star derived from the photometric solution. We therefore introduce KIC 10989032 and KIC 8087799 as the eleventh and twelfth dA+WD eclipsing binaries in the Kepler field. Moreover, both binaries display marked multi-periodic pulsations superimposed on binary effects. A preliminary frequency analysis is applied to the light residuals when subtracting the synthetic eclipsing light curves from the observations, revealing that the light pulsations of the two systems are both due to the δ Sct-type primaries. We hence classify KIC 10989032 and KIC 8087799 as two WD+δ Sct binaries.

Did Aboriginal Australians record a simultaneous eclipse and aurora in their oral traditions?

NASA Astrophysics Data System (ADS)

Fuller, Robert S.; Hamacher, Duane W.

2017-12-01

We investigate an Australian Aboriginal cultural story that seems to describe an extraordinary series of astronomical events occurring at the same time. We hypothesise that this was a witnessed natural event and explore natural phenomena that could account for the description. We select a thunderstorm, total solar eclipse, and strong Aurora Australis as the most likely candidates, then conclude a plausible date of 764 CE. We evaluate the different factors that would determine whether all these events could have been visible, include meteorological data, alternative total solar eclipse dates, solar activity cycles, aurorae appearances, and sky brightness during total solar eclipses. We conduct this study as a test-case for rigorously and systematically examining descriptions of rare natural phenomena in oral traditions, highlighting the difficulties and challenges with interpreting this type of hypothesis.

Observations of eclipses of UU Sge

NASA Astrophysics Data System (ADS)

Shimansky, V. V.; Borisov, N. V.; Bikmaev, I. F.; Shimanskaya, N. N.

2012-06-01

We have performed spectroscopy and photometry of eclipses of the pre-cataclysmic variable UUSge using the 6-m telescope of the Special AstrophysicalObservatory and the 1.5-mRussian-Turkish telescope. Our analysis of variations of the B- V and V- R color indices during the eclipses indicates that the temperature of the secondary is T eff,2 = 6000-6300 K. A similar value, T eff,2 = 6200 ± 200 K, follows from our comparison of the observed spectrum of UU Sge at the total eclipse phase and theoretical spectra of late-type stars. We identify 27 absorption lines of 11 chemical elements in the secondary's spectrum. Their abnormal intensities indicate possible high-velocity turbulent motions (up to ξ turb = 10.0 km/s) in the atmosphere of the star and the presence of hot gas above its surface.

An eclipsing-binary distance to the Large Magellanic Cloud accurate to two per cent.

PubMed

Pietrzyński, G; Graczyk, D; Gieren, W; Thompson, I B; Pilecki, B; Udalski, A; Soszyński, I; Kozłowski, S; Konorski, P; Suchomska, K; Bono, G; Moroni, P G Prada; Villanova, S; Nardetto, N; Bresolin, F; Kudritzki, R P; Storm, J; Gallenne, A; Smolec, R; Minniti, D; Kubiak, M; Szymański, M K; Poleski, R; Wyrzykowski, L; Ulaczyk, K; Pietrukowicz, P; Górski, M; Karczmarek, P

2013-03-07

In the era of precision cosmology, it is essential to determine the Hubble constant to an accuracy of three per cent or better. At present, its uncertainty is dominated by the uncertainty in the distance to the Large Magellanic Cloud (LMC), which, being our second-closest galaxy, serves as the best anchor point for the cosmic distance scale. Observations of eclipsing binaries offer a unique opportunity to measure stellar parameters and distances precisely and accurately. The eclipsing-binary method was previously applied to the LMC, but the accuracy of the distance results was lessened by the need to model the bright, early-type systems used in those studies. Here we report determinations of the distances to eight long-period, late-type eclipsing systems in the LMC, composed of cool, giant stars. For these systems, we can accurately measure both the linear and the angular sizes of their components and avoid the most important problems related to the hot, early-type systems. The LMC distance that we derive from these systems (49.97 ± 0.19 (statistical) ± 1.11 (systematic) kiloparsecs) is accurate to 2.2 per cent and provides a firm base for a 3-per-cent determination of the Hubble constant, with prospects for improvement to 2 per cent in the future.

Photometry of the SW Sextantis-type nova-like BH Lyncis in high state

NASA Astrophysics Data System (ADS)

Stanishev, V.; Kraicheva, Z.; Genkov, V.

2006-08-01

Aims.We present a photometric study of the deeply eclipsing SW Sex-type nova-like cataclysmic variable star BH Lyn. Methods: .Time-resolved V-band CCD photometry was obtained for seven nights between 1999 and 2004. Results: .We determined 11 new eclipse timings of BH Lyn and derived a refined orbital ephemeris with an orbital period of 0.155875577(14) °. During the observations, BH Lyn was in high-state with V≃15.5 mag. The star presents ~1.5 mag deep eclipses with mean full-width at half-flux of 0.0683(±0.0054)P_orb. The eclipse shape is highly variable, even changing form cycle to cycle. This is most likely due to accretion disc surface brightness distribution variations, most probably caused by strong flickering. Time-dependent accretion disc self-occultation or variations of the hot spot(s) intensity are also possible explanations. Negative superhumps with period of ˜0.145 ° are detected in two long runs in 2000. A possible connection between SW Sex and negative superhump phenomena through the presence of tilted accretion disc is discussed, and a way to observationally test this is suggested.

Detection of the supercycle in V4140 Sagittarii: First eclipsing ER Ursae Majoris-like object

NASA Astrophysics Data System (ADS)

Kato, Taichi; Hambsch, Franz-Josef; Cook, Lewis M.

2018-05-01

We observed the deeply eclipsing SU UMa-type dwarf nova V4140 Sgr and established the very short supercycle of 69.7(3) d. There were several short outbursts between superoutbursts. These values, together with the short orbital period (0.06143 d), were similar to, but not as extreme as, those of ER UMa-type dwarf novae. The object is thus the first, long sought, eclipsing ER UMa-like object. This ER UMa-like nature can naturally explain the high (apparent) quiescent viscosity and unusual temperature profile in quiescence, which were claimed observational features against the thermal-tidal instability model. The apparently unusual outburst behavior can be reasonably explained by a combination of this ER UMa-like nature and the high orbital inclination, and there is no need to introduce mass transfer bursts from its donor star.

Detection of the supercycle in V4140 Sagittarii: First eclipsing ER Ursae Majoris-like object

NASA Astrophysics Data System (ADS)

Kato, Taichi; Hambsch, Franz-Josef; Cook, Lewis M.

2018-06-01

We observed the deeply eclipsing SU UMa-type dwarf nova V4140 Sgr and established the very short supercycle of 69.7(3) d. There were several short outbursts between superoutbursts. These values, together with the short orbital period (0.06143 d), were similar to, but not as extreme as, those of ER UMa-type dwarf novae. The object is thus the first, long sought, eclipsing ER UMa-like object. This ER UMa-like nature can naturally explain the high (apparent) quiescent viscosity and unusual temperature profile in quiescence, which were claimed observational features against the thermal-tidal instability model. The apparently unusual outburst behavior can be reasonably explained by a combination of this ER UMa-like nature and the high orbital inclination, and there is no need to introduce mass transfer bursts from its donor star.

The Evolution of NR TrA (Nova TrA 2008) from 2008 through 2017

NASA Astrophysics Data System (ADS)

Walter, Frederick M.; Burwitz, Vadim; Kafka, Stella

2018-06-01

The classical nova NR TrA was discovered as an O-type optically-thick classical nova. There is no evidence that it formed dust. Within four years the envelope became sufficiently thin to reveal an eclipsing accretion disk-dominated system with orbitally-modulated permitted lines of C IV, N V, and O VI. XMM observations reveal a non-eclipsing soft X-ray source and a deeply-eclipsing UV continuum. We will present the first ten years of optical spectral evolution of this system accompanied by ten years of BVRIJHK photometry, with an eye to deciphering the current nature of the system.

The OGLE Collection of Variable Stars. Over 450 000 Eclipsing and Ellipsoidal Binary Systems Toward the Galactic Bulge

NASA Astrophysics Data System (ADS)

Soszyński, I.; Pawlak, M.; Pietrukowicz, P.; Udalski, A.; Szymański, M. K.; Wyrzykowski, Ł.; Ulaczyk, K.; Poleski, R.; Kozłowski, S.; Skowron, D. M.; Skowron, J.; Mróz, P.; Hamanowicz, A.

2016-12-01

We present a collection of 450 598 eclipsing and ellipsoidal binary systems detected in the OGLE fields toward the Galactic bulge. The collection consists of binary systems of all types: detached, semi-detached, and contact eclipsing binaries, RS CVn stars, cataclysmic variables, HW Vir binaries, double periodic variables, and even planetary transits. For all stars we provide the I- and V-band time-series photometry obtained during the OGLE-II, OGLE-III, and OGLE-IV surveys. We discuss methods used to identify binary systems in the OGLE data and present several objects of particular interest.

Observations of candidate oscillating eclipsing binaries and two newly discovered pulsating variables

NASA Astrophysics Data System (ADS)

Liakos, A.; Niarchos, P.

2009-03-01

CCD observations of 24 eclipsing binary systems with spectral types ranging between A0-F0, candidate for containing pulsating components, were obtained. Appropriate exposure times in one or more photometric filters were used so that short-periodic pulsations could be detected. Their light curves were analyzed using the Period04 software in order to search for pulsational behaviour. Two new variable stars, namely GSC 2673-1583 and GSC 3641-0359, were discov- ered as by-product during the observations of eclipsing variables. The Fourier analysis of the observations of each star, the dominant pulsation frequencies and the derived frequency spectra are also presented.

Kepler Eclipsing Binary Stars. I. Catalog and Principal Characterization of 1879 Eclipsing Binaries in the First Data Release

NASA Astrophysics Data System (ADS)

Prša, Andrej; Batalha, Natalie; Slawson, Robert W.; Doyle, Laurance R.; Welsh, William F.; Orosz, Jerome A.; Seager, Sara; Rucker, Michael; Mjaseth, Kimberly; Engle, Scott G.; Conroy, Kyle; Jenkins, Jon; Caldwell, Douglas; Koch, David; Borucki, William

2011-03-01

The Kepler space mission is devoted to finding Earth-size planets orbiting other stars in their habitable zones. Its large, 105 deg2 field of view features over 156,000 stars that are observed continuously to detect and characterize planet transits. Yet, this high-precision instrument holds great promise for other types of objects as well. Here we present a comprehensive catalog of eclipsing binary stars observed by Kepler in the first 44 days of operation, the data being publicly available through MAST as of 2010 June 15. The catalog contains 1879 unique objects. For each object, we provide its Kepler ID (KID), ephemeris (BJD0, P 0), morphology type, physical parameters (T eff, log g, E(B - V)), the estimate of third light contamination (crowding), and principal parameters (T 2/T 1, q, fillout factor, and sin i for overcontacts, and T 2/T 1, (R 1 + R 2)/a, esin ω, ecos ω, and sin i for detached binaries). We present statistics based on the determined periods and measure the average occurrence rate of eclipsing binaries to be ~1.2% across the Kepler field. We further discuss the distribution of binaries as a function of galactic latitude and thoroughly explain the application of artificial intelligence to obtain principal parameters in a matter of seconds for the whole sample. The catalog was envisioned to serve as a bridge between the now public Kepler data and the scientific community interested in eclipsing binary stars.

ON THE PULSATIONAL-ORBITAL-PERIOD RELATION OF ECLIPSING BINARIES WITH δ-SCT COMPONENTS

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

Zhang, X. B.; Luo, C. Q.; Fu, J. N.

2013-11-01

We have deduced a theoretical relation between the pulsation and orbital-periods of pulsating stars in close binaries based on their Roche lobe filling. It appears to be of a simple linear form, with the slope as a function of the pulsation constant, the mass ratio, and the filling factor for an individual system. Testing the data of 69 known eclipsing binaries containing δ-Sct-type components yields an empirical slope of 0.020 ± 0.006 for the P{sub pul}-P{sub orb} relation. We have further derived the upper limit of the P{sub pul}/P{sub orb} ratio for the δ-Sct stars in eclipsing binaries with amore » value of 0.09 ± 0.02. This value could serve as a criterion to distinguish whether or not a pulsator in an eclipsing binary pulsates in the p-mode. Applying the deduced P{sub pul}-P{sub orb} relation, we have computed the dominant pulsation constants for 37 δ-Sct stars in eclipsing systems with definite photometric solutions. These ranged between 0.008 and 0.033 days with a mean value of about 0.014 days, indicating that δ-Sct stars in eclipsing binaries mostly pulsate in the fourth or fifth overtones.« less

Asiago eclipsing binaries program IV. SZ Camelopardalis, a β Cephei pulsator in a quadruple, eclipsing system

NASA Astrophysics Data System (ADS)

Tamajo, E.; Munari, U.; Siviero, A.; Tomasella, L.; Dallaporta, S.

2012-03-01

We present a spectroscopic and photometric analysis of the multiple system and early-type eclipsing binary SZ Cam (O9 IV + B0.5 V), which consists of an eclipsing SB2 pair of orbital period P = 2.7 days in a long orbit (~55 yrs) around a non-eclipsing SB1 pair of orbital period P = 2.8 days. We have reconstructed the spectra of the individual components of SZ Cam from the observed composite spectra using the technique of spectral disentangling. We used them together with extensive and accurate BVIC CCD photometry to obtain an orbital solution. Our photometry revealed the presence of a β Cep variable in the SZ Cam hierarchical system, probably located within the non-eclipsing SB1 pair. The pulsation period is (0.33265 ± 0.00005) days and the observed total amplitude in the B band is (0.0105 ± 0.0005) mag. NLTE analysis of the disentangled spectra provided atmospheric parameters for all three components, consistent with those derived from orbital solution. Full Table 3 is only available at the CDS via anonymous ftp to cdsarc.u-strasbg.fr (130.79.128.5) or via http://cdsarc.u-strasbg.fr/viz-bin/qcat?J/A+A/539/A139

The Light-time Effect in the Eclipsing Binaries with Early-type Components U CrB and RW Tau

NASA Astrophysics Data System (ADS)

Khaliullina, A. I.

2018-04-01

A detailed study of the orbital-period variations of the Algol-type eclipsing binaries with earlyspectral- type primary components U CrB and RW Tau has been performed. The period variations in both systems can be described as a superposition of secular and cyclic variations of the period. A secular period increase at a rate of 2.58d × 10-7/year is observed for U CrB, which can be explained if there is a uniform flow of matter from the lower-mass to the higher-mass component, with the total angular momentum conserved. RW Tau features a secular period decrease at a rate of -8.6d × 10-7/year; this could be due to a loss of angular momentum by the binary due to magnetic braking. The cyclic orbital-period variations of U CrB and RWTau can be explained by the motion of the eclipsing binary systems along their long-period orbits. In U CrB, this implies that the eclipsing binary moves with a period of 91.3 years around a third body with mass M 3 > 1.13 M ⊙; in RW Tau, the period of the motion around the third body is 66.6 years, and the mass of the third body is M 3 > 1.24 M ⊙. It also cannot be ruled out that the variations are due to the magnetic cycles of the late-type secondaries. The residual period variations could be a superposition of variations due to non-stationary ejection of matter and effects due to magnetic cycles.

Detection of the secondary star in HT Cassiopeiae

NASA Technical Reports Server (NTRS)

Marsh, T. R.

1990-01-01

Low-resolution spectra of the eclipsing dwarf nova HT Cas, taken over the range 5000-9800 A show TiO bands and Na I absorption lines from the secondary star. From the TiO band ratio at mid-eclipse it is estimated that the secondary star contributes about 37 percent of the light at 7500 A during the eclipse, and that it has a Boeshaar spectral type M5.4 + or - 0.3. The mass, radius, and luminosity of the secondary star are all consistent with main-sequence values. The TiO band strength diminishes greatly near phase 0.5, but an eclipse by the disk is not sufficient to explain this. The radial velocity is measured from the Na line near 8200 A for most of the spectra and (after a correction for the asymmetric distribution of absorption over the secondary star) its radial velocity semiamplitude K2 = 430 + or - 25 km/sec.

The eclipsing AM Herculis variable H1907 + 690

NASA Technical Reports Server (NTRS)

Remillard, R. A.; Silber, A.; Stroozas, B. A.; Tapia, S.

1991-01-01

The discovery is reported of an eclipsing cataclysmic variable that exhibits up to 10 percent circular polarization at optical wavelengths, securing its classification as an AM Herculis type binary. The object, H1907 + 609, was located with the guidance of X-ray positions from the HEAO 1 survey. Optical CCD photometry exhibits deep eclipses, from which is derived a precise orbital period of 1.743750 hr. The eclipse duration suggests an inclination angle about 80 deg for a main-sequence secondary star. The optical flux has been persistently faint during observations spanning 1987-1990, while the X-ray measurements suggest long-term X-ray variability. The polarization and photometric light curves can be interpreted with a geometric model in which most of the accretion is directed toward a single magnetic pole, with an accretion spot displaced about 17 deg in longitude from the projection of the secondary star on the white dwarf surface.

Eclipse-Like Events on This Week @NASA – August 18, 2017

NASA Image and Video Library

2017-08-18

ena such as the Aug. 21, 2017 solar eclipse can inspire awe, but scientists can also use eclipse-like events to learn more about the universe. For instance, a total eclipse, or an occultation in scientific terms – happens when a celestial body completely blocks light from a star, like our sun. This type of event can help astronomers learn more about an object’s atmosphere, including whether it might be surrounded by rings or other planetary matter. During a similar event, called a transit, variations in light that result when a closer object passes in front of a star, but only blocks a small part of the star, have been used by missions such as our Kepler space telescope, to discover new planets outside our solar system. Also, SpaceX Launches Science, Supplies to Space Station, New Communications Satellite Launched, Cassini Begins Final Five Orbits around Saturn and Spacewalk aboard the Space Station!

Campaign for a New Eclipsing Cepheid

NASA Astrophysics Data System (ADS)

Henden, Arne; Welch, Doug; Terrell, Dirk

2007-06-01

ASAS 182611+1212.6, discovered by Pojmanski et al. during the ASAS survey, independently discovered by Antipin at al. on Moscow archive plates, and found in the NSVS (Wozniak et al. 2004, AJ 127, 2436), was initially classified as a typical Type II Cepheid with a period of 4.1523 days. However, scatter in the light curve indicated possible multiperiodic behavior. After 3 years of CCD observations by Antipin, the system was seen to exhibit eclipses of period 51.38 days and amplitude about 0.3 mag (primary) and possibly about 0.2 mag (secondary). This is the first known glactic eclipsing binary Cepheid. The AAVSO is conducting a campaign to study this star via high-precision, multicolor photometry obtained over several eclipse cycles. Observers are requested to obtain multicolor photometry with a S/N=100 or better on every image. Time resolution of one hour is adequate, so cycling through the filters need not be rushed. Apply transformation coefficients when possible. For calculating ephemerides, the pulsational maximum occurred on HJD 2453196.529 with a period of 4.1523 days; the eclipse primary minimum occurred on HJD 2453571.36 with a period of 51.38 days. The next primary eclipse will occur around July 9, but these eclipses are several days wide. A finding chart may be found at http://www.aavso.org/observing/charts/vsp (enter ASAS182612 for its name, or use the coordinates) with suitable comparison stars marked. Report/upload observations to the AAVSO.

Engaging Citizen Scientists across North America to Monitor Eclipse-driven Environmental Change through NASA GLOBE Observer, Results and Lessons Learned

NASA Astrophysics Data System (ADS)

Riebeek Kohl, H.; Weaver, K.; Overoye, D.; Martin, A.; Andersen, T.

2017-12-01

How cool was the eclipse? NASA GLOBE Observer challenged citizen scientists across North America to answer that question by observing temperature and cloud changes throughout the August 2017 Total Solar Eclipse. The experiment was meant to chart the impact of changes in solar energy at Earth's surface across all regions that experienced the eclipse, both partial and total. Citizen scientists reported air temperature every 5-10 minutes from first contact to last contact through the free GLOBE Observer app. They also reported cloud cover and cloud type every 15-30 minutes or as changes happened as a proxy for changes in the atmosphere. No data were collected during totality, as we wanted citizen scientists to focus on the eclipse at that time. To recruit citizen scientists, members of the GLOBE Observer Team participated in six large outreach events across the path of totality. We also encouraged participation outside the path of totality though partnerships with informal education institutions and direct communication to the public through NASA communication channels. This presentation will report statistics on citizen science participation and lessons learned about citizen science as an outreach tool. Did participation in the experiment enhance a person's eclipse experience? Did citizen scientists find enough value in the experiment to continue to participate in GLOBE Observer, a long-term citizen science program, after the eclipse? We will also present early results of observed temperature and cloud changes.

Photometric study and absolute parameters of the short-period eclipsing binary HH Bootis

NASA Astrophysics Data System (ADS)

Gürol, B.; Bradstreet, D. H.; Demircan, Y.; Gürsoytrak, S. H.

2015-11-01

We present the results of our investigation on the geometrical and physical parameters of the W UMa type binary system HH Bootis from new CCD (BVRI) light curves and published radial velocity data. The photometric data were obtained in 2011 and 2012 at Ankara University Observatory (AUO). Light and radial velocity observations were analyzed simultaneously using the Wilson-Devinney (2013 revision) code to obtain absolute and geometrical parameters. The system was determined to be a W-type W UMa system of a type different from that suggested by Dal and Sipahi (2013). An interesting cyclic period variation in the time intervals between primary and secondary eclipses ("half-period variation") was discovered and analyzed and its possible cause is discussed. Combining our photometric solution with the spectroscopic data we derived masses and radii of the eclipsing system to be M1 = 0.627M⊙ , M2 = 1.068M⊙ , R1 = 0.782R⊙ and R2 = 0.997R⊙ . New light elements were derived and finally the evolutionary status of the system is discussed.

The Late-type Eclipsing Binaries in the Large Magellanic Cloud: Catalog of Fundamental Physical Parameters

NASA Astrophysics Data System (ADS)

Graczyk, Dariusz; Pietrzyński, Grzegorz; Thompson, Ian B.; Gieren, Wolfgang; Pilecki, Bogumił; Konorski, Piotr; Villanova, Sandro; Górski, Marek; Suchomska, Ksenia; Karczmarek, Paulina; Stepień, Kazimierz; Storm, Jesper; Taormina, Mónica; Kołaczkowski, Zbigniew; Wielgórski, Piotr; Narloch, Weronika; Zgirski, Bartłomiej; Gallenne, Alexandre; Ostrowski, Jakub; Smolec, Radosław; Udalski, Andrzej; Soszyński, Igor; Kervella, Pierre; Nardetto, Nicolas; Szymański, Michał K.; Wyrzykowski, Łukasz; Ulaczyk, Krzysztof; Poleski, Radosław; Pietrukowicz, Paweł; Kozłowski, Szymon; Skowron, Jan; Mróz, Przemysław

2018-06-01

We present a determination of the precise fundamental physical parameters of 20 detached, double-lined, eclipsing binary stars in the Large Magellanic Cloud (LMC) containing G- or early K-type giant stars. Eleven are new systems; the remaining nine are systems already analyzed by our team for which we present updated parameters. The catalog results from our long-term survey of eclipsing binaries in the Magellanic Clouds suitable for high-precision determination of distances (the Araucaria Project). The V-band brightnesses of the systems range from 15.4 to 17.7 mag, and their orbital periods range from 49 to 773 days. Six systems have favorable geometry showing total eclipses. The absolute dimensions of all eclipsing binary components are calculated with a precision of better than 3%, and all systems are suitable for a precise distance determination. The measured stellar masses are in the range 1.4 to 4.6 M ⊙, and comparison with the MESA isochrones gives ages between 0.1 and 2.1 Gyr. The systems show an age–metallicity relation with no evolution of metallicity for systems older than 0.6 Gyr, followed by a rise to a metallicity maximum at age 0.5 Gyr and then a slow metallicity decrease until 0.1 Gyr. Two systems have components with very different masses: OGLE LMC-ECL-05430 and OGLE LMC-ECL-18365. Neither system can be fitted by a single stellar evolution isochrone, explained by a past mass transfer scenario in the case of ECL-18365 and a gravitational capture or hierarchical binary merger scenario in the case of ECL-05430. The longest-period system, OGLE LMC SC9_230659, shows a surprising apsidal motion that shifts the apparent position of the eclipses. This is a clear sign of a physical companion to the system; however, neither investigation of the spectra nor light-curve analysis indicates a third-light contribution larger than 2%–3%. In one spectrum of OGLE LMC-ECL-12669, we noted a peculiar dimming of one of the components by 65% well outside of the eclipses. We interpret this observation as arising from an extremely rare occultation event, as a foreground Galactic object covers only one component of an extragalactic eclipsing binary.

Period changes of cataclysmic variables below the period gap: V2051 Oph, OY Car and Z Cha

NASA Astrophysics Data System (ADS)

Pilarčík, L.; Wolf, M.; Zasche, P.; Vraštil, J.

2018-04-01

We present our results of a long-term monitoring of cataclysmic variable stars (CVs). About 40 new eclipses were measured for the three southern SU UMa-type eclipsing CVs: V2051 Oph, OY Car and Z Cha. Based on the current O - C diagrams we confirmed earlier findings that V2051 Oph and OY Car present cyclic changes of their orbital periods lasting 25 and 29 years, respectively. In case of Z Cha we propose the light-time effect caused probably by a presence of the third component orbiting the eclipsing CV with the period of 43.5 years. The minimal mass of this companion results about 15 MJup.

Observations and Light Curve Solutions of the Eclipsing Binaries KR Lyn, CSS J110212+244412, NSVS 4917488 and NSVS 7336024

NASA Astrophysics Data System (ADS)

Kjurkchieva, D.; Popov, V. A.; Eneva, J.; Petrov, N.

2018-05-01

We present photometric observations in Sloan filters g', i' of the short-period eclipsing stars KR Lyn, CSS J110212+244412, NSVS 4917488 and NSVS 7336024. The light curve solutions revealed that all targets are overcontact binaries whose components are G and K stars. Their temperature differences do not exceed 300 K but they differ considerably in size and mass. NSVS 4917488 and NSVS 7336024 reveal total eclipses and their parameters can be considered as well-determined. We found that KR Lyn, NSVS 4917488 and NSVS 7336024 are of W-subtype while CSS J110212+244412 is A-subtype W UMa-type star.

KEPLER ECLIPSING BINARY STARS. I. CATALOG AND PRINCIPAL CHARACTERIZATION OF 1879 ECLIPSING BINARIES IN THE FIRST DATA RELEASE

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

Prsa, Andrej; Engle, Scott G.; Conroy, Kyle

2011-03-15

The Kepler space mission is devoted to finding Earth-size planets orbiting other stars in their habitable zones. Its large, 105 deg{sup 2} field of view features over 156,000 stars that are observed continuously to detect and characterize planet transits. Yet, this high-precision instrument holds great promise for other types of objects as well. Here we present a comprehensive catalog of eclipsing binary stars observed by Kepler in the first 44 days of operation, the data being publicly available through MAST as of 2010 June 15. The catalog contains 1879 unique objects. For each object, we provide its Kepler ID (KID),more » ephemeris (BJD{sub 0}, P{sub 0}), morphology type, physical parameters (T{sub eff}, log g, E(B - V)), the estimate of third light contamination (crowding), and principal parameters (T{sub 2}/T{sub 1}, q, fillout factor, and sin i for overcontacts, and T{sub 2}/T{sub 1}, (R{sub 1} + R{sub 2})/a, esin {omega}, ecos {omega}, and sin i for detached binaries). We present statistics based on the determined periods and measure the average occurrence rate of eclipsing binaries to be {approx}1.2% across the Kepler field. We further discuss the distribution of binaries as a function of galactic latitude and thoroughly explain the application of artificial intelligence to obtain principal parameters in a matter of seconds for the whole sample. The catalog was envisioned to serve as a bridge between the now public Kepler data and the scientific community interested in eclipsing binary stars.« less

RED GIANTS IN ECLIPSING BINARY AND MULTIPLE-STAR SYSTEMS: MODELING AND ASTEROSEISMIC ANALYSIS OF 70 CANDIDATES FROM KEPLER DATA

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

Gaulme, P.; McKeever, J.; Rawls, M. L.

2013-04-10

Red giant stars are proving to be an incredible source of information for testing models of stellar evolution, as asteroseismology has opened up a window into their interiors. Such insights are a direct result of the unprecedented data from space missions CoRoT and Kepler as well as recent theoretical advances. Eclipsing binaries are also fundamental astrophysical objects, and when coupled with asteroseismology, binaries provide two independent methods to obtain masses and radii and exciting opportunities to develop highly constrained stellar models. The possibility of discovering pulsating red giants in eclipsing binary systems is therefore an important goal that could potentiallymore » offer very robust characterization of these systems. Until recently, only one case has been discovered with Kepler. We cross-correlate the detected red giant and eclipsing-binary catalogs from Kepler data to find possible candidate systems. Light-curve modeling and mean properties measured from asteroseismology are combined to yield specific measurements of periods, masses, radii, temperatures, eclipse timing variations, core rotation rates, and red giant evolutionary state. After using three different techniques to eliminate false positives, out of the 70 systems common to the red giant and eclipsing-binary catalogs we find 13 strong candidates (12 previously unknown) to be eclipsing binaries, one to be a non-eclipsing binary with tidally induced oscillations, and 10 more to be hierarchical triple systems, all of which include a pulsating red giant. The systems span a range of orbital eccentricities, periods, and spectral types F, G, K, and M for the companion of the red giant. One case even suggests an eclipsing binary composed of two red giant stars and another of a red giant with a {delta}-Scuti star. The discovery of multiple pulsating red giants in eclipsing binaries provides an exciting test bed for precise astrophysical modeling, and follow-up spectroscopic observations of many of the candidate systems are encouraged. The resulting highly constrained stellar parameters will allow, for example, the exploration of how binary tidal interactions affect pulsations when compared to the single-star case.« less

Period Study and Analyses of 2017 Observations of the Totally Eclipsing, Solar Type Binary, MT Camelopardalis

NASA Astrophysics Data System (ADS)

Faulkner, Danny R.; Samec, Ronald G.; Caton, Daniel B.

2018-06-01

We report here on a period study and the analysis of BVRcIc light curves (taken in 2017) of MT Cam (GSC03737-01085), which is a solar type (T ~ 5500K) eclipsing binary. D. Caton observed MT Cam on 05, 14, 15, 16, and 17, December 2017 with the 0.81-m reflector at Dark Sky Observatory. Six times of minimum light were calculated from four primary eclipses and two secondary eclipses:HJD I = 24 58092.4937±0.0002, 2458102.74600±0.0021, 2458104.5769±0.0002, 2458104.9434±0.0029HJD II = 2458103.6610±0.0001, 2458104.7607±0.0020,Six times of minimum light were also calculated from data taken by Terrell, Gross, and Cooney, in their 2016 and 2004 observations (reported in IBVS #6166; TGC, hereafter). In addition, six more times of minimum light were taken from the literature. From all 18 times of minimum light, we determined the following light elements:JD Hel Min I=2458102.7460(4) + 0.36613937(5) EWe found the orbital period was constant over the 14 years spanning all observations. We note that TGC found a slightly increasing period. However, our results were obtained from a period study rather than comparison of observations from only two epochs by the Wilson-Devinney (W-D) Program. A BVRcIc Johnson-Cousins filtered simultaneous W-D Program solution gives a mass ratio (0.3385±0.0014) very nearly the same as TGC’s (0.347±0.003), and a component temperature difference of only ~40 K. As with TGC, no spot was needed in the modeling. Our modeling (beginning with Binary Maker 3.0 fits) was done without prior knowledge of TGC’s. This shows the agreement achieved when independent analyses are done with the W-D code. The present observations were taken 1.8 years later than the last curves by TGC, so some variation is expected.The Roche Lobe fill-out of the binary is ~13% and the inclination is ~83.5 degrees. The system is a shallow contact W-type W UMa Binary, albeit, the amplitudes of the primary and secondary eclipse are very nearly identical. An eclipse duration of ~21 minutes was determined for the secondary eclipse and the light curve solution. Additional and more detailed information is given in the poster paper.

IUE observations of the atmospheric eclipsing binary system Zeta Aurigae

NASA Technical Reports Server (NTRS)

Champman, R. D.

1980-01-01

IUE observations of the eclipsing binary system Zeta Aurigae made prior to and during the eclipse of the relatively small B8 V star by the cool supergiant star (spectral type K2 II) are reported. Spectral lines produced by the absorption of B star radiation in the atmosphere of the K star during eclipse can be used as a probe of the extended K star atmosphere, due to the negligible cool star continuum in the 1200-3200 A region. Spectra taken prior to eclipse are found to be similar to those of the single B8 V star 64 Ori, with the exception of very strong multi-component absorption lines of Si II, Si IV, C IV and the Mg resonance doublet with strong P Cygni profiles, indicating a double shell. Absorption lines including those corresponding to Al II, Al III, Cr II, Mn II, Fe II, Ni II and Ca II are observed to increase in strength and number as the eclipse progresses, with high-ionization-potential lines formed far from the K star, possibly in a shock wave, and low-ionization potential lines, formed in cool plasma, probably a cool wind, nearer to the K star. Finally, an emission-line spectra with lines corresponding to those previously observed in absorption is noted at the time the B-star continuum had disappeared.

HD 66051: the first eclipsing binary hosting an early-type magnetic star

NASA Astrophysics Data System (ADS)

Kochukhov, O.; Johnston, C.; Alecian, E.; Wade, G. A.

2018-05-01

Early-type magnetic stars are rarely found in close binary systems. No such objects were known in eclipsing binaries prior to this study. Here we investigated the eclipsing, spectroscopic double-lined binary HD 66051, which exhibits out-of-eclipse photometric variations suggestive of surface brightness inhomogeneities typical of early-type magnetic stars. Using a new set of high-resolution spectropolarimetric observations, we discovered a weak magnetic field on the primary and found intrinsic, element-dependent variability in its spectral lines. The magnetic field structure of the primary is dominated by a nearly axisymmetric dipolar component with a polar field strength Bd ≈ 600 G and an inclination with respect to the rotation axis of βd = 13°. A weaker quadrupolar component is also likely to be present. We combined the radial velocity measurements derived from our spectra with archival optical photometry to determine fundamental masses (3.16 and 1.75 M⊙) and radii (2.78 and 1.39 R⊙) with a 1-3% precision. We also obtained a refined estimate of the effective temperatures (13000 and 9000 K) and studied chemical abundances for both components with the help of disentangled spectra. We demonstrate that the primary component of HD 66051 is a typical late-B magnetic chemically peculiar star with a non-uniform surface chemical abundance distribution. It is not an HgMn-type star as suggested by recent studies. The secondary is a metallic-line star showing neither a strong, global magnetic field nor intrinsic spectral variability. Fundamental parameters provided by our work for this interesting system open unique possibilities for probing interior structure, studying atomic diffusion, and constraining binary star evolution.

Kepler Observations of V447 Lyr: an Eclipsing U Gem Cataclysmic Variable

NASA Technical Reports Server (NTRS)

Ramsay, Gavin; Cannizzo, John K.; Howell, Steve B.; Wood, Matt A.; Still, Martin; Barclay, Thomas; Smale, Alan

2012-01-01

We present the results of an analysis of Kepler data covering 1.5 yr of the dwarf nova V447 Lyr. We detect eclipses of the accretion disc by the mass donating secondary star every 3.74 h which is the binary orbital period. V447 Lyr is therefore the first dwarf nova in the Kepler field to show eclipses.We also detect five long outbursts and six short outbursts showing V447 Lyr is a U Gem-type dwarf nova. We show that the orbital phase of the mid-eclipse occurs earlier during outbursts compared to quiescence and that the width of the eclipse is greater during outburst. This suggests that the bright spot is more prominent during quiescence and that the disc is larger during outburst than quiescence. This is consistent with an expansion of the outer disc radius due to the presence of high viscosity material associated with the outburst, followed by a contraction in quiescence due to the accretion of low angular momentum material. We note that the long outbursts appear to be triggered by a short outburst, which is also observed in the super-outbursts of SU UMa dwarf novae as observed using Kepler.

First X-ray Statistical Tests for Clumpy-Torus Models: Constraints from RXTEmonitoring of Seyfert AGN

NASA Astrophysics Data System (ADS)

Markowitz, Alex; Krumpe, Mirko; Nikutta, R.

2016-06-01

In two papers (Markowitz, Krumpe, & Nikutta 2014, and Nikutta et al., in prep.), we derive the first X-ray statistical constraints for clumpy-torus models in Seyfert AGN by quantifying multi-timescale variability in line of-sight X-ray absorbing gas as a function of optical classification.We systematically search for discrete absorption events in the vast archive of RXTE monitoring of 55 nearby type Is and Compton-thin type IIs. We are sensitive to discrete absorption events due to clouds of full-covering, neutral/mildly ionized gas transiting the line of sight. Our results apply to both dusty and non-dusty clumpy media, and probe model parameter space complementary to that for eclipses observed with XMM-Newton, Suzaku, and Chandra.We detect twelve eclipse events in eight Seyferts, roughly tripling the number previously published from this archive. Event durations span hours to years. Most of our detected clouds are Compton-thin, and most clouds' distances from the black hole are inferred to be commensurate with the outer portions of the BLR or the inner regions of infrared-emitting dusty tori.We present the density profiles of the highest-quality eclipse events; the column density profile for an eclipsing cloud in NGC 3783 is doubly spiked, possibly indicating a cloud that is being tidallysheared. We discuss implications for cloud distributions in the context of clumpy-torus models. We calculate eclipse probabilities for orientation-dependent Type I/II unification schemes.We present constraints on cloud sizes, stability, and radial distribution. We infer that clouds' small angular sizes as seen from the SMBH imply 107 clouds required across the BLR + torus. Cloud size is roughly proportional to distance from the black hole, hinting at the formation processes (e.g., disk fragmentation). All observed clouds are sub-critical with respect to tidal disruption; self-gravity alone cannot contain them. External forces, such as magnetic fields or ambient pressure, are needed to contain them; otherwise, clouds must be short-lived.

Monitoring HD 148703 during upcoming eclipses

NASA Astrophysics Data System (ADS)

Waagen, Elizabeth O.

2017-06-01

Dr. Milena Ratajczak (University of Wrocław) has requested AAVSO observers' assistance in monitoring the very bright (V = 4.23) and very unusual eclipsing binary HD 148703 (HR 6143, N Sco) during its infrequent primary and secondary eclipses scheduled for 2017 June 11 and June 14, respectively. Dr. Ratajczak writes: "[HD 148703] N Sco is a B-type detached eclipsing binary, which turned out to be an exceptionally interesting object to study when we realised its orbital period is 223 days and time between eclipses is only 3.5 days. Such configuration makes it an extremely eccentric system, probably the most eccentric from any objects of that class ever studied...Since the object is very bright, it's difficult to use professional photometric telescopes due to saturation issues. That is why we kindly invite amateur astronomers to join the campaign. Data taken during times of eclipses (photometry) and time between eclipses (radial velocities from spectroscopy) which occur next week are crucial to cover in order to determine orbital and stellar parameters of system's components. Data taken over that time will be of very high value for us." The next primary eclipse time of minimum is on 2017 June 11 (UT 00:41:45), and the secondary on June 14 (UT 09:17:34). Each eclipse lasts about 20 hours. The amplitude of the primary eclipse is 0.15 magnitude, and the secondary 0.35 mag. PEP V and DSLR V photometry is requested. (CCD V is welcome if saturation can be avoided.) Beginning immediately, one to a few snapshots each night are requested to establish an out-of-eclipse baseline for each observer; they should continue for a few nights after the secondary eclipse has occurred.Time series photometry is requested beginning 12 hours before each time of minimum and continuing until 12 hours after. Precision to 0.01 mag or better per single observation is needed. Exposures should be as long as possible without saturating; don't make very short exposures simply for the purpose of gathering more data points. B or Ic data would also be useful; B is preferred to Ic. If imaging in more than one filter, please make five V observations for each B or Ic.Visual observations are also welcome. For spectroscopy now through June 20, resolution of at least a few thousands is needed. Coordinates: RA = 16 31 22.93 Dec = -34 42 15.7 (2000.0). Finder charts may be created and data from the AAVSO International Database may be viewed, plotted, or downloaded (www.aavso.org).

LX Leo: A High Mass-Ratio Totally Eclipsing W-type W UMa System

NASA Astrophysics Data System (ADS)

Gürol, B.; Michel, R.; Gonzalez, C.

2017-10-01

We present the results of our investigation of the geometrical and physical parameters of the binary system LX Leo. Based on CCD BVRc light curves, and their analyses with the Wilson-Devinney code, new times of minima and light elements have been determined. According to our solution, the system is a high mass-ratio, totally eclipsing, W-type W UMa system. Combining our photometric solution with the empirical relation for W UMa type systems by Dimitrow & Kjurkchieva (2015), we derived the masses and radii of the components to be M1=0.43 M⊙, M2=0.81 M⊙, R1=0.58 R⊙ and R2=0.77 R⊙. In addition, the evolutionary condition of the system is discussed.

Data Mining the Ogle-II I-band Database for Eclipsing Binary Stars

NASA Astrophysics Data System (ADS)

Ciocca, M.

2013-08-01

The OGLE I-band database is a searchable database of quality photometric data available to the public. During Phase 2 of the experiment, known as "OGLE-II", I-band observations were made over a period of approximately 1,000 days, resulting in over 1010 measurements of more than 40 million stars. This was accomplished by using a filter with a passband near the standard Cousins Ic. The database of these observations is fully searchable using the mysql database engine, and provides the magnitude measurements and their uncertainties. In this work, a program of data mining the OGLE I-band database was performed, resulting in the discovery of 42 previously unreported eclipsing binaries. Using the software package Peranso (Vanmuster 2011) to analyze the light curves obtained from OGLE-II, the eclipsing types, the epochs and the periods of these eclipsing variables were determined, to one part in 106. A preliminary attempt to model the physical parameters of these binaries was also performed, using the Binary Maker 3 software (Bradstreet and Steelman 2004).

Tidally Induced Pulsations in Kepler Eclipsing Binary KIC 3230227

NASA Astrophysics Data System (ADS)

Guo, Zhao; Gies, Douglas R.; Fuller, Jim

2017-01-01

KIC 3230227 is a short period (P ≈ 7.0 days) eclipsing binary with a very eccentric orbit (e = 0.6). From combined analysis of radial velocities and Kepler light curves, this system is found to be composed of two A-type stars, with masses of M1 = 1.84 ± 0.18 M⊙, M2 = 1.73 ± 0.17 M⊙ and radii of R1 = 2.01 ± 0.09 R⊙, R2 = 1.68 ± 0.08 R⊙ for the primary and secondary, respectively. In addition to an eclipse, the binary light curve shows a brightening and dimming near periastron, making this a somewhat rare eclipsing heartbeat star system. After removing the binary light curve model, more than 10 pulsational frequencies are present in the Fourier spectrum of the residuals, and most of them are integer multiples of the orbital frequency. These pulsations are tidally driven, and both the amplitudes and phases are in agreement with predictions from linear tidal theory for l = 2, m = -2 prograde modes.

Period variations of Algol-type eclipsing binaries AD And, TWCas and IV Cas

NASA Astrophysics Data System (ADS)

Parimucha, Štefan; Gajdoš, Pavol; Kudak, Viktor; Fedurco, Miroslav; Vaňko, Martin

2018-04-01

We present new analyses of variations in O – C diagrams of three Algol-type eclipsing binary stars: AD And, TW Cas and IV Cas. We have used all published minima times (including visual and photographic) as well as newly determined ones from our and SuperWasp observations. We determined orbital parameters of 3rd bodies in the systems with statistically significant errors, using our code based on genetic algorithms and Markov chain Monte Carlo simulations. We confirmed the multiple nature of AD And and the triple-star model of TW Cas, and we proposed a quadruple-star model of IV Cas.

Photometric Study of The Solar Type, Total Eclipsing Binary, TYC 2853-18-1

NASA Astrophysics Data System (ADS)

Samec, Ronald G.; Figg, E. R.; Faulkner, D.; Van Hamme, W.

2009-12-01

We present an analysis of the Solar-Type eclipsing binary, TYC 2853-18-1 (Persei), based on observations taken at the National Undergraduate Research Observatory (NURO) and the Southeastern Association for Research in Astronomy (SARA) in the Fall, 2007 and Spring, 2008. Light curves, a period study and a synthetic light curve solution are presented for this variable which was recently discovered by TYCHO as an eclipsing binary (2006, IBVS 5700). Our CCD observations of TYC 2853-18-1 [GSC 2853 0018, RA(2000) = 02h 47m 07.996s, DEC(2000) = +41° 22’ 32.80"] were taken on 20,27 December, 2007 at Lowell Observatory with the 0.81-m reflector with NURO time and 25 November, 3 December, 2007 and 19 February, 2008 via remote observing from Kitt Peak with SARA. NURO observations were take with the thermoelectrically cooled (<-100C) 2KX2K CCD NASACAM. Standard BVRcIc Johnson-Cousins filters were used. Our light curve solution was calculated with the 2004 Wilson code. Mean times of eclipse include, HJDMinI = 2454516.6131(±0.0005), 2454440.52974(±0.00008), 2454438.7605 (±0.0001), 2454462.6464 (±0.0003), HJDMinII = 2454455.71985 (±0.00060), 255462.7943 (±0.0002). These, including the epoch by ROTSE (2006, IBVS 5699) and the epoch calculated by the Wilson code, yielded the following ephemeris: HJD Hel Min I =2451370.8753(±.0.0010)d + 0.2949039 (±0.0000001)E Our unspotted Wilson code solution reveals TYC 2853-18-1 to be a W-type W UMa contact binary with unequal eclipse depths (amplitudes are 0.72 and 0.61 mags in V). It has shallow contact (8% fill-out) and a brief, but total eclipse. Its curves dictate a mass ratio of 2.62±0.01, a component temperature difference of only 73±5 ° K and an inclination of 82.0±0.2°. Spot activity is indicated by night to night variations. We wish to thank the NURO and SARA for their allocation of observing time, as well as NASA and the AAS for their support in paying for travel and publication expenses.

The Eclipsing Binary On-Line Atlas (EBOLA)

NASA Astrophysics Data System (ADS)

Bradstreet, D. H.; Steelman, D. P.; Sanders, S. J.; Hargis, J. R.

2004-05-01

In conjunction with the upcoming release of \\it Binary Maker 3.0, an extensive on-line database of eclipsing binaries is being made available. The purposes of the atlas are: \\begin {enumerate} Allow quick and easy access to information on published eclipsing binaries. Amass a consistent database of light and radial velocity curve solutions to aid in solving new systems. Provide invaluable querying capabilities on all of the parameters of the systems so that informative research can be quickly accomplished on a multitude of published results. Aid observers in establishing new observing programs based upon stars needing new light and/or radial velocity curves. Encourage workers to submit their published results so that others may have easy access to their work. Provide a vast but easily accessible storehouse of information on eclipsing binaries to accelerate the process of understanding analysis techniques and current work in the field. \\end {enumerate} The database will eventually consist of all published eclipsing binaries with light curve solutions. The following information and data will be supplied whenever available for each binary: original light curves in all bandpasses, original radial velocity observations, light curve parameters, RA and Dec, V-magnitudes, spectral types, color indices, periods, binary type, 3D representation of the system near quadrature, plots of the original light curves and synthetic models, plots of the radial velocity observations with theoretical models, and \\it Binary Maker 3.0 data files (parameter, light curve, radial velocity). The pertinent references for each star are also given with hyperlinks directly to the papers via the NASA Abstract website for downloading, if available. In addition the Atlas has extensive searching options so that workers can specifically search for binaries with specific characteristics. The website has more than 150 systems already uploaded. The URL for the site is http://ebola.eastern.edu/.

Annular and Total Solar Eclipses of 2010

NASA Technical Reports Server (NTRS)

Espenak, Fred; Anderson, J.

2008-01-01

While most NASA eclipse bulletins cover a single eclipse, this publication presents predictions for two solar eclipses during 2010. This has required a different organization of the material into the following sections. Section 1 -- Eclipse Predictions: The section consists of a general discussion about the eclipse path maps, Besselian elements, shadow contacts, eclipse path tables, local circumstances tables, and the lunar limb profile. Section 2 -- Annular Solar Eclipse of 2010 Ja n 15: The section covers predictions and weather prospects for the annular eclipse. Section 3 -- Total Solar Eclipse of 2010 Jul 11: The se ction covers predictions and weather prospects for the total eclipse. Section 4 -- Observing Eclipses: The section provides information on eye safety, solar filters, eclipse photography, and making contact timings from the path limits. Section 5 -- Eclipse Resources: The final section contains a number of resources including information on the IAU Working Group on Eclipses, the Solar Eclipse Mailing List, the NASA eclipse bulletins on the Internet, Web sites for the two 2010 eclipses, and a summary identifying the algorithms, ephemerides, and paramete rs used in the eclipse predictions.

AXAF-I Low Intensity-Low Temperature (LILT) Testing of the Development Verification Test (DVT) Solar Panel

NASA Technical Reports Server (NTRS)

Alexander, Doug; Edge, Ted; Willowby, Doug

1998-01-01

The planned orbit of the AXAF-I spacecraft will subject the spacecraft to both short, less than 30 minutes for solar and less than 2 hours for lunar, and long earth eclipses and lunar eclipses with combined conjunctive duration of up to 3 to 4 hours. Lack of proper Electrical Power System (EPS) conditioning prior to eclipse may cause loss of mission. To avoid this problem, for short eclipses, it is necessary to off-point the solar array prior to or at the beginning of the eclipse to reduce the battery state of charge (SOC). This yields less overcharge during the high charge currents at sun entry. For long lunar eclipses, solar array pointing and load scheduling must be tailored for the profile of the eclipse. The battery SOC, loads, and solar array current-voltage (I-V) must be known or predictable to maintain the bus voltage within acceptable range. To address engineering concerns about the electrical performance of the AXAF-I solar array under Low Intensity and Low Temperature (LILT) conditions, Marshall Space Flight Center (MSFC) engineers undertook special testing of the AXAF-I Development Verification Test (DVT) solar panel in September-November 1997. In the test the DVT test panel was installed in a thermal vacuum chamber with a large view window with a mechanical "flapper door". The DVT test panel was "flash" tested with a Large Area Pulse Solar Simulator (LAPSS) at various fractional sun intensities and panel (solar cell) temperatures. The testing was unique with regards to the large size of the test article and type of testing performed. The test setup, results, and lessons learned from the testing will be presented.

1998 UBV Light Curves of Eclipsing Binary AI Draconis and Absolute Parameters

NASA Astrophysics Data System (ADS)

Jassur, D. M. Z.; Khaledian, M. S.; Kermani, M. H.

New UBV photometry of Algol-Type eclipsing binary star AI Dra and the absolute physical parameters of this system have been presented. The light curve analysis carried out by the method of differential corrections indicates that both components are inside their Roche-Lobes. From combining the photometric solution with spectroscopic data obtained from velocity curve analysis, it has been found that the system consist of a main sequence primary and an evolved (subgiant) secondary.

A Photometric Study of the Eclipsing Binary NSV 1000

NASA Astrophysics Data System (ADS)

Richards, T. J.; Bembrick, C. S.

2018-06-01

Abstract NSV 1000 is an unstudied eclipsing binary in Hydrus. Our photometric research in the period 2014-2016 shows it is a W UMa system with a period of 0.336 579 6(3) d, consistent with the catalogued period. Model fitting to our B, V, and Ic light curves shows the two stars are barely in contact. The parameters derived from the fit satisfy the broadly defined characteristics of a W-type W UMa system.

First Precision Photometric Observations and Analyses of the Totally Eclipsing, Solar Type Binary V573 Pegasi

NASA Astrophysics Data System (ADS)

Samec, R. G.; Caton, D. B.; Faulkner, D. R.

2018-06-01

CCD VRcIc light curves of V573 Peg were taken 26 and 27 September and 2, 4, and 6 October, 2017, at the Dark Sky Observatory in North Carolina with the 0.81-m reflector of Appalachian State University. Five times of minimum light were calculated, two primary and three secondary eclipses, from our present observations. The following quadratic ephemeris was determined from all available times of minimum light: JD Hel MinI = 2456876.4958 (2) d + 0.41744860 (8) × E -2.74 (12) × 10^-10 × E2, where the parentheses hold the ± error in the last two digits of the preceding value. A 14-year period study (covered by 24 times of minimum light) reveals a decreasing orbital period with high confidence, possibly due to magnetic braking. The mass ratio is found to be somewhat extreme, M2 / M1 = 0.2629 ± 0.0006 (M1 / M2 = 3.8). Its Roche Lobe fill-out is ˜25%. The solution had no need of spots. The component temperature difference is about 130 K, with the less massive component as the hotter one, so it is a W-type W UMa Binary. The inclination is 80.4 ± 0.1°. Our secondary eclipse shows a time of constant light with an eclipse duration of 24 minutes. More information is given in the following report.

THE NEW ECLIPSING CV MASTER OTJ192328.22+612413.5—A POSSIBLE SW SEXTANTIS STAR

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

Kennedy, M. R.; Callanan, P.; Bouanane, S.

2016-07-01

We present optical photometry and spectroscopy of the new eclipsing cataclysmic variable MASTER OTJ192328.22+612413.5, discovered by the MASTER team. We find the orbital period to be P = 0.16764612(5) day/4.023507(1) hr. The depth of the eclipse (2.9 ± 0.1 mag) suggests that the system is nearly edge on, and modeling of the system confirms the inclination to be between 81.°3 and 83.°6. The brightness outside the eclipse varies between observations, with a change of 1.6 ± 0.1 mag. Spectroscopy reveals double-peaked Balmer emission lines. By using spectral features matching a late M-type companion, we bound the distance to be 750more » ± 250 pc, depending on the companion’s spectral type. The source displays 2 mag brightness changes on timescales of days. The amplitude of these changes, along with the spectrum at the faint state, suggest that the system is possibly a dwarf nova. The lack of any high-excitation He ii lines suggests that this system is not magnetically dominated. The light curve in both quiescence and outburst resembles that of Lanning 386, implying MASTER OTJ192328.22+612413.5 is a possible cross between a dwarf nova and a SW Sextantis star.« less

Periodicity and eclipse minima timing of CM Draconis.

NASA Astrophysics Data System (ADS)

Vázquez-Martín, S.; Deeg, H. J.; Dreizler, S.; von Essen, C.; Kozhevnikov, V. P.

2015-05-01

Periodic deviations from a linear ephemeris of a binary star's eclipses can indicate the presence of a third body in orbit around both. Hints for such companion around the M4.5/M4.5 binary CMDra were published by Deeg et al. (2008). The assignment of a planet in the CMDra system can however only be accepted if the earlier observed periodicity trends can be verified through further observations over several years. For eclipsing binary stars of low mass, the method of eclipse minimum timing allows one to set mass limits for the detection of a third body. Deeg et al. (2008) concluded that the two possibilities for the source of CMDra's timing variations that remain valid are a planet of a few Jupiter masses on a two decade-long orbit, or an object on a century-to-millenium long orbit with masses 1.5M_J < M_{p} < 0.1M_{⊙}. However, they concluded that it is necessary to do continued observations of the timing of CMDra's eclipses to be decisive regarding the continued viability of the sinusoidal-fit-model, and hence, about the validity of a Jovian-type planet in a circumbinary orbiting around the system. Here we update the analysis of Deeg et al. (2008), including further data presented in Morales et al. (2009r) and new observations taken at Ural Observatory (2008-2013). Eclipse minimum times were obtained using the Kwee-van-Woerden method.

David Levy's Guide to Eclipses, Transits, and Occultations

NASA Astrophysics Data System (ADS)

Levy, David H.

2010-08-01

Introduction; Part I. The Magic and History of Eclipses: 1. Shakespeare, King Lear, and the Great Eclipse of 1605; 2. Three centuries later: Einstein, relativity, and the solar eclipse of 1919; 3. What causes solar and lunar eclipses; Part II. Observing Solar Eclipses: 4. Safety considerations; 5. What to expect during a partial eclipse; 6. Annular eclipses and what to see in them; 7. Total eclipse of the Sun: introduction to the magic; 8. The onset: temperature drop, Baily's Beads, Diamond Ring; 9. Totality: Corona, Prominences, Chromosphere, and surrounding area; 10. Photographing and imaging a solar eclipse; Part III. Observing Lunar Eclipses: 11. Don't forget the penumbral eclipses!; 12. Partial lunar eclipses; 13. Total lunar eclipses; 14. Photographing and imaging lunar eclipses; Part IV. Occultations: 15. When the Moon occults a star; Part V. Transits: 16. When planets cross the Sun; Part VI. My Favorite Eclipses: 17. A personal canon of eclipses, occultations, and transits I have seen; Appendices; Index.

An Extreme Analogue of ɛ Aurigae: An M-giant Eclipsed Every 69 Years by a Large Opaque Disk Surrounding a Small Hot Source

NASA Astrophysics Data System (ADS)

Rodriguez, Joseph E.; Stassun, Keivan G.; Lund, Michael B.; Siverd, Robert J.; Pepper, Joshua; Tang, Sumin; Kafka, Stella; Gaudi, B. Scott; Conroy, Kyle E.; Beatty, Thomas G.; Stevens, Daniel J.; Shappee, Benjamin J.; Kochanek, Christopher S.

2016-05-01

We present TYC 2505-672-1 as a newly discovered and remarkable eclipsing system comprising an M-type red giant that undergoes a ˜3.45 year long, near-total eclipse (depth of ˜4.5 mag) with a very long period of ˜69.1 years. TYC 2505-672-1 is now the longest-period eclipsing binary system yet discovered, more than twice as long as that of the currently longest-period system, ɛ Aurigae. We show from analysis of the light curve including both our own data and historical data spanning more than 120 years and from modeling of the spectral energy distribution, both before and during eclipse, that the red giant primary is orbited by a moderately hot source (Teff ≈ 8000 K) that is itself surrounded by an extended, opaque circumstellar disk. From the measured ratio of luminosities, the radius of the hot companion must be in the range of 0.1-0.5 R⊙ (depending on the assumed radius of the red giant primary), which is an order of magnitude smaller than that for a main sequence A star and 1-2 orders of magnitude larger than that for a white dwarf. The companion is therefore most likely a “stripped red giant” subdwarf-B type star destined to become a He white dwarf. It is, however, somewhat cooler than most sdB stars, implying a very low mass for this “pre-He-WD” star. The opaque disk surrounding this hot source may be a remnant of the stripping of its former hydrogen envelope. However, it is puzzling how this object became stripped, given that it is at present so distant (orbital semimajor axis of ˜24 au) from the current red giant primary star. Extrapolating from our calculated ephemeris, the next eclipse should begin in early UT 2080 April and end in mid UT 2083 September (eclipse center UT 2081 December 24). In the meantime, radial velocity observations would establish the masses of the components, and high-cadence UV observations could potentially reveal oscillations of the hot companion that would further constrain its evolutionary status. In any case, this system is poised to become an exemplar of a very rare class of systems, even more extreme in several respects than the well studied archetype ɛ Aurigae.

The Eclipse Megamovie Tour: building awareness of the eclipse and gathering public support for the Megamovie Project

NASA Astrophysics Data System (ADS)

Peticolas, L. M.; Yan, D.; Cable, C.; Zevin, D.; Johnson, C.; Bender, M.

2017-12-01

The "Eclipse Megamovie" project aimed to gather scientifically useful photographs of the corona from the public at large during the Aug 21, 2017 total solar eclipse. The project used many different mechanisms for gathering 3 types of volunteers: the over 1,000 trained photographers positioned along the path of totality, members of the public along the path of totality using the Megamovie App, and members of the public who took photographs on their own and then uploaded photographs. In order to interest the public in becoming volunteers to provide photographs for this scientific effort, we drove across the path of totality providing presentations in a town hall fashion. We drove through nine states in week-long trips with a total of six trips. The first week took place in August, 2016 through Oregon. The remaining trips took place February-June, 2017. The tour gained press in each town seeded our recruitment efforts, which then gained momentum via articles and press releases in the Spring and Summer, 2017. By Aug 2, 2017 over 1,000 photographers had signed up to be trained volunteers. This presentation will present information on the tours and their impact in seeding the overall recruitment effort for the Eclipse Megamovie Project.

New O-C Observations for 150 Algols: Insight to the Origins of Period Shifts

NASA Astrophysics Data System (ADS)

Hoffman, D. I.; Harrison, T. E.; McNamara, B. J.; Vestrand, W. T.

2005-12-01

Many eclipsing binaries of type Algol, RS CVn, and W UMa have observed orbital period shifts. Of these, many show both increasing and decreasing period shifts. Two leading explanations for these shifts are third body effects and magnetic activity changing the oblateness of the secondary, though neither one can explain all of the observed period oscillations. The first-generation Robotic Optical Transient Search Experiment (ROTSE-I) based in Los Alamos, NM, was primarily designed to look for the optical counterparts to gamma-ray bursts as well as searching for other optical transients not detected in gamma-rays. The telescope, consisting of four 200mm camera lenses, can image the entire northern sky twice in a night, which is a very useful tool in monitoring relatively bright eclipsing binaries for period shifts. The public data release from ROTSE-I, the Northern Sky Variability Survey (NSVS), spans one year of data stating in April, 1999. O-C data for 150 eclipsing binaries are presented using the NSVS data. We revisit work by Borkovits and Hegedüs on some third body candidates in several eclipsing binary systems using recent AAVSO and NSVS data. Some unusual light curves of eclipsing binaries produced from NSVS data is presented and discussed.

Dayside atmospheric structure of HD209458b from Spitzer eclipses

NASA Astrophysics Data System (ADS)

Reinhard, Matthew; Harrington, Joseph; Challener, Ryan; Cubillos, Patricio; Blecic, Jasmina

2017-10-01

HD209458b is a hot Jupiter with a radius of 1.26 ± 0.08 Jupiter radii (Richardson et al, 2006) and a mass of 0.64 ± 0.09 Jupiter masses (Snellen et al, 2010). The planet orbits a G0 type star with an orbital period of 3.52472 ± 2.81699e-05 days, and a relatively low eccentricity of 0.0082 +0.0078/-0.0082 (Wang and Ford 2013). We report the analysis of observations of HD209458b during eclipse, taken in the 3.6 and 4.5 micron channels by the Spitzer Space Telescope's Infrared Array Camera (Program 90186). We produce a photometric light curve of the eclipses in both channels, using our Photometry for Orbits Eclipses and Transits (POET) code, and calculate the brightness temperatures and eclipse depths. We also present best estimates of the atmospheric parameters of HD209458b using our Bayesian Atmospheric Radiative Transfer (BART) code. These are some preliminary results of what will be an analysis of all available Spitzer data for HD209458b. Spitzer is operated by the Jet Propulsion Laboratory, California Institute of Technology, under a contract with NASA. This work was supported by NASA Planetary Atmospheres grant NX12AI69G and NASA Astrophysics Data Analysis Program grant NNX13AF38G.

Observation and Analysis of Secondary Eclipses of WASP-32b

NASA Astrophysics Data System (ADS)

Garland, Justin; Harrington, Joseph; Cubillos, Patricio E.; Blecic, Jasmina; Foster, Andrew S.; Bowman, Oliver; Maxted, Pierre F. L.

2015-11-01

We report two Spitzer secondary eclipses of the exoplanet WASP-32b. Discovered in 2010 by Maxted et al, this hot-Jupiter planet has a mass of 3.6 ± 0.07 Mj, a radius of 1.18 ± 0.07 Rj, an equilibrium temperature of 1560 ± 50 K, and an orbital period of 2.71865 ± 0.00008 days around a G-type star. We observed two secondary eclipses in the 3.6 µm and 4.5 µm channels using the Spitzer Space Telescope in 2010 as a part of the Spitzer Exoplanet Target of Opportunity program (program 60003). We present eclipse depth estimates of 0.0013 ± 0.00023 in the 4.5 µm band and inconclusive results in the 3.6 µm band. We also report an infrared brightness temperature of 1538 ± 110 in the 4.5 µm channel and refinements of orbital parameters for WASP-32b from our eclipse measurement as well as amatuer and professional data that closely match previous results. Spitzer is operated by the Jet Propulsion Laboratory, California Institute of Technology, under a contract with NASA. This work was supported by NASA Planetary Atmospheres grant NNX12AI69G and NASA Astrophysics Data Analysis Program grant NNX13AF38G. JB holds a NASA Earth and Space Science Fellowship.

Secondary Eclipse Observations and Orbital Analysis of WASP-32b

NASA Astrophysics Data System (ADS)

Garland, Justin; Harrington, Joseph; Cubillos, Patricio; Blecic, Jasmina; Foster, Andrew S.; Bowman, Oliver; Maxted, Pierre F. L.

2016-01-01

We report two Spitzer secondary eclipses of the exoplanet WASP-32b. Discovered by Maxted et al. (2010), this hot-Jupiter planet has a mass of 3.6 ± 0.07 MJ a radius of 1.18 ± 0.07 RJ and an orbital period of 2.71865 ± 0.00008 days around a G-type star. We observed two secondary eclipses in the 3.6 μm and 4.5 μm channels using the Spitzer Space Telescope in 2010 as a part of the Spitzer Exoplanet Target of Opportunity program (program 60003). We present eclipse depth estimates of 0.0013 ± 0.00023 in the 4.5 μm band and inconclusive results in the 3.6 μm band. We also report an infrared brightness temperature of 1538 ± 110 in the 4.5 μm channel and refinements of orbital parameters for WASP-32b from our eclipse measurement as well as amatuer and professional data that closely match previous results. Spitzer is operated by the Jet Propulsion Laboratory, California Institute of Technology, under a contract with NASA. This work was supported by NASA Planetary Atmospheres grant NNX12AI69G and NASA Astrophysics Data Analysis Program grant NNX13AF38G. JB holds a NASA Earth and Space Science Fellowship.

[Survey of ocular injury by solar eclipse 2009].

PubMed

Obana, Akira; Takahashi, Jun; Ohnishi, Kouji; Shinohara, Hideo; Matsuo, Atsushi; Saito, Izumi; Ohkawa, Takuya; Ono, Tomoko

2011-07-01

Incidence of ocular injury caused by the solar eclipse of 2009 has been investigated using the questionnaire of the Japan Committee of the International Year of Astronomy 2009. The questionnaire was available to the public on the website. Answers were obtained from 14 people (12 men, 2 women), aged from sixteen to fifty-four. All had looked at the sun either with the naked eye or through some shading device (plastic sheet, plastic bag, compact disc, etc.) the safty of which is unknown. Reported symptoms included a sense of incongruity, heat, pain, central scotoma or visual disturbance, classified into four periods of duration. Three people with transient symptoms watched the eclipse with the naked eye for one minute in cloudy weather. Three people with symptoms lasting for one day and three people with symptoms lasting for one week had watched it with the naked eye and some shading device for 10 minutes in cloudy weather. Five people with symptoms lasting for more than one week watched the eclipse with the naked eye and through some sort of device in fine or slightly cloudy weather. Three people consulted their ophthalmologist. Those who reported adverse symptoms did not comply with the instructions for safe watching of the eclipse and the duration of the symptoms depended on the weather and the type of device used.

A New Binary Star System of EW Type in Draco: GSC 03905-01870

NASA Astrophysics Data System (ADS)

Barquin, S.

2018-05-01

Discovery of a new binary star system (GSC 03905-01870 = USNO-B1.0 1431-0327922 = UCAC4 716-059522) in the Draco constellation is presented. It was discovered during a search for previously unreported eclipsing binary stars through the ASAS-SN database. The shape of the light curve and its characteristics (period of 0.428988+-0.000001 d, amplitude of 0.34+-0.02 V Mag, primary minimum epoch HJD 2457994.2756+-0.0002) indicates that the new variable star is an eclipsing binary of W Ursae Majoris type. I registered this variable star in The International Variable Star Index (VSX), its AAVSO UID is 000-BMP-891.

Orbital period variation study of the low-mass Algol eclipsing binary AI Draconis

NASA Astrophysics Data System (ADS)

Hanna, Magdy A.

2013-06-01

Orbital period changes for the Algol-type eclipsing binary AI Dra were studied based on the analysis of its observed times of light minimum. The period variation showed cyclic changes in the interval from JD. ≈ 24 36000 to JD. ≈ 24 47500 and a secular period increase rate (dP/dt = 2.44 × 10-7 d/year) starting from JD. ≈ 24 48500 up to 24 55262, in a time scale equals to 5 × 106 year.

Photometric Properties of the HW Vir-type Binary OGLE-GD-ECL-11388

NASA Astrophysics Data System (ADS)

Hong, Kyeongsoo; Lee, Jae Woo; Lee, Dong-Joo; Kim, Seung-Lee; Koo, Jae-Rim; Park, Jang-Ho; Lee, Chung-Uk; Kim, Dong-Jin; Cha, Sang-Mok; Lee, Yongseok

2017-01-01

We present the first extensive photometric results for the eclipsing binary OGLE-GD-ECL-11388 with a period of about 3.5 hours located in the Galactic disk. For the photometric solutions, we obtained the BVI light curves from both the KMTNet observations in 2015 and the OGLE-III survey data from 2001-2009, which show striking reflection effects and very sharp eclipses. The light curve synthesis indicates that the eclipsing system is a HW Vir-type binary with a mass ratio of q = 0.289, an orbital inclination of i = 81.9 deg, and a temperature ratio between both components of T 2/T 1 = 0.091. A frequency analysis was applied to the light residuals from our binary model; however, no pulsating periodicity from the subdwarf B-type primary component was detected under signal-to-noise amplitude ratios larger than 4.0. A total of 27 minimum epochs spanning 15 yr were used to analyze the eclipse timing variations of OGLE-GD-ECL-11388. It was found that the orbital period has varied due to a continuous period decrease at a rate of dP/dt = -1.1 × 10-8 day yr-1 or a sinusoidal oscillation with a semiamplitude of K = 35 s and a cycle of P 3 = 8.9 yr. The period decrease may be explained by an angular momentum loss via magnetic stellar wind braking or may be only a part of the sinusoidal variation. We think the most likely interpretation of the orbital period change, at present, is the light-time effect via the presence of a third body with a mass of {M}3\\sin {i}3=12.5 M Jup, putting it in the boundary zone between planets and brown dwarfs.

VizieR Online Data Catalog: BVIc light curves of SZ Cam (Tamajo+, 2012)

NASA Astrophysics Data System (ADS)

Tamajo, E.; Munari, U.; Siviero, A.; Tomasella, L.; Dallaporta, S.

2012-01-01

We present a spectroscopic and photometric analysis of the multiple system and early-type eclipsing binary SZ Cam (O9 IV + B0.5 V), which consists of an eclipsing SB2 pair of orbital period P=2.7-days in a long orbit (~55yrs) around a non-eclipsing SB1 pair of orbital period P=2.8-days. We have reconstructed the spectra of the individual components of SZ Cam from the observed composite spectra using the technique of spectral disentangling. We used them together with extensive and accurate BV IC CCD photometry to obtain an orbital solution. Our photometry revealed the presence of a beta Cep variable in the SZ Cam hierarchical system, probably located within the non-eclipsing SB1 pair. The pulsation period is 0.33265+/-0.00005-days and the observed total amplitude in the B band is 0.0105+/-0.0005mag. NLTE analysis of the disentangled spectra provided atmospheric parameters for all three components, consistent with those derived from orbital solution. (1 data file).

Structure and Dynamics of the 2009 July 22 Eclipse White-light Corona

NASA Astrophysics Data System (ADS)

Pasachoff, J. M.; Rušin, V.; Saniga, M.; Druckmüllerová, H.; Babcock, B. A.

2011-11-01

The white-light corona (WLC) during the total solar eclipse of 2009 July 22 was observed by several teams in the Moon's shadow stretching from India and China across the Pacific Ocean with its many isolated islands. We present a comparison of the WLC as observed by eclipse teams located in China (Shanghai region) and on the Enewetak Atoll in the Marshall Islands, with observations taken 112 minutes apart, combined with near-simultaneous space observations. The eclipse was observed at the beginning of solar cycle 24, during a deep solar minimum (officially estimated as 2008 December according to the smoothed sunspot number, but very extended). The solar corona shows several different types of features (coronal holes, polar rays, helmet streamers, faint loops, voids, etc.), though it was extremely sparse in streamers as shown from Large-Angle Spectroscopic Coronagraph data. No large-scale dynamical phenomena were seen when comparing the observations from the two sites, confirming that the corona was quiescent. We measure a Ludendorff flattening coefficient of 0.238, typical of solar minimum.

Orbital Period Variations in the NY Vir System, Revisited in the Light of New Data

NASA Astrophysics Data System (ADS)

Baştürk, Özgür; Esmer, Ekrem Murat

2018-02-01

NY Virginis is an eclipsing binary system with a subdwarf B primary and an M type dwarf secondary. Recent studies (Qian et al. 2012; Lee et al. 2014) suggested the presence of two circumbinary planets with a few Jovian masses within the system. Lee et al. (2014) examined the orbital stabilities of the suggested planets, using the best-fit parameters derived from their eclipse timing variation analysis. They found that the outer companion should be ejected from the system in about 800 000 years. An observational report from Pulley et al. (2016) pointed out that the recent mideclipse times of the binary deviate significantly from the models suggested by Lee et al. (2014). In fact, variations in the orbital period of the system had already been recognized by many authors, but the parameters of these variations vary significantly as new data accumulate. Here, we analyze the eclipse timing variations of the NY Vir system, using new mid-eclipse times that we have obtained together with earlier published measurements in order to understand the nature of the system and constrain its parameters.

Highlights of Odessa Branch of AN in 2017

NASA Astrophysics Data System (ADS)

Andronov, I. L.

2017-12-01

An annual report with a list of publications. Our group works on the variable star research within the international campaign "Inter-Longitude Astronomy" (ILA) based on temporarily working groups in collaboration with Poland, Slovakia, Korea, USA and other countries. A recent self-review on highlights was published in 2017. Our group continues the scientific school of Prof. Vladymir P. Tsesevich (1907 - 1983). Another project we participate is "AstroInformatics". The unprecedented photo-polarimetric monitoring of a group of AM Her - type magnetic cataclysmic variable stars was carried out since 1989 (photometry in our group - since 1978). A photometric monitoring of the intermediate polars (MU Cam, V1343 Her, V2306 Cyg et al.) was continued to study rotational evolution of magnetic white dwarfs. The super-low luminosity state was discovered in the outbursting intermediate polar = magnetic dwarf nova DO Dra. Previously typical low state was some times interrupted by outbursts, which are narrower than usual dwarf nova outbursts. Once there were detected TPO - "Transient Periodic Oscillations". The orbital and quasi-periodic variability was recently studied. Such super-low states are characteristic for nova-like variables (e.g. MV Lyr, TT Ari) or intermediate polars, but unusual for the dwarf novae. The electronic "Catalogue of Characteristics and Atlas of the Light Curves of Newly-Discovered Eclipsing Binary Stars" was compiled and is being prepared for publication. The software NAV ("New Algol Variable") with specially developed algorithms was used. It allows to determine the begin and end of the eclipses even in EB and EW - type stars, whereas the current classification (GCVS, VSX) claims that the begin and end of eclipses only in the EA - type objects. The further improvements of the NAV algorithm were comparatively studied. The "Wall-Supported Polynomial" (WSP) algoritms were implemented in the software MAVKA for statistically optimal modeling of flat eclipses and exoplanet transitions. MAVKA was used for studies of effects of the mass transfer and presence of the third components in close binary stellar systems and analysis of the poorly studied eclipsing binary 2MASS J20355082+5242136. Atlas of the Light Curves and Phase Plane Portraits of Selected Long-Period Variables was compiled.

KIC 4150611: a rare multi-eclipsing quintuple with a hybrid pulsator

NASA Astrophysics Data System (ADS)

Hełminiak, K. G.; Ukita, N.; Kambe, E.; Kozłowski, S. K.; Pawłaszek, R.; Maehara, H.; Baranec, C.; Konacki, M.

2017-06-01

Aims: We aim to analyse KIC 4150611 (HD 181469) - an interesting, bright quintuple system that includes a hybrid δ Sct/γ Dor pulsator. Four periods of eclipses - 94.2, 8.65, 1.52 and 1.43 d - have been observed by the Kepler satellite, and three point sources (A, B, and C) are seen in high angular resolution images. Methods: From spectroscopic observations made with the HIDES spectrograph attached to the 1.88-m telescope of the Okayama Astrophysical Observatory (OAO), we have calculated for the first time radial velocities (RVs) of the component B - a pair of G-type stars - and combined them with Kepler photometry in order to obtain absolute physical parameters of this pair. We also managed to directly measure RVs of the pulsator, for the first time. Additionally, we modelled the light curves of the 1.52 and 1.43-day pairs, and measured their eclipse timing variations (ETVs). We also performed relative astrometry and photometry of three sources seen on the images taken with the NIRC2 camera of the Keck II telescope. Finally, we compared our results with theoretical isochrones. Results: The brightest component Aa is the hybrid pulsator, transited every 94.2 days by a pair of K/M-type stars (Ab1+Ab2), which themselves form a 1.52-day eclipsing binary. The components Ba and Bb are late G-type stars, forming another eclipsing pair with a 8.65 day period. Their masses and radii are MBa = 0.894 ± 0.010 M⊙, RBa = 0.802 ± 0.044 R⊙ for the primary, and MBb = 0.888 ± 0.010 M⊙, RBb = 0.856 ± 0.038 R⊙ for the secondary. The remaining period of 1.43 days is possibly related to a faint third star C, which itself is most likely a background object. The system's properties are well-represented by a 35 Myr isochrone, basing on which the masses of the pulsator and the 1.52-day pair are MAa = 1.64(6) M⊙, and MAb,tot = 0.90(13) M⊙, respectively. There are also suggestions of additional bodies in the system.

First Precision Photometric Observations and Analyses of The Totally Eclipsing, Solar Type Binary, V573 Pegasi

NASA Astrophysics Data System (ADS)

Samec, Ronald G.; Caton, Daniel B.; Faulkner, Danny R.

2018-06-01

CCD, VRI light curves of V573 Peg were taken in 26,27 September and 2, 4 and 6 October, 2017 at the Dark Sky Observatory in North Carolina with the 0.81-m reflector of Appalachian State University by D. Caton. V573 Peg was discovered by the SAVS survey which classified it as a V= 0.51 amplitude, EW variable. They included a rough spectrum identifying the binary was about a type G, although the period would indicate it is an F-type contact binary. Five times of minimum light were calculated, two primary eclipses and three secondary, from our present observations:HJD I = 2458023.6420±0.0012, 2458028.6522±0.0021,HJD II = 2458022.5991±0.0011, 2458023.8510±0.0010 and 2458028.8608±0.0005,The following linear and quadratic ephemerides were determined from all available times of minimum light.JD Hel MinI = 2456876.49437±0.00078d + 0.41745021±0. 00000017 × E, -JD Hel MinI = 2456876.49580±0.00023d + 0. 417448601±0.000000083× E - 0.000000000274±0.000000000012 X E2A 14-year period study (24 times of minimum light) revealed that the orbital period decreasing with a high level of confidence, possibly due to magnetic braking. The mass ratio is found to be somewhat extreme, M2/M1=0.2629±0.0006.Its Roche Lobe fill-out is 25%. The solution had no need of spots. The temperature difference of the components is about ~130 K, with the secondary as the hotter star, so it is a W-type W UMa Binary. The inclination is 80.4±0.1° . The secondary eclipse shows a time of constant light with an eclipse duration of 24 minutes. More details of our results will be given at the meeting.

K2 Variable Catalogue: Variable stars and eclipsing binaries in K2 campaigns 1 and 0

NASA Astrophysics Data System (ADS)

Armstrong, D. J.; Kirk, J.; Lam, K. W. F.; McCormac, J.; Walker, S. R.; Brown, D. J. A.; Osborn, H. P.; Pollacco, D. L.; Spake, J.

2015-07-01

Aims: We have created a catalogue of variable stars found from a search of the publicly available K2 mission data from Campaigns 1 and 0. This catalogue provides the identifiers of 8395 variable stars, including 199 candidate eclipsing binaries with periods up to 60 d and 3871 periodic or quasi-periodic objects, with periods up to 20 d for Campaign 1 and 15 d for Campaign 0. Methods: Lightcurves are extracted and detrended from the available data. These are searched using a combination of algorithmic and human classification, leading to a classifier for each object as an eclipsing binary, sinusoidal periodic, quasi periodic, or aperiodic variable. The source of the variability is not identified, but could arise in the non-eclipsing binary cases from pulsation or stellar activity. Each object is cross-matched against variable star related guest observer proposals to the K2 mission, which specifies the variable type in some cases. The detrended lightcurves are also compared to lightcurves currently publicly available. Results: The resulting catalogue gives the ID, type, period, semi-amplitude, and range of the variation seen. We also make available the detrended lightcurves for each object. The catalogue is available at http://deneb.astro.warwick.ac.uk/phrlbj/k2varcat/ and at the CDS via anonymous ftp to http://cdsarc.u-strasbg.fr (ftp://130.79.128.5) or via http://cdsarc.u-strasbg.fr/viz-bin/qcat?J/A+A/579/A19

Inter-Longitude Astronomy (ILA) Project: Current Highlights And Perspectives. I. Magnetic vs. Non-Magnetic Interacting Binary Stars

NASA Astrophysics Data System (ADS)

Andronov, I. L.; Antoniuk, K. A.; Baklanov, A. V.; Breus, V. V.; Burwitz, V.; Chinarova, L. L.; Chochol, D.; Dubovsky, P. A.; Han, W.; Hegedus, T.; Henden, A.; Hric, L.; Chun-Hwey, Kim; Yonggi, Kim; Kolesnikov, S. V.; Kudzej, I.; Liakos, A.; Niarchos, P. G.; Oksanen, A.; Patkos, L.; Petrik, K.; Pit', N. V.; Shakhovskoy, N. M.; Virnina, N. A.; Yoon, J.; Zola, S.

2010-12-01

We present a review of highlights of our photometric and photo-polarimetric monitoring and mathematical modeling of interacting binary stars of different types classical, asynchronous, intermedi ate polars with 25 timescales corresponding to differ ent physical mechanisms and their combinations (part "Polar"); negative and positive superhumpers in nova- like and dwarf novae stars ("Superhumper"); symbiotic ("Symbiosis"); eclipsing variables with and without ev idence for a current mass transfer ("Eclipser") with a special emphasis on systems with a direct impact of the stream into the gainor star's atmosphere, which we propose to call "Impactors", or V361 Lyr-type stars. Other parts of the ILA project are "Stellar Bell" (pul sating variables of different types and periods - M, SR, RV Tau, RR Lyr, Delta Sct) and "New Variable".

Spectroscopy and Photometry of EUVE J1429-38.0:An Eclipsing Magnetic Cataclysmic Variable

NASA Astrophysics Data System (ADS)

Howell, Steve B.; Craig, Nahide; Roberts, Bryce; McGee, Paddy; Sirk, Martin

1997-06-01

EUVE J1429-38.0 was originally discovered as a variable source by the Extreme Ultraviolet Explorer (EUVE) satellite. We present new optical observations which unambiguously confirm this star to be an eclipsing magnetic system with an orbital period of 4() h 46() m. The photometric data are strongly modulated by ellipsoidal variations during low states which allow a system inclination of near 80 degrees to be determined. Our time-resolved optical spectra, which cover only about one-third of the orbital cycle, indicate the clear presence of a gas stream. During high states, EUVE J1429-38.0 shows ~ 1 mag deep eclipses and the apparent formation of a partial accretion disk. EUVE J1429-38.0 presents the observer with properties of both the AM Herculis and the DQ Herculis types of magnetic cataclysmic variable.

NSV 1907 - A new eclipsing, nova-like cataclysmic variable

NASA Astrophysics Data System (ADS)

Hümmerich, Stefan; Gröbel, Rainer; Hambsch, Franz-Josef; Dubois, Franky; Ashley, Richard; Gänsicke, Boris T.; Vanaverbeke, Siegfried; Bernhard, Klaus; Wils, Patrick

2017-01-01

NSV 1907, formerly listed as an irregular variable in variability catalogues, was classified as an Algol-type eclipsing binary in the Catalina Surveys Periodic Variable Star Catalogue. We have identified NSV 1907 as an ultraviolet (UV) bright source using measurements from the GALEX space telescope and detected obvious out-of-eclipse variability in archival photometric data from the Catalina Sky Survey, which instigated a closer examination of the object. A spectrum and extensive multicolour photometric observations were acquired, from which we deduce that NSV 1907 is a deeply eclipsing, nova-like cataclysmic variable. Apart from the orbital variations (deep eclipses with a period of P ≈ 6.63 hours), changes in mean brightness and irregular short-term variability (flickering) were observed. The presence of a secondary minimum at phase φ ≈ 0.5 was established, which indicates a significant contribution of the companion star to the optical flux of the system. We find possible evidence for sinusoidal variations with a period of P ≈ 4.2 d, which we interpret as the nodal precession period of the accretion disc. No outbursts or VY Scl-like drops in brightness were detected either by the CSS or during our photometric monitoring. Because of its spectral characteristics and the observed variability pattern, we propose NSV 1907 as a new moderately bright long-period SW Sextantis star. Further photometric and spectroscopic observations are encouraged.

Double-lined M dwarf eclipsing binaries from Catalina Sky Survey and LAMOST

NASA Astrophysics Data System (ADS)

Lee, Chien-Hsiu; Lin, Chien-Cheng

2017-02-01

Eclipsing binaries provide a unique opportunity to determine fundamental stellar properties. In the era of wide-field cameras and all-sky imaging surveys, thousands of eclipsing binaries have been reported through light curve classification, yet their basic properties remain unexplored due to the extensive efforts needed to follow them up spectroscopically. In this paper we investigate three M2-M3 type double-lined eclipsing binaries discovered by cross-matching eclipsing binaries from the Catalina Sky Survey with spectroscopically classified M dwarfs from the Large Sky Area Multi-Object Fiber Spectroscopic Telescope survey data release one and two. Because these three M dwarf binaries are faint, we further acquire radial velocity measurements using GMOS on the Gemini North telescope with R˜ 4000, enabling us to determine the mass and radius of individual stellar components. By jointly fitting the light and radial velocity curves of these systems, we derive the mass and radius of the primary and secondary components of these three systems, in the range between 0.28-0.42M_⊙ and 0.29-0.67R_⊙, respectively. Future observations with a high resolution spectrograph will help us pin down the uncertainties in their stellar parameters, and render these systems benchmarks to study M dwarfs, providing inputs to improving stellar models in the low mass regime, or establishing an empirical mass-radius relation for M dwarf stars.

1SWASP J200503.05-343726.5: A high mass ratio eclipsing binary near the period limit

NASA Astrophysics Data System (ADS)

Bin, Zhang; Shengbang, Qian; Zejda, Miloslav; Liying, Zhu; Nianping, Liu

2017-07-01

First CCD photometric light curves of the eclipsing binary system 1SWASP J200503.05-343726.5 are presented. Our complete light curves in V, R and I bands using the Bessell filter show an out-of-eclipsing distortion, which means that the components of the system may be active. The preliminary photometric solutions with a cool star-spot are derived by using the 2013 version of the Wilson-Devinney (W-D) code. The photometric solutions suggest that 1SWASP J200503.05-343726.5 is a shallow-contact eclipsing binary(f = 9.0 %) with a mass ratio of q = 1.0705 , which is very high for late-type binary systems near the period limit. The primary component is about 230 K hotter than the secondary component. Based on our new CCD eclipse times, the orbital period change was analyzed. According to O - C diagram, the orbital period of the 1SWASP J200503.05-343726.5 shows an increase at a rate of P˙ = + 5.43 ×10-8 days year-1. The period increase may be caused by mass transfer from the less massive component to the more massive one. This shallow-contact system may be formed from a detached short-period binary via orbital shrinkage because of dynamical interactions with a third component or by magnetic braking.

On the SW Sex-type eclipsing cataclysmic variable SDSS0756+0858

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

Tovmassian, Gagik; Hernandez, Mercedes Stephania; González-Buitrago, Diego

We conducted a spectroscopic and photometric study of SDSS J075653.11+085831. X-ray observations were also attempted. We determined the orbital period of this binary system to be 3.29 hr. It is a deep eclipsing system, whose spectra show mostly single-peaked, Balmer emission lines and a rather intense He II line. There is also the presence of faint (often double-peaked) He I emission lines as well as several absorption lines, Mg I being the most prominent. All of these features point toward the affiliation of this object with the growing number of SW Sex-type objects. We developed a phenomenological model of anmore » SW Sex system to reproduce the observed photometric and spectral features.« less

Multicolor eclipse studies of UU Aquarii. 1: Observations and system parameters

NASA Technical Reports Server (NTRS)

Baptista, R.; Steiner, J. E.; Cieslinski, D.

1994-01-01

A study of the eclipses in UU Aqr from multicolor high-speed photometry is presented. A revised ephemeris for the times of minimum and an upper limit for orbital period variations are obtained. We use measurements of contact phases in the eclipse light curve to derive the binary geometry and to estimate masses and relevant dimensions. We find a mass ratio of q = 0.30 +/- 0.07 and an inclination of i = 78 deg +/- 2 deg. The masses of the component stars are M(sub 1) = 0.67 +/- 0.14 solar mass and M(sub 2) = 0.20 +/- 0.07 solar mass. Our photometric model predicts K(sub 1) = 84 +/- 26 km/s, which is approximately 30% smaller than the velocity amplitude obtained from the emission lines. From the white dwarf fluxes we estimate T(sub wd) approximately = 34,000 K and a distance of d = 270 +/- 50 pc if the inner disk is opaque. UU Aqr has long term brightness variations of approximately = 0.3 m on timescales of approximately 4 yr. The system was in a 'high' state in 1989 and 1990 and in a 'low' state in 1988 and 1992. The high state results from an increase in the brightness of the outer and cooler parts of the disk, mainly due to the appearance of a bright spot at disk rim. Based on the smooth and gradual eclipse shape and on the absence of a prominent hump in the light curve we suggest that UU Aqr is a high mass-transfer nova-like system with a relatively bright and optically thick accretion disk. We find no perceptible eclipse in the H-alpha emission line. The fluxes at mid-eclipse can be fitted by a compostion of a late-type spectrum plus an optically thin hydrogen emission-line spectrum. These evidences suggest that the emission lines are formed in an extended region only partially occulted during eclipse.

Timing of AB And eclipses

NASA Astrophysics Data System (ADS)

Kozyreva, V. S.; Ibrahimov, M. A.; Gaynullina, E. R.; Karimov, R. G.; Hafizov, B. M.; Satovskii, B. L.; Krushevska, V. N.; Kuznyetsova, Yu. G.; Bogomazov, A. I.; Irsmambetova, T. R.; Tutukov, A. V.

2018-01-01

This study aims timing the eclipses of the short period low mass binary star AB And. The times of minima are taken from the literature and from our observations in October 2013 (22 times of minima) and in August 2014 (23 times of minima). We find and discuss an inaccuracy in the determination of the types of minima in the previous investigation by Li et al. (2014). We study the secular evolution of the central binary's orbital period and the possibility of the existence of third and fourth companions in the system.

The ultraviolet spectrum of the eclipsing binary IM Aurigae

NASA Technical Reports Server (NTRS)

Bruhweiler, F. C.; Feibelman, W. A.; Kondo, Y.

1986-01-01

Low dispersion IUE spectra have been obtained at primary and secondary minima, together with a high dispersion spectrum near maximum, for the eclipsing Algol-type IM Aurigae system. The weak, sharp absorption features noted at two distinct velocities in the high dispersion data are attributed to circumbinary gaseous shells and/or gas streams between the stellar components. The implications of these results for the recently observed increase in O-C values of the primary minimum, which prompted this UV spectral search for evidence of a recent mass-loss event, are discussed.

SARA South Observations and Analysis of the Solar Type, Totally Eclipsing, Over Contact Binary, PY Aquarii

NASA Astrophysics Data System (ADS)

Chamberlain, Heather; Samec, Ronald G.; Caton, Daniel Bruce; Van Hamme, Walter

2018-01-01

PY Aqr (GSC 05191-00853) is a solar Type (T ~ 5750K) eclipsing binary. It was observed in July to October, 2017 at Cerro Tololo in remote mode with the 0.6-m SARA South reflector. Two times of minimum light were calculated from our present observations, a primary and a secondary eclipse:HJD Min I = 2457951.7762±0.0006 HJD Min II = 2458019.5295±00.0003. Both weighted as 1.0.In addition, four timings were determined from online data given in IBVS 5600 and five observations at minima were determined from archived All Sky Automated Survey Data:HJD Min I = 2452908.3165, 2452912.33612 HJD Min II = 2452877.5621, 2452913.34465. All weighted as 0.5.ASAS Observations at minima: 2452094.688, 2453478.882, 2453266.576, 2452093.685 and 54729.600. Each weighted as 0.10The following linear and quadratic ephemerides were determined from all available times of minimum light:JD Hel Min I=2452951.7443±0.0008d + 0.402093441±0.000000099 X E {1} JD Hel Min I=2452951.7439±0.0007d + 0.4020912±0.0000007 X E +0.00000000018 ± 0.00000000006 X E2 {2}A BVRI Bessell filtered simultaneous Wilson-Devinney Program (W-D) solution reveals that the system has a mass ratio of ~0.34 and a component temperature difference of only ~40 K. One low luminosity (Tfact ~ 0.94, ~66 degree radius) large cool region of spots was iterated on the primary component in the WD Synthetic Light Curve computations. It appears in the Southern Hemisphere (colatitude 155 degrees). The Roche Lobe fill-out of the binary is ~17%. The inclination is ~86 degrees. An eclipse duration of ~10 minutes was determined for the primary eclipse and the light curve solution. Additional and more detailed information is given in this report.

ON THE ORBIT OF EXOPLANET WASP-12b

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

Campo, Christopher J.; Harrington, Joseph; Hardy, Ryan A.

We observed two secondary eclipses of the exoplanet WASP-12b using the Infrared Array Camera on the Spitzer Space Telescope. The close proximity of WASP-12b to its G-type star results in extreme tidal forces capable of inducing apsidal precession with a period as short as a few decades. This precession would be measurable if the orbit had a significant eccentricity, leading to an estimate of the tidal Love number and an assessment of the degree of central concentration in the planetary interior. An initial ground-based secondary-eclipse phase reported by Lopez-Morales et al. (0.510 {+-} 0.002) implied eccentricity at the 4.5{sigma} level.more » The spectroscopic orbit of Hebb et al. has eccentricity 0.049 {+-} 0.015, a 3{sigma} result, implying an eclipse phase of 0.509 {+-} 0.007. However, there is a well-documented tendency of spectroscopic data to overestimate small eccentricities. Our eclipse phases are 0.5010 {+-} 0.0006 (3.6 and 5.8 {mu}m) and 0.5006 {+-} 0.0007 (4.5 and 8.0 {mu}m). An unlikely orbital precession scenario invoking an alignment of the orbit during the Spitzer observations could have explained this apparent discrepancy, but the final eclipse phase of Lopez-Morales et al. (0.510 {+-}{sup +0.007}{sub -0.006}) is consistent with a circular orbit at better than 2{sigma}. An orbit fit to all the available transit, eclipse, and radial-velocity data indicates precession at <1{sigma}; a non-precessing solution fits better. We also comment on analysis and reporting for Spitzer exoplanet data in light of recent re-analyses.« less

Mass-Luminosity Relations for Rapid and Slow Rotators.

NASA Astrophysics Data System (ADS)

Malkov, O. Yu.

2006-08-01

Comparing the radii of eclipsing binaries components and single stars we have found a noticeable difference between observational parameters of B0V-G0V components of eclipsing binaries and those of single stars of the corresponding spectral type. This difference was confirmed by re-analysing the results of independent investigations published in the literature. Larger radii and higher temperatures of A-F eclipsing binaries can be explained by synchronization of such stars in close systems that prevents them to rotate rapidly. So, we have found that the mass-luminosity relation based on eclipsing binary data cannot be used to derive the initial mass function of single stars. While our current knowledge of the empirical mass-luminosity relation for intermediate-mass (1.5 to 10 m[*]) stars is based exclusively on data from eclipsing binaries, knowledge of the mass-luminosity relation should come from dynamical mass determinations of visual binaries, combined with spatially resolved precise photometry. Then the initial mass function should be revised for m>1.5m[*]. Data were collected on fundamental parameters of stars with masses m > 1.5.m [*]). They are components of binaries with P > 15^d and consequently are not synchronised with the orbital periods and presumably are rapid rotators. These stars are believed to evolve similarly with single stars, so these data allow us to construct mass-luminosity and other relations that can more confidently be used for statistical and astrophysical investigations of single stars than so called standard relations, based on data on detached main-sequence double-lined short-period eclipsing binaries. Mass-luminosity, mass-temperature and mass-radius relations of single stars are presented, as well as their HR diagram.

Spectroscopic observations of the detached binary PG 1413 + 015

NASA Technical Reports Server (NTRS)

Fulbright, Michael S.; Liebert, James; Bergeron, P.; Green, Richard

1993-01-01

We present improved estimates of the stellar parameters of the eclipsing, precataclysmic binary system PG 1413 + 015 (GH Vir), which has an orbital period of only 8h16m. Model atmosphere fits a Balmer line profiles yield T(eff) = 48,800 +/- 1200 K and log g = 7.70 +/- 0.11 for the DAO white dwarf primary star, from which a mass of 0.51 +/- 0.04 solar mass is inferred using evolutionary models. An ultraviolet spectrum obtained with the IUE Observatory has a slope consistent with this temperature and the assumption of no interstellar extinction. A red CCD spectrum of the secondary star during the 12-minute total eclipse indicates a spectral type of M3 V-M5 V. Reanalysis of the eclipse light curve leads to an inferred radius of 0.15 solar radius and a mass of 0.10 solar mass for the secondary, the latter being marginally consistent with the spectral type. Reprocessing on the facing side of the secondary produces phase-dependent Balmer line emission and detectable variations in the continuum from 6500-9000 A. The observed levels of reprocessing are consistent with expectations based on the above stellar parameters.

A New Light Curve and Analysis of the Long Period Eclipsing Binary BF Draconis

NASA Astrophysics Data System (ADS)

Wolf, G. W.; Craig, L. E.; Caffey, J. F.

1999-01-01

The star BF Draconis was found to be an eclipsing binary by Strohmeier, Knigge and Ott (1962) and originally thought to be an Algol-type system with a period of 5.6 days. A spectrographic study by Imbert (1985) showed that the period was actually double this value and that the system consisted of two well-separated, almost-equal F-type stars in elliptical orbit. Diethelm, Wolf and Agerer (1993) later published a preliminary light curve of this system showing minima of unequal depth and width with a displaced secondary, confirming the elliptical orbit but disagreeing with Imbert on the specific orbital parameters. As a part of our long-term program of obtaining improved light curves of double-lined spectroscopic and eclipsing binaries, we have observed BF Draconis for the past four years using the 0.4 meter telescope at the Baker Observatory of Southwest Missouri State University. Complete light curves in the Cousins BVRI passbands have been obtained with our Photometrics CCD system, and a new model and orbital parameters for the binary have been determined using the Wilson-Devinney program. This research has been supported by NSF Grants AST-9315061 and AST-9605822 and NASA Grant NGT5-40060.

Determination of the Fundamental Properties of the Eclipsing Binary V541 Cygni

NASA Astrophysics Data System (ADS)

McGruder, Chima; Torres, Guillermo; Siverd, Robert; Pepper, Joshua; Rodriguez, Joseph; KELT Collaboration

2017-01-01

We report new high-resolution spectroscopic observations of the B-type detached spectroscopic eclipsing binary V541 Cygni (e = 0.465 and P =15.34 days). We combine analysis of these new spectra with analysis of V-band photometry from the literature to obtain the most precise measurements of the fundamental properties of the stars to date (yielding ~1% errors in the masses and ~2% for the radii). A comparison with current stellar evolution models indicates good fits for an age of ~ 200 million years and [Fe/H] ~ -0.2. Available eclipse timings gathered over 40 years were used to re-determine the apsidal motion of the system, dω/dt = 0.993 degs/cent, which is larger than what theory suggests.The SAO REU program was funded in part by the National Science Foundation REU and Department of Defense ASSURE programs under NSF Grant no. 1262851, and by the Smithsonian Institution.

Photometric Analysis of Eclipsing Binary Az Vir

NASA Astrophysics Data System (ADS)

Neugarten, Andrew; Akiba, Tatsuya; Gokhale, Vayujeet

2018-06-01

We present photometric analysis of the eclipsing binary star system Az Vir. Standard BVR filter data were obtained using the 17-inch PlaneWave Instruments CDK telescope at the Truman State University Observatory in Kirksville, Mo and the 31-inch NURO telescope at the Lowell Observatory complex in Flagstaff, AZ. We apply an eight-term truncated Fourier fit to the light curves generated from these data to confirm the classification of Az Vir as a W Ursae Majoris-type eclipsing variable, using criteria specified by Rucinski (1997). We also calculate the values for the O’Connell Effect Ratio (OER) and the Light Curve Asymmetry (LCA) to quantify the asymmetry in the BVR light curves. In addition, we use data provided by the SuperWASP mission to perform long term O-C (observed minus calculated) analysis on the system to determine if and how its period is changing.

Einstein observations of selected close binaries and shell stars

NASA Technical Reports Server (NTRS)

Guinan, E. F.; Koch, R. H.; Plavec, M. J.

1984-01-01

Several evolved close binaries and shell stars were observed with the IPC aboard the HEAO 2 Einstein Observatory. No eclipsing target was detected, and only two of the shell binaries were detected. It is argued that there is no substantial difference in L(X) for eclipsing and non-eclipsing binaries. The close binary and shell star CX Dra was detected as a moderately strong source, and the best interpretation is that the X-ray flux arises primarily from the corona of the cool member of the binary at about the level of Algol-like or RS CVn-type sources. The residual visible-band light curve of this binary has been modeled so as to conform as well as possible with this interpretation. HD 51480 was detected as a weak source. Substantial background information from IUE and ground scanner measurements are given for this binary. The positions and flux values of several accidentally detected sources are given.

Absolute Parameters for the F-type Eclipsing Binary BW Aquarii

NASA Astrophysics Data System (ADS)

Maxted, P. F. L.

2018-05-01

BW Aqr is a bright eclipsing binary star containing a pair of F7V stars. The absolute parameters of this binary (masses, radii, etc.) are known to good precision so they are often used to test stellar models, particularly in studies of convective overshooting. ... Maxted & Hutcheon (2018) analysed the Kepler K2 data for BW Aqr and noted that it shows variability between the eclipses that may be caused by tidally induced pulsations. ... Table 1 shows the absolute parameters for BW Aqr derived from an improved analysis of the Kepler K2 light curve plus the RV measurements from both Imbert (1979) and Lester & Gies (2018). ... The values in Table 1 with their robust error estimates from the standard deviation of the mean are consistent with the values and errors from Maxted & Hutcheon (2018) based on the PPD calculated using emcee for a fit to the entire K2 light curve.

There's An App For That: Planning Ahead for the Solar Eclipse in August 2017

NASA Astrophysics Data System (ADS)

Chizek Frouard, Malynda R.; Lesniak, Michael V.; Bell, Steve

2017-01-01

With the total solar eclipse of 2017 August 21 over the continental United States approaching, the U.S. Naval Observatory (USNO) on-line Solar Eclipse Computer can now be accessed via an Android application, available on Google Play.Over the course of the eclipse, as viewed from a specific site, several events may be visible: the beginning and ending of the eclipse (first and fourth contacts), the beginning and ending of totality (second and third contacts), the moment of maximum eclipse, sunrise, or sunset. For each of these events, the USNO Solar Eclipse 2017 Android application reports the time, Sun's altitude and azimuth, and the event's position and vertex angles. The app also lists the duration of the total phase, the duration of the eclipse, the magnitude of the eclipse, and the percent of the Sun obscured for a particular eclipse site.All of the data available in the app comes from the flexible USNO Solar Eclipse Computer Application Programming Interface (API), which produces JavaScript Object Notation (JSON) that can be incorporated into third-party Web sites or custom applications. Additional information is available in the on-line documentation (http://aa.usno.navy.mil/data/docs/api.php).For those who prefer using a traditional data input form, the local circumstances can still be requested at http://aa.usno.navy.mil/data/docs/SolarEclipses.php.In addition the 2017 August 21 Solar Eclipse Resource page (http://aa.usno.navy.mil/data/docs/Eclipse2017.php) consolidates all of the USNO resources for this event, including a Google Map view of the eclipse track designed by Her Majesty's Nautical Almanac Office (HMNAO).Looking further ahead, a 2024 April 8 Solar Eclipse Resource page (http://aa.usno.navy.mil/data/docs/Eclipse2024.php) is also available.

The moderately interacting Algol-type eclipsing binary RY Geminorum

NASA Technical Reports Server (NTRS)

Plavec, Mirek J.; Dobias, Jan J.

1987-01-01

Ultraviolet spectra of the Algol-type semidetached system RY Geminorum, whose components can be described as A0 V and K0 IV, have been matched to the ultraviolet spectrum by Kurucz (1979) model atmospheres, and a best fit is found for T(eff) = 9150 K. Comparison with standard star spectra requires that this value be raised to 9400 K. The color excess of the system is determined to be no more than E(B-V) = 0.03 mag; the distance to the system is about 360 pc. The masses are approximately 2.36 and 0.38 solar masses, and the radii are 2.5 and 5.8 solar radii, respectively. The separation of the two centers is 26 solar radii. Evidence for a circumstellar line absorption is found in optical and ultraviolet spectrograms, and evidence is found in IUE spectra taken in partial eclipse for circumstellar emission lines of the type detected previously in the WS Serpentis stars and in several semidetected systems of the Algol type.

Record-Breaking Eclipsing Binary

NASA Astrophysics Data System (ADS)

Kohler, Susanna

2016-05-01

A new record holder exists for the longest-period eclipsing binary star system: TYC-2505-672-1. This intriguing system contains a primary star that is eclipsed by its companion once every 69 years with each eclipse lasting several years!120 Years of ObservationsIn a recent study, a team of scientists led by Joseph Rodriguez (Vanderbilt University) characterizes the components of TYC-2505-672-1. This binary star system consists of an M-type red giant star that undergoes a ~3.45-year-long, near-total eclipse with a period of ~69.1 years. This period is more than double that of the previous longest-period eclipsing binary!Rodriguez and collaborators combined photometric observations of TYC-2505-672-1 by the Kilodegree Extremely Little Telescope (KELT) with a variety of archival data, including observations by the American Association of Variable Star Observers (AAVSO) network and historical data from the Digital Access to a Sky Century @ Harvard (DASCH) program.In the 120 years spanned by these observations, two eclipses are detected: one in 1942-1945 and one in 2011-2015. The authors use the observations to analyze the components of the system and attempt to better understand what causes its unusual light curve.Characterizing an Unusual SystemObservations of TYC-2505-672-1 plotted from 1890 to 2015 reveal two eclipses. (The blue KELT observations during the eclipse show upper limits only.) [Rodriguez et al. 2016]By modeling the systems emission, Rodriguez and collaborators establish that TYC-2505-672-1 consists of a 3600-K primary star thats the M giant orbited by a small, hot, dim companion thats a toasty 8000 K. But if the companion is small, why does the eclipse last several years?The authors argue that the best model of TYC-2505-672-1 is one in which the small companion star is surrounded by a large, opaque circumstellar disk. Rodriguez and collaborators suggest that the companion could be a former red giant whose atmosphere was stripped from it, leaving behind the small, hot core shrouded by a large, cool disk of stripped gas. The large size of the disk causes the eclipse of the primary to last for years, as viewed from Earth.The authors estimate the properties such a disk would need to produce the observed light curve. They find that if the companion were surrounded by a disk several AU in diameter, it could orbit at a distance of ~20-30 AU from the primary and reproduce the emission we see.The next eclipse of TYC-2505-672-1 will begin in April 2080. We neednt wait until then to gather more information about this system, however! Radial velocity measurements will help establish the masses of the two components, and high-cadence UV observations could reveal more about the evolutionary state of the system. Studying this extreme binary provides an excellent opportunity to learn more about the environments in late-life star systems.CitationJoseph E. Rodriguez et al 2016 AJ 151 123. doi:10.3847/0004-6256/151/5/123

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

Rodriguez, Joseph E.; Stassun, Keivan G.; Lund, Michael B.

We present TYC 2505-672-1 as a newly discovered and remarkable eclipsing system comprising an M-type red giant that undergoes a ∼3.45 year long, near-total eclipse (depth of ∼4.5 mag) with a very long period of ∼69.1 years. TYC 2505-672-1 is now the longest-period eclipsing binary system yet discovered, more than twice as long as that of the currently longest-period system, ϵ Aurigae. We show from analysis of the light curve including both our own data and historical data spanning more than 120 years and from modeling of the spectral energy distribution, both before and during eclipse, that the red giantmore » primary is orbited by a moderately hot source ( T {sub eff} ≈ 8000 K) that is itself surrounded by an extended, opaque circumstellar disk. From the measured ratio of luminosities, the radius of the hot companion must be in the range of 0.1–0.5 R {sub ⊙} (depending on the assumed radius of the red giant primary), which is an order of magnitude smaller than that for a main sequence A star and 1–2 orders of magnitude larger than that for a white dwarf. The companion is therefore most likely a “stripped red giant” subdwarf-B type star destined to become a He white dwarf. It is, however, somewhat cooler than most sdB stars, implying a very low mass for this “pre-He-WD” star. The opaque disk surrounding this hot source may be a remnant of the stripping of its former hydrogen envelope. However, it is puzzling how this object became stripped, given that it is at present so distant (orbital semimajor axis of ∼24 au) from the current red giant primary star. Extrapolating from our calculated ephemeris, the next eclipse should begin in early UT 2080 April and end in mid UT 2083 September (eclipse center UT 2081 December 24). In the meantime, radial velocity observations would establish the masses of the components, and high-cadence UV observations could potentially reveal oscillations of the hot companion that would further constrain its evolutionary status. In any case, this system is poised to become an exemplar of a very rare class of systems, even more extreme in several respects than the well studied archetype ϵ Aurigae.« less

Solar Eclipse Computer API: Planning Ahead for August 2017

NASA Astrophysics Data System (ADS)

Bartlett, Jennifer L.; Chizek Frouard, Malynda; Lesniak, Michael V.; Bell, Steve

2016-01-01

With the total solar eclipse of 2017 August 21 over the continental United States approaching, the U.S. Naval Observatory (USNO) on-line Solar Eclipse Computer can now be accessed via an application programming interface (API). This flexible interface returns local circumstances for any solar eclipse in JavaScript Object Notation (JSON) that can be incorporated into third-party Web sites or applications. For a given year, it can also return a list of solar eclipses that can be used to build a more specific request for local circumstances. Over the course of a particular eclipse as viewed from a specific site, several events may be visible: the beginning and ending of the eclipse (first and fourth contacts), the beginning and ending of totality (second and third contacts), the moment of maximum eclipse, sunrise, or sunset. For each of these events, the USNO Solar Eclipse Computer reports the time, Sun's altitude and azimuth, and the event's position and vertex angles. The computer also reports the duration of the total phase, the duration of the eclipse, the magnitude of the eclipse, and the percent of the Sun obscured for a particular eclipse site. On-line documentation for using the API-enabled Solar Eclipse Computer, including sample calls, is available (http://aa.usno.navy.mil/data/docs/api.php). The same Web page also describes how to reach the Complete Sun and Moon Data for One Day, Phases of the Moon, Day and Night Across the Earth, and Apparent Disk of a Solar System Object services using API calls.For those who prefer using a traditional data input form, local circumstances can still be requested that way at http://aa.usno.navy.mil/data/docs/SolarEclipses.php. In addition, the 2017 August 21 Solar Eclipse Resource page (http://aa.usno.navy.mil/data/docs/Eclipse2017.php) consolidates all of the USNO resources for this event, including a Google Map view of the eclipse track designed by Her Majesty's Nautical Almanac Office (HMNAO). Looking further ahead, a 2024 April 8 Solar Eclipse Resource page (http://aa.usno.navy.mil/data/docs/Eclipse2024.php) is also available.

On-line Eclipse Resources from the U.S. Naval Observatory: Planning Ahead for April 2024

NASA Astrophysics Data System (ADS)

Fredericks, Amy C.; Bartlett, J. L.; Bell, S.; Stapleton, J. C.

2014-01-01

On 8 April 2024, “…night from mid-day…” (Archilochus, 648 BCE) will appear to fortunate observers along a narrow band, approximately 115 mi (185 km) wide, that crosses fifteen states from Texas to Maine. In response to growing interest in the two total solar eclipses that will sweep the continental United States in the next 11 years, the U.S. Naval Observatory has developed an on-line resource center with direct links to 2024-specific services: the 2024 April 8 Total Solar Eclipse page (http://aa.usno.navy.mil/data/docs/Eclipse2024.php). The Solar Eclipse Computer (http://aa.usno.navy.mil/data/docs/SolarEclipses.php) calculates tables of local circumstances for events visible throughout the world. A similar service is available for lunar eclipses, Lunar Eclipse Computer (http://aa.usno.navy.mil/data/docs/LunarEclipse.php). The USNO Eclipse Portal (http://astro.ukho.gov.uk/eclbin/query_usno.cgi) provides diagrams and animations showing the global circumstances for events visible throughout the world and local circumstances for events visible at selected locations. The Web site, which includes both solar and lunar eclipses, is a joint effort with Her Majesty’s Nautical Almanac Office. The Eclipses of the Sun and Moon page (http://aa.usno.navy.mil/data/docs/UpcomingEclipses.php) links to electronic copies of the visibility maps from The Astronomical Almanac. The Eclipse Reference List (http://aa.usno.navy.mil/faq/docs/eclipse_ref.php) is a representative survey of the available literature for those interested in delving into these phenomena, either technically or historically. As exciting as the 2024 total solar eclipse, another spectacular event will precede it; a total solar eclipse will cross a different swath of the continent on August 21, 2017. The U.S. Naval Observatory has a resource center for that event as well (http://aa.usno.navy.mil/data/docs/Eclipse2017.php) . If your plans for 2024 are not yet made, visit the 2024 April 8 Total Solar Eclipse page to prepare for up to 4 minutes 31 seconds of “unexampled beauty, grandeur, and impressiveness” (Newcomb 1890) and of darkness.

Practicing for 2023 and 2024: What the AAS Solar Eclipse Task Force Learned from the "Great American Eclipse" of 2017

NASA Astrophysics Data System (ADS)

Fienberg, R. T.; Speck, A. K.; Habbal, S. R.

2017-12-01

More than three years ahead of the "Great American Eclipse" of August 2017, the American Astronomical Society formed the AAS Solar Eclipse Task Force to function as a think tank, coordinating body, and communication gateway to the vast resources available about the 2017 eclipse and solar eclipses more generally. The task force included professional and amateur astronomers, formal and informal educators, and science journalists; many had experienced total solar eclipses before, and others would experience their first totality in August 2017. The AAS task force secured funding from the AAS Council, the National Science Foundation, and NASA. These resources were used mainly for three purposes: (1) to build a website that contains basic information about solar eclipses, safe viewing practices, and eclipse imaging and video, along with resources for educators and the media and a searchable map of eclipse-related events and activities, with links to other authoritative websites with more detailed information; (2) to solicit, receive, evaluate, and fund proposals for mini-grants to support eclipse-related education and public outreach to underrepresented groups both inside and outside the path of totality; and (3) to organize a series of multidisciplinary workshops across the country to prepare communities for the eclipse and to facilitate collaborations between astronomers, meteorologists, school administrators, and transporation and emergency-management professionals. Most importantly, the AAS Solar Eclipse Task Force focused on developing and disseminating appropriate eclipse safety information. The AAS and NASA jointly developed safety messaging that won the endorsement of the American Academies of Opthalmology and Optometry. In the weeks immediately preceding the eclipse, it became clear that the marketplace was being flooded by counterfeit eclipse glasses and solar viewers, leading to a last minute change in our communication strategy. In this talk, we'll review the task force's activities, take stock of what went right and what went wrong, and consider how to do an even better job preparing the nation for the next two "Great American" solar eclipses: the annular eclipse of October 14, 2023, and the total eclipse of April 8, 2024.

Anomalous Eclipses of the Young Star RW Aur A

NASA Astrophysics Data System (ADS)

Lamzin, S.; Cheryasov, D.; Chuntonov, G.; Dodin, A.; Grankin, K.; Malanchev, K.; Nadzhip, A.; Safonov, B.; Shakhovskoy, D.; Shenavrin, V.; Tatarnikov, A.; Vozyakova, O.

2017-06-01

Results of UBVRIJHKLM photometry, VRI polarimetry and optical spectroscopy of a young star RW Aur A obtained during 2010-11 and 2014-16 dimming events are presented. During the second dimming the star decreased its brightness to ΔV >4.5 mag, polarization of its light in I-band was up to 30 %, and color-magnitude diagramm was similar to that of UX Ori type stars. We conclude that the reason of both dimmings is an eclipses of the star by dust screen, but the size of the screen is much larger than in the case of UXORs.

Books and Other Resources for Education about the August 21, 2017, Solar Eclipse

NASA Astrophysics Data System (ADS)

Pasachoff, Jay M.; Fraknoi, Andrew; Kentrianakis, Michael

2017-06-01

As part of our work to reach and educate the 300+ million Americans of all ages about observing the August 21 solar eclipse, especially by being outdoors in the path of totality but also for those who will see only partial phases, we have compiled annotated lists of books, pamphlets, travel guides, websites, and other information useful for teachers, students, and the general public and made them available on the web, at conferences, and through webinars. Our list includes new eclipse books by David Barron, Anthony Aveni, Frank Close, Tyler Nordgren, John Dvorak, Michael Bakich, and others. We list websites accessible to the general public including those of the International Astronomical Union Working Group on Eclipses (http://eclipses.info, which has links to all the sites listed below); the AAS Eclipse 2017 Task Force (http://eclipse2017.aas.org); NASA Heliophysics (http://eclipse.nasa.gov); Fred Espenak (the updated successor to his authoritative "NASA website": http://EclipseWise.com); Michael Zeiler (http://GreatAmericanEclipse.com); Xavier Jubier (http://xjubier.free.fr/en/site_pages/solar_eclipses/); Jay Anderson (meteorology: http://eclipsophile.com); NASA's Eyes (http://eyes.nasa.gov/eyes-on-eclipse.html and its related app); the Astronomical Society of the Pacific (http://www.astrosociety.org/eclipse); Dan McGlaun (http://eclipse2017.org/); Bill Kramer (http://eclipse-chasers.com). Specialized guides include Dennis Schatz and Andrew Fraknoi's Solar Science for teachers (from the National Science Teachers Association:http://www.nsta.org/publications/press/extras/files/solarscience/SolarScienceInsert.pdf), and a printing with expanded eclipse coverage of Jay Pasachoff's, Peterson Field Guide to the Stars and Planets (14th printing of the fourth edition, 2016: http://solarcorona.com).A version of our joint list is to be published in the July issue of the American Journal of Physics as a Resource Letter on Eclipses, adding to JMP's 2010, "Resource Letter SP-1 on Solar Physics," AJP, 78, September, 890-901.

Preparing for and Observing the 2017 Total Solar Eclipse

NASA Astrophysics Data System (ADS)

Pasachoff, J.

2015-11-01

I discuss ongoing plans and discussions for EPO and scientific observing of the 21 August 2017 total solar eclipse. I discuss aspects of EPO based on my experiences at the 60 solar eclipses I have seen. I share cloud statistics along the eclipse path compiled by Jay Anderson, the foremost eclipse meteorologist. I show some sample observations of composite imagery, of spectra, and of terrestrial temperature changes based on observations of recent eclipses, including 2012 from Australia and 2013 from Gabon. Links to various mapping sites of totality, partial phases, and other eclipse-related information, including that provided by Michael Zeiler, Fred Espenak (retired from NASA) and Xavier Jubier can be found on the website I run for the International Astronomical Union's Working Group on Eclipses at http://www.eclipses.info.

Fifty year canon of solar eclipses: 1986 - 2035

NASA Technical Reports Server (NTRS)

Espenak, Fred

1987-01-01

A complete catalog is presented, listing the general characteristics of every solar eclipse from 1901 through 2100. To complement this catalog, a detailed set of cylindrical projection world maps shows the umbral paths of every solar eclipse over the 200 year interval. Focusing in on the next 50 years, accurate geodetic path coordinates and local circumstances for the 71 central eclipses from 1987 through 2035 are tabulated. Finally, the geodetic paths of the umbral and penumbral shadows of all 109 solar eclipses in this period are plotted on orthographic projection maps of the Earth. Appendices are included which discuss eclipse geometry, eclipse frequency and occurrence, modern eclipse prediction and time determination. Finally, code for a simple Fortran program is given to predict the occurrence and characteristics of solar eclipses.

R Aqr observing campaign

NASA Astrophysics Data System (ADS)

Waagen, Elizabeth O.

2016-01-01

Dr. George Wallerstein (University of Washington) has requested AAVSO coverage of the long period/symbiotic variable R Aquarii beginning immediately in support of high resolution spectroscopic observations planned for 2016 January 19 and 21. Several other astronomers, including Drs. Lee Anne Willson (Iowa State University), Ulisse Munari (INAF, Astronomical Observatory of Padua, Italy), and Fred Walter (Stony Brook University) are studying R Aqr closely and additional spectroscopic and other observations are planned for the near future. R Aqr is both a Mira (M) and a symbiotic (ZAND) - it is a close binary system consisting of a hot star and a late-type star (the Mira), both enveloped in nebulosity. As a result, the very interesting light curve shows not only the Mira pulsation but also complex eclipse behavior as the two stars interact. The period of Mira variation is 387.0 days; the eclipse period is 43.6-44 years. The cause of the eclipse is unknown; several theories h! ave been proposed, including a focused accretion stream, a disk or cloud around the secondary, and a triggered mass loss that produces an opaque cloud. Careful investigation of this upcoming event should help to resolve this question. The last eclipse of R Aqr was in 1978. The next eclipse is predicted for 2022, but may be early. The current behavior of R Aqr suggests that the eclipse, which lasts for several years, may either be beginning or its beginning may be imminent. R Aqr was at minimum in early December 2015 at magnitude V=11.4, and is currently at visual magnitude 11.0. During this phase of the approximately 44-year eclipse cycle, at maximum it may be as bright as V 6.0-6.5 but is not expected to become brighter. Beginning immediately, nightly BVRI CCD and DSLR photometry and visual observations are requested. As R Aqr brightens towards maximum and is in range, PEP observations are also requested. Ongoing spectroscopy over the next several years will be interesting to see as the system evolves throughout the eclipse. Finder charts with sequence may be created using the AAVSO Variable Star Plotter (https://www.aavso.org/vsp). Observations should be submitted to the AAVSO International Database. See full Alert Notice for more details.

THE CHANGE OF THE ORBITAL PERIODS ACROSS ERUPTIONS AND THE EJECTED MASS FOR RECURRENT NOVAE CI AQUILAE AND U SCORPII

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

Schaefer, Bradley E.

2011-12-01

I report on the cumulative results from a program started 24 years ago designed to measure the orbital period change of recurrent novae (RNe) across an eruption. The goal is to use the orbital period change to measure the mass ejected during each eruption as the key part of trying to measure whether the RNe white dwarfs are gaining or losing mass over an entire eruption cycle, and hence whether they can be progenitors for Type Ia supernovae. This program has now been completed for two eclipsing RNe: CI Aquilae (CI Aql) across its eruption in 2000 and U Scorpiimore » (U Sco) across its eruption in 1999. For CI Aql, I present 78 eclipse times from 1991 to 2009 (including four during the tail of the 2000 eruption) plus two eclipses from 1926 and 1935. For U Sco, I present 67 eclipse times, including 46 times during quiescence from 1989 to 2009, plus 21 eclipse times in the tails of the 1945, 1999, and 2010 eruptions. The eclipse times during the tails of eruptions are systematically and substantially shifted with respect to the ephemerides from the eclipses in quiescence, with this being caused by shifts of the center of light during the eruption. These eclipse times are plotted on an O - C diagram and fitted to models with a steady period change ( P-dot ) between eruptions (caused by, for example, conservative mass transfer) plus an abrupt period change ({Delta}P) at the time of eruption. The primary uncertainty arises from the correlation between {Delta}P with P-dot , such that a more negative P-dot makes for a more positive {Delta}P. For CI Aql, the best fit is {Delta}P = -3.7{sup +9.2}{sub -7.3} Multiplication-Sign 10{sup -7}. For U Sco, the best fit is {Delta}P = (+ 43 {+-} 69) Multiplication-Sign 10{sup -7} days. These period changes can directly give a dynamical measure of the mass ejected (M{sub ejecta}) during each eruption with negligible sensitivity to the stellar masses and no uncertainty from distances. For CI Aql, the 1{sigma} upper limit is M{sub ejecta} < 10 Multiplication-Sign 10{sup -7} M{sub Sun }. For U Sco, I derive M{sub ejecta} = (43 {+-} 67) Multiplication-Sign 10{sup -7} M{sub Sun }.« less

Report of the IAU Working Group on Solar Eclipses

NASA Astrophysics Data System (ADS)

Pasachoff, Jay M.

2015-08-01

The Working Group on Solar Eclipses coordinates scientists and information in the study of the Sun and the heliosphere at solar eclipses. Our Website at http://eclipses.info has a wide variety of information, including links to maps and other websites dealing with solar eclipses, as well as information on how to observe the partial-phases of solar eclipses safely and why it is interesting for not only scientists but also for the public to observe eclipses and to see how we work to uncover the mysteries of the sun's upper atmosphere. In the last triennium, there were total eclipses in Australia and the Pacific in 2012; in an arc across Africa from Gabon to Uganda and Kenya in 2013; and in the Arctic, including Svalbard and the Faeroes plus many airplanes aloft, in 2015. In the coming triennium, there will be total solar eclipses in Indonesia and the Pacific in 2016 and then, on 21 August 2017, a total solar eclipse that will sweep across the Continental United States from northwest to southeast. Mapping websites, all linked to http://eclipses.info, include Fred Espenak's http://EclipseWise.com; Michael Zeiler's http://GreatAmericanEclipse.com and http://eclipse-maps.com; Xavier Jubier's http://xjubier.free.fr; and (with weather and cloudiness analysis) Jay Anderson's http://eclipser.ca. Members of the Working Group, chaired by Jay Pasachoff (U.S.), include Iraida Kim (Russia), Kiroki Kurokawa (Japan), Jagdev Singh (India), Vojtech Rusin (Slovakia), Zhongquan Qu (China), Fred Espenak (U.S.), Jay Anderson (Canada), Glenn Schneider (U.S.), Michael Gill (U.K.), Xavier Jubier (France), Michael Zeiler (U.S.), and Bill Kramer (U.S.).

Mapping the 2017 Eclipse: Education, Navigation, Inspiration

NASA Astrophysics Data System (ADS)

Zeiler, M.

2015-12-01

Eclipse maps are a unique vessel of knowledge. At a glance, they communicate the essential knowledge of where and when to successfully view a total eclipse of the sun. An eclipse map also provides detailed knowledge of eclipse circumstances superimposed on the highway system for optimal navigation, especially in the event that weather forces relocation. Eclipse maps are also a vital planning tool for solar physicists and astrophotographers capturing high-resolution imagery of the solar corona. Michael Zeiler will speak to the role of eclipse maps in educating the American public and inspiring people to make the effort to reach the path of totality for the sight of a lifetime. Michael will review the role of eclipse maps in astronomical research and discuss a project under development, the 2017 Eclipse Atlas for smartphones, tablets, and desktop computers.

Outburst-related period changes of recurrent nova CI aquilae

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

Wilson, R. E.; Honeycutt, R. K., E-mail: honey@astro.indiana.edu, E-mail: rewilson@ufl.edu

2014-11-01

Pre-outburst and post-outburst light curves and post-outburst eclipse timings are analyzed to measure any period (P) change related to nova CI Aql's outburst of early 2000 and a mean post-outburst dP/dt, which then lead to estimates of the accreting component's rate of mass (M) change and its overall outburst-related change of mass over roughly a decade of observations. We apply a recently developed procedure for unified analysis of three timing-related data types (light curves, radial velocities, and eclipse timings), although with only light curves and timings in this case. Fits to the data are reasonably good without need for amore » disk in the light-curve model, although the disk certainly exists and has an important role in our post-outburst mass flow computations. Initial experiments showed that, although there seems to be an accretion hot spot, it has essentially no effect on derived outburst-related ΔP or on post-outburst dP/dt. Use of atomic time (HJED) in place of HJD also has essentially nil effect on ΔP and dP/dt. We find ΔP consistently negative in various types of solutions, although at best only marginally significant statistically in any one experiment. Pre-outburst HJD {sub 0} and P results are given, as are post-outburst HJD {sub 0}, P, and dP/dt, with light curves and eclipse times as joint input, and also with only eclipse time input. Post-outburst dP/dt is negative at about 2.4σ. Explicit formulae for mass transfer rates and epoch-to-epoch mass change are developed and applied. A known offset in the magnitude zero point for 1991-1994 is corrected.« less

GLOBAL ANALYSIS OF KOI-977: SPECTROSCOPY, ASTEROSEISMOLOGY, AND PHASE-CURVE ANALYSIS

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

Hirano, Teruyuki; Sato, Bun'ei; Kobayashi, Atsushi

2015-01-20

We present a global analysis of KOI-977, one of the planet host candidates detected by Kepler. The Kepler Input Catalog (KIC) reports that KOI-977 is a red giant, for which few close-in planets have been discovered. Our global analysis involves spectroscopic and asteroseismic determinations of stellar parameters (e.g., mass and radius) and radial velocity (RV) measurements. Our analyses reveal that KOI-977 is indeed a red giant, possibly in the red clump, but its estimated radius (≳ 20 R {sub ☉} = 0.093 AU) is much larger than KOI-977.01's orbital distance (∼0.027 AU) estimated from its period (P {sub orb} ∼more » 1.35 days) and host star's mass. RV measurements show a small variation, which also contradicts the amplitude of ellipsoidal variations seen in the light curve folded with KOI-977.01's period. Therefore, we conclude that KOI-977.01 is a false positive, meaning that the red giant, for which we measured the radius and RVs, is different from the object that produces the transit-like signal (i.e., an eclipsing binary). On the basis of this assumption, we also perform a light curve analysis including the modeling of transits/eclipses and phase-curve variations, adopting various values for the dilution factor D, which is defined as the flux ratio between the red giant and eclipsing binary. Fitting the whole folded light curve as well as individual transits in the short cadence data simultaneously, we find that the estimated mass and radius ratios of the eclipsing binary are consistent with those of a solar-type star and a late-type star (e.g., an M dwarf) for D ≳ 20.« less

V773 Cas, QS Aql, AND BR Ind: ECLIPSING BINARIES AS PARTS OF MULTIPLE SYSTEMS

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

Zasche, P.; Juryšek, J.; Nemravová, J.

2017-01-01

Eclipsing binaries remain crucial objects for our understanding of the universe. In particular, those that are components of multiple systems can help us solve the problem of the formation of these systems. Analysis of the radial velocities together with the light curve produced for the first time precise physical parameters of the components of the multiple systems V773 Cas, QS Aql, and BR Ind. Their visual orbits were also analyzed, which resulted in slightly improved orbital elements. What is typical for all these systems is that their most dominant source is the third distant component. The system V773 Cas consists of two similarmore » G1-2V stars revolving in a circular orbit and a more distant component of the A3V type. Additionally, the improved value of parallax was calculated to be 17.6 mas. Analysis of QS Aql resulted in the following: the inner eclipsing pair is composed of B6V and F1V stars, and the third component is of about the B6 spectral type. The outer orbit has high eccentricity of about 0.95, and observations near its upcoming periastron passage between the years 2038 and 2040 are of high importance. Also, the parallax of the system was derived to be about 2.89 mas, moving the star much closer to the Sun than originally assumed. The system BR Ind was found to be a quadruple star consisting of two eclipsing K dwarfs orbiting each other with a period of 1.786 days; the distant component is a single-lined spectroscopic binary with an orbital period of about 6 days. Both pairs are moving around each other on their 148 year orbit.« less

Optical Photometry and X-Ray Monitoring of the ``Cool Algol'' BD +05°706: Determination of the Physical Properties

NASA Astrophysics Data System (ADS)

Torres, Guillermo; Mader, Jeff A.; Marschall, Laurence A.; Neuhäuser, Ralph; Duffy, Alaine S.

2003-06-01

We present new photometric observations in the BVRI bands of the double-lined eclipsing binary BD +05°706 conducted over three observing seasons, as well as new X-ray observations obtained with ROSAT covering a full orbital cycle (P=18.9 days). A detailed light-curve analysis of the optical data shows the system to be semidetached, confirming indications from an earlier analysis by Torres et al. (published in 1998), with the less massive and cooler star filling its Roche lobe. The system is a member of the rare class of cool Algol systems, which are different from the ``classical'' Algol systems in that the mass-gaining component is also a late-type star rather than a B- or A-type star. By combining the new photometry with a reanalysis of the spectroscopic observations reported by Torres et al., we derive accurate absolute masses for the components of M1=2.633+/-0.028 Msolar and M2=0.5412+/-0.0093 Msolar, radii of R1=7.55+/-0.20 Rsolar and R2=11.02+/-0.21 Rsolar, as well as effective temperatures of 5000+/-100 and 4640+/-150 K, for the primary and secondary, respectively. There are obvious signs of activity (spottedness) in the optical light curve of the binary. Our X-ray light curve clearly shows the primary eclipse but not the secondary eclipse, suggesting that the primary star is the dominant source of the activity in the system. The depth and duration of the eclipse allow us to infer some of the properties of the X-ray-emitting region around that star.

Orbital Circularization of Hot and Cool Kepler Eclipsing Binaries

NASA Astrophysics Data System (ADS)

Van Eylen, Vincent; Winn, Joshua N.; Albrecht, Simon

2016-06-01

The rate of tidal circularization is predicted to be faster for relatively cool stars with convective outer layers, compared to hotter stars with radiative outer layers. Observing this effect is challenging because it requires large and well-characterized samples that include both hot and cool stars. Here we seek evidence of the predicted dependence of circularization upon stellar type, using a sample of 945 eclipsing binaries observed by Kepler. This sample complements earlier studies of this effect, which employed smaller samples of better-characterized stars. For each Kepler binary we measure e cos ω based on the relative timing of the primary and secondary eclipses. We examine the distribution of e cos ω as a function of period for binaries composed of hot stars, cool stars, and mixtures of the two types. At the shortest periods, hot-hot binaries are most likely to be eccentric; for periods shorter than four days, significant eccentricities occur frequently for hot-hot binaries, but not for hot-cool or cool-cool binaries. This is in qualitative agreement with theoretical expectations based on the slower dissipation rates of hot stars. However, the interpretation of our results is complicated by the largely unknown ages and evolutionary states of the stars in our sample.

Photometric, Spectroscopic, and X-ray Analysis of the Cool Algol BD+05 706

NASA Astrophysics Data System (ADS)

Torres, G.; Mader, J.; Marschall, L. A.; Neuhaeuser, R.; Duffy, A. S.

2000-12-01

BD+05 706 is an example of a rare class of a dozen or so interacting binaries called ``cool Algols", in which both components of the system are late-type stars. By contrast, the ``classical Algols" are systems in which the star transfering mass is of late spectral type, but the mass gainer is much hotter. BD+05 706 was shown previously to be eclipsing (Marschall, Torres & Neuhaeuser 1998, BAAS, 30, 835). In this paper we report our complete analysis of BVRI light curves for the system obtained at Gettysburg College Observatory, together with spectroscopy from the Harvard-Smithsonian Center for Astrophysics reported previously (Torres, Neuhaeuser & Wichmann 1998, AJ, 115, 2028), and X-ray observations obtained with the ROSAT satellite. Our light curve analysis indicates the presence of spots, most likely on the more massive, active component (primary), which change from season to season. Our results confirm the semi-detached nature of the system, and combined with the spectroscopy they have allowed us to obtain the most precise absolute masses and radii for any object of this class. Our X-ray light curve for BD+05 706 shows the primary eclipse clearly, but no sign of a secondary eclipse, confirming that the primary is the active star. Strong X-ray flares are also visible.

ORBITAL CIRCULARIZATION OF HOT AND COOL KEPLER ECLIPSING BINARIES

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

Eylen, Vincent Van; Albrecht, Simon; Winn, Joshua N., E-mail: vincent@phys.au.dk

The rate of tidal circularization is predicted to be faster for relatively cool stars with convective outer layers, compared to hotter stars with radiative outer layers. Observing this effect is challenging because it requires large and well-characterized samples that include both hot and cool stars. Here we seek evidence of the predicted dependence of circularization upon stellar type, using a sample of 945 eclipsing binaries observed by Kepler . This sample complements earlier studies of this effect, which employed smaller samples of better-characterized stars. For each Kepler binary we measure e cos ω based on the relative timing of themore » primary and secondary eclipses. We examine the distribution of e cos ω as a function of period for binaries composed of hot stars, cool stars, and mixtures of the two types. At the shortest periods, hot–hot binaries are most likely to be eccentric; for periods shorter than four days, significant eccentricities occur frequently for hot–hot binaries, but not for hot–cool or cool–cool binaries. This is in qualitative agreement with theoretical expectations based on the slower dissipation rates of hot stars. However, the interpretation of our results is complicated by the largely unknown ages and evolutionary states of the stars in our sample.« less

Common pressure vessel battery performance

NASA Technical Reports Server (NTRS)

Otzinger, B.

1978-01-01

Performance tests run on two common pressure vessel type nickel hydrogen batteries are described and the results presented. The study included: (1) charge retention tests, (2) synchronous eclipse season cycling tests, and (3) temperature differential tests.

Fifty Year Canon of Lunar Eclipses: 1986-2035

NASA Technical Reports Server (NTRS)

Espenak, Fred

1989-01-01

A complete catalog is presented, listing the general circumstances of every lunar eclipse from 1901 through 2100. To compliment this catalog, a set of figures illustrate the basic Moon-shadow geometry and global visibility for every lunar eclipse over the 200 year interval. Focusing in on the next fifty years, 114 detailed diagrams show the Moon's path through Earth's shadow during every eclipse, including contact times at each phase. The accompanying cylindrical projection maps of Earth show regions of hemispheric visibility for all phases. The appendices discuss eclipse geometry, eclipse frequency and recurrence, enlargement of Earth's shadow, crater timings, eclipse brightness and time determination. Finally, a simple FORTRAN program is provided which can be used to predict the occurrence and general characteristics of lunar eclipses. This work is a companion volume to NASA Reference Publication 1178: Fifty Year Canon of Solar Eclipses: 1986-2035.

Outreach to Scientists and to the Public about the Scientific Value of Solar Eclipses

NASA Astrophysics Data System (ADS)

Pasachoff, J.

2017-12-01

The Great American Eclipse of August 21, 2017, provided an unprecedented opportunity for outreach among American audiences on a giant scale in the age of social media. Professonal scientists and other educators, however, were not exempt from ignorance of the remaining scientific value of observing solar eclipses, often mistakenly thinking that space satellites or mountaintop observatories could make artificial eclipses as good as natural ones, which they can't. Further, as Chair of the Working Group on Eclipses of the International Astronomical Union and as a frequent observer of solar eclipses in other countries, I felt an obligation to provide at-least-equal hospitality in our country. Here I discuss our welcome to and interaction with eclipse scientists from Greece, Slovakia, Australia, Bulgaria, Iran, China, and Japan and their participation in the eclipse observations. I describe my own outreach about the still-vital solar-eclipse observations through my August 2017 articles in Nature Astronomy and Scientific American as well as through book reviews in Nature and Phi Beta Kappa's Key Reporter and co-authorship of a Resource Letter on Observing Solar Eclipses in the July issue og the American Journal of Physics. I describe my eclipse-day Academic Minute on National Public Radio via WAMC and on http://365daysofastronomy.org, a website started during the International Year of Astronomy. I discuss my blog post on lecturing to pre-school through elementary-school students for the National Geographic Society's Education Blog. I show my Op-Ed pre-eclipse in the Washington Post. I discuss our eclipse-night broadcast of an eclipse program on PBS's NOVA, and its preparation over many months, back as far and farther than the February 26, 2017, annular solar eclipse observed from Argentinian Patagonia, with images from prior eclipses including 2013 in Gabon and 2015 in Svalbard. My work at the 2017 total solar eclipse was supported in large part with grants from the Committee for Research and Exploration of the National Geographic Society and from the Solar Terrestrial Program of the Division of Atmospheric and Geospace Sciences of the National Science Foundation.

The dynamical mass of a classical Cepheid variable star in an eclipsing binary system.

PubMed

Pietrzyński, G; Thompson, I B; Gieren, W; Graczyk, D; Bono, G; Udalski, A; Soszyński, I; Minniti, D; Pilecki, B

2010-11-25

Stellar pulsation theory provides a means of determining the masses of pulsating classical Cepheid supergiants-it is the pulsation that causes their luminosity to vary. Such pulsational masses are found to be smaller than the masses derived from stellar evolution theory: this is the Cepheid mass discrepancy problem, for which a solution is missing. An independent, accurate dynamical mass determination for a classical Cepheid variable star (as opposed to type-II Cepheids, low-mass stars with a very different evolutionary history) in a binary system is needed in order to determine which is correct. The accuracy of previous efforts to establish a dynamical Cepheid mass from Galactic single-lined non-eclipsing binaries was typically about 15-30% (refs 6, 7), which is not good enough to resolve the mass discrepancy problem. In spite of many observational efforts, no firm detection of a classical Cepheid in an eclipsing double-lined binary has hitherto been reported. Here we report the discovery of a classical Cepheid in a well detached, double-lined eclipsing binary in the Large Magellanic Cloud. We determine the mass to a precision of 1% and show that it agrees with its pulsation mass, providing strong evidence that pulsation theory correctly and precisely predicts the masses of classical Cepheids.

The atmospheric structures of the companion stars of eclipsing binary x ray sources

NASA Technical Reports Server (NTRS)

Clark, George W.

1992-01-01

This investigation was aimed at determining structural features of the atmospheres of the massive early-type companion stars of eclipse x-ray pulsars by measurement of the attenuation of the x-ray spectrum during eclipse transitions and in deep eclipse. Several extended visits were made to ISAS in Japan by G. Clark and his graduate student, Jonathan Woo to coordinate the Ginga observations and preliminary data reduction, and to work with the Japanese host scientist, Fumiaki Nagase, in the interpretation of the data. At MIT extensive developments were made in software systems for data interpretation. In particular, a Monte Carlo code was developed for a 3-D simulation of the propagation of x-rays from the neutron star through the ionized atmosphere of the companion. With this code it was possible to determine the spectrum of Compton-scattered x-rays in deep eclipse and to subtract that component from the observed spectra, thereby isolating the software component that is attributable in large measure to x-rays that have been scattered by interstellar grains. This research has culminated in the submission of paper to the Astrophysical Journal on the determination of properties of the atmosphere of QV Nor, the BOI companion of 4U 1538-52, and the properties of interstellar dust grains along the line of sight from the source. The latter results were an unanticipated byproduct of the investigation. Data from Ginga observations of the Magellanic binaries SMC X-1 and LMC X-4 are currently under investigation as the PhD thesis project of Jonathan Woo who anticipated completion in the spring of 1993.

Satellite observations of surface temperature during the March 2015 total solar eclipse.

PubMed

Good, Elizabeth

2016-09-28

The behaviour of remotely sensed land surface temperatures (LSTs) from the spinning-enhanced visible and infrared imager (SEVIRI) during the total solar eclipse of 20 March 2015 is analysed over Europe. LST is found to drop by up to several degrees Celcius during the eclipse, with the minimum LST occurring just after the eclipse mid-point (median=+1.5 min). The drop in LST is typically larger than the drop in near-surface air temperatures reported elsewhere, and correlates with solar obscuration (r=-0.47; larger obscuration = larger LST drop), eclipse duration (r=-0.62; longer duration = larger LST drop) and time (r=+0.37; earlier eclipse = larger LST drop). Locally, the LST drop is also correlated with vegetation (up to r=+0.6), with smaller LST drops occurring over more vegetated surfaces. The LSTs at locations near the coast and at higher elevation are also less affected by the eclipse. This study covers the largest area and uses the most observations of eclipse-induced surface temperature drops to date, and is the first full characterization of satellite LST during an eclipse (known to the author). The methods described could be applied to Geostationary Operational Environmental Satellite (GOES) LST data over North America during the August 2017 total solar eclipse.This article is part of the themed issue 'Atmospheric effects of solar eclipses stimulated by the 2015 UK eclipse'. © 2016 The Author(s).

Addressing Students' Misconceptions about Eclipses

ERIC Educational Resources Information Center

Slater, Timothy F.; Gelderman, Richard

2017-01-01

The upcoming Aug. 21, 2017, total solar eclipse, with its 70-mile wide path of totality stretching across much of North America, provides us with a unique opportunity to teach students about eclipses. One might naturally assume that students have little difficulty understanding the nature of eclipses. After all, the notion that eclipses occur when…

Public outreach and education during the 2016 total solar eclipse in Palu and Malang

NASA Astrophysics Data System (ADS)

Rachmadian, A. P.; Kunjaya, C.; Wahono, W.; Anugrah, A. A.

2016-11-01

MAGIC (Ma Chung Galactic Club) of Ma Chung University, Malang, is one of the amateur astronomers club who did public outreach and education during the Total Solar Eclipse March 9, 2016. The motivation for doing this was the bad experience during Total Solar Eclipse 1983. At that time the Indonesian government forbid the people to observe the Total Solar Eclipse in a way to avoid blindness. We try to fix this misunderstanding by educating people the safe way to enjoy the partial and total solar eclipse. MAGIC team was divided into two teams, one team went to Palu and did the solar eclipse related education in six high schools before and during the eclipse. The other team did the observation on Ma Chung University campus, Malang, to accompany people who want to see the partial solar eclipse through filtered telescopes. The sky during the solar eclipse was clear both in Malang and Palu. People were very excited and satisfied with the solar eclipse, and their interest to astronomy is increased.

Light Curves and Analyses of the Eclipsing Overcontact Binaries V546 And & V566 And & the Discovery of a New Variable Star

NASA Astrophysics Data System (ADS)

Bradstreet, David H.; Sanders, S. J.; Volpert, C. G.

2013-01-01

New precision V & Rc light curves of the eclipsing binaries V546 And and V566 And have been obtained using the 41-cm telescopes at the Eastern University Observatory equipped with SBIG ST-10XME CCD’s. V546 And (GSC 2828:18, P = 0.3831 days, m = 11.2) has only one published discovery light curve with significant scatter in the data. The system was observed on seven nights from 30 Aug - 20 Sep 2012, accumulating approximately 900 observations in both V and Rc. The light curves show distinctly that the system is totally eclipsing and preliminary analysis indicates that the binary is W-type (the larger, more massive star is the cooler component), has a mass ratio of 0.34, small temperature difference between the stars of 300 K, and a fillout of 0.30. There is also strong evidence of the presence of starspots influencing the slopes of both eclipses. V566 And (GSC 2321:257, P = 0.3897 days, m = 10.9) is a totally eclipsing overcontact system likewise showing obvious O’Connell effects likely due to starspots. V566 And was observed on seven nights from 30 Aug - 25 Sep 2012, accumulating more than 900 observations in both V and Rc. Preliminary light curve models indicate a W-type system with a small temperature difference between the stars of 200 K and a mass ratio of only 0.20. The original comparison star for V566 And, GSC 2321:911 (m = 12.0), turned out to be a previously unknown variable star with a period of approximately 0.466 days and a light amplitude in Rc of 0.15 mag. This new variable has no information concerning it in the online archives and initial analysis seems to indicate that this may be an ellipsoidal variable. The complete light curve analyses will be presented for both systems and the new variable’s light curves will also be discussed.

Orbital period study of the Algol-type eclipsing binary system TW Draconis

NASA Astrophysics Data System (ADS)

Qian, S. B.; Boonrucksar, S.

2002-10-01

The century-long times of light minimum of the Algol-type eclipsing binary star, TW Dra (BD +64°1077, Sp A5V+K2III), are investigated by considering a new pattern of period change. Two sudden period increases and two successive period decreases are discovered to superimpose on a rapid secular increase (d P/d t=+4.43×10 -6 days/year). The secular increase may be caused by a dynamical mass transfer from the secondary to the primary component (d m/d t=6.81×10 -7 M ⊙/year) that is in agreement with the semi-detached configuration of the system and with the existence of a hot spot and a gaseous stream in the binary system. The irregular period jumps superimposed on the secular increase can be explained by the structure variation of the K2-type giant via instabilities of the outer convective layer or via magnetic activity cycles.

ECLIPSING BINARY SCIENCE VIA THE MERGING OF TRANSIT AND DOPPLER EXOPLANET SURVEY DATA-A CASE STUDY WITH THE MARVELS PILOT PROJECT AND SuperWASP

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

Fleming, Scott W.; Ge Jian; De Lee, Nathan M.

2011-08-15

Exoplanet transit and Doppler surveys discover many binary stars during their operation that can be used to conduct a variety of ancillary science. Specifically, eclipsing binary stars can be used to study the stellar mass-radius relationship and to test predictions of theoretical stellar evolution models. By cross-referencing 24 binary stars found in the MARVELS Pilot Project with SuperWASP photometry, we find two new eclipsing binaries, TYC 0272-00458-1 and TYC 1422-01328-1, which we use as case studies to develop a general approach to eclipsing binaries in survey data. TYC 0272-00458-1 is a single-lined spectroscopic binary for which we calculate a massmore » of the secondary and radii for both components using reasonable constraints on the primary mass through several different techniques. For a primary mass of M{sub 1} = 0.92 {+-} 0.1 M{sub sun}, we find M{sub 2} = 0.610 {+-} 0.036 M{sub sun}, R{sub 1} = 0.932 {+-} 0.076 R{sub sun}, and R{sub 2} = 0.559 {+-} 0.102 R{sub sun}, and find that both stars have masses and radii consistent with model predictions. TYC 1422-01328-1 is a triple-component system for which we can directly measure the masses and radii of the eclipsing pair. We find that the eclipsing pair consists of an evolved primary star (M{sub 1} = 1.163 {+-} 0.034 M{sub sun}, R{sub 1} = 2.063 {+-} 0.058 R{sub sun}) and a G-type dwarf secondary (M{sub 2} = 0.905 {+-} 0.067 M{sub sun}, R{sub 2} = 0.887 {+-} 0.037 R{sub sun}). We provide the framework necessary to apply this analysis to much larger data sets.« less

The X-ray eclipse of the LMC binary CAL 87

NASA Technical Reports Server (NTRS)

Schmidtke, P. C.; Mcgrath, T. K.; Cowley, A. P.; Frattare, L. M.

1993-01-01

ROSAT-PSPC observations of the LMC eclipsing binary CAL 87 show a short-duration, shallow X-ray eclipse which coincides in phase with the primary optical minimum. Characteristics of the eclipse suggest the X-ray emitting region is only partially occulted. Similarities with the eclipse of the accretion-disk corona in X 1822-37 are discussed. However, no temperature variation through eclipse is found for CAL 87. A revised orbital period, combining published data and recent optical photometry, is given.

Kepler eclipsing binary stars. IV. Precise eclipse times for close binaries and identification of candidate three-body systems

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

Conroy, Kyle E.; Stassun, Keivan G.; Prša, Andrej

2014-02-01

We present a catalog of precise eclipse times and analysis of third-body signals among 1279 close binaries in the latest Kepler Eclipsing Binary Catalog. For these short-period binaries, Kepler's 30 minute exposure time causes significant smearing of light curves. In addition, common astrophysical phenomena such as chromospheric activity, as well as imperfections in the light curve detrending process, can create systematic artifacts that may produce fictitious signals in the eclipse timings. We present a method to measure precise eclipse times in the presence of distorted light curves, such as in contact and near-contact binaries which exhibit continuously changing light levelsmore » in and out of eclipse. We identify 236 systems for which we find a timing variation signal compatible with the presence of a third body. These are modeled for the light travel time effect and the basic properties of the third body are derived. This study complements J. A. Orosz et al. (in preparation), which focuses on eclipse timing variations of longer period binaries with flat out-of-eclipse regions. Together, these two papers provide comprehensive eclipse timings for all binaries in the Kepler Eclipsing Binary Catalog, as an ongoing resource freely accessible online to the community.« less

Candidates of eclipsing multiples based on extraneous eclipses on binary light curves: KIC 7622486, KIC 7668648, KIC 7670485 and KIC 8938628

NASA Astrophysics Data System (ADS)

Zhang, Jia; Qian, Sheng-Bang; He, Jian-Duo

2017-02-01

Four candidates of eclipsing multiples, based on new extraneous eclipses found on Kepler binary light curves, are presented and studied. KIC 7622486 is a double eclipsing binary candidate with orbital periods of 2.2799960 d and 40.246503 d. The two binary systems do not eclipse each other in the line of sight, but there is mutual gravitational influence between them which leads to the small but definite eccentricity of 0.0035(0.0022) associated with the short 2.2799960 d period orbit. KIC 7668648 is a hierarchical quadruple system candidate, with two sets of solid 203 ± 5 d period extraneous eclipses and another independent set of extraneous eclipses. A clear and credible extraneous eclipse is found on the binary light curve of KIC 7670485 which makes it a triple system candidate. Two sets of extraneous eclipses with periods of about 390 d and 220 d are found on KIC 8938628 binary curves, which not only confirm the previous conclusion of the 388.5 ± 0.3 triple system, but also indicate new additional objects that make KIC 8938628 a hierarchical quadruple system candidate. The results from these four candidates will contribute to the field of eclipsing multiples.

Poster 16: Eclipse-induced changes of Titan's meteorology at equinox

NASA Astrophysics Data System (ADS)

Tokano, Tetsuya

2016-06-01

Titan experiences solar eclipses by Saturn on ˜20 consecutive orbits around equinox for durations of up to ˜6 hours. The impact of these eclipses on Titan's surface, lower atmosphere and middle atmosphere is investigated by a global climate model. When an eclipse commences, the surface temperature on the subsaturnian side drops by up to 0.3 K, so that the diurnal maximum surface temperature remains lower than on the antisaturnian side, which is never eclipsed. By contrast, the tropospheric air temperature does not abruptly decrease during the eclipses because of the large thermal inertia, but the diurnal mean temperature slightly decreases. The surface wind at low latitudes becomes less gusty in the presence of eclipse due to damping of turbulence. The troposphere outside the planetary boundary layer is not sensitive to eclipses. In most parts of the stratosphere and mesosphere the temperature decreases by up to 2 K due to eclipses, but there are also layers, which experience relative warming due to thermal contraction of the underlying layers. The temperature in the middle atmosphere rapidly recovers after the end of the eclipse season. Eclipse-induced cooling and warming changes the zonal wind speed by a few m/s due to thermal wind adjustment to changing latitudinal temperature gradients.

The Great American Eclipse: Lessons Learned from Public Education

NASA Astrophysics Data System (ADS)

Edson, Shauna Elizabeth; Phoebe Waterman Haas Public Observatory

2018-01-01

The total solar eclipse of 2017 was a high-profile opportunity for nationwide public education. Astronomy experts suddenly became vital sources of information for a lay population whose interest in the eclipse greatly surpassed expectations. At the National Air and Space Museum, we leveraged our relatively accessible location and particularly diverse audience to help thousands of people, from novices to enthusiasts, prepare to view the eclipse safely. The goal was to empower all people so they could experience this unique astronomical event, understand what was happening, and observe the Sun safely. Over the course of two years spent talking with the public about the eclipse, we encountered common misconceptions, worries about safety or liability, and people experiencing confusion or information overload. We developed guidelines for handling these challenges, from correcting misinformation to managing the sudden spike in demand for glasses just before August 21.In particular, we helped people understand the following essential points:- The total phase of the eclipse is only visible from a limited path.- The partial eclipse is visible from a large area outside the path of totality.- The eclipse takes up to three hours from start to finish, providing ample time for viewing.- The Sun can be observed safely using several methods, including but not limited to eclipse glasses.- The eclipse happens because the Moon’s orbit is taking it directly between the Sun and the Earth.- Eclipses do not happen every month because the Moon’s orbit is tilted with respect to the Earth's orbital plane.- Students in schools can safely view the eclipse, with proper protection and supervision, to prevent eye damage and minimize liability.Public education about the eclipse appears to have been successful, as evidenced by the large number of people who saw their first total solar eclipse and the absence of reported eye damage cases. Amidst the excitement, photographs, and stories that emerged from the eclipse, there are valuable lessons that will be useful in helping the public prepare for future eclipses, in 2024 and beyond.

2016 SPD: Day 3

NASA Astrophysics Data System (ADS)

Kohler, Susanna

2016-06-01

Editors note:This week were in Boulder, Colorado at the47th meeting of the AAS Solar Physics Division (SPD). Follow along to catch some of the latest news from the field of solar physics!Yesterdayspress conference was titled Preparing for the 2017 Great American Eclipse. Four speakers highlighted both outreach and research projects that are planned for the eclipse that will cross the continental United States on August 21st next year.Eclipse from High AltitudeFirst up, Angela Des Jardins (Montana Space Grant Consortium) introduced us to the nationwide Eclipse Ballooning Project.An eclipse as seen from the ISS. Being up high gives you a very different perspective on eclipses! [NASA]The last total solar eclipse in the continental United States was in 1979, and people were told to stay inside and watch from their TVs! For the next total solar eclipse in the US, we want the opposite: for everyone to be outdoors and in the path of totality to watch (with eclipse glasses lets be safe)! This eclipse is a fantastic educational opportunity, and a way to reach an enormous audience.And what better way to experience the eclipse than to be involved? The Eclipse Ballooning Project is involving more than 50 student teams from 30 states to fly high-altitude balloons at 20 locations along the total eclipse path. These balloons will send live videos and images from the edge of space to the NASA website.Why? Being someplace high up provides an entirely different view for an eclipse! Instead of looking up to watch the Moon slide in front of the Sun, you can look down to watch the Moons shadow race across the Earths surface at thousands of miles per hour. This unique perspective is rare, and has certainly never been covered live. This will be an awesome addition to other coverage of the eclipse!At Maximum TotalityThe next speaker, Gordon Emslie, described the outreach efforts planned at his institution, Western Kentucky University (WKU). The location where the eclipse totality will last the longest 2 minutes and 40 seconds is the small town of Hopkinsville, KY. WKU is located a little over an hour away, and both locations are prepared for a large influx of people on eclipse day!Partial solar eclipse as viewed by the space-based Solar Dynamics Observatory. [NASA/SDO]WKU is located just off the centerline of eclipse path, which has some advantages: this provides better viewing of some of the chromospheric features of the Sun during the eclipse, like priminences and solar loops. WKU is setting up a variety of educational and public outreach activities at their football stadium and the WKU farm, and they encourage you to come visit for the eclipse!In addition, they are participating in a nationwide experiment called Citizen CATE, short for the Continental American Telescopic Eclipse. This project will use 60 telescopes spanning the 2500 mile path of totality to record continuous data of the eclipse as it travels across the US. The result will be data of a remarkable 90 minutes of totality, revealing the activity of the solar corona and providing an extended view of the eclipse as has never been seen before.Science During the EclipseNext up was Shadia Habbal (University of Hawaii), who is a co-leader of the AAS 2017 Eclipse Task Force. In addition to her education and outreach efforts associated with the eclipse, however, Habbal is a solar eclipse researcher. She and her collaborators are known as the Solar Wind Sherpas, due to the fact that they hand-carry their science equipment around the world for solar eclipses!Solar corona during a 2008 eclipse, with color overlay indicating emission from highly ionized iron lines. [Habbal et al. 2010]The primary science done during solar eclipses is the study of the solar corona, the region that extends from the solar surface out to several solar radii. This region is too faint to observe normally, but when the light from the Suns disk is blocked out, we can examine it.Unfortunately, the space telescopes that observe the Sun all have relatively narrow fields of view. But during an eclipse, we can gain the larger context for the corona with ground-based observations, with the Moon conveniently blocking the light from the Suns disk! The cover photo is a spectacular example of this.Observations of the corona during eclipses can provide information on both enormous events, like coronal mass ejections, and faint dynamical features, like plasma instabilities and expanding loops. In addition, we can learn about the plasma properties by examining emission from highly charged ions. The upcoming eclipse should provide a great opportunity to do some coronal science!A Unique OpportunityThe final press-conference speaker for the meeting was Jay Pasachoff (Williams College and Caltech), a veteran solar eclipse observer who was able to speak to what we could expect if we make it into the path of totality next year.Path of totality across the continental US for the August 2017 eclipse. [Fred Espenak/NASA GSFC]Pasachoff pointed out that there are nearly 12 million people located within the band of totality. There are probably another 200 million within a days drive! He strongly encouraged anyone able to make it to the path of totality to do so, pointing out that the experience in person is completely unlike the experience of watching a video. The process of watching the world around you go dark, he says, is something that simply isnt captured when you watch an eclipse on TV.If you plan to travel for the eclipse, Pasachoffs recommendation is to aim for the northwest end of the path of totality, rather than the southeast end surprisingly, weather statistics suggest you have a better chance of not getting clouded out in the northwest.We now have a year left to educate everyone likely to view the eclipse on when and how to view it safely! Accordingly, Pasachoff concluded the conference by providing a series of links on where to find more information:eclipses.infototalsolareclipse.orgGreatAmericanEclipse.comeclipsophile.com

Studies of coronal lines with electronic cameras during the eclipse of 7 march 1970.

PubMed

Fort, B

1970-12-01

The experimental design described here allows us to study with 2-A. bandpass filters the brightness distribution of the green coronal line, the two infrared lines of Fe XIII, and the neighboring coronal continuum. For the first time, in an eclipse expedition, electrostatic cameras derived from the Lallemand type are used; full advantage was taken of their speed, especially in the near infrared spectral range, and their good photometric qualities. They permit the measurement of intensity and polarization of the lines in the corona to a height of 1.25 solar radii above the limb of the sun, with a spatial resolution >/= (10")(2).

Proton acceleration measurements using fs laser irradiation of foils in the target normal sheath acceleration regime

NASA Astrophysics Data System (ADS)

Batani, D.; Boutoux, G.; Burgy, F.; Jakubowska, K.; Ducret, J. E.

2018-05-01

We present experimental results obtained at the CELIA laboratory using the laser ECLIPSE to study proton acceleration from ultra-intense laser pulses. Several types of targets were irradiated with different laser conditions (focusing and prepulse level). Proton emission was characterized using time-of-flight detectors (SiC and diamond) and a Thomson parabola spectrometer. In all cases, the maximum energy of observed protons was of the order of 260 keV with a large energy spectrum. Such characteristics are typical of protons emitted following the target normal sheath acceleration mechanism for low-energy short-pulse lasers like ECLIPSE.

Fraction of free-base nicotine in fresh smoke particulate matter from the Eclipse "cigarette" by 1H NMR spectroscopy.

PubMed

Pankow, James F; Barsanti, Kelley C; Peyton, David H

2003-01-01

Solution 1H NMR (proton-NMR) spectroscopy was used to measure the distribution of nicotine between its free-base and protonated forms at 20 degrees C in (a) water; (b) glycerin/water mixtures; and (c) puff-averaged "smoke" particulate matter (PM) produced by the Eclipse cigarette, a so-called "harm reduction" cigarette manufactured by R. J. Reynolds (RJR) Tobacco Co. Smoke PM from the Eclipse contains glycerin, water, nicotine, and numerous other components. Smoke PM from the Eclipse yielded a signal for the three N-methyl protons on nicotine at a chemical shift of delta (ppm) = 2.79 relative to a trimethylsilane standard. With alpha fb = fraction of the total liquid nicotine in free-base form, and alpha a = fraction in the acidic, monoprotonated NicH+ form, then alpha a + alpha fb approximately 1. (The diprotonated form of nicotine was assumed negligible.) When the three types of solutions were adjusted so that alpha a approximately 1, the N-methyl protons yielded delta a = 2.82 (Eclipse smoke PM); 2.79 (35% water/65% glycerin); and 2.74 (water). When the solutions were adjusted so that alpha fb approximately 1, the N-methyl protons yielded delta fb = 2.16 (Eclipse smoke PM); 2.13 (35% water/65% glycerin); and 2.10 (water). In all of the solutions, the rate of proton exchange between NicH+ and Nic was fast relative to the 1H-NMR chemical shift difference in hertz. Each solution containing both NicH+ and Nic thus yielded a single N-methyl peak at a delta given by delta = alpha a delta a + alpha fb delta fb so that delta varied linearly between delta a and delta fb. Since alpha fb = (delta a-delta)/(delta a-delta fb), then delta = 2.79 for the unadjusted Eclipse smoke PM indicates alpha fb approximately 0.04. The effective pH of the Eclipse smoke PM at 20 degrees C may then be calculated as pHeff = 8.06 + log[alpha fb/(1-alpha fb)] = 6.69, where 8.06 is the pKa of NicH+ in water at 20 degrees C. The measurements obtained for the puff-averaged Eclipse smoke PM pertain to the chemistry of the smoke PM as it might be initially inhaled at 20 degrees C. Upon inhalation, the volatilization of nicotine and other acid/base active compounds (as well as a warming toward a body temperature of 37 degrees C) will alter the pHeff value of the smoke PM during the time that it resides and ages in the respiratory tract.

Eclipse Soundscapes Project: Making the August 21, 2017 Total Solar Eclipse Accessible to Everyone

NASA Astrophysics Data System (ADS)

Winter, H. D., III

2017-12-01

The Eclipse Soundscapes Project delivered a multisensory experience that allowed the blind and visually impaired to engage with the August 21, 2017 total solar eclipse along with their sighted peers in a way that would not have been possible otherwise. The project, from the Smithsonian Astrophysical Observatory and NASA's Heliophysics Education Consortium, includes illustrative audio descriptions of the eclipse in real time, recordings of the changing environmental sounds during the eclipse, and an interactive "rumble map" app that allows users to experience the eclipse through touch and sound. The Eclipse Soundscapes Project is working with organizations such as the National Parks Service (NPS), Science Friday, and Brigham Young University and by WGBH's National Center for Accessible Media (NCAM) to bring the awe and wonder of the total solar eclipse and other astronomical phenomena to a segment of the population that has been excluded from and astronomy and astrophysics for far too long, while engaging all learners in new and exciting ways.

Educating the Public about the 2017 Total Solar Eclipse

NASA Astrophysics Data System (ADS)

Pasachoff, Jay M.

2017-01-01

On behalf of the International Astronomical Union's Working Group on Solar Eclipses, I have long worked to bring knowledge about eclipses and how to observe the safely to the people of the various countries from which partial, annular, or total solar eclipses are visible. In 2017, we have first a chance to educate the people of South America on the occasion of the February 26 annular eclipse through southern Chile and Argentina that is partial throughout almost the entire continent (and an eclipse workshop will be held February 22-24 in Esquel, Argentina: http://sion.frm.utn.edu.ar/WDEAII) and then a chance to educate the 300 million people of the United States and others in adjacent countries as far south as northern South America about the glories of totality and how to observe partial phases. Our website, a compendium of links to information about maps, safe observing, science, and more is at http://eclipses.info. We link to important mapping sites at EclipseWise.com, GreatAmericanEclipse.com, and http://xjubier.free.fr/en/site_pages/solar_eclipses/xSE_GoogleMap3.php?Ecl=+20170821&Acc=2&Umb=1&Lmt=1&Mag=1&Max=1, and information about cloudiness statistics at http://eclipsophile.com, as well as simulation sites at https://svs.gsfc.nasa.gov/cgi-bin/details.cgi?aid=4314 and http://eyes.jpl.nasa.gov. The American Astronomical Society's task force on the 2017 eclipse has a website at http://eclipse.aas.org. We are working to disseminate accurate information about how and why to observe the total solar eclipse, trying among other things to head off common misinformation about the hazards of looking at the sun at eclipses or otherwise. About 12 million Americans live within the 70-mile-wide band of totality, and we encourage others to travel into it, trying to make clear the difference between even a 99% partial eclipse and a total eclipse, with its glorious Baily's beads, diamond rings, and totality that on this occasion lasts between 2 minutes and 2 minutes 40 seconds on the centerline. Our research on the 2017 total solar eclipse is supported by grants from the Committee for Research and Exploration of the National Geographic Society and from the Solar Terrestrial Program of the Atmospheric and Geospace Sciences Division of the National Science Foundation.

Eclipsing the Light...Fantastic! Teaching Science.

ERIC Educational Resources Information Center

Leyden, Michael B.

1995-01-01

Features the concepts of optics and geometry of eclipses. Presents the "eclipse rule," suggesting classroom activities in which students derive this rule. Includes some triangles activities for outdoors that illustrate eclipsing and sighting phenomena. (ET)

Bringing the Great American Solar Eclipse to West Virginia

NASA Astrophysics Data System (ADS)

Keesee, A. M.; Williamson, K.; Robertson-Honecker, J.

2017-12-01

West Virginia experienced up to 90% coverage during the Great American Solar Eclipse on August 21st. To reach the greatest number of West Virginians, we targeted educators and the 4-H program to provide those community leaders with the tools to help students learn about and safely view the eclipse. We developed a website that consolodated relevant eclipse activities, fact sheets, and outreach videos to train educators and others in the public about the science of the eclipse and how to view a partial eclipse safely. The 4-H Summer Experiement used at all 4-H summer camps and events was designed to focus on the eclipse. We distributed over 20,000 custom designed eclipse glasses. These were distributed to teachers through an online request system and to 4-H members involved in summer activities. We hosted a pre-eclipse event on the campus of West Virginia University for the public to learn about the science of the eclipse, relevant research being conducted at the university, and provide tips for safe viewing. Student volunteers were available on campus during the day of the eclipse to hand out glasses and answer questions. We will present the results of our outreach and events as well as lessons learned for the 2024 eclipse. Support for this project was provided by the WVU Department of Physics and Astronomy, WVU Extension, the WV Space Grant Consortium, a WVU internal grant, the Green Bank Observatory, and individual supporters of a crowdfunding campaign.

Revision of the Phenomenological Characteristics of the Algol-Type Stars Using the Nav Algorithm

NASA Astrophysics Data System (ADS)

Tkachenko, M. G.; Andronov, I. L.; Chinarova, L. L.

Phenomenological characteristics of the sample of the Algol-type stars are revised using a recently developed NAV ("New Algol Variable") algorithm (2012Ap.....55..536A, 2012arXiv 1212.6707A) and compared to that obtained using common methods of Trigonometric Polynomial Fit (TP) or local Algebraic Polynomial (A) fit of a fixed or (alternately) statistically optimal degree (1994OAP.....7...49A, 2003ASPC..292..391A). The computer program NAV is introduced, which allows to determine the best fit with 7 "linear" and 5 "nonlinear" parameters and their error estimates. The number of parameters is much smaller than for the TP fit (typically 20-40, depending on the width of the eclipse, and is much smaller (5-20) for the W UMa and β Lyrae-type stars. This causes more smooth approximation taking into account the reflection and ellipsoidal effects (TP2) and generally different shapes of the primary and secondary eclipses. An application of the method to two-color CCD photometry to the recently discovered eclipsing variable 2MASS J18024395 + 4003309 = VSX J180243.9 +400331 (2015JASS...32..101A) allowed to make estimates of the physical parameters of the binary system based on the phenomenological parameters of the light curve. The phenomenological parameters of the light curves were determined for the sample of newly discovered EA and EW-type stars (VSX J223429.3+552903, VSX J223421.4+553013, VSX J223416.2+553424, USNO-B1.0 1347-0483658, UCAC3-191-085589, VSX J180755.6+074711= UCAC3 196-166827). Despite we have used original observations published by the discoverers, the accuracy estimates of the period using the NAV method are typically better than the original ones.

The Solar Eclipse Predictions of Chiljeongsam-Oepyeon in Early Choseon

NASA Astrophysics Data System (ADS)

Ahn, Young Sook; Lee, Yong Sam

2004-12-01

The history books of East Asia about astronomical phenomena have the more records of the solar eclipse frequently than any other ones. It is because traditionally, the solar eclipse meaned the fate of dynasty and the king's rule. The Sun, the biggest thing in the heaven symbolized the king, and the solar eclipse foresaw that the king had the problem in private including the body, and the country might suffer from difficulties in a great scale. So the king and all of the ministers used to gather to hold a ceremony named Gusikrye which solar eclipse may pass safely. Consequently, kings always had concernments on collecting informations of solar eclipse. Inspite of importance of solar eclipse predictions, but at the beginning of the Choseon, the predictions of the solar eclipse didn't fit. King Sejong compiled the Chiljeongsan-naepion and the Chiljeongsan-oepyeon to calculate the celestial phenomena including the solar eclipse. By the publications of these two books, the calendar making system of Choseon was firmly established. The Chiljeongsan-oepyeon adopted Huihui calendar of Arabia. The Solar eclipse predictions of Chiljeongsan-oepyeon were relative correct compared to modern method in early Choseon dynasty.

Changes in Latitude, Changes in Attitude: U.S. Naval Observatory Observations of Solar Eclipses 1869 to the Present

NASA Astrophysics Data System (ADS)

Chizek Frouard, Malynda R.; Towne, Linda; Kaplan, George H.

2017-01-01

In anticipation of the 2017 August 21 total solar eclipse over the continental United States, the history of U.S. Naval Observatory eclipse observations illustrates the changes in science, technology, and policy over the past 148 years.USNO eclipse observations began in 1869, when staff traveled to Des Moines, Iowa and the Bering Strait to look for intra-mercurial planets and to observe the solar corona. During the golden age of eclipse expeditions, the USNO officially participated in a dozen expeditions between 1869 and 1929. Seven of these expeditions were to US locations: 1869 in Iowa; 1878 in Colorado, Wyoming, and Texas; 1880 in California; 1900 in Georgia and North Carolina; 1918 in Oregon; 1923 in California; and 1925 in New York. A total solar eclipse has not traced a path across the width of the continental US since 1918 although several eclipses have passed over parts of the US since then.A few official expeditions occurred later in the 20th century to measure the solar diameter, including a total eclipse in the northwest US in 1979 and an annular eclipse across the southeast in 1984. However, observations began transitioning to mostly personal adventures as individual astronomers arranged unofficial trips.Historians can use the USNO Multi-year Interactive Computer Almanac (MICA) to compute local circumstances for solar eclipses world-wide starting with the annual eclipse of 1800 April 24, which was visible from Alaska. Those looking to make history in 2017 may consult the USNO 2017 August 21 Solar Eclipse Resource page (http://aa.usno.navy.mil/data/docs/Eclipse2017.php).

NASA Videofile of Solar Eclipse from Jefferson City, Missouri

NASA Image and Video Library

2017-08-21

During the eclipse, 14 states across the U.S. were in the path of totality and experienced more than two minutes of darkness in the middle of the day – with a partial eclipse viewable all across North America. The broadcast – Eclipse Across America: Through the Eyes of NASA – covered locations along the path of totality, from Oregon to South Carolina including public reactions from all ages. During this event, NASA Glenn Research Center celebrates the eclipse at the capital eclipse event in Jefferson City, MO

Building on the US Eclipse Experience in Schools, with the Public, and Beyond the US

NASA Astrophysics Data System (ADS)

Simmons, Mike; Chee, Zoe; Bartolone, Lindsay

2018-01-01

Astronomers Without Borders (AWB) organized several programs for the August 21, 2017 total solar eclipse, both before and after the event, to increase participation, build on the inspiration of the eclipse, share the eclipse experience, and prepare for the eclipse in 2024.AWB focused on preparing institutions that were least likely to receive resources despite extensive nationwide efforts. AWB distributed more than 100,000 donated glasses, to isolated schools, children's cancer hospitals, abused women’s shelters, and other institutions without access to other resource providers.AWB’s Building on the Eclipse Education Program builds on the inspiration of the eclipse for STEM education. The program uses a small, personal spectroscope kit to study sunlight in different scientific fields and includes free classroom activities that meet NGSS standards.A program to collect eclipse observing glasses for schools in developing countries for future eclipses was announced around the time of the eclipse and quickly went viral, with coverage by national and innumerable local media outlets. This effort builds on AWB’s earlier programs for schools in Africa and in South America for past eclipses. Well over one million pairs are expected, as compared to the tens of thousands AWB provided through crowdfunding for previous efforts. Nearly 1000 glasses collection centers were created spontaneously, without a public call. Factors leading to widespread and diverse public participation will be presented.A program calling for first-time eclipse observers to share their experiences addresses a major issue in encouraging people to travel to the path of totality. Expert and eclipse-enthusiast testimony often fails to convince people of the value of the experience of totality as “a few minutes of darkness.” This program will share the disconnect between expectation and experience from first-time “ordinary” observers to encourage others to travel to the path of totality for the total solar eclipse in 2024.Analysis and planned follow-up and expanded programs will also be described.

Satellite observations of surface temperature during the March 2015 total solar eclipse

PubMed Central

2016-01-01

The behaviour of remotely sensed land surface temperatures (LSTs) from the spinning-enhanced visible and infrared imager (SEVIRI) during the total solar eclipse of 20 March 2015 is analysed over Europe. LST is found to drop by up to several degrees Celcius during the eclipse, with the minimum LST occurring just after the eclipse mid-point (median=+1.5 min). The drop in LST is typically larger than the drop in near-surface air temperatures reported elsewhere, and correlates with solar obscuration (r=−0.47; larger obscuration = larger LST drop), eclipse duration (r=−0.62; longer duration = larger LST drop) and time (r=+0.37; earlier eclipse = larger LST drop). Locally, the LST drop is also correlated with vegetation (up to r=+0.6), with smaller LST drops occurring over more vegetated surfaces. The LSTs at locations near the coast and at higher elevation are also less affected by the eclipse. This study covers the largest area and uses the most observations of eclipse-induced surface temperature drops to date, and is the first full characterization of satellite LST during an eclipse (known to the author). The methods described could be applied to Geostationary Operational Environmental Satellite (GOES) LST data over North America during the August 2017 total solar eclipse. This article is part of the themed issue ‘Atmospheric effects of solar eclipses stimulated by the 2015 UK eclipse’. PMID:27550764

Glorious Eclipses

NASA Astrophysics Data System (ADS)

Brunier, Serge; Luminet, Jean-Pierre

2000-12-01

Stargazers who may have missed the last total solar eclipse of the 20th century this past summer have just been given another chance to observe this "once in a lifetime" occurrence. Inside Glorious Eclipses they will find startling images and rich personal accounts that fully capture this event and other recent eclipses. The book will also insure that readers will not miss another eclipse in the next 60 years! Specially designed in a beautiful, large format, the volume portrays eclipses of all kinds--lunar, solar, and those occurring elsewhere in the Solar System and beyond. Brunier and Luminet have gathered together all aspects of eclipses, and carefully selected a host of lavish images. The authors detail the history of eclipses, the celestial mechanics involved, their observation, and scientific interest. Personal accounts of recent eclipses are also included as well as all relevant information about forthcoming eclipses up to 2060. Complete with NASA maps and data, Glorious Eclipses is the ultimate source for all those interested in these remarkable (and rare) celestial events. Serge Brunier is chief editor of the journal Ciel et Espace, a photo-journalist, and the author of many nonfiction books aimed at both specialists and the general public. Jean-Pierre Luminet is an astrophysicist at the Paris-Meudon Observatory and director of research at the Centre pour la Recherche Scientifique. He is the author of many popular astronomy books, including Black Holes (Cambridge University Press, 1992).

Photometric study of two eclipsing binary stars: Light curve analysis and system parameters for GU CMa and SWASP J011732.10+525204.9

NASA Astrophysics Data System (ADS)

Shokry, A.; Saad, S. M.; Hamdy, M. A.; Beheary, M. M.; Abolazm, M. S.; Gadallah, K. A.; El-Depsey, M. H.; Al-Gazzar, M. S.

2018-02-01

A new photometric study of two eclipsing binary systems (GU CMa and SWASP J011732.10+525204.9) is presented. The accepted solutions of analyzing the light curves revealed that GU CMa is a semi-detached system consisting of two early spectral type components, (B2 and B2.5) while SWASP J011732.10+525204.9 is a contact binary with two late type components (K2 and M1). The primary component of each system is the massive one. The geometric configuration indicates that SWASP J011732.10+525204.9 passes through a very critical phase in which each component exactly fills its limited lobe with zero fill out ratio. New times of minimum and the absolute physical parameters for each system are determined. The evolution status for each system has been investigated.

Symbolism and discovery: eclipses in art.

PubMed

Blatchford, Ian

2016-09-28

There is a fascinating tradition of depicting solar eclipses in Western art, although these representations have changed over time. Eclipses have often been an important feature of Christian iconography, but valued as much for their biblical significance as for the splendour of the physical event. However, as Western culture passed through the Renaissance and Enlightenment the depictions of eclipses came to reflect new astronomical knowledge and a thirst for rational learning well beyond the confines of the church and other elites. Artists also played a surprisingly important role in helping scientists in the nineteenth century understand and record the full phenomena of an eclipse, even as the advent of photography also came to solve a number of scientific puzzles. In the most recent century, artists have responded to eclipses with symbolism, abstraction and playfulness.This article is part of the themed issue 'Atmospheric effects of solar eclipses stimulated by the 2015 UK eclipse'. © 2016 The Author(s).

Geospatial Analysis of Low-frequency Radio Signals Collected During the 2017 Solar Eclipse

NASA Astrophysics Data System (ADS)

Liles, W. C.; Nelson, J.; Kerby, K. C.; Lukes, L.; Henry, J.; Oputa, J.; Lemaster, G.

2017-12-01

The total solar eclipse of 2017, with a path that crosses the continental United States, offers a unique opportunity to gather geospatially diverse data. The EclipseMob project has been designed to crowdsource this data by building a network of citizen scientists across the country. The project focuses on gathering low-frequency radio wave data before, during, and after the eclipse. WWVB, a 60 KHz transmitter in Ft. Collins, CO operated by the National Institutes of Standard and Technology, will provide the transmit signal that will be observed by project participants. Participating citizen scientists are building simple antennas and receivers designed by the EclipseMob team and provided to participants in the form of "receiver kits." The EclipseMob receiver downsamples the 60 KHz signal to 18 KHz and supplies the downsampled signal to the audio jack of a smartphone. A dedicated app is used to collect data and upload it to the EclipseMob server. By studying the variations in WWVB amplitude observed during the eclipse at over 150 locations across the country, we aim to understand how the ionization of the D layer of the ionosphere is impacted by the eclipse as a function of both time and space (location). The diverse locations of the EclipseMob participants will provide data from a wide variety of propagation paths - some crossing the path of the total eclipse, and some remaining on the same side of the eclipse path as the transmitter. Our initial data analysis will involve identifying characteristics that define geospatial relationships in the behavior of observed WWVB signal amplitudes.

On the Importance of Solar Eclipse Geometry in the Interpretation of Ionospheric Observations

NASA Astrophysics Data System (ADS)

Stankov, S.; Verhulst, T. G. W.

2017-12-01

A reliable interpretation of solar eclipse effects on the geospace environment, and on the ionosphere in particular, necessitates a careful consideration of the so-called eclipse geometry. A solar eclipse is a relatively rare astronomical phenomenon, which geometry is rather complex, specific for each event, and fast changing in time. The standard, most popular way to look at the eclipse geometry is via the two-dimensional representation (map) of the solar obscuration on the Earth's surface, in which the path of eclipse totality is drawn together with isolines of the gradually-decreasing eclipse magnitude farther away from this path. Such "surface maps" are widely used to readily explain some of the solar eclipse effects including, for example, the well-known decrease in total ionisation (due to the substantial decrease in solar irradiation), usually presented by the popular and easy to understand ionospheric characteristic of Total Electron Content (TEC). However, many other effects, especially those taking place at higher altitudes, cannot be explained in this fashion. Instead, a complete, four-dimensional (4D) description of the umbra (and penumbra), would be required. This presentation will address the issue of eclipse geometry effects on various ionospheric observations carried out during the total solar eclipse of August 21, 2017. In particular, GPS-based TEC and ionosonde measurements will be analysed and the eclipse effects on the ionosphere will be interpreted with respect to the actual eclipse geometry at ionospheric heights. Whenever possible, a comparison will be made with results from previous events, such as the ones from March 20, 2015 and October 3, 2005.

Structure in the Disk of epsilon Aurigae - Analysis of ARCES and TripleSpec spectra from the 2010 eclipse

NASA Astrophysics Data System (ADS)

Gibson, Justus L.; Stencel, Robert E.; Ketzeback, William; Barentine, John; Coughlin, Jeffrey; Leadbeater, Robin; Saurage, Gabrelle

2018-06-01

Worldwide interest in the recent eclipse of epsilon Aurigae resulted in the generation of several extensive data sets, including high resolution spectroscopic monitoring. This lead to the discovery, among other things, of the existence of a mass transfer stream, seen notably during third contact. We explored spectroscopic facets of the mass transfer stream during third contact, using high resolution spectra obtained with the ARCES and TripleSpec instruments at Apache Point Observatory. One hundred and sixteen epochs of data were obtained between 2009 and 2012, and equivalent widths and line velocities measured for high versus low eccentricity accretion disk lines. These datasets also enable greater detail to be measured of the mid-eclipse enhancement of the He I 10830Å line, and the discovery of the P Cygni shape of the Pa-β line at third contact. We found evidence of higher speed material, associated with the mass transfer stream, persisting between third and fourth eclipse contacts. We visualized the disk and stream interaction using SHAPE software, and used CLOUDY software to estimate that the source of the enhanced He I 10830A absorption arises from a region with nH = 1011 cm-3 and temperature of 20,000 K, consistent with a mid-B type central star. Van Rensbergen binary star evolutionary models are somewhat consistent with the current binary parameters for their case of a 9 plus 8 solar mass initial binary, evolving into a 2.3 and 14.11 solar mass end product after 35 Myr. With these results, it is possible to make predictions which suggest that continued monitoring prior to the next eclipse (2036) will help resolve standing questions about the mass and age of this binary.

Selected results from the epsilon Aurigae eclipse campaign, and what lies ahead

NASA Astrophysics Data System (ADS)

Stencel, Robert E.

2013-07-01

The torrent of data generated during the 2009-2011 eclipse of the enigmatic binary, epsilon Aurigae, has provided abundant opportunity to test and refine the many ideas associated with this system. The UBVRIJH photometric light curves established times of ingress and egress, and also revealed that the differential color of the disk varied, relative to pre- or post- mid-eclipse phase. Inter-eclipse monitoring indicated secular variations suggestive of a rapidly evolving F supergiant star. Interferometric imaging decisively identified the eclipse-causing agent to be an opaque disk (CHARA+MIRC). Spectroscopy has shown that a hot source occupies the center of this disk (He I 10830A, Far-UV excess), that the disk exhibits substructure (K I 7699A) and may have an extended atmosphere (CHARA+VEGA), and that the disk is isotopically-enhanced in 13C (GNIRS) and in rare-earth elements during a third contact "still-stand" in the light curve, suggestive of a mass transfer stream. Polarimetry and spectro-polarimetry provided additional constraints on the F star atmospheric variation and the nature of the dust scattering in the disk. Numerical models of the disk are exploring its relationship to the wider class of transitional and debris-type disks, and how differential heating of the dust may reveal properties not otherwise detected spectroscopically. As the system moves to quadrature in coming years, continued observing opportunities will continue to exist. I am grateful for support from the estate of William Herschel Womble for astronomy at the University of Denver, which has made possible two decades of research on this star that otherwise has revealed its secrets only very slowly.

STRUCTURE AND DYNAMICS OF THE 2012 NOVEMBER 13/14 ECLIPSE WHITE-LIGHT CORONA

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

Pasachoff, J. M.; Rušin, V.; Saniga, M.

2015-02-20

Continuing our series of observations of coronal motion and dynamics over the solar-activity cycle, we observed from sites in Queensland, Australia, during the 2012 November 13 (UT)/14 (local time) total solar eclipse. The corona took the low-ellipticity shape typical of solar maximum (flattening index ε = 0.01), a change from the composite coronal images we observed and analyzed in this journal and elsewhere for the 2006 and 2008-2010 eclipses. After crossing the northeast Australian coast, the path of totality was over the ocean, so further totality was seen only by shipborne observers. Our results include velocities of a coronal massmore » ejection (CME; during the 36 minutes of passage from the Queensland coast to a ship north of New Zealand, we measured 413 km s{sup –1}) and we analyze its dynamics. We discuss the shapes and positions of several types of coronal features seen on our higher-resolution composite Queensland coronal images, including many helmet streamers, very faint bright and dark loops at the bases of helmet streamers, voids, and radially oriented thin streamers. We compare our eclipse observations with models of the magnetic field, confirming the validity of the predictions, and relate the eclipse phenomenology seen with the near-simultaneous images from NASA's Solar Dynamics Observatory (SDO/AIA), NASA's Extreme Ultraviolet Imager on Solar Terrestrial Relations Observatory, ESA/Royal Observatory of Belgium's Sun Watcher with Active Pixels and Image Processing (SWAP) on PROBA2, and Naval Research Laboratory's Large Angle and Spectrometric Coronagraph Experiment on ESA's Solar and Heliospheric Observatory. For example, the southeastern CME is related to the solar flare whose origin we trace with a SWAP series of images.« less

Cognitive aspects of ancient Maya eclipse theory.

NASA Astrophysics Data System (ADS)

Closs, M. P.

This paper is concerned with determining the nature of eclipse phenomena as it was perceived by the ancient Maya. It approaches the problem by considering the linguistic information pertaining to eclipses and by exploring the traditional beliefs associated with the occurrence of eclipses among the postconquest Maya. These data yield a model of a native eclipse theory which is compatible with hieroglyphic and iconographic materials pertaining to the ancient Maya.

The Araucaria project. The distance to the small Magellanic Cloud from late-type eclipsing binaries

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

Graczyk, Dariusz; Pietrzyński, Grzegorz; Gieren, Wolfgang

2014-01-01

We present a distance determination to the Small Magellanic Cloud (SMC) based on an analysis of four detached, long-period, late-type eclipsing binaries discovered by the Optical Gravitational Lensing Experiment (OGLE) survey. The components of the binaries show negligible intrinsic variability. A consistent set of stellar parameters was derived with low statistical and systematic uncertainty. The absolute dimensions of the stars are calculated with a precision of better than 3%. The surface brightness-infrared color relation was used to derive the distance to each binary. The four systems clump around a distance modulus of (m – M) = 18.99 with a dispersionmore » of only 0.05 mag. Combining these results with the distance published by Graczyk et al. for the eclipsing binary OGLE SMC113.3 4007, we obtain a mean distance modulus to the SMC of 18.965 ± 0.025 (stat.) ± 0.048 (syst.) mag. This corresponds to a distance of 62.1 ± 1.9 kpc, where the error includes both uncertainties. Taking into account other recent published determinations of the SMC distance we calculated the distance modulus difference between the SMC and the Large Magellanic Cloud equal to 0.458 ± 0.068 mag. Finally, we advocate μ{sub SMC} = 18.95 ± 0.07 as a new 'canonical' value of the distance modulus to this galaxy.« less

BVRI Photometric Study of the High Mass Ratio, Detached, Pre-contact W UMa Binary GQ Cancri

NASA Astrophysics Data System (ADS)

Samec, R. G.; Olson, A.; Caton, D.; Faulkner, D. R.

2017-12-01

CCD BVRcIc light curves of GQ Cancri were observed in April 2013 using the SARA North 0.9-meter Telescope at Kitt Peak National Observatory in Arizona in remote mode. It is a high-amplitude (V 0.9 magnitude) K0±V type eclipsing binary (T1 5250 K) with a photometrically-determined mass ratio of M2 / M1 = 0.80. Its spectral color type classifies it as a pre-contact W UMa Binary (PCWB). The Wilson-Devinney Mode 2 solutions show that the system has a detached binary configuration with fill-outs of 94% and 98% for the primary and secondary component, respectively. As expected, the light curve is asymmetric due to spot activity. Three times of minimum light were calculated, for two primary eclipses and one secondary eclipse, from our present observations. In total, some 26 times of minimum light covering nearly 20 years of observation were used to determine linear and quadratic ephemerides. It is noted that the light curve solution remained in a detached state for every iteration of the computer runs. The components are very similar with a computed temperature difference of only 4 K, and the flux of the primary component accounts for 53±55% of the system's light in B, V, Rc, and Ic. A 12-degree radius high latitude white spot (faculae) was iterated on the primary component.

WW Geminorum: An Early B-type Eclipsing Binary Evolving into the Contact Phase

NASA Astrophysics Data System (ADS)

Yang, Y.-G.; Yang, Y.; Dai, H.-F.; Yin, X.-G.

2014-11-01

WW Gem is a B-type eclipsing binary with a period of 1.2378 days. The CCD photometry of this binary was performed in 2013 December using the 85 cm telescope at the Xinglong Stations of the National Astronomical Observatories of China. Using the updated W-D program, the photometric model was deduced from the VRI light curves. The results imply that WW Gem is a near-contact eclipsing binary whose primary component almost fills its Roche lobe. The photometric mass ratio is q ph = 0.48(± 0.05). All collected times of minimum light, including two new ones, were used for the period studies. The orbital period changes of WW Gem could be described by an upward parabola, possibly overlaid by a light-time orbit with a period of P mod = 7.41(± 0.04) yr and a semi-amplitude of A = 0.0079 days(± 0.0005 days), respectively. This kind of cyclic oscillation may be attributed to the light-travel time effect via the third body. The long-term period increases at a rate of dP/dt = +3.47(±0.04) × 10-8 day yr-1, which may be explained by the conserved mass transfer from the less massive component to the more massive one. With mass transfer, the massive binary WW Gem may be evolving into a contact binary.

The extraneous eclipses on binary light curves: KIC 5255552, KIC 10091110, and KIC 11495766

NASA Astrophysics Data System (ADS)

Zhang, J.; Qian, S. B.; Wang, S. M.; Sun, L. L.; Wu, Y.; Jiang, L. Q.

2018-03-01

Aims: We aim to find more eclipsing multiple systems and obtain their parameters, thus increasing our understanding of multiple systems. Methods: The extraneous eclipses on the Kepler binary light curves indicating extraneous bodies were searched. The binary light curves were analyzed using the binary model, and the extraneous eclipses were studied on their periodicity and shape changes. Results: Three binaries with extraneous eclipses on the binary light curves were found and studied based on the Kepler observations. The object KIC 5255552 is an eclipsing triple system with a fast changing inner binary and an outer companion uncovered by three groups of extraneous eclipses of 862.1(±0.1) d period. The KIC 10091110 is suggested to be a double eclipsing binary system with several possible extraordinary coincidences: the two binaries share similar extremely small mass ratios (0.060(13) and 0.0564(18)), similar mean primary densities (0.3264(42) ρ⊙ and 0.3019(28) ρ⊙), and, most notably, the ratio of the two binaries' periods is very close to integer 2 (8.5303353/4.2185174 = 2.022). The KIC 11495766 is a probable triple system with a 120.73 d period binary and (at least) one non-eclipse companion. Furthermore, very close to it in the celestial sphere, there is a blended background stellar binary of 8.3404432 d period. A first list of 25 eclipsing multiple candidates is presented, with the hope that it will be beneficial for study of eclipsing multiples.

Using the ionospheric response to the solar eclipse on 20 March 2015 to detect spatial structure in the solar corona.

PubMed

Scott, C J; Bradford, J; Bell, S A; Wilkinson, J; Barnard, L; Smith, D; Tudor, S

2016-09-28

The total solar eclipse that occurred over the Arctic region on 20 March 2015 was seen as a partial eclipse over much of Europe. Observations of this eclipse were used to investigate the high time resolution (1 min) decay and recovery of the Earth's ionospheric E-region above the ionospheric monitoring station in Chilton, UK. At the altitude of this region (100 km), the maximum phase of the eclipse was 88.88% obscuration of the photosphere occurring at 9:29:41.5 UT. In comparison, the ionospheric response revealed a maximum obscuration of 66% (leaving a fraction, Φ, of uneclipsed radiation of 34±4%) occurring at 9:29 UT. The eclipse was re-created using data from the Solar Dynamics Observatory to estimate the fraction of radiation incident on the Earth's atmosphere throughout the eclipse from nine different emission wavelengths in the extreme ultraviolet (EUV) and X-ray spectrum. These emissions, having varying spatial distributions, were each obscured differently during the eclipse. Those wavelengths associated with coronal emissions (94, 211 and 335 Å) most closely reproduced the time varying fraction of unobscured radiation observed in the ionosphere. These results could enable historic ionospheric eclipse measurements to be interpreted in terms of the distribution of EUV and X-ray emissions on the solar disc.This article is part of the themed issue 'Atmospheric effects of solar eclipses stimulated by the 2015 UK eclipse'. © 2016 The Author(s).

78 FR 49908 - Airworthiness Directives; Eclipse Aerospace, Inc. Airplanes

Federal Register 2010, 2011, 2012, 2013, 2014

2013-08-16

... Airworthiness Directives; Eclipse Aerospace, Inc. Airplanes AGENCY: Federal Aviation Administration (FAA), DOT. ACTION: Final rule. SUMMARY: We are adopting a new airworthiness directive (AD) for all Eclipse Aerospace... Eclipse Aerospace, Inc., 26 East Palatine Road, Wheeling, Illinois 60090; telephone: (877) 373-7978...

The near-infrared properties of compact binary systems

NASA Astrophysics Data System (ADS)

Froning, Cynthia Suzanne

I present H- and K-band light curves of the dwarf nova cataclysmic variable (CV), IP Peg, and the novalike CV, RW Tri, and an H-band light curve of the novalike CV, SW Sex. All three systems showed contributions from the late-type secondary star and the accretion disk, including a primary eclipse of the accretion disk by the secondary star and a secondary eclipse of the star by the disk. The ellipsoidal variations of the secondary star in IP Peg were modeled and subtracted from the data. The subtracted light curves show a pronounced double-hump variation, resembling those seen in the dwarf novae WZ Sge and AL Com. The primary eclipse was modeled using maximum entropy disk mapping techniques. The accretion disk has a flat intensity distribution and a low brightness temperature (Tbr ~= 3000-4000 K). Superimposed on the face of the disk is the bright spot, where the mass accretion stream impacts the disk; the position of the bright spot is different from the range of positions seen at visible wavelengths. The near-infrared accretion disk flux is dominated by optically thin emission. The eclipse depth is too shallow to be caused by a fully opaque accretion disk. The NIR light curves in RW Tri show a deep primary eclipse of the accretion disk, ellipsoidal variations from the secondary star, a secondary eclipse, and strong flickering in the disk flux. The depth of the secondary eclipse indicates that the accretion disk is opaque. The light curve also has a hump extending from φ = 0.1-0.9 which was successfully modeled as flux from the inner face of the secondary star when heated by a ~0.2 L Lsolar source. The radial brightness temperature profile of the outer disk is consistent with models of a disk in steady-state for a mass transfer rate of M~=5×10- 10 Msolaryr- 1 . At small disk radii, however, the brightness temperature profile is flatter than the steady-state model. The H-band light curve of SW Sex is dominated by emission from the accretion disk. As in RW Tri, the light curve has a hump outside of primary eclipse which was modeled as flux from the secondary star when irradiated by a 0.2-0.3 Lsolar source. The light curve has a dip at φ = 0.5 which is consistent with an eclipse of the irradiated face of the secondary star by an opaque accretion disk. The accretion disk has a brightness temperature profile much flatter than the theoretical profile of a steady- state disk. The disk is asymmetric, with the front of the disk (the side facing the secondary star at mid-eclipse) hotter than the back. The bright spot, which appears in visible disk maps of SW Sex, is not seen in the NIR light curve. I also present H-band light curves of the X-ray binary system, A0620-00, and NIR spectra of two X-ray binaries, CI Cam, and the relativistic jet source, SS 433. (Abstract shortened by UMI.)

Public Education and Outreach for Observing Solar Eclipses and Transits

NASA Astrophysics Data System (ADS)

Pasachoff, Jay M.

2015-08-01

The general public is often very interested in observing solar eclipses, with widespread attention from newspapers and other sources often available only days before the events. Recently, the 2012 eclipse's partial phases in Australia and the 2015 eclipse's partial phases throughout Europe as well as western Asia and northern Africa, were widely viewed. The 21 August 2017 eclipse, whose totality will sweep across the Continental United States from northwest to southeast, will have partial phases visible throughout the U.S., Canada, Mexico, Central America, and into South America. The 2019 and 2020 partial phases of total eclipses will be visible throughout South America, and partial phases from annular eclipses will be visible from other parts of the world. The 9 May 2016 transit of Mercury will be best visible from the Western Hemisphere, Europe, and Africa. Many myths and misunderstandings exist about the safety of observing partial phases, and it is our responsibility as astronomers and educators to transmit accurate information and to attempt the widest possible distribution of such information. The Working Group on Public Education at Eclipses and Transits, formerly of Commission 46 on Education and Development and now of New Commission 11, tries to coordinate the distribution of information. In collaboration with the Solar Division's Working Group on Solar Eclipses, their website at http://eclipses.info is a one-stop shop for accurate information on how to observe eclipses, why it is interesting to do so, where they will be visible (with links to online maps and weather statistics), and how encouraging students to observe eclipses can be inspirational for them, perhaps even leading them to realize that the Universe can be understood and therefore renewing the strength of their studies. Links to information about transits of Mercury and Venus are also included.

Campaign Photometry During The 2010 Eclipse Of Epsilon Aurigae

NASA Astrophysics Data System (ADS)

Hopkins, Jeff; Stencel, R. E.

2011-01-01

Epsilon Aurigae is a long period (27.1 years) eclipsing binary star system with an eclipse that lasts nearly 2 years, but with severe ambiguities about component masses and shape. The current eclipse began on schedule in August of 2009. During the previous, 1982-1984 eclipse, an International Campaign was formed to coordinate a detailed study of the system. While that Campaign was deemed successful, the evolutionary status of the star system remained unclear. Epsilon Aurigae has been observed nearly continuously since the 1982 eclipse. The current Campaign was officially started in 2006. In addition to a Yahoo forum we have a dedicated web site and more than 18 online newsletters reporting photometry, spectroscopy, interferometry and polarimetry data. High quality UBVRIJH band photometric data since before the start of the current eclipse has been submitted. We explore the color differences among the light curves in terms of eclipse phases and archival data. At least one new model of the star system has been proposed since the current Campaign began: a low mass but very high luminosity F star plus a B star surrounded by a debris disk. The current eclipse and in particular the interferometry and spectroscopic data have caused new thoughts on defining eclipsing variable star contact points and phases of an eclipse. Second contact may not be the same point as start of totality and third contact may not be the same point as the start of egress and end of totality. In addition, the much awaited mid-eclipse brightening may or may not have appeared. This paper identifies the current Campaign contributors and the photometric data. This work was supported in part by the bequest of William Herschel Womble in support of astronomy at the University of Denver, by NSF grant 1016678 to the University of Denver.

Solar Eclipses and the International Year of Astronomy

NASA Astrophysics Data System (ADS)

Pasachoff, Jay M.

2009-05-01

Solar eclipses capture the attention of millions of people in the countries from which they are visible and provide a major opportunity for public education, in addition to the scientific research and student training that they provide. The 2009 International Year of Astronomy began with an annular eclipse visible from Indonesia on 26 January, with partial phases visible also in other parts of southeast Asia. On 22 July, a major and unusually long total solar eclipse will begin at dawn in India and travel across China, with almost six minutes of totality visible near Shanghai and somewhat more visible from Japanese islands and from ships at sea in the Pacific. Partial phases will be visible from most of eastern Asia, from mid-Sumatra and Borneo northward to mid-Siberia. Eclipse activities include many scientific expeditions and much ecotourism to Shanghai, Hangzhou, and vicinity. My review article on "Eclipses as an Astrophysical Laboratory" will appear in Nature as part of their IYA coverage. Our planetarium presented teacher workshops and we made a film about solar research. Several new books about the corona or eclipses are appearing or have appeared. Many articles are appearing in astronomy magazines and other outlets. Eclipse interviews are appearing on the Planetary Society's podcast "365 Days of Astronomy" and on National Geographic Radio. Information about the eclipse and safe observation of the partial phases are available at http://www.eclipses.info, the Website of the International Astronomical Union's Working Group on Solar Eclipses and of its Program Group on Public Education at the Times of Eclipses of its Commission on Education and Development. The Williams College Expedition to the 2009 Eclipse in the mountains near Hangzhou, China, is supported in part by a grant from the Committee for Research and Exploration of the National Geographic Society. E/PO workshops were supported by NASA.

The eclipse of the Sun from 20 May 2015

NASA Astrophysics Data System (ADS)

Tiron, S. D.

2015-04-01

The interview of the Radio Moldova with astronomer about the coming Eclipse of the Sun, included the following topics: 1) The circumstances of the Total eclipse 2) The circumstances of the Partial Eclipse in the Republic of Moldova 3) Protection of eyes during Observations

Suppression of the Polar Tongue of Ionization During the 21 August 2017 Solar Eclipse

NASA Astrophysics Data System (ADS)

Dang, Tong; Lei, Jiuhou; Wang, Wenbin; Burns, Alan; Zhang, Binzheng; Zhang, Shun-Rong

2018-04-01

It has long been recognized that during solar eclipses, the ionosphere-thermosphere system changes greatly within the eclipse shadow, due to the rapid reduction of solar irradiation. However, the concept that a solar eclipse impacts polar ionosphere behavior and dynamics as well as magnetosphere-ionosphere coupling has not been appreciated. In this study, we investigate the potential impact of the 21 August 2017 solar eclipse on the polar tongue of ionization (TOI) using a high-resolution, coupled ionosphere-thermosphere-electrodynamics model. The reduction of electron densities by the eclipse in the middle latitude TOI source region leads to a suppressed TOI in the polar region. The TOI suppression occurred when the solar eclipse moved into the afternoon sector. The Global Positioning System total electron content observations show similar tendency of polar region total electron content suppression. This study reveals that a solar eclipse occurring at middle latitudes may have significant influences on the polar ionosphere and magnetosphere-ionosphere coupling.

Outreach activities in anticipation of the 2016 solar eclipse in Sorong

NASA Astrophysics Data System (ADS)

Putra Raharja, Endra; Pramudya, Yudhiakto

2016-11-01

Sorong is located outside the narrow path of total solar eclipse on March 9th, 2016. The predicted obscuration of the sun was 94.2%. The public outreach to anticipate the solar eclipse was intended to educate students in junior and senior high school in Sorong Regency. Some of them are located in the remote area where the educational materials are difficult to find. The public outreach is unique, since it was run by the local person who is student of physics education. The student has both the ability to explain the solar eclipse phenomenon and able to adapt to knowledge level of students. The materials that were given to the schools are brochure and the eclipse glasses. Beside solar eclipse lectures in class, the pinhole workshop and observation practice were held. The limited materials and resources were faced during the public outreach. However, the enthusiasm was shown by the students and teachers. At least one of the schools held the solar eclipse observation on the day of the eclipse.

W UMa Type Eclipsing Binary VW Cep

NASA Astrophysics Data System (ADS)

Kang, Bong-Seok; Lee, Yong-Sam; Jeong, Jang-Hae

2000-06-01

A total of 1,018 observations (509 in B, 509 in V ) of the eclipsing binary VW Cep was made during 7 nights from April through May in 1999 at Sobaeksan Optical Astronomy Observatory, using the CCD camera attached to the 61cm telescope. A time of minimum light of HJD2451327.2282 was determined from our data, and we constructed BV light curves with the data. Using Wilson-Devinney's binary model, we analized the light curves. The absolute dimension of M1 = 0.95Msolar, M2 = 0.33Msolar, R1 = 1.02Rsolar, R2 = 0.66Rsolar of the VW Cep system were derived from our light curve solution and Kaszas et al. (1998) spectroscoppic rsult.

Photometric study of the eclipsing binary GR Bootis

NASA Astrophysics Data System (ADS)

Zhang, Z. L.; Zhang, Y. P.; Fu, J. N.; Xue, H. F.

2016-07-01

We present CCD photometry and low-resolution spectra of the eclipsing binary GR Boo. A new ephemeris is determined based on all the available times of the minimum light. The period analysis reveals that the orbital period is decreasing with a rate of dP / dt = - 2.05 ×10-10 d yr-1 . A photometric analysis for the obtained light curves is performed with the Wilson-Devinney Differential Correction program for the first time. The photometric solutions confirm the W UMa-type nature of the binary system. The mass ratio turns out to be q = 0.985 ± 0.001 . The evolutionary status and physical nature of the binary system are briefly discussed.

The 1982 ultraviolet eclipse of the symbiotic binary AR Pav

NASA Technical Reports Server (NTRS)

Hutchings, J. B.; Cowley, A. P.; Ake, T. B.; Imhoff, C. L.

1983-01-01

Observations with the International Ultraviolet Explorer (IUE) of the symbiotic binary AR Pav through its 1982 eclipse show that the hot star is not eclipsed. The hot star is associated with an extended region of continuum emission which is partially eclipsed. The eclipsed radiation is hotter near to its center, with a maximum temperature of about 9000 K. The uneclipsed flux is hotter than this. UV emission lines are not measurably eclipsed and presumably arise in a much larger region than the continuum. These data provide new constraints on models of the system but also are apparently in contradiction to those based on ground-based data.

On the detection and attribution of gravity waves generated by the 20 March 2015 solar eclipse.

PubMed

Marlton, G J; Williams, P D; Nicoll, K A

2016-09-28

Internal gravity waves are generated as adjustment radiation whenever a sudden change in forcing causes the atmosphere to depart from its large-scale balanced state. Such a forcing anomaly occurs during a solar eclipse, when the Moon's shadow cools part of the Earth's surface. The resulting atmospheric gravity waves are associated with pressure and temperature perturbations, which in principle are detectable both at the surface and aloft. In this study, surface pressure and temperature data from two UK sites at Reading and Lerwick are examined for eclipse-driven gravity wave perturbations during the 20 March 2015 solar eclipse over northwest Europe. Radiosonde wind data from the same two sites are also analysed using a moving parcel analysis method, to determine the periodicities of the waves aloft. On this occasion, the perturbations both at the surface and aloft are found not to be confidently attributable to eclipse-driven gravity waves. We conclude that the complex synoptic weather conditions over the UK at the time of this particular eclipse helped to mask any eclipse-driven gravity waves.This article is part of the themed issue 'Atmospheric effects of solar eclipses stimulated by the 2015 UK eclipse'. © 2016 The Authors.

An Outreach Project to Provide 2.1 Million Eclipse Glasses and Eclipse Information through 7,100 Libraries Nationwide

NASA Astrophysics Data System (ADS)

Fraknoi, Andrew; Schatz, Dennis; Dusenbery, Paul; Duncan, Douglas; Holland, Anne; Laconte, Keliann

2018-01-01

With support from the Moore Foundation, Google, the Research Corporation, and NASA, we were able to distribute about 2.1 million eclipse glasses and an extensive booklet of eclipse information and outreach suggestions to 7,100 public libraries throughout the nation. It appears that this project was the single largest program to provide glasses and eclipse information to the public in the U.S. The project using (and significantly enlarged) the existing STARNet network of libraries set up and maintained by the Space Science Institute. We were able to get glasses to a diverse set of institutions, including urban, rural, Native American, small town and large city libraries. In this poster, we will summarize the history of the project, the various components and how they worked together, and the results of a post survey of the librarians, which provided numbers, photographs, and impressions from the many libraries and their patrons. A map of the libraries involved is at www.starnetlibraries.org/2017eclipse/. The booklet of information that was sent to help train librarians in eclipse science and eclipse outreach can still be downloaded free at: http://www.starnetlibraries.org/EclipseGuide/.”

78 FR 30243 - Airworthiness Directives; Eclipse Aerospace, Inc. Airplanes

Federal Register 2010, 2011, 2012, 2013, 2014

2013-05-22

... Airworthiness Directives; Eclipse Aerospace, Inc. Airplanes AGENCY: Federal Aviation Administration (FAA), DOT... (AD) for all Eclipse Aerospace, Inc. Model EA500 airplanes equipped with Avio, Avio with ETT, or Avio... identified in this proposed AD, contact Eclipse Aerospace, Inc. 26 East Palatine Road, Wheeling, Illinois...

Effects of the March 2015 solar eclipse on near-surface atmospheric electricity.

PubMed

Bennett, A J

2016-09-28

Measurements of atmospheric electrical and standard meteorological parameters were made at coastal and inland sites in southern England during the 20 March 2015 partial solar eclipse. Clear evidence of a reduction in air temperature resulting from the eclipse was found at both locations, despite one of them being overcast during the entire eclipse. The reduction in temperature was expected to affect the near-surface electric field (potential gradient (PG)) through a reduction in turbulent transfer of space charge. No such effect could be unambiguously confirmed, however, with variability in PG and air-Earth current during the eclipse being comparable to pre- and post-eclipse conditions. The already low solar radiation for this latitude, season and time of day was likely to have contributed to the reduced effect of the eclipse on atmospheric electricity through boundary layer stability. The absence of a reduction in mean PG shortly after time of maximum solar obscuration, as observed during eclipses at lower geomagnetic latitude, implied that there was no significant change in atmospheric ionization from cosmic rays above background variability. This finding was suggested to be due to the relative importance of cosmic rays of solar and galactic origin at geomagnetic mid-latitudes.This article is part of the themed issue 'Atmospheric effects of solar eclipses stimulated by the 2015 UK eclipse'. © 2016 The Author(s).

Solar Eclipses Observed from Antarctica

NASA Astrophysics Data System (ADS)

Pasachoff, Jay M.

2013-01-01

Aspects of the solar corona are still best observed during totality of solar eclipses, and other high-resolution observations of coronal active regions can be observed with radio telescopes by differentiation of occultation observations, as we did with the Jansky Very Large Array for the annular solar eclipse of 2012 May 20 in the US. Totality crossing Antarctica included the eclipse of 2003 November 23, and will next occur on 2021 December 4; annularity crossing Antarctica included the eclipse of 2008 February 7, and will next occur on 2014 April 29. Partial phases as high as 87% coverage were visible and were imaged in Antarctica on 2011 November 25, and in addition to partial phases of the total and annular eclipses listed above, partial phases were visible in Antarctica on 2001 July 2011, 2002 December 4, 2004 April 19, 2006 September 22, 2007 September 11, and 2009 January 26, and will be visible on 2015 September 13, 2016 September 1, 2017 February 26, 2018 February 15, and 2020 December 14. On behalf of the Working Group on Solar Eclipses of the IAU, the poster showed the solar eclipses visible from Antarctica and this article shows a subset (see www.eclipses.info for the full set). A variety of investigations of the Sun and of the response of the terrestrial atmosphere and ionosphere to the abrupt solar cutoff can be carried out at the future eclipses, making the Antarctic observations scientifically useful.

Ionospheric effects over Europe during the solar eclipse on 20 March 2015

NASA Astrophysics Data System (ADS)

Hoque, Mainul; Jakowski, Norbert; Berdermann, Jens

2017-04-01

A total solar eclipse occurred on March 20, 2015 moving from the North-West Europe towards the North-East. Due to strong solar radiation changes dynamic processes were initiated in the atmosphere and ionosphere causing a measurable impact e.g. on the temperature and ionization during the eclipse. We analyzed the 20 March 2015 solar eclipse effects on the ionospheric structure over Europe using multi-sensor observations such as vertical sounding (VS) and Global Positioning System (GPS) measurements. Whereas the VS measurements are used to provide peak electron density information at the ionospheric F2, F1 and E layers over selected ionosonde stations, a dense network of GPS stations is used to provide high spatial resolution of the total electron content (TEC) estimates over Europe. We reconstructed the TEC maps with 5 minutes time resolution and thus investigated the original TEC maps and differential TEC maps obtained by subtracting 27 days medians from the actual TEC map values on 20 March 2015. By combining VS and GPS measurements the equivalent slab thickness has been estimated over several ionosonde stations to get information how the shape of the vertical electron density profile changes during the eclipse. The analysis of the solar eclipse on 20 March 2015 presented here will contribute to understand the ionospheric response on solar eclipses occurring at different latitudes. The observations indicate that a number of competitive processes initiated by an eclipse are often enhanced by dynamic forces associated with large scale geophysical conditions not directly impacted by the solar eclipse. Our TEC estimation shows that the total ionization reduces up to 60% (after bias correction 40%) as a function of obscuration. Since the 20 March 2015 eclipse occurred during the negative phase of a severe geomagnetic storm on 17 March 2015, the observed TEC depletion is higher than those reported earlier for 1999 and 2005 eclipses. Thus, a negative bias of up to 20% was observed over Northern Europe already before the eclipse occurred. Moreover, the eclipse path of the solar eclipse in 2015 is traced at higher latitudes compared with eclipses observed in the years 1999 and 2005. The ionospheric response to the obscuration function is delayed up to 40 minutes decreasing with growing distance from the totality zone and increasing with altitude. The increasing delay with altitude is in agreement with earlier findings for other eclipses. The equivalent slab thickness was found to increase by approximately 80 -100 km during the solar eclipse on 20 March 2015 showing evidence for a pronounced loss in the bottomside ionosphere causing a delayed depletion of the topside ionosphere.

Public education in developing countries on the occasions of eclipses

NASA Astrophysics Data System (ADS)

Pasachoff, Jay M.

Total solar eclipses will cross southern Africa on June 21, 2001, and on December 4, 2002. Most of Africa will see partial phases. The total phase of the 2001 eclipse will be visible from parts of Angola, Zambia, Zimbabwe, Mozambique and Madagascar. The total phase of the 2002 eclipse will be visible from parts of Angola, Botswana, Zimbabwe, South Africa and Mozambique. Public education must be undertaken to tell the people how to look at the eclipse safely. We can take advantage of having the attention of the people and of news media to teach about not only eclipses but also the rest of astronomy. I am Chair of a "Public Education at Eclipses" subcommission of IAU Commission 46 on the Teaching of Astronomy, and we are able to advise educators and others about materials, procedures and information releases.

Solar Eclipse Effect on Shelter Air Temperature

NASA Technical Reports Server (NTRS)

Segal, M.; Turner, R. W.; Prusa, J.; Bitzer, R. J.; Finley, S. V.

1996-01-01

Decreases in shelter temperature during eclipse events were quantified on the basis of observations, numerical model simulations, and complementary conceptual evaluations. Observations for the annular eclipse on 10 May 1994 over the United States are presented, and these provide insights into the temporal and spatial changes in the shelter temperature. The observations indicated near-surface temperature drops of as much as 6 C. Numerical model simulations for this eclipse event, which provide a complementary evaluation of the spatial and temporal patterns of the temperature drops, predict similar decreases. Interrelationships between the temperature drop, degree of solar irradiance reduction, and timing of the peak eclipse are also evaluated for late spring, summer, and winter sun conditions. These simulations suggest that for total eclipses the drops in shelter temperature in midlatitudes can be as high as 7 C for a spring morning eclipse.

Observing Solar Eclipses in the Developing World

NASA Astrophysics Data System (ADS)

Pasachoff, J. M.

2006-08-01

The paths of totality of total solar eclipses cross the world, with each spot receiving such a view about every 300 years. The areas of the world from which partial eclipses are visible are much wider. For the few days prior to a total eclipse, the attention of a given country is often drawn toward the eclipse, providing a teachable moment that we can use to bring astronomy to the public's attention. Also, it is important to describe how to observe the partial phases of the eclipse safely. Further, it is important to describe to those people in the zone of totality that it is not only safe but also interesting to view totality. Those who are misled by false warnings that overstate the hazards of viewing the eclipse, or that fail to distinguish between safe and unsafe times for naked-eye viewing, may well be skeptical when other health warnings--perhaps about AIDS or malaria prevention or polio inoculations--come from the authorities, meaning that the penalties for misunderstanding the astronomical event can be severe. Through the International Astronomical Union's Working Group on Solar Eclipses and through the I.A.U.'s Program Group on Public Education at the Times of Eclipses, part of the Commission on Education and Development, we make available information to national authorities, to colleagues in the relevant countries, and to others, through our Websites at http://www.eclipses.info and http://www.totalsolareclipse.net and through personal communication. Among our successes at the 29 March 2006 total solar eclipse was the distribution through a colleague in Nigeria of 400,000 eye-protection filters.

75 FR 45075 - Airworthiness Directives; Eclipse Aerospace, Inc. Model EA500 Airplanes

Federal Register 2010, 2011, 2012, 2013, 2014

2010-08-02

... Airworthiness Directives; Eclipse Aerospace, Inc. Model EA500 Airplanes AGENCY: Federal Aviation Administration... in the Federal Register on July 9, 2010 (75 FR 39472), and applies to certain Eclipse Aerospace, Inc... Federal holidays. For service information identified in this proposed AD, contact Eclipse Aerospace, Inc...

Light from Exoplanets: Present and Future

NASA Technical Reports Server (NTRS)

Deming, Leo

2010-01-01

Measurements using the Spitzer Space Telescope have revealed thermal emission from planets orbiting very close to solar-type stars, primarily transiting "hot Jupiter" exoplanets. The thermal emission spectrum of these worlds has been measured by exploiting their secondary eclipse. Also, during transit of the planet, absorption signatures from atoms and molecules in the planet's atmosphere are imprinted onto the spectrum of the star. Results to date from transit and eclipse studies show that the hot Jupiters often have significant haze and cloud components in their atmospheres, and the temperature structure can often be inverted, i.e. temperature is rising with height. New and very strongly irradiated examples of hot Jupiters have been found that are being stripped of their atmospheres by tidal forces from the star. In parallel, transiting superEarth exoplanets are being discovered, and their atmospheres should also be amenable to study using transit techniques. The 2014 launch of the James Webb Space Telescope will clarify the physical nature of hot Jupiters, and will extend transit and eclipse studies to superEarths orbiting in the habitable zones of lower main sequence stars.

The first comprehensive catalog of γ Dor pulsators and their characteristics

NASA Astrophysics Data System (ADS)

Ibanoglu, C.; Çakırlı, Ö.; Sipahi, E.

2018-07-01

We present the first comprehensive catalog of the γ Doradus type pulsating stars. This catalog covers observational properties of all γ Dor variables obtained until January 2017. The photometric and physical properties of 109 well - known γ Dor pulsators, 18 hybrid stars, 13 anomalous γ Dor stars, and 22 γ Dor stars in eclipsing plus 1 non-eclipsing SB2 binary systems are presented as separate tables. In addition, 291 candidate γ Dor variables discovered by CoRot, 307 candidate γ Dor, 205 hybrid and 11 candidate γ Dor in binaries discovered by Kepler were also presented. Distribution of the genuine single γ Dor pulsators in the Ppuls-Teff, Amplitude-Teff, Amplitude-Ppuls and L-Teff diagrams are presented and discussed. We find following correlations for the γ Dor pulsators in the eclipsing binaries: Ppuls ∝ Porb0.27, Ppuls ∝ Q0.45, and Ppuls ∝ r-0.44, where (Q) is the pulsation constant and r is the fractional radius of the pulsating component in the binary system. The correlation coefficients are not high enough due to limited sample and scattering in the data.

Experimental and Monte Carlo evaluation of Eclipse treatment planning system for effects on dose distribution of the hip prostheses

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

Çatlı, Serap, E-mail: serapcatli@hotmail.com; Tanır, Güneş

2013-10-01

The present study aimed to investigate the effects of titanium, titanium alloy, and stainless steel hip prostheses on dose distribution based on the Monte Carlo simulation method, as well as the accuracy of the Eclipse treatment planning system (TPS) at 6 and 18 MV photon energies. In the present study the pencil beam convolution (PBC) method implemented in the Eclipse TPS was compared to the Monte Carlo method and ionization chamber measurements. The present findings show that if high-Z material is used in prosthesis, large dose changes can occur due to scattering. The variance in dose observed in the presentmore » study was dependent on material type, density, and atomic number, as well as photon energy; as photon energy increased back scattering decreased. The dose perturbation effect of hip prostheses was significant and could not be predicted accurately by the PBC method for hip prostheses. The findings show that for accurate dose calculation the Monte Carlo-based TPS should be used in patients with hip prostheses.« less

The Chandra Delta Ori Large Project: Occultation Measurements of the Shocked Gas tn the Nearest Eclipsing O-Star Binary

NASA Technical Reports Server (NTRS)

Corcoran, Michael F.; Nichols, Joy; Naze, Yael; Rauw, Gregor; Pollock, Andrew; Moffat, Anthony; Richardson, Noel; Evans, Nancy; Hamaguchi, Kenji; Oskinova, Lida;

False Positives in Exoplanet Detection

NASA Astrophysics Data System (ADS)

Leuquire, Jacob; Kasper, David; Jang-Condell, Hannah; Kar, Aman; Sorber, Rebecca; Suhaimi, Afiq; KELT (Kilodegree Extremely Little Telescope)

2018-06-01

Our team at the University of Wyoming uses a 0.6 m telescope at RBO (Red Buttes Observatory) to help confirm results on potential exoplanet candidates from low resolution, wide field surveys shared by the KELT (Kilodegree Extremely Little Telescope) team. False positives are common in this work. We carry out transit photometry, and this method comes with special types of false positives. The most common false positive seen at the confirmation level is an EB (eclipsing binary). Low resolution images are great in detecting multiple sources for photometric dips in light curves, but they lack the precision to decipher single targets at an accurate level. For example, target star KC18C030621 needed RBO’s photometric precision to determine there was a nearby EB causing exoplanet type light curves. Identifying false positives with our telescope is important work because it helps eliminate the waste of time taken by more expensive telescopes trying to rule out negative candidate stars. It also furthers the identification of other types of photometric events, like eclipsing binaries, so they can be studied on their own.

The Totality App — General Lessons and Future Eclipses

NASA Astrophysics Data System (ADS)

Bennett, Jeffrey

2018-06-01

With the excitement around the 2017 eclipse, I worked with an app development company to create the Totality app, which featured eclipse predictions from the code of Xavier Jubier. We have since updated the app for future eclipses, including a Spanish version given the upcoming eclipses in Chile/Argentina. I will briefly discuss the current app, the process through which we developed it, and relevant lessons learned along the way that may be useful to others interested in developing apps for astronomy education.

A spectroscopic investigation of the eclipsing binary Epsilon Aurigae

NASA Technical Reports Server (NTRS)

Balachandran, Suchitra

1991-01-01

The objectives were to examine, in detail, the spectra of the eclipsing binary Epsilon Aurigae taken with the IUE satellite telescope during the 1982 to 1984 eclipse. All of the low resolution spectra were analyzed and UV light curves are presented. The primary findings are as follows: (1) a constant eclipse depth from 1600 A to longer wavelengths and a sharp drop in the eclipse depth from 1600 to 1200 A; (2) the absence of large amplitude fluctuations in the UV as expected from a Cepheid primary; and (3) equal ingress and egress times in contradiction to that interpreted from visible light curves. The effects of these findings on the eclipse geometry are being studied.

Eclipses in Australian Aboriginal Astronomy

NASA Astrophysics Data System (ADS)

Hamacher, Duane W.; Norris, Ray P.

2011-07-01

We explore about fifty different Australian Aboriginal accounts of lunar and solar eclipses to determine how Aboriginal groups understood this phenomenon. We summarize the literature on Aboriginal references to eclipses. We show that many Aboriginal groups viewed eclipses negatively, frequently associating them with bad omens, evil magic, disease, blood and death. In many communities, elders or medicine men claimed to be able to control or avert eclipses by magical means, solidifying their roles as providers and protectors within their communities. We also show that some Aboriginal groups seem to have understood the motions of the Sun-Earth-Moon system, the connection between the lunar phases and tides, and acknowledged that solar eclipses were caused by the Moon blocking the Sun.

Eclipse Across America on This Week @NASA – August 25, 2017

NASA Image and Video Library

2017-08-25

The Aug. 21 eclipse across America generated interest and excitement far and wide. Our coverage of the historic eclipse – the first coast-to-coast total solar eclipse for the U.S. in 99 years – was widespread … Anchored from the College of Charleston, in South Carolina – we showed you views of the eclipse that only NASA could. Views from space, from Earth’s atmosphere and from the ground – with expert observation and analysis provided from many of the 14 states around the country, situated along the path of totality. That’s where thousands of people flocked – for the ultimate eclipse experience – total darkness in the middle of the day!

Determination of Spatio-Temporal Characteristics of D-region Electron Density during Annular Solar Eclipse from VLF Network Observations

NASA Astrophysics Data System (ADS)

Basak, T.; Hobara, Y.

2015-12-01

A major part of the path of the annular solar eclipse of May 20, 2012 (magnitude 0.9439) was over southern Japan. The D-region ionospheric changes associated with that eclipse, led to several degree of observable perturbations of sub-ionospheric very low frequency (VLF) radio signal. The University of Electro-Communications (UEC) operates VLF observation network over Japan. The solar eclipse associated signal changes were recorded in several receiving stations (Rx) simultaneously for the VLF signals coming from NWC/19.8kHz, JJI/22.2kHz, JJY/40.0kHz, NLK/24.8kHz and other VLF transmitters (Tx). These temporal dependences of VLF signal perturbation have been analyzed and the spatio-temporal characteristics of respective sub-ionospheric perturbations has already been studied by earlier workers using 2D-Finite Difference Time Domain method of simulation. In this work, we determine the spatial scale, depth and temporal dependence of lower ionospheric perturbation in consistence with umbral and penumbral motion. We considered the 2-parameter D-region ionospheric model with exponential electron density profile. To model the solar obscuration effect over it, we assumed a generalized space-time dependent 2-dimensional elliptical Gaussian distribution for ionospheric parameters, such as, effective reflection height (h') and sharpness factor (β). The depth (△hmax, △βmax), center of shadow (lato(t), lono(t)) and spatial scale (σlat,lon) of that Gaussian distribution are used as model parameters. In the vicinity of the eclipse zone, we compute the VLF signal perturbations using Long Wave Propagation Capability (LWPC) code for several signal propagation paths. The propagation path characteristics, such as, ground and water conductivity and geomagnetic effect on ionosphere are considered from standard LWPC prescriptions. The model parameters are tuned to set an optimum agreement between our computation and observed positive and negative type of VLF perturbations. Thus, appropriate set of parameters lead us to the possible determination of spatial scale, depth and temporal dependence of eclipse associated D-region electron density perturbation solely from the VLF-network observations coupled with theoretical modeling.

The Eclipsing System EP Andromedae and Its Circumbinary Companions

NASA Astrophysics Data System (ADS)

Lee, Jae Woo; Hinse, Tobias Cornelius; Park, Jang-Ho

2013-04-01

We present new long-term CCD photometry for EP And acquired during the period 2007-2012. The light curves display total eclipses at primary minima and season-to-season light variability. Our synthesis for all available light curves indicates that the eclipsing pair is a W-type overcontact binary with parameters of q = 2.578, i = 83.°3, ΔT = 27 K, f = 28%, and l 3 = 2%-3%. The asymmetric light curves in 2007 were satisfactorily modeled by a cool spot on either of the eclipsing components from a magnetic dynamo. Including our 95 timing measurements, a total of 414 times of minimum light spanning about 82 yr was used for a period study. A detailed analysis of the eclipse timing diagram revealed that the orbital period of EP And has varied as a combination of an upward-opening parabola and two periodic variations, with cycle lengths of P 3 = 44.6 yr and P 4 = 1.834 yr and semi-amplitudes of K 3 = 0.0100 days and K 4 = 0.0039 days, respectively. The observed period increase at a fractional rate of +1.39 × 10-10 is in excellent agreement with that calculated from the W-D code and can be plausibly explained by some combination of mass transfer from the primary to the secondary star and angular momentum loss due to magnetic braking. The most reasonable explanation for both cycles is a pair of light-travel-time effects driven by the possible existence of a third and fourth component with projected masses of M 3 = 0.25 M ⊙ and M 4 = 0.90 M ⊙. The more massive companion could be revealed using high-resolution spectroscopic data extending over the course of a few years and could also be a binary itself. It is possible that the circumbinary objects may have played an important role in the formation and evolution of the eclipsing pair, which would cause it to have a short initial orbital period and thus evolve into an overcontact configuration by angular momentum loss.

Recent Observations of the Neglected Southern Eclipsing Binary Systems V343 Cen, UY Mus, HT Aps, and V1961 Sgr

NASA Astrophysics Data System (ADS)

Faulkner, D. R.; Samec, R. G.; Stoddard, M. L.; McKenzie, R.; Rebar, D.; Lavoie, G. D.; Moody, S.; Miller, J.; Van Hamme, W.

2002-12-01

As a part of our continuing search for solar type binaries with impacting gas streams, we present light curves of V343 Cen, UY Mus, HT Aps, and V1961 Sgr. These are all neglected variables whose observing histories show little or no observations since their discovery. The CCD observations were taken at the 0.9-m at CTI0 in the UBVRI Johnson-Cousins system. The observations were taken in on 2002, May 31-June 8 and 2001, May 16 - 23 respectively. UY Mus is a near contact binary with a large difference in eclipse depths of V = 0.67 mag. Otherwise the curve appears symmetric. The times of minimum light determined from our data are HJD Min I = 242047.62316(6) and Min II = 2452050.4874(3) where the value in parentheses is the standard error in the last decimal place. V1961 Sgr (GCVS 6848 485) is a W UMa binary with a difference in eclipse depths of V = 0.11 mag and a possible variable spot area causing a V = 0.04 mag variation in MAX I from night to night. HT Aps is a near contact solar type binary with a large difference in eclipse depths of V= 0.47 mag and a somewhat asymmetric (difference in maxima, V= 0.4 mag) light curve. It is a possibly a candidate for a binary with a gas stream. One time of minimum light determined from our data is HJD Min I = 2452331.63725 (12). V343 Cen is a near contact binary with a large difference in eclipse depths of V= 0.42 mag and distortions that give evidence of a gas stream collision. The difference in maxima is V = 0.07 mag. The curve shows little variation over the 4 day interval of observation. Light curves analyses, new period determinations and photometric data will be presented for these variables. Acknowledgements: We wish to thank the American Astronomical Society for their continued support of our undergraduate research programs through their small research grants. Faulkner and Samec were visiting Astronomers, Cerro Tololo InterAmerican Observatory, National Optical Astronomical Observatories, which are operated by the Association of Universities for Research in Astronomy, Inc. under contract with the National Science Foundation.

KEPLER ECLIPSING BINARIES WITH STELLAR COMPANIONS

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

Gies, D. R.; Matson, R. A.; Guo, Z.

2015-12-15

Many short-period binary stars have distant orbiting companions that have played a role in driving the binary components into close separation. Indirect detection of a tertiary star is possible by measuring apparent changes in eclipse times of eclipsing binaries as the binary orbits the common center of mass. Here we present an analysis of the eclipse timings of 41 eclipsing binaries observed throughout the NASA Kepler mission of long duration and precise photometry. This subset of binaries is characterized by relatively deep and frequent eclipses of both stellar components. We present preliminary orbital elements for seven probable triple stars amongmore » this sample, and we discuss apparent period changes in seven additional eclipsing binaries that may be related to motion about a tertiary in a long period orbit. The results will be used in ongoing investigations of the spectra and light curves of these binaries for further evidence of the presence of third stars.« less

Light curve solutions of the eclipsing eccentric binaries KIC 8111622, KIC 10518735, KIC 8196180 and their out-of-eclipse variability

NASA Astrophysics Data System (ADS)

Kjurkchieva, Diana P.; Vasileva, Doroteya L.

2018-02-01

We determined the orbits and stellar parameters of three eccentric eclipsing binaries by light curve solutions of their Kepler data. KIC 8111622 and KIC 10518735 undergo total eclipses while KIC 8196180 reveals partial eclipses. The target components are G and K stars, excluding the primary of KIC 8196180 which is early F star. KIC 8196180 reveals well-visible tidally-induced feature at periastron, i.e. it is an eclipsing heartbeat star. The characteristics of the observed periastron feature (shape, width and amplitude) confirm the theoretical predictions. There are additional out-of-eclipse variations of KIC 8196180 with the orbital period which may be explained by spot activity of synchronously rotating component. Besides worse visible periastron feature KIC 811162 exhibits small-amplitude light variations whose period is around 2.3 times shorter than the orbital one. These oscillations were attributed to spot(s) on asynchronously rotating component.

Fall 2011 Eclipse Season Begins

NASA Image and Video Library

2017-12-08

The Fall 2011 eclipse season started on September 11. Here is an AIA 171 image from 0657 UT with the first eclipse! SDO has eclipse seasons twice a year near each equinox. For three weeks near midnight Las Cruces time (about 0700 UT) our orbit has the Earth pass between SDO and the Sun. These eclipses can last up to 72 minutes in the middle of an eclipse season. The current eclipse season started on September 11 and lasts until October 4. To read more about SDO go to: sdo.gsfc.nasa.gov/ Credit: NASA/GSFC/SDO NASA Goddard Space Flight Center enables NASA’s mission through four scientific endeavors: Earth Science, Heliophysics, Solar System Exploration, and Astrophysics. Goddard plays a leading role in NASA’s accomplishments by contributing compelling scientific knowledge to advance the Agency’s mission. Follow us on Twitter Like us on Facebook Find us on Instagram

What are the Perspectives of Indonesian Students to Japanese Ritual during Solar Eclipse?

NASA Astrophysics Data System (ADS)

Haristiani, N.; Rusli, A.; Wiryani, A. S.; Nandiyanto, A. B. D.; Purnamasari, A.; Sucahya, T. N.; Permatasari, N.

2018-02-01

In this globalization era, many people still believe the myths about solar eclipse. The myths about solar eclipse are different between one country or are to another. In this context, the aim of this study was to investigate the perspective of Indonesian students in viewing how the Japanese people face their believing myths in solar eclipse. This research also investigated the student belief on several mythical stories in Indonesia, their understanding of the Islamic view, and their knowledge based on science concept relating to the solar eclipse phenomenon. To understand the Indonesian students’ perspective about the solar eclipse myths in Japanese, we took a survey to Indonesian students which are studying Japanese culture and language. Based on the results, the Indonesian student think that there is no significant difference between Indonesian and Japanese people in facing the solar eclipse.

High-speed photometry of the eclipsing dwarf nova OY Carinae

NASA Technical Reports Server (NTRS)

Cook, M. C.

1985-01-01

High-speed photometry of the eclipsing dwarf nova OY Car in the quiescent state is presented. OY Car becomes highly reddened during eclipse, with minimum flux colours inconsistent with optically thick emission in the U and B bandpasses. Mass ratios in the range 6.5 to 12 are required to reconcile the eclipse structure with theoretical gas stream trajectories. Primary eclipse timings reveal a significant decrease in the orbital period and the duration of primary eclipse indicates the presence of a luminous ring about the white dwarf. The hotspot eclipse reveals a hotspot which is elongated along the rim of the accretion disc, with optical emission being non-uniformly distributed along the rim. The location of the hotspot in the accretion disc implies a disc radius larger than that of an inviscid disc, with variation in the position of the hotspot being consistent with a fixed stream trajectory.

Eclipse 2017: Through the eyes of NASA

NASA Astrophysics Data System (ADS)

Mayo, Louis; NASA/GSFC Heliophysics Education Consortium

2016-10-01

The August 21, 2017 eclipse will be the first time a total solar eclipse has traversed the Continental US since June 8th, 1918. Anticipation y for energy for this eclipse is off the charts. Over 500 million in North America alone will catch the eclipse in either partial or total phase. Parts of South America, Africa, and Europe will see a partial eclipse as well. NASA is planning to take full advantage of this unique celestial event as an education and public engagement opportunity by leveraging its extensive networks of partners, numerous social media platforms, broadcast media, and its significant unique space assets and people to bring the eclipse to America and the world as only NASA can. This talk will outline NASA's education plans in some detail replicating our many Big Events successes including the 2012 Transit of Venus and the MSL/Curiosity landing and show how scientists and the public can get involved.

The 2017 Total Solar Eclipse: Through the Eyes of NASA

NASA Astrophysics Data System (ADS)

Young, C. Alex; Mayo, Louis; Ng, Carolyn; Cline, Troy; Lewis, Elaine; Reed, Shannon; Debebe, Asidesach; Stephenson, Bryan; Odenwald, Sten; Hill, Steele; Wright, Ernest

2017-01-01

The August 21, 2017 eclipse will be the first time a total solar eclipse has traversed the Continental US since June 8th, 1918. Anticipation and energy for this eclipse is off the charts! Over 500 million in North America alone will catch the eclipse in either partial or total phase. Parts of South America, Africa, and Europe will see a partial eclipse as well. NASA is planning to take full advantage of this unique celestial event as an education and public engagement opportunity by leveraging its extensive networks of partners, numerous social media platforms, broadcast media, and its significant unique space assets and people to bring the eclipse to America and the world as only NASA can.This talk will outline NASA’s education plans in some detail replicating our many Big Events successes including the 2012 Transit of Venus and the MSL/Curiosity landing and show how scientists and the public can get involved.

Observations and Analysis of the F-type Near-Contact Binary, NSVS 1054 1123

NASA Astrophysics Data System (ADS)

Caton, Daniel Bruce; Samec, Ronald G.; Faulkner, Danny R.

2018-01-01

NSVS 1054 1123 is a F2±2 type (T~ 6750K) eclipsing binary. It was observed in April and May, 2015 at the Appalachian State University’s Dark Sky Observatory in North Carolina with the 32-inch telescope. Six times of minimum light were determined from our present observations, which include two primary eclipses and four secondary eclipses:HJD Min I = 2457113.9330 ±0. 0.0002, 24 57147.8761 ±0.0001,HJD Min II = 2457117.80391 ±0.0006, 2457136.8600 ±0. 0007, 2457148.77040 ±0.0004, 2457151.7468 ±0.0002In addition, six observations at minima were introduced as low weighted times of minimum light taken from archived NSVS Data.The following quadratic ephemerides was determined from all available times of minimum light:JD Hel Min I=2457147.87646±0.00049d + 0 .5954966±0.0000065 X E -0.0000000017± 0.0000000007 X E2A period decrease may indicate that the binary is undergoing magnetic braking and is approaching its contact configuration. A BVRcIc simultaneous (preliminary) Wilson-Devinney Program (W-D) solution indicates that the system has a mass ratio of 0.5828±0.0004, and a component temperature difference of 2350 K. The large DT in the components verify that the binary is not in contact. A Binary Maker fitted hot spot altered slightly but was not eliminated in the WD Synthetic Light Curve Computations. It remains on the larger component at the equator on the correct (following) side for a stream spot directed from the secondary component (as dictated by the Coriolis effect). This could indicate that the components are near filling their respective Roche Lobes. The fill-out of our model is -0.036 for the primary component and -0.048 for the secondary component. The inclination is ~79 degrees, not enough for the system to undergo a total eclipse.Additional and more detailed information is given in this report.

The MUCHFUSS photometric campaign

NASA Astrophysics Data System (ADS)

Schaffenroth, V.; Geier, S.; Heber, U.; Gerber, R.; Schneider, D.; Ziegerer, E.; Cordes, O.

2018-06-01

Hot subdwarfs (sdO/Bs) are the helium-burning cores of red giants, which have lost almost all of their hydrogen envelope. This mass loss is often triggered by common envelope interactions with close stellar or even substellar companions. Cool companions like late-type stars or brown dwarfs are detectable via characteristic light-curve variations like reflection effects and often also eclipses. To search for such objects, we obtained multi-band light curves of 26 close sdO/B binary candidates from the MUCHFUSS project with the BUSCA instrument. We discovered a new eclipsing reflection effect system (P = 0.168938 d) with a low-mass M dwarf companion (0.116 M⊙). Three more reflection effect binaries found in the course of the campaign have already been published; two of them are eclipsing systems, and in one system only showing the reflection effect but no eclipses, the sdB primary is found to be pulsating. Amongst the targets without reflection effect a new long-period sdB pulsator was discovered and irregular light variations were found in two sdO stars. The found light variations allowed us to constrain the fraction of reflection effect binaries and the substellar companion fraction around sdB stars. The minimum fraction of reflection effect systems amongst the close sdB binaries might be greater than 15% and the fraction of close substellar companions in sdB binaries may be as high as 8.0%. This would result in a close substellar companion fraction to sdB stars of about 3%. This fraction is much higher than the fraction of brown dwarfs around possible progenitor systems, which are solar-type stars with substellar companions around 1 AU, as well as close binary white dwarfs with brown dwarf companions. This might suggest that common envelope interactions with substellar objects are preferentially followed by a hot subdwarf phase.

Solar Eclipse Engagement and Outreach in Madras and Warm Springs, Oregon

NASA Astrophysics Data System (ADS)

Kirk, M. S.; Pesnell, W. D.; Ahern, S.; Boyle, M.; Gonzales, T.; Leone, C.

2017-12-01

The Central Oregon towns of Madras and Warm Springs were in an ideal location to observe the total solar eclipse of 2017. In anticipation of this event, we embarked on a yearlong partnership to engage and excite these communities. We developed educational events for all students in the school district, grades K-12, as well as two evening keynote addresses during an eclipse week in May. This eclipse week provided resources, learning opportunities, and safety information for all students and families prior to the end of the school year. With the collaboration of graphic design students at Oregon State University, we produced static educational displays as an introduction to the Museum at Warm Springs' exhibit featuring eclipse art. The weekend before the eclipse, we gave away 15,000 pairs of solar viewing glasses to the local community and manned a science booth at the Oregon Solarfest to engage the arriving eclipse tourists. These efforts culminated on Monday, August 21st with tens of thousands of people viewing eclipse totality in Madras and Warm Springs.

Spatiotemporal change of sky polarization during the total solar eclipse on 29 March 2006 in Turkey: polarization patterns of the eclipsed sky observed by full-sky imaging polarimetry.

PubMed

Sipocz, Brigitta; Hegedüs, Ramón; Kriska, György; Horváth, Gábor

2008-12-01

Using 180 degrees field-of-view (full-sky) imaging polarimetry, we measured the spatiotemporal change of the polarization of skylight during the total solar eclipse on 29 March 2006 in Turkey. We present our observations here on the temporal variation of the celestial patterns of the degree p and angle alpha of linear polarization of the eclipsed sky measured in the red (650 nm), green (550 nm), and blue (450 nm) parts of the spectrum. We also report on the temporal and spectral change of the positions of neutral (unpolarized, p = 0) points, and points with local minima or maxima of p of the eclipsed sky. Our results are compared with the observations performed by the same polarimetric technique during the total solar eclipse on 11 August 1999 in Hungary. Practically the same characteristics of celestial polarization were encountered during both eclipses. This shows that the observed polarization phenomena of the eclipsed sky may be general.

Coordinated weather balloon solar radiation measurements during a solar eclipse.

PubMed

Harrison, R G; Marlton, G J; Williams, P D; Nicoll, K A

2016-09-28

Solar eclipses provide a rapidly changing solar radiation environment. These changes can be studied using simple photodiode sensors, if the radiation reaching the sensors is unaffected by cloud. Transporting the sensors aloft using standard meteorological instrument packages modified to carry extra sensors, provides one promising but hitherto unexploited possibility for making solar eclipse radiation measurements. For the 20 March 2015 solar eclipse, a coordinated campaign of balloon-carried solar radiation measurements was undertaken from Reading (51.44°N, 0.94°W), Lerwick (60.15°N, 1.13°W) and Reykjavik (64.13°N, 21.90°W), straddling the path of the eclipse. The balloons reached sufficient altitude at the eclipse time for eclipse-induced variations in solar radiation and solar limb darkening to be measured above cloud. Because the sensor platforms were free to swing, techniques have been evaluated to correct the measurements for their changing orientation. In the swing-averaged technique, the mean value across a set of swings was used to approximate the radiation falling on a horizontal surface; in the swing-maximum technique, the direct beam was estimated by assuming that the maximum solar radiation during a swing occurs when the photodiode sensing surface becomes normal to the direction of the solar beam. Both approaches, essentially independent, give values that agree with theoretical expectations for the eclipse-induced radiation changes.This article is part of the themed issue 'Atmospheric effects of solar eclipses stimulated by the 2015 UK eclipse'. © 2016 The Authors.

The National Eclipse Weather Experiment: an assessment of citizen scientist weather observations

PubMed Central

2016-01-01

The National Eclipse Weather Experiment (NEWEx) was a citizen science project designed to assess the effects of the 20 March 2015 partial solar eclipse on the weather over the United Kingdom (UK). NEWEx had two principal objectives: to provide a spatial network of meteorological observations across the UK to aid the investigation of eclipse-induced weather changes, and to develop a nationwide public engagement activity-based participation of citizen scientists. In total, NEWEx collected 15 606 observations of air temperature, cloudiness and wind speed and direction from 309 locations across the UK, over a 3 h window spanning the eclipse period. The headline results were processed in near real time, immediately published online, and featured in UK national press articles on the day of the eclipse. Here, we describe the technical development of NEWEx and how the observations provided by the citizen scientists were analysed. By comparing the results of the NEWEx analyses with results from other investigations of the same eclipse using different observational networks, including measurements from the University of Reading’s Atmospheric Observatory, we demonstrate that NEWEx provided a fair representation of the change in the UK meteorological conditions throughout the eclipse. Despite the simplicity of the approach adopted, robust reductions in both temperature and wind speed during the eclipse were observed. This article is part of the themed issue ‘Atmospheric effects of solar eclipses stimulated by the 2015 UK eclipse’. PMID:27550767

Using the ionospheric response to the solar eclipse on 20 March 2015 to detect spatial structure in the solar corona

PubMed Central

Bradford, J.; Bell, S. A.; Wilkinson, J.; Smith, D.; Tudor, S.

2016-01-01

The total solar eclipse that occurred over the Arctic region on 20 March 2015 was seen as a partial eclipse over much of Europe. Observations of this eclipse were used to investigate the high time resolution (1 min) decay and recovery of the Earth’s ionospheric E-region above the ionospheric monitoring station in Chilton, UK. At the altitude of this region (100 km), the maximum phase of the eclipse was 88.88% obscuration of the photosphere occurring at 9:29:41.5 UT. In comparison, the ionospheric response revealed a maximum obscuration of 66% (leaving a fraction, Φ, of uneclipsed radiation of 34±4%) occurring at 9:29 UT. The eclipse was re-created using data from the Solar Dynamics Observatory to estimate the fraction of radiation incident on the Earth’s atmosphere throughout the eclipse from nine different emission wavelengths in the extreme ultraviolet (EUV) and X-ray spectrum. These emissions, having varying spatial distributions, were each obscured differently during the eclipse. Those wavelengths associated with coronal emissions (94, 211 and 335 Å) most closely reproduced the time varying fraction of unobscured radiation observed in the ionosphere. These results could enable historic ionospheric eclipse measurements to be interpreted in terms of the distribution of EUV and X-ray emissions on the solar disc. This article is part of the themed issue ‘Atmospheric effects of solar eclipses stimulated by the 2015 UK eclipse’. PMID:27550766

Student artistry sparks eclipse excitement on Maui: NSO/DKIST EPO for the 2016 Partial Solar Eclipse

NASA Astrophysics Data System (ADS)

Schad, Thomas A.; Penn, Matthew J.; Armstrong, James

2016-05-01

Local creativity and artistry is a powerful resource that enhances education programs and helps us generate excitement for science within our communities. In celebration of the 2016 Solar Eclipse, the National Solar Observatory (NSO) and its Daniel K Inouye Solar Telescope (DKIST) project were pleased to engage with students across Maui County, Hawai`i, via the 2016 Maui Eclipse Art Contest. With the help of the Maui Economic Development Board and the University of Hawai'is Institute for Astronomy, we solicited art entries from all K-12 schools in Maui County approximately 6 months prior to the eclipse. Along with divisional prizes, a grand prize was selected by a panel of local judges, which was subsequently printed on 25,000 solar eclipse viewing glasses and distributed to all Maui students. We found that the impact of a locally-sourced glasses design cannot be understated. Overall, the success of this program relied upon reaching out to individual teachers, supplying educational flyers to all schools, and visiting classrooms. On the day of the eclipse, all of the art entries were prominently displayed during a community eclipse viewing event at Kalama Beach Park in Kihei, HI, that was co-hosted by NSO and the Maui Science Center. This eclipse art contest was integral to making local connections to help promote science education on Maui, and we suggest that it could be adapted to the solar community's EPO activities for the upcoming 2017 Great American Solar Eclipse.

Preparing for the Great American Eclipse of Aug. 21: for Yourself, and for Holding an Event for the Public and Students.

NASA Astrophysics Data System (ADS)

Duncan, D. K.

2016-12-01

On Aug. 21, 2017 a Total Eclipse of the Sun will cross the US. For the first time in 40 years every state will have at least 80% of the sun covered by the moon, and lucky people from Oregon to South Carolina will see the beauty of the total eclipse and remember it all their lives. It is as difficult to convey the impression of a total eclilpse as it is to convey what the Grand Canyon is like. Words cannot do it justice. It looks like the end of the world as the flames of solar prominances rise from the edge of the "black hole" of the eclipsed sun, and silver streamers of the sun's corona stretch across the sky. People scream, applaud, or cry. Animals do strange things. At a total eclipse in the Galapagos dozens of whales and dolphins surfaced at the time of the total elcipse, surrounded our boat, and after the eclipse swam away. At a partial eclipse, even a 99% eclipse, those spectacular aspects are not seen, so it is a good idea to make plans to go to where the eclipse is total. This session will use examples from 10 total eclipses the author has viewed and made available to the public, since March 7, 1970, to suggest practical preparations for the evnt. Advice will be given on how and where to see the eclipse yourself, and how to help the public, teachers, and students where you live enjoy the spectacle and raise their interest in science. It is hoped that by the time of the AGU meeting "Kits" of educational materials and safe eclipse-watching glasses will be available to AGU members. This will be discussed. A Public Service Announcement suitable for use on television, the Internet, or in schools should also be available.

Line Identifications in the Far Ultraviolet Spectrum of the Eclipsing Binary System 31 Cygni

NASA Astrophysics Data System (ADS)

Hagen Bauer, Wendy; Bennett, P. D.

2011-05-01

The eclipsing binary system 31 Cygni (K4 Ib + B3 V) was observed at several phases with the Far Ultraviolet Spectrosocopic Explorer (FUSE) satellite. During total eclipse, a rich emission spectrum was observed, produced by scattering of hot star photons in the extended wind of the K supergiant. The system was observed during deep chromospheric eclipse, and 2.5 months after total eclipse ended. We present an atlas of line identifications in these spectra. During total eclipse, emission features from C II , C III, N I, N II, N III, O I, Si II, P II, P III, S II, S III, Ar I, Cr III, Fe II, Fe III, and Ni II were detected. The strongest emission features arise from N II. These lines appear strongly in absorption during chromospheric eclipse, and even 2.5 months after total eclipse, the absorption bottoms out on the underlying emission seen during total eclipse. The second strongest features in the emission spectrum arise from Fe III. Any chromospheric Fe III absorption is buried within strong chromospheric absorption from other species, mainly Fe II. The emission profiles of most of the doubly-ionized species are red-shifted relative to the systemic velocity, with asymmetric profiles with a steeper long-wavelength edge. Emission profiles from singly-ionized species tend to be more symmetric and centered near the systemic velocity. In deep chromospheric eclipse, absorption features are seen from neutral and singly-ionized species, arising from lower levels up to 3 eV. Many strong chromospheric features are doubled in the observation obtained during egress from eclipse. The 31 Cygni spectrum taken 2.5 months after total eclipse ended ws compared to single-star B spectra from the FUSE archives. There was still some additional chromospheric absorption from strong low-excitation Fe II, O I and Ar I.

Changes of atmospheric properties over Belgrade, observed using remote sensing and in situ methods during the partial solar eclipse of 20 March 2015

NASA Astrophysics Data System (ADS)

Ilić, L.; Kuzmanoski, M.; Kolarž, P.; Nina, A.; Srećković, V.; Mijić, Z.; Bajčetić, J.; Andrić, M.

2018-06-01

Measurements of atmospheric parameters were carried out during the partial solar eclipse (51% coverage of solar disc) observed in Belgrade on 20 March 2015. The measured parameters included height of the planetary boundary layer (PBL), meteorological parameters, solar radiation, surface ozone and air ions, as well as Very Low Frequency (VLF, 3-30 kHz) and Low Frequency (LF, 30-300 kHz) signals to detect low-ionospheric plasma perturbations. The observed decrease of global solar and UV-B radiation was 48%, similar to the solar disc coverage. Meteorological parameters showed similar behavior at two measurement sites, with different elevations and different measurement heights. Air temperature change due to solar eclipse was more pronounced at the lower measurement height, showing a decrease of 2.6 °C, with 15-min time delay relative to the eclipse maximum. However, at the other site temperature did not decrease; its morning increase ceased with the start of the eclipse, and continued after the eclipse maximum. Relative humidity at both sites remained almost constant until the eclipse maximum and then decreased as the temperature increased. The wind speed decreased and reached minimum 35 min after the last contact. The eclipse-induced decrease of PBL height was about 200 m, with minimum reached 20 min after the eclipse maximum. Although dependent on UV radiation, surface ozone concentration did not show the expected decrease, possibly due to less significant influence of photochemical reactions at the measurement site and decline of PBL height. Air-ion concentration decreased during the solar eclipse, with minimum almost coinciding with the eclipse maximum. Additionally, the referential Line-of-Sight (LOS) radio link was set in the area of Belgrade, using the carrier frequency of 3 GHz. Perturbation of the receiving signal level (RSL) was observed on March 20, probably induced by the solar eclipse. Eclipse-related perturbations in ionospheric D-region were detected based on the VLF/LF signal variations, as a consequence of Lyα radiation decrease.

Fifty year canon of solar eclipses: 1986-2035

NASA Technical Reports Server (NTRS)

Espenak, Fred

1986-01-01

A reference of moderately detailed eclipse predictions and maps for use by the professional astronomical community is provided. The general characteristics of every solar eclipse and a detailed set of cylindrical project world maps which show the umbral paths of every solar eclipse from 1901 to 2100 are presented. The geodetic path coordinates and local circumstance on the center line, and a series of orthographic projection maps which show the regions of visibility of both partial and central phases for every eclipse from 1986 through 2035 are also provided.

Resource Letter OSE-1: Observing Solar Eclipses

NASA Astrophysics Data System (ADS)

Pasachoff, Jay M.; Fraknoi, Andrew

2017-07-01

This Resource Letter provides a guide to the available literature, listing selected books, articles, and online resources about scientific, cultural, and practical issues related to observing solar eclipses. It is timely, given that a total solar eclipse will cross the continental United States on August 21, 2017. The next total solar eclipse path crossing the U.S. and Canada will be on April 8, 2024. In 2023, the path of annularity of an annular eclipse will cross Mexico, the United States, and Canada, with partial phases visible throughout those countries.

Lunar eclipses: Probing the atmosphere of an inhabited planet

NASA Astrophysics Data System (ADS)

García Muñoz, A.

2013-04-01

The Moon's brightness during a lunar eclipse is indicative of the composition, cloudiness and aerosol loading of the Earth's atmosphere. The idea of using lunar eclipse observations to characterize the Earth's atmosphere is not new, but the interest raised by the prospects of discovering Earth-like exoplanets transiting their host stars has brought renewed attention to the method. We review some recent efforts made in the prediction and interpretation of lunar eclipses. We also comment on the contribution of the lunar eclipse theory to the refractive theory of planetary transits.

Moon eclipse from 21 december 2010 in Romania

NASA Astrophysics Data System (ADS)

Gaina, Alex; Haus, Marian; Conovici, Matei; Vasiliu, Dan

2010-12-01

The authors discuss the Total Moon's eclipse from 21 december 2010, their circumstances for Romania and Central Europe. One notes that the informations from the NASA eclipses website do not inform correctly about the observability of the initial penumbral phase (P1-U1) of the eclipse. The same reffer to the Anuarul Astronomic Roman, published by the Institutul Astronomic Roman for 2010. By contrary the web site by Fred Espenac informed correctly the astronomical community. The Moon setted before the begining of the penumbral phase of the eclipse.

Total Solar Eclipse of 2008 August 01

NASA Technical Reports Server (NTRS)

Espenak, F.; Anderson, J.

2007-01-01

On 2008 August 01, a total eclipse of the Sun is visible from within a narrow corridor that traverses half the Earth. The path of the Moon's umbral shadow begins in northern Canada and extends across Greenland, the Arctic, central Russia, Mongolia, and China. A partial eclipse is seen within the much broader path of the Moon's penumbral shadow, which includes northeastern North America, most of Europe and Asia. Detailed predictions for this event are presented and include besselian elements, geographic coordinates of the path of totality, physical ephemeris of the umbra, topocentric limb profile corrections, local circumstances for 308 cities, maps of the eclipse path, weather prospects, the lunar limb profile and the sky during totality. Information on safe eclipse viewing and eclipse photography is included.

Structure in the Disk of epsilon Aurigae -- Analysis of ARCES and TripleSpec data from the 2010 eclipse

NASA Astrophysics Data System (ADS)

Gibson, Justus; Stencel, Robert E.; ARCES Team; Ketzeback, W.; Barentine, J.; Bradley, A.; Coughlin, J.; Dembicky, J.; Hawley, S.; Huehnerhoff, J.; Leadbeater, R.; McMillan, R.; Saurage, G.; Schmidt, S.; Ule, N.; Wallerstein, G.; York, D.

2018-06-01

Worldwide interest in the recent eclipse of epsilon Aurigae resulted in the generation of several extensive data sets, including high resolution spectroscopic monitoring. This lead to the discovery, among other things, of the existence of a mass transfer stream, seen notably during third contact. We explored spectroscopic facets of the mass transfer stream during third contact, using high resolution spectra obtained with the ARCES and TripleSpec instruments at Apache Point Observatory. One hundred and sixteen epochs of data were obtained between 2009 and 2012, and equivalent widths and line velocities measured for high versus low eccentricity accretion disk lines. These datasets also enable greater detail to be measured of the mid-eclipse enhancement of the He I 10830A line, and the discovery of the P Cygni shape of the Pa-beta line at third contact. We found evidence of higher speed material, associated with the mass transfer stream, persisting between third and fourth eclipse contacts. We visualized the disk and stream interaction using SHAPE software, and used CLOUDY software to estimate that the source of the enhanced He I 10830A absorption arises from a region with log nH = 11 cm-3 and temperature of 20,000 K, consistent with a mid-B type central star. We thank the following for their contributions to this paper: William Ketzeback, John Barentine, Jeffrey Coughlin, Robin Leadbeater, Gabrelle Saurage, and others. This paper has been submitted to Monthly Notices.

WW Geminorum: An early B-type eclipsing binary evolving into the contact phase

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

Yang, Y.-G.; Dai, H.-F.; Yin, X.-G.

2014-11-01

WW Gem is a B-type eclipsing binary with a period of 1.2378 days. The CCD photometry of this binary was performed in 2013 December using the 85 cm telescope at the Xinglong Stations of the National Astronomical Observatories of China. Using the updated W-D program, the photometric model was deduced from the VRI light curves. The results imply that WW Gem is a near-contact eclipsing binary whose primary component almost fills its Roche lobe. The photometric mass ratio is q {sub ph} = 0.48(± 0.05). All collected times of minimum light, including two new ones, were used for the periodmore » studies. The orbital period changes of WW Gem could be described by an upward parabola, possibly overlaid by a light-time orbit with a period of P {sub mod} = 7.41(± 0.04) yr and a semi-amplitude of A = 0.0079 days(± 0.0005 days), respectively. This kind of cyclic oscillation may be attributed to the light-travel time effect via the third body. The long-term period increases at a rate of dP/dt = +3.47(±0.04) × 10{sup –8} day yr{sup –1}, which may be explained by the conserved mass transfer from the less massive component to the more massive one. With mass transfer, the massive binary WW Gem may be evolving into a contact binary.« less

Discovery and Characterization of Eclipsing Binary Stars and Transiting Planets in Young Benchmark Clusters: The Pleiades and Hyades

NASA Astrophysics Data System (ADS)

Stassun, Keivan; David, Trevor J.; Conroy, Kyle E.; Hillenbrand, Lynne; Stauffer, John R.; Pepper, Joshua; Rebull, Luisa M.; Cody, Ann Marie

2016-06-01

Prior to K2, only one eclipsing binary in the Pleiades was known (HD 23642). We present the discovery and characterization of three additional eclipsing binaries (EBs) in this ~120 Myr old benchmark open cluster. Unlike HD 23642, all three of the new EBs are low mass (Mtot < 1 M⊙) and thus their components are still undergoing pre-main-sequence contraction at the Pleiades age. Low mass EBs are rare, especially in the pre-main-sequence phase, and thus these systems are valuable for constraining theoretical stellar evolution models. One of the three new EBs is single-lined with a K-type primary (HII 2407). The second (HCG 76) comprises two nearly equal-mass 0.3 M⊙ stars, with masses and radii measured with precisions of better than 3% and 5%, respectively. The third (MHO 9) has an M-type primary with a secondary that is possibly quite close to the hydrogen-burning limit, but needs additional follow-up observations to better constrain its parameters. We use the precise parameters of HCG 76 to test the predictions of stellar evolution models, and to derive an independent distance to the Pleiades of 132±5 pc. Finally, we present tentative evidence for differential rotation in the primary component of the newly discovered Pleiades EB HII 2407, and we also characterize a newly discovered transiting Neptune-sized planet orbiting an M-dwarf in the Hyades.

HD 66051, an eclipsing binary hosting a highly peculiar, HgMn-related star.

PubMed

Niemczura, Ewa; Hümmerich, Stefan; Castelli, Fiorella; Paunzen, Ernst; Bernhard, Klaus; Hambsch, Franz-Josef; Hełminiak, Krzysztof

2017-07-19

HD 66051 is an eclipsing system with an orbital period of about 4.75 d that exhibits out-of-eclipse variability with the same period. New multicolour photometric observations confirm the longevity of the secondary variations, which we interpret as a signature of surface inhomogeneities on one of the components. Using archival and newly acquired high-resolution spectra, we have performed a detailed abundance analysis. The primary component is a slowly rotating late B-type star (T eff  = 12500 ± 200 K; log g = 4.0, v sin i = 27 ± 2 km s -1 ) with a highly peculiar composition reminiscent of the singular HgMn-related star HD 65949, which seems to be its closest analogue. Some light elements as He, C, Mg, Al are depleted, while Si and P are enhanced. Except for Ni, all the iron-group elements, as well as most of the heavy elements, and in particular the REE elements, are overabundant. The secondary component was estimated to be a slowly rotating A-type star (T eff  ~ 8000 K; log g = 4.0, v sin i ~ 18 km s -1 ). The unique configuration of HD 66051 opens up intriguing possibilities for future research, which might eventually and significantly contribute to the understanding of such diverse phenomena as atmospheric structure, mass transfer, magnetic fields, photometric variability and the origin of chemical anomalies observed in HgMn stars and related objects.

Public Education Plans for the 2017 August 21 Total Solar Eclipse

NASA Astrophysics Data System (ADS)

Pasachoff, Jay M.

2016-06-01

A total solar eclipse will cross the continental United States on 2017 August 21, the first such in 99 years and the first whose path of totality on land is entirely in the United States since 1776. People in the rest of the United States-as well as in Canada, Central America, and northern South America-will have a partial solar eclipse. Totality will range up to about 70 km in diameter, and will be visible from a path that extends from Oregon to South Carolina. Cloudiness statistics based on decades on satellite infrared imaging are more favorable for western sites. The sun's diameter will be 80% covered in Miami (south of totality) and New York (north of totality), and 70% covered in Los Angeles (south of totality). For the Working Group on Solar Eclipses of the International Astronomical Union, I maintain a website at http://eclipses.info that provides links to a wide variety of eclipse-related material and to useful websites run by others.Prior to this total eclipse, annular eclipses will cross Africa (from Gabon to Tanzania and Madagascar) and Isle de la Réunion on 2016 September 1, and Chile and Argentina on 2017 February 26, at which time we plan an eclipse workshop in Esquel, Argentina.For the forthcoming 2017 eclipse, we acknowledge grants to JMP and Williams College from the Solar Terrestrial Program of the Atmospheric and Geospace Sciences Division of the National Science Foundation and from the Committee for Research and Exploration of the National Geographic Society.

78 FR 46295 - Special Conditions: Eclipse, EA500, Certification of Autothrottle Functions Under Part 23

Federal Register 2010, 2011, 2012, 2013, 2014

2013-07-31

... supplemental type certificate for an update to the aircraft software to activate the previously installed...Airspeeds ACE-05-34: 14 CFR Sec. 23.181(b), Dynamic Stability ACE-05-35: 14 CFR Sec. 23.1353(h), Storage... defined in 14 CFR 11.19, in accordance with Sec. 11.38, and they become part of the type- certification...

The 2017 Solar Eclipse Community Impacts through Public Library Engagement

NASA Astrophysics Data System (ADS)

Dusenbery, P.; Holland, A.; LaConte, K.; Mosshammer, G.; Harold, J. B.; Fraknoi, A.; Schatz, D.; Duncan, D. K.

2017-12-01

More than two million pairs of eclipse glasses were distributed free through public libraries in the U.S. for the solar eclipse of the Sun taking place on August 21, 2017. About 7,000 organizations, including public library branches, bookmobiles, tribal libraries, library consortia, and state libraries took part in the celestial event of the century. Many organizations received a package of free safe-viewing glasses, plus a 24-page information booklet about eclipse viewing and suggested program ideas. An educational video was also produced on how best to do public outreach programs about the eclipse. The project was supported, in part, by the Gordon and Betty Moore Foundation, with additional help from Google, NASA, the Research Corporation, and the National Science Foundation (NSF). The program was managed through the Space Science Institute's National Center for Interactive Learning as part of its STAR Library Network (STAR_Net). Resources developed by STAR_Net for this event included an Eclipse Resource Center; a newsletter for participating libraries to learn about eclipses and how to implement an effective and safe eclipse program; eclipse program activities on its STEM Activity Clearinghouse; webinars; and connections to subject matter experts from NASA's and the American Astronomical Society's volunteer networks. This presentation will provide an overview of the extensive collaboration that made this program possible as well as highlight the national impact that public libraries made in their communities.

Eclipse-induced wind changes over the British Isles on the 20 March 2015

PubMed Central

2016-01-01

The British Isles benefits from dense meteorological observation networks, enabling insights into the still-unresolved effects of solar eclipse events on the near-surface wind field. The near-surface effects of the solar eclipse of 20 March 2015 are derived through comparison of output from the Met Office’s operational weather forecast model (which is ignorant of the eclipse) with data from two meteorological networks: the Met Office’s land surface station (MIDAS) network and a roadside measurement network operated by Vaisala. Synoptic-evolution relative calculations reveal the cooling and increase in relative humidity almost universally attributed to eclipse events. In addition, a slackening of wind speeds by up to about 2 knots in already weak winds and backing in wind direction of about 20° under clear skies across middle England are attributed to the eclipse event. The slackening of wind speed is consistent with the previously reported boundary layer stabilization during eclipse events. Wind direction changes have previously been attributed to a large-scale ‘eclipse-induced cold-cored cyclone’, mountain slope flows, and changes in the strength of sea breezes. A new explanation is proposed here by analogy with nocturnal wind changes at sunset and shown to predict direction changes consistent with those observed. This article is part of the themed issue ‘Atmospheric effects of solar eclipses stimulated by the 2015 UK eclipse’. PMID:27550759

Is an eclipse described in the Odyssey?

PubMed

Baikouzis, Constantino; Magnasco, Marcelo O

2008-07-01

Plutarch and Heraclitus believed a certain passage in the 20th book of the Odyssey ("Theoclymenus's prophecy") to be a poetic description of a total solar eclipse. In the late 1920s, Schoch and Neugebauer computed that the solar eclipse of 16 April 1178 B.C.E. was total over the Ionian Islands and was the only suitable eclipse in more than a century to agree with classical estimates of the decade-earlier sack of Troy around 1192-1184 B.C.E. However, much skepticism remains about whether the verses refer to this, or any, eclipse. To contribute to the issue independently of the disputed eclipse reference, we analyze other astronomical references in the Epic, without assuming the existence of an eclipse, and search for dates matching the astronomical phenomena we believe they describe. We use three overt astronomical references in the epic: to Boötes and the Pleiades, Venus, and the New Moon; we supplement them with a conjectural identification of Hermes's trip to Ogygia as relating to the motion of planet Mercury. Performing an exhaustive search of all possible dates in the span 1250-1115 B.C., we looked to match these phenomena in the order and manner that the text describes. In that period, a single date closely matches our references: 16 April 1178 B.C.E. We speculate that these references, plus the disputed eclipse reference, may refer to that specific eclipse.

ION Configuration Editor

NASA Technical Reports Server (NTRS)

Borgen, Richard L.

2013-01-01

The configuration of ION (Inter - planetary Overlay Network) network nodes is a manual task that is complex, time-consuming, and error-prone. This program seeks to accelerate this job and produce reliable configurations. The ION Configuration Editor is a model-based smart editor based on Eclipse Modeling Framework technology. An ION network designer uses this Eclipse-based GUI to construct a data model of the complete target network and then generate configurations. The data model is captured in an XML file. Intrinsic editor features aid in achieving model correctness, such as field fill-in, type-checking, lists of valid values, and suitable default values. Additionally, an explicit "validation" feature executes custom rules to catch more subtle model errors. A "survey" feature provides a set of reports providing an overview of the entire network, enabling a quick assessment of the model s completeness and correctness. The "configuration" feature produces the main final result, a complete set of ION configuration files (eight distinct file types) for each ION node in the network.

Star-spot distributions and chromospheric activity on the RS CVn type eclipsing binary SV Cam

NASA Astrophysics Data System (ADS)

Şenavcı, H. V.; Bahar, E.; Montes, D.; Zola, S.; Hussain, G. A. J.; Frasca, A.; Işık, E.; Yörükoǧlu, O.

2018-06-01

Using a time series of high-resolution spectra and high-quality multi-colour photometry, we reconstruct surface maps of the primary component of the RS CVn type rapidly rotating eclipsing binary, SV Cam (F9V + K4V). We measure a mass ratio, q, of 0.641(2) using our highest quality spectra and obtain surface brightness maps of the primary component, which exhibit predominantly high-latitude spots located between 60° - 70° latitudes with a mean filling factor of ˜35%. This is also indicated by the R-band light curve inversion, subjected to rigourous numerical tests. The spectral subtraction of the Hα line reveals strong activity of the secondary component. The excess Hα absorption detected near the secondary minimum hints to the presence of cool material partially obscuring the primary star. The flux ratios of Ca II IRT excess emission indicate that the contribution of chromospheric plage regions associated with star-spots is dominant, even during the passage of the filament-like absorption feature.

Configuring Eclipse for GMAT Builds: Instructions for Windows Users, Rev. 0.3

NASA Technical Reports Server (NTRS)

Conway, Darrel J.

2007-01-01

This document provides instructions about how to configure the Eclipse IDE to build GMAT on Windows based PCs. The current instructions are preliminary; the Windows builds using Eclipse are currently a bit crude. These instructions are intended to give you enough information to get Eclipse setup to build wxWidgets based executables in general, and GMAT in particular.

Eclipsing cataclysmic variables. Deep eclipses in H0928+501. YY Draconis, the whirling dervish. New x ray pulsar candidates from HEAO-1

NASA Technical Reports Server (NTRS)

Patterson, Joseph

1993-01-01

The status report covering the period from 1 June 1992 to 31 May 1993 is included. Areas of research include: (1) eclipsing cataclysmic variables; (2) deep eclipses in H0928+501; (3) YY Draconis, the Whirling Dervish; and (4) new x ray pulsar candidates from HEAO-1.

The Astrophysics of the Solar Corona at the August 21, 2017, American Total Solar Eclipse

NASA Astrophysics Data System (ADS)

Pasachoff, Jay

2017-01-01

The first total solar eclipse to cross the United States from coast to coast in 99 years will occur on August 21, 2017, with a 70-mile-wide path of totality from Oregon to South Carolina, with cloudiness statistics more favorable in the northwest than in the southeast. I will discuss a series of observations of the solar corona made during recent solar eclipses and related spacecraft observations. I will further discuss plans for using the 2017 eclipse for furthering our studies of the heating of the solar corona to millions of kelvins, of the dynamics of coronal mass ejections and polar plumes, and of the response of the corona to the solar magnetic field. I will conclude by discussing public-education plans for the eclipse, during which the whole U.S., Mexico, Central America, and Canada will enjoy a partial eclipse. My work at solar eclipses has recently been supported by the NSF and the Committee for Research and Exploration of the National Geographic Society, and I thank them both for research grants for our scientific studies of the 2017 total eclipse, including AGS-1602461 from the NSF and 987816 from National Geographic.

On the detection and attribution of gravity waves generated by the 20 March 2015 solar eclipse

PubMed Central

2016-01-01

Internal gravity waves are generated as adjustment radiation whenever a sudden change in forcing causes the atmosphere to depart from its large-scale balanced state. Such a forcing anomaly occurs during a solar eclipse, when the Moon’s shadow cools part of the Earth’s surface. The resulting atmospheric gravity waves are associated with pressure and temperature perturbations, which in principle are detectable both at the surface and aloft. In this study, surface pressure and temperature data from two UK sites at Reading and Lerwick are examined for eclipse-driven gravity wave perturbations during the 20 March 2015 solar eclipse over northwest Europe. Radiosonde wind data from the same two sites are also analysed using a moving parcel analysis method, to determine the periodicities of the waves aloft. On this occasion, the perturbations both at the surface and aloft are found not to be confidently attributable to eclipse-driven gravity waves. We conclude that the complex synoptic weather conditions over the UK at the time of this particular eclipse helped to mask any eclipse-driven gravity waves. This article is part of the themed issue ‘Atmospheric effects of solar eclipses stimulated by the 2015 UK eclipse’. PMID:27550763

Confirming Variability in the Secondary Eclipse Depth of the Rocky Super-Earth 55 Cancri e

NASA Astrophysics Data System (ADS)

Tamburo, Patrick; Mandell, Avi; Deming, Drake; Garhart, Emily

2017-01-01

We present a reanalysis of Spitzer transit and secondary eclipse observations of the rocky super Earth 55 Cancri e using Pixel Level Decorrelation (Deming et al. 2015). Secondary eclipses of this planet were found to be significantly variable by Demory et al. (2016), implying a changing brightness temperature which could be evidence of volcanic activity due to tidal forces. If genuine, this result would represent the first evidence for such a process outside of bodies in our own solar system, and would further expand our understanding of the huge variety of planetary systems that can develop in our universe. Spitzer eclipse observations, however, are subject to strong systematic effects which can heavily impact the retrieved eclipse model. A reanalysis of this result with an independent method is therefore needed to confirm eclipse depth variability. We tentatively confirm variability, finding a shallower increase in eclipse depth over the course of observations compared to Demory et al. (2015).

The 1st of April 2470 BC Total Solar Eclipse Seen by the Prophet Ibraheem

NASA Astrophysics Data System (ADS)

Yousef, S. M.

The Holy Quran describes a phenomenon seen by young Abraham that can only fit a solar eclipse. Two criteria were given for this particular eclipse; first only one planet was seen as soon as it got dark and second no corona was seen. In order to justify the first selection rule, examinations of solar and planetary longitudes for total solar eclipses passing over Babel were carried out. Only the eclipse of the 1st of April 2470 BC meets this condition, as it was only Venus that was seen at that eclipse. The second selection rule was also naturally fulfilled, as Babel happened to be on the border of the totality zone hence no corona was seen, however all the time the moon glistened as Baily's beads. There is no doubt that the prophet Abraham witnessed the 1st of April total solar eclipse that passed over Babel. This will put him about 470 years backward than it was previously anticipated.

Modeling the Effects of Asynchronous Rotation on Secondary Eclipse Timings in HW VIr Binaries

NASA Astrophysics Data System (ADS)

Clancy, Padraig

2018-01-01

HW Vir binaries are post common envelope binaries consisting of a hot subdwarf and red dwarf, with light curves dominated by primary eclipses, a strong reflection effect, and secondary eclipses. They have orbital periods ranging from a few hours to half a day and are generally thought to be tidally locked; most studies assume both synchronous rotation and zero eccentricity when modeling HW Vir light curves and radial velocities. Their stable eclipse timings are frequently used in O-C studies to look for the presence of circumbinary objects, measure evolutionary changes in the orbital period, and even constrain the component masses through Roemer delay measurements of the secondary eclipse. While most systems are probably tidally locked or close to it, even slightly asynchronous rotation could theoretically shift the orbital phase of the reflection effect. Here we investigate how asynchronous rotation might affect measurements of secondary eclipse timings by generating thousands of synthetic light curves with a range of reflection effect phases, fitting eclipse timings, and creating O-C diagrams.

Preparing for Eclipse 2017 on This Week @NASA – August 11, 2017

NASA Image and Video Library

2017-08-11

The Aug. 21 total solar eclipse across America is generating a lot of interest – and a lot of questions. You’ll find answers to many of your eclipse questions at NASA’s Eclipse 2017 website -- eclipse2017.nasa.gov. The site is full of information to help you prepare for this rare celestial event – including eclipse-related activities, events, viewing safety tips, and other resources. Then, on the day of the eclipse, you can see the event “Through the Eyes of NASA” – during a special NASA TV broadcast that includes coast-to-coast coverage from the ground, from the air and from space. Coverage begins with a special pre-show at noon eastern – followed by in-depth coverage at 1pm. You can also watch on Aug. 21 at www.nasa.gov/eclipselive. Also, TDRS-M Update, Webb’s Sunshield Layers Installed, RS-25 Engine Testing Rolls On, and Chief Technologist Visits Industry Partner!

Two Commemorative Expeditions to Celebrate the Return to Totality

NASA Astrophysics Data System (ADS)

Thompson, Kristen; English, Tom

2018-01-01

Throughout history, total solar eclipses have generated excitement across the scientific community, as they provide a unique opportunity to study the Sun’s corona. Occurrences of such events have prompted many American astronomy programs to organize expeditions aimed at studying and photographing the eclipse. Only two observing stations from any of the major 19th and early 20th century eclipse expeditions were once again found in the path of totality of the 21 August 2017 Great American Eclipse. These stations, one in Newberry, SC and the other in Winnsboro, SC, were located in the shadow of the 28 May 1900 eclipse that passed through the southeastern United States from New Orleans to Norfolk. To celebrate this unique opportunity, we organized two expeditions that travelled to these towns to commemorate their return to totality. In this talk, I will describe the circumstances of the 1900 solar eclipse, our modern expeditions, and our effort to bring this eclipse history to life for the community.

HF Band Observations and Modeling of the 2017 Eclipse

NASA Astrophysics Data System (ADS)

Earle, G. D.; Kordella, L.; Han, X.; Moses, M. L.; Sweeney, D.; McGwier, R. W.; Lloyd, W.; Ruohoniemi, J. M.

2017-12-01

A nationwide network of observatories has been created to study the effects of the 2017 eclipse on the F-region of the ionosphere. These include the SuperDARN HF radars in Oregon and Kansas, software defined radios in Oregon, Kansas, and South Carolina, and scintillation receivers placed northward of the central eclipse line across the continent. In this talk we will present data obtained by these systems during the eclipse, and interpret these data using a ray-tracing numerical code in conjunction with the SAMI-3 first principles model. Comparisons to results from the CORS network of GPS-TEC receivers will be made, and the F-region density and altitude perturbations observed during the eclipse will be contrasted with ionosonde data from an eclipse that occurred over the United Kingdom in 1999.

Constructing 'Black Sun': the Documentary Film of the 2012 Eclipses

NASA Astrophysics Data System (ADS)

Holbrook, Jarita

2014-06-01

2012 offered an opportunity that was not to be missed: two solar eclipses. Drs Alphonse Sterling and Hakeem Oluseyi began doing collaborative research during total solar eclipses in 2006 in Ghana. Since then they have continued to do eclipse observation when funds and whether permitted. As a filmmaker, the opportunity to film Sterling and Oluseyi during the 2012 eclipses in Tokyo and Cairns fulfilled the goal of showing the excitement of time-sensitive research, the lives of astrophysicists, and diversity within the astronomy community. As an astrophysicist who did not specialize in solar astrophysics, it was an opportunity for me both to learn and to solidify for the audience what we know about the sun and the importance of eclipse observation. Clips of the film will be included.

Preparing a Nation for the Eclipse of a Generation -

NASA Astrophysics Data System (ADS)

Speck, Angela; Habbal, Shadia; Tresch Fienberg, Richard; Kentrianakis, Michael; Fraknoi, Andrew; Nordgren, Tyler; Penn, Matthew; Pasachoff, Jay M.; Bakich, Michael; Winter, Henry; Gay, Pamela; Motta, Mario

2018-01-01

On August 21st 2017, there was a total solar eclipse visible from a vast swath of the US.In preparation for that event, the American Astronomical society created a taskforce charged with planning for the eclipse for the entire nation. The preparations included interfacing with the public, the media, non-profit organizations and governmental organizations. Preliminary data suggests that nearly 90% of American adults watched the eclipse either directly or via live streams. Moreover, there were no major problems associated with the event, in spite of valiant attempts from, e.g. imprope solar viewing materials. The eclipse offered opportunities for many scientific experiments within and ebyond astronomy. Here we present on the work of the taskforce, and the lessons learned as well as lesser known science experiments undertaken during the eclipse.

Modeling of the Ionospheric Scintillation and Total Electron Content Observations during the 21 August 2017 Total Solar Eclipse

NASA Astrophysics Data System (ADS)

Datta-Barua, S.; Gachancipa, J. N.; Deshpande, K.; Herrera, J. A.; Lehmacher, G. A.; Su, Y.; Gyuk, G.; Bust, G. S.; Hampton, D. L.

2017-12-01

High concentration of free electrons in the ionosphere can cause fluctuations in incoming electromagnetic waves, such as those from the different Global Navigation Satellite Systems (GNSS). The behavior of the ionosphere depends on time and location, and it is highly influenced by solar activity. The purpose of this study is to determine the impact of a total solar eclipse on the local ionosphere in terms of ionospheric scintillations, and on the global ionosphere in terms of TEC (Total Electron Content). The studied eclipse occurred on 21 August 2017 across the continental United States. During the eclipse, we expected to see a decrease in the scintillation strength, as well as in the TEC values. As a broader impact part of our recently funded NSF proposal, we temporarily deployed two GNSS receivers on the eclipse's totality path. One GNSS receiver was placed in Clemson, SC. This is a multi-frequency GNSS receiver (NovAtel GPStation-6) capable of measuring high and low rate scintillation data as well as TEC values from four different GNSS systems. We had the receiver operating before, during, and after the solar eclipse to enable the comparison between eclipse and non-eclipse periods. A twin receiver collected data at Daytona Beach, FL during the same time, where an 85% partial solar eclipse was observed. Additionally, we set up a ground receiver onsite in the path of totality in Perryville, Missouri, from which the Adler Planetarium of Chicago launched a high-altitude balloon to capture a 360-degree video of the eclipse from the stratosphere. By analyzing the collected data, this study looks at the effects of partial and total solar eclipse periods on high rate GNSS scintillation data at mid-latitudes, which had not been explored in detail. This study also explores the impact of solar eclipses on signals from different satellite constellations (GPS, GLONASS, and Galileo). Throughout the eclipse, the scintillation values did not appear to have dramatic changes. However, we observed lower scintillation activity on several satellites from different constellations. For example, between 16 UTC and 22 UTC, there was a slight drop in the S4 scintillation Index (amplitude) values, reaching a local minimum during the time of eclipse totality ( 18:30 UTC). Regarding the Total Electron Content (TEC), which measures the quantity of electrons in the ionosphere, there was a more drastic decrease in the values throughout the partial and total solar eclipse. Additionally, σφ (sigma-phi) values for phase scintillation showed the similar behavior compared to previous few days. This reveals that the solar eclipse did not have a major effect on the phase scintillation. In any case, the totality path was entirely in mid-latitude regions, where phase scintillations are expected to be lower compared to high latitudes.

First Results from the August 21, 2017, Total Solar Eclipse

NASA Astrophysics Data System (ADS)

Pasachoff, Jay M.

2017-08-01

I report on the observations planned and, weather permitting, made from our site in Salem, Oregon, at the August 21, 2017, total solar eclipse. I also give a first report on collaborators' successes, including Megamovie and simultaneous space observations. We also describe our participation in PBS's NOVA on the eclipse that was to be aired on public television on eclipse night. Our eclipse expedition is supported in large part by grants from the Solar Terrestrial Program of the Atmospheric Sciences Division of NSF and by the Committee for Research and Exploration of the National Geographic Society.

Solar diameter measurements from eclipses as a solar variability proxy

NASA Astrophysics Data System (ADS)

Dunham, David W.; Sofia, Sabatino; Guhl, Konrad; Herald, David

The widths of total solar eclipse paths depends on the diameter of the Sun, so if observations are obtained near both the northern and southern limits of the eclipse path, in principle, the angular diameter of the Sun can be measured. Concerted efforts have been made to obtain contact timings from locations near total solar eclipse path edges since the mid 19th century, and Edmund Halley organized a rather successful first effort in 1715. Members of IOTA have been making increasingly sophisticated observations of the Baily's bead phenomena near central solar eclipse path edges since 1970.

The Optical Gravitational Lensing Experiment. Eclipsing Binary Stars in the Large Magellanic Cloud

NASA Astrophysics Data System (ADS)

Wyrzykowski, L.; Udalski, A.; Kubiak, M.; Szymanski, M.; Zebrun, K.; Soszynski, I.; Wozniak, P. R.; Pietrzynski, G.; Szewczyk, O.

2003-03-01

We present the catalog of 2580 eclipsing binary stars detected in 4.6 square degree area of the central parts of the Large Magellanic Cloud. The photometric data were collected during the second phase of the OGLE microlensing search from 1997 to 2000. The eclipsing objects were selected with the automatic search algorithm based on an artificial neural network. Basic statistics of eclipsing stars are presented. Also, the list of 36 candidates of detached eclipsing binaries for spectroscopic study and for precise LMC distance determination is provided. The full catalog is accessible from the OGLE Internet archive.

2017 Total Solar Eclipse

NASA Image and Video Library

2017-08-21

NASA employees and contractors use protective glasses to view a partial solar eclipse from NASA Headquarters Monday, Aug. 21, 2017 in Washington. A total solar eclipse swept across a narrow portion of the contiguous United States from Lincoln Beach, Oregon to Charleston, South Carolina. A partial solar eclipse was visible across the entire North American continent along with parts of South America, Africa, and Europe. Photo Credit: (NASA/Gwen Pitman)

2017 Total Solar Eclipse

NASA Image and Video Library

2017-08-22

NASA employees and contractors use protective glasses to view a partial solar eclipse from NASA Headquarters Tuesday, Aug. 22, 2017 in Washington. A total solar eclipse swept across a narrow portion of the contiguous United States from Lincoln Beach, Oregon to Charleston, South Carolina. A partial solar eclipse was visible across the entire North American continent along with parts of South America, Africa, and Europe. Photo Credit: (NASA/Gwen Pitman)

Solar Eclipse from NASA Goddard

NASA Image and Video Library

2017-08-21

View of the partial solar eclipse from NASA's Goddard Space Flight Center in Greenbelt, Md on Monday, August 21, 2017. A total solar eclipse swept across a narrow portion of the contiguous United States from Lincoln Beach, Oregon to Charleston, South Carolina. A partial solar eclipse was visible across the entire North American continent along with parts of South America, Africa, and Europe. Credit: NASA/Goddard/Rebecca Roth

2017 Total Solar Eclipse

NASA Image and Video Library

2017-08-21

Robert Lightfoot, acting NASA administrator and Thomas Zurbuchen NASA AA for the science mission directorate view a partial eclipse solar eclipse Monday, August 21, 2017, from onboard a NASA Armstrong Flight Research Center’s Gulfstream III 35,000 feet above the Oregon Coast. A total solar eclipse swept across a narrow portion of the contiguous United States from Lincoln Beach, Oregon to Charleston, South Carolina. Photo Credit: (NASA/Carla Thomas)

2017 Total Solar Eclipse

NASA Image and Video Library

2017-08-21

This composite image of nine pictures shows the progression of a partial solar eclipse near Banner, Wyoming on Monday, Aug. 21, 2017. A total solar eclipse swept across a narrow portion of the contiguous United States from Lincoln Beach, Oregon to Charleston, South Carolina. A partial solar eclipse was visible across the entire North American continent along with parts of South America, Africa, and Europe. Photo Credit: (NASA/Joel Kowsky)

Lessons from Distributing Eclipse Glasses: Planning Ahead for April 2024

NASA Astrophysics Data System (ADS)

Bartlett, Jennifer Lynn; Wilson, Teresa; Chizek Frouard, Malynda R.; Phlips, Alan

2018-01-01

In preparation for the 2017 August 21 total solar eclipse across the continental United States, a multifaceted effort encouraged safe public observation of this spectacular event. However, we experienced mixed results distributing free ISO 12312-2 compliant eclipse glasses.On the positive side, we successfully dispensed several hundred in Virginia through in-school programs about the eclipse. We created a 2017-eclipse information sheet to accompany a safe-viewing handout. To facilitate sending glasses home in student backpacks, we wrapped each pair in a double-sided flyer and sealed the bundle in an individual envelope. We also passed out glasses during evening and weekend activities at a planetarium. Religious, business, and educational groups were all excited to receive them as were co-workers, family, and friends.On the negative side, planetarium staff declined to give eclipse glasses to students without a parent due to safety and liability concerns. Then, a day camp returned 200 pairs less than 72 hours before the event for the same reasons. However, we also received several requests from groups that had waited until too late to be accommodated easily.During the week before the eclipse, demand for eclipse glasses in New York, Michigan, Indiana, Illinois, Wisconsin, Minnesota, South Dakota, Nebraska, and Missouri was less than anticipated. While many people were well prepared, the recalls and reported counterfeiting made others suspicious. Concurrently, vendors were offering their remaining stock for $1–10 each.The experiences of the 2017 total solar eclipse, both good and bad, will not completely fade before preparations for 2024 begin. We look forward enthusiastically to sharing that event with as many people as possible and hope that the overall distribution of eclipse glasses goes more smoothly.We thank the AAS for providing 1,000+ of the eclipse glasses we shared, which were donated to them by Google to promote the Eclipse Megamovie project; Rainbow Symphony was the manufacturer. The authors supplemented these with a few personal purchases. AAS, NASA, NSF, American Academies of Ophthalmology and Optometry, and the American Optometric Association jointly disseminated the safe-viewing handout.

Solar Eclipse-Induced Changes in the Ionosphere over the Continental US

NASA Astrophysics Data System (ADS)

Erickson, P. J.; Zhang, S.; Goncharenko, L. P.; Coster, A. J.; Hysell, D. L.; Sulzer, M. P.; Vierinen, J.

2017-12-01

For the first time in 26 years, a total solar eclipse occurred over the continental United States on 21 August 2017, between 16:00-20:00 UT. We report on American solar eclipse observations of the upper atmosphere, conducted by a team led by MIT Haystack Observatory. Efforts measured ionospheric and thermospheric eclipse perturbations. Although eclipse effects have been studied for more than 50 years, recent major sensitivity and resolution advances using radio-based techniques are providing new information on the eclipse ionosphere-thermosphere-mesosphere (ITM) system response. Our study was focused on quantifying eclipse effects on (1) traveling ionospheric disturbances (TIDs) and atmospheric gravity waves (AGWs); (2) spatial ionospheric variations associated with the eclipse; and (3) altitudinal and temporal ionospheric profile variations. We present selected early findings on ITM eclipse response including a dense global network of 6000 GNSS total electron content (TEC) receivers (100 million measurements per day; 1x1 degree spatial grid) and the Millstone Hill and Arecibo incoherent scatter radars. TEC depletions of up to 60% in magnitude were associated with the eclipse umbra and penumbra and consistently trailed the eclipse totality center. TEC enhancements associated with prominent orographic features were observed in the western US due to complex interactions as the lower atmosphere cooled in response to decreasing EUV energy inputs. Strong TIDs in the form of bow waves, stern waves, and a stern wake were observed in TEC data. Altitude-resolved plasma parameter profiles from Millstone Hill saw a nearly 50% decrease in F region electron density in vertical profiles, accompanied by a corresponding 200-250 K decrease in electron temperature. Wide field Millstone Hill radar scans showed similar decreases in electron density to the southwest, maximizing along the line of closest approach to totality. Data is available to the research community through the MIT Haystack Madrigal system. Alongside a summary of observations, we will also present preliminary quantitative comparisons with several ongoing modeling efforts.

Effects of interstellar dust scattering on the X-ray eclipses of the LMXB AX J1745.6-2901 in the Galactic Centre

NASA Astrophysics Data System (ADS)

Jin, Chichuan; Ponti, Gabriele; Haberl, Frank; Smith, Randall; Valencic, Lynne

2018-07-01

AX J1745.6-2901 is an eclipsing low-mass X-ray binary in the Galactic Centre (GC). It shows significant X-ray excess emission during the eclipse phase, and its eclipse light curve shows an asymmetric shape. We use archival XMM-Newton and Chandra observations to study the origin of these peculiar X-ray eclipsing phenomena. We find that the shape of the observed X-ray eclipse light curves depends on both photon energy and the shape of the source extraction region, and also shows differences between the two instruments. By performing detailed simulations for the time-dependent X-ray dust-scattering halo, as well as directly modelling the observed eclipse and non-eclipse halo profiles of AX J1745.6-2901, we obtained solid evidence that its peculiar eclipse phenomena are indeed caused by the X-ray dust scattering in multiple foreground dust layers along the line of sight (LOS). The apparent dependence on the instruments is caused by different instrumental point spread functions. Our results can be used to assess the influence of dust-scattering in other eclipsing X-ray sources, and raise the importance of considering the timing effects of dust-scattering halo when studying the variability of other X-ray sources in the GC, such as Sgr A⋆. Moreover, our study of halo eclipse reinforces the existence of a dust layer local to AX J1745.6-2901 as reported by Jin et al. (2017), as well as identifying another dust layer within a few hundred parsecs to the Earth, containing up to several tens of percent LOS dust, which is likely to be associated with the molecular clouds in the Solar neighbourhood. The remaining LOS dust is likely to be associated with the molecular clouds located in the Galactic disc in-between.

The EB factory project. II. Validation with the Kepler field in preparation for K2 and TESS

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

Parvizi, Mahmoud; Paegert, Martin; Stassun, Keivan G., E-mail: mahmoud.parvizi@vanderbilt.edu

Large repositories of high precision light curve data, such as the Kepler data set, provide the opportunity to identify astrophysically important eclipsing binary (EB) systems in large quantities. However, the rate of classical “by eye” human analysis restricts complete and efficient mining of EBs from these data using classical techniques. To prepare for mining EBs from the upcoming K2 mission as well as other current missions, we developed an automated end-to-end computational pipeline—the Eclipsing Binary Factory (EBF)—that automatically identifies EBs and classifies them into morphological types. The EBF has been previously tested on ground-based light curves. To assess the performancemore » of the EBF in the context of space-based data, we apply the EBF to the full set of light curves in the Kepler “Q3” Data Release. We compare the EBs identified from this automated approach against the human generated Kepler EB Catalog of ∼2600 EBs. When we require EB classification with ⩾90% confidence, we find that the EBF correctly identifies and classifies eclipsing contact (EC), eclipsing semi-detached (ESD), and eclipsing detached (ED) systems with a false positive rate of only 4%, 4%, and 8%, while complete to 64%, 46%, and 32%, respectively. When classification confidence is relaxed, the EBF identifies and classifies ECs, ESDs, and EDs with a slightly higher false positive rate of 6%, 16%, and 8%, while much more complete to 86%, 74%, and 62%, respectively. Through our processing of the entire Kepler “Q3” data set, we also identify 68 new candidate EBs that may have been missed by the human generated Kepler EB Catalog. We discuss the EBF's potential application to light curve classification for periodic variable stars more generally for current and upcoming surveys like K2 and the Transiting Exoplanet Survey Satellite.« less

The Eb Factory Project. Ii. Validation With the Kepler Field in Preparation for K2 and Tess

NASA Astrophysics Data System (ADS)

Parvizi, Mahmoud; Paegert, Martin; Stassun, Keivan G.

2014-12-01

Large repositories of high precision light curve data, such as the Kepler data set, provide the opportunity to identify astrophysically important eclipsing binary (EB) systems in large quantities. However, the rate of classical “by eye” human analysis restricts complete and efficient mining of EBs from these data using classical techniques. To prepare for mining EBs from the upcoming K2 mission as well as other current missions, we developed an automated end-to-end computational pipeline—the Eclipsing Binary Factory (EBF)—that automatically identifies EBs and classifies them into morphological types. The EBF has been previously tested on ground-based light curves. To assess the performance of the EBF in the context of space-based data, we apply the EBF to the full set of light curves in the Kepler “Q3” Data Release. We compare the EBs identified from this automated approach against the human generated Kepler EB Catalog of ˜ 2600 EBs. When we require EB classification with ≥slant 90% confidence, we find that the EBF correctly identifies and classifies eclipsing contact (EC), eclipsing semi-detached (ESD), and eclipsing detached (ED) systems with a false positive rate of only 4%, 4%, and 8%, while complete to 64%, 46%, and 32%, respectively. When classification confidence is relaxed, the EBF identifies and classifies ECs, ESDs, and EDs with a slightly higher false positive rate of 6%, 16%, and 8%, while much more complete to 86%, 74%, and 62%, respectively. Through our processing of the entire Kepler “Q3” data set, we also identify 68 new candidate EBs that may have been missed by the human generated Kepler EB Catalog. We discuss the EBF's potential application to light curve classification for periodic variable stars more generally for current and upcoming surveys like K2 and the Transiting Exoplanet Survey Satellite.

Total Eclipse of the Ballpark: Connecting Space and Sports

NASA Astrophysics Data System (ADS)

Wasser, Molly; Petro, Noah; Jones, Andrea; Bleacher, Lora; Keller, John; Wes Patterson, G.

2018-01-01

The anticipation and excitement surrounding the total solar eclipse of 2017 provided astronomy educators with an incredible platform to share space science with huge audiences. The Public Engagement Team for NASA’s Lunar Reconnaissance Orbiter (LRO) took advantage of this opportunity to share lunar science with the public by highlighting the often-overlooked central player in the eclipse – the Moon. As the sole planetary science representatives on NASA’s Science Mission Directorate eclipse leadership team, the LRO team had limited resources to conduct national public outreach. In order to increase our reach, we found success in partnerships.In early 2017, we began working with Minor League Baseball (MiLB) teams across the path of totality on August eclipse events. These partnerships proved fruitful for both parties. While MiLB is a national organization, each team is deeply rooted in its community. This proved essential as each of our four main MiLB partners handled event logistics, provided facilities, connected NASA Subject Matter Experts (SMEs) with local media, and drew in captive crowds. With this tactic, a handful of NASA representatives were able to reach nearly 30,000 people. In turn, LRO provided engaging educational content relevant to the context, SMEs to guide the eclipse viewing experience, eclipse glasses, and safety information. Our participation drew in an audience who would not typically attend baseball games while we were able to reach individuals who would not normally attend a science event. In addition, the eclipse inspired one team, the Salem-Keizer Volcanoes from Salem, OR, to make baseball history by holding the first ever eclipse delay in professional sports.In this talk, we will present on the benefits of the partnership, offer lessons learned, and suggest ways to get involved for the 2024 eclipse – and all the baseball seasons in between.

Geographically Distributed Citizen Scientist Training for the 2017 Citizen CATE Experiment

NASA Astrophysics Data System (ADS)

Gelderman, Richard; Penn, Matt; Baer, Robert; Isberner, Fred; Pierce, Michael; Walter, Donald K.; Yanamandra-Fisher, Padma; Sheeley, Neil R.

2016-01-01

The solar eclipse of 21 August 2017 will be visible to over a half billion people across the entire North American continent. The roughly 100-mile wide path of totality, stretching from Oregon to South Carolina, will be the destination for tens of millions of people. In the decades since 1979, when the last total solar eclipse was visible from the continental USA, the phenomenon of Internet enabled citizen science has grown to be an accepted mode for science. The Citizen Continental-America Telescopic Eclipse (Citizen CATE) experiment has been funded as one of the three 2017 eclipse related NASA STEM agreements to engage citizen scientists in a unique, cutting-edge solar physics experiment. Teams across the USA will be trained to use standardized refracting telescope and digital imager set-ups to observe the solar corona during the eclipse, acquiring multiple exposures to create one high dynamic range image. After observing during the eclipse, the CATE volunteers will upload the combined image to a cloud-storage site and the CATE team will then work to properly orient and align all the images collected from across the continent to produce a continuous 90-minutes movie. A time-compressed first cut of the entire sequence will be made available to media outlets on the same afternoon of the eclipse, with hope that high quality images will encourage the most accurate coverage of this Great American Eclipse. We discuss overall the project, as well as details of the initial tests of the prototype set-up (including in the Faroe Islands during the March 2015 total solar eclipse) and plans for the future night-time and day-time observing campaigns, and for a handful of observing teams positioned for overlapping observations of the March 2016 total solar eclipse in the South Pacific.

Can Pedagogical Concerns Eclipse Mathematical Knowledge?

ERIC Educational Resources Information Center

Creager, Mark A.; Jacobson, Erik; Aydeniz, Fetiye

2016-01-01

Mathematical knowledge for teaching (MKT) is often thought of as a transformed, mutually-influencing mixture of content and pedagogy. However when individuals' MKT does not integrate content and pedagogy, one type of knowledge can supersede the other, sometimes unconsciously. We exemplify this with Emma, a prospective elementary teacher, whose…

Total Solar Eclipse of 2006 March 29

NASA Technical Reports Server (NTRS)

Espenak, F.; Anderson, J.

2004-01-01

On 2006 March 29, a total eclipse of the Sun will be visible from within a narrow corridor which traverses half the Earth. The path of the Moon's umbral shadow begins in Brazil and extends across the Atlantic, northern Africa, and central Asia where it ends at sunset in western Mongolia. A partial eclipse will be seen within the much broader path of the Moon's penumbral shadow, which includes the northern two thirds of Africa, Europe, and central Asia.Detailed predictions for this event are presented and include besselian elements, geographic coordinates of the path of totality, physical ephemeris of the umbra, topocentric limb profile corrections, local circumstances for approximately 350 cities, maps of the eclipse path, weather prospects, the lunar limb profile, and the sky during totality. Information on safe eclipse viewing and eclipse photography is included.

Solar Eclipse: Concept of “Science” and “Language” Literacy

NASA Astrophysics Data System (ADS)

Haristiani, N.; Zaen, R.; Nandiyanto, A. B. D.; Rusmana, A. N.; Azis, F.; Danuwijaya, A. A.; Abdullah, A. G.

2018-02-01

The purpose of this study was to evaluate the concept of science and language literacy of solar eclipse. The study was conducted through a survey to 250 students with different ages (from 17 to 23 years old), grades, and majors in Universitas Pendidikan Indonesia. The survey was completed with a questionnaire consisting of 41 questions. In the case of the language literacy, experimental results showed that various expressions in facing the solar eclipse phenomenon are found. Relating to the science literacy, most students have good science understanding to the solar eclipse phenomenon. In conclusion, the understanding about the solar eclipse is affected by formal science education and religion understanding that they have been accepted since their childhood. These factors have also influenced the belief of Indonesian people to the solar eclipse myth and the way of expressions a language literacy.

SPECIAL SEMINAR - The NOTTE experiment, or how to become a Total Solar Eclipse chaser

ScienceCinema

None

2017-12-09

The NOTTE experiment (Neutrino Oscillations with Telescope during Total Eclipse) aims at searching for visible photons emitted through a possible radiative decay of solar neutrinos. The experiment and the expeditions organized by a group of physicists and astrophysicists from INFN and INAF Bologna hunting for Total Solar Eclipses from 1998 to 2006 wil be described. The results of observations performed during total solar eclipse expeditions in 2001 (Zambia) and 2006 (Sahara desert, Libya) are presented and a beautiful photo gallery will be shown. Other peculiar observations that can be made during a solar eclipse are also illustrated. The seminar will be followed by a brief presentation of future camps for solar eclipse chasers and scientists organized in 2008 in Russia, Kazakhstan, China and Mongolia, in 2009 in Shanghai and on the Easter Island in 2010.

A study of integrated learning and the value of science in remote education: using the Internet to relay the total solar eclipse of 2001 June 11 in Africa

NASA Astrophysics Data System (ADS)

Takahashi, N.; Agata, H.; Maeda, K.; Okyudo, M..; Yamazaki, Y.

A total solar eclipse was observed on 2001 June 21 in Angola, Zambia, and Zimbabwe in Africa. For the purpose of promotion of science education using a solar eclipse as an educational project, the whole image and an enlarged image of the Sun, that showed the process of an eclipse and how things went in the observation area, were broadcast to the world through the Internet (Live Eclipse). Such images were distributed to four primary schools in Hiroshima and the Science and Technology Museum in Tokyo to give a remote lecture through computers. To find the effectiveness of the lecture, the learning effect on the participating children was examined two times before and after the remote lecture on the solar eclipse.

The Unique Scientific Assets of Multi-Wavelength Total Solar Eclipse Observations

NASA Astrophysics Data System (ADS)

Habbal, S. R.; Druckmuller, M.; Ding, A.

2017-12-01

Total solar eclipses continue to yield new discoveries regarding the dynamics and thermodynamics of the corona, due to the radial span of the field of view available during totality, starting from the solar surface out to several solar radii, and due to the diagnostic potential provided by coronal emission lines. Scientific highlights from past eclipse observations as well as from the 21 August 2017 eclipse, now spanning a solar cycle, will be presented. These include white light and spectral line imaging as well as imaging spectrometry. Emphasis will be placed on the unique insights into the origin of dynamic structures captured in eclipse images, and the temperature distribution in the corona derived from these eclipse observations. Implications of these results for the general problem of coronal heating, as well as for the next generation of space instrumentation will be discussed.

Analysis of ionospheric irregularities during total solar eclipse 2016 based on GNSS observation

NASA Astrophysics Data System (ADS)

Husin, A.; Jiyo; Anggarani, S.; Ekawati, S.; Dear, V.

2016-11-01

A total solar eclipse occurred over Indonesia in the morning hours on 9 March 2016. Ionisations in the ionosphere which is associated with the solar radiation during the total eclipse provided a good opportunity to study the ionospheric irregularities. Using global navigation satellite system (GNSS) data taken from dual-frequency receivers in Manado, we investigated and analysed the total electron content (TEC) perturbations with a time resolution of 60 s to reveal ionospheric irregularities during total eclipse. Result showed that TEC conditions based on IPP were decreased during solar eclipse on March 9, comparing with the neighbour day. The maximum percentage deviation (DTEC) from the average value during eclipse period, 00:00 - 02:40 UT reach -41.5%. The duration of maximum decrement in TEC occurs were around 2-30 minutes after the maximum obscuration.

Total Solar Eclipse of 2002 December 04

NASA Technical Reports Server (NTRS)

Espenak, Fred; Anderson, Jay

2001-01-01

On 2002 December 04, a total eclipse of the Sun will be visible from within a narrow corridor which traverses the Southern Hemisphere. The path of the Moon's umbral shadow begins in the South Atlantic, crosses southern Africa and the Indian Ocean, and ends at sunset in southern Australia. A partial eclipse will be seen within the much broader path of the Moon's penumbral shadow, which includes the southern two thirds of Africa, Antarctica, Indian Ocean and Australia. Detailed predictions for this event are presented and include besselian elements, geographic coordinates of the path of totality, physical ephemeris of the umbra, topocentric limb profile corrections, local circumstances for approximately 400 cities, maps of the eclipse path, weather prospects, the lunar limb profile and the sky during totality. Information on safe eclipse viewing and eclipse photography is included.

Coordinated weather balloon solar radiation measurements during a solar eclipse

PubMed Central

2016-01-01

Solar eclipses provide a rapidly changing solar radiation environment. These changes can be studied using simple photodiode sensors, if the radiation reaching the sensors is unaffected by cloud. Transporting the sensors aloft using standard meteorological instrument packages modified to carry extra sensors, provides one promising but hitherto unexploited possibility for making solar eclipse radiation measurements. For the 20 March 2015 solar eclipse, a coordinated campaign of balloon-carried solar radiation measurements was undertaken from Reading (51.44°N, 0.94°W), Lerwick (60.15°N, 1.13°W) and Reykjavik (64.13°N, 21.90°W), straddling the path of the eclipse. The balloons reached sufficient altitude at the eclipse time for eclipse-induced variations in solar radiation and solar limb darkening to be measured above cloud. Because the sensor platforms were free to swing, techniques have been evaluated to correct the measurements for their changing orientation. In the swing-averaged technique, the mean value across a set of swings was used to approximate the radiation falling on a horizontal surface; in the swing-maximum technique, the direct beam was estimated by assuming that the maximum solar radiation during a swing occurs when the photodiode sensing surface becomes normal to the direction of the solar beam. Both approaches, essentially independent, give values that agree with theoretical expectations for the eclipse-induced radiation changes. This article is part of the themed issue ‘Atmospheric effects of solar eclipses stimulated by the 2015 UK eclipse’. PMID:27550757

Evaluating the Eclipse: How good was it?

NASA Astrophysics Data System (ADS)

Noel-Storr, Jacob; InsightSTEM Evaluation Team

2018-01-01

We present findings from the evaluation program carried out of education, public outreach, and communication activities around the "Great American Eclipse" of August 21, 2017. We include findings drawn from the experiences of 30 participants in planning activities prior to the eclipse and 31 recipients of mini-grants for eclipse activities supported by the American Astronomical Society through a grant from the National Science Foundation. We synthesize evaluations gathered by these and other volunteering organizations to provide a multi-site picture of experiences and learning outcomes at eclipse-related events - both in the path of totality and in partial eclipse settings. We make use of qualitative and quantitative responses representing over 30,000 individuals who observed (or tried to observe) the eclipse. We will share findings from across the range of programs included in our evaluation network along with specific highlights. We emphasize a reflection on the motivation and activity behind the 2017 eclipse, and how to leverage the lessons learned for future events on this scale (such as the eclipse of April 8, 2024) along with messages relevant to other events connected with astronomical phenomena, or in multi-site settings.This work was supported in part by the National Science Foundation under Grant No. 1564535 awarded to the American Astronomical Society. Any opinions, findings, and conclusions or recommendations expressed in this material are those of the author and do not necessarily reflect the views of the National Science Foundation or the American Astronomical Society.

Statistical analysis of geomagnetic field variations during solar eclipses

NASA Astrophysics Data System (ADS)

Kim, Jung-Hee; Chang, Heon-Young

2018-04-01

We investigate the geomagnetic field variations recorded by INTERMAGNET geomagnetic observatories, which are observed while the Moon's umbra or penumbra passed over them during a solar eclipse event. Though it is generally considered that the geomagnetic field can be modulated during solar eclipses, the effect of the solar eclipse on the observed geomagnetic field has proved subtle to be detected. Instead of exploring the geomagnetic field as a case study, we analyze 207 geomagnetic manifestations acquired by 100 geomagnetic observatories during 39 solar eclipses occurring from 1991 to 2016. As a result of examining a pattern of the geomagnetic field variation on average, we confirm that the effect can be seen over an interval of 180 min centered at the time of maximum eclipse on a site of a geomagnetic observatory. That is, demonstrate an increase in the Y component of the geomagnetic field and decreases in the X component and the total strength of the geomagnetic field. We also find that the effect can be overwhelmed, depending more sensitively on the level of daily geomagnetic events than on the level of solar activity and/or the phase of solar cycle. We have demonstrated it by dividing the whole data set into subsets based on parameters of the geomagnetic field, solar activity, and solar eclipses. It is suggested, therefore, that an evidence of the solar eclipse effect can be revealed even at the solar maximum, as long as the day of the solar eclipse is magnetically quiet.

Heliophysics at total solar eclipses

NASA Astrophysics Data System (ADS)

Pasachoff, Jay M.

2017-08-01

Observations during total solar eclipses have revealed many secrets about the solar corona, from its discovery in the 17th century to the measurement of its million-kelvin temperature in the 19th and 20th centuries, to details about its dynamics and its role in the solar-activity cycle in the 21st century. Today's heliophysicists benefit from continued instrumental and theoretical advances, but a solar eclipse still provides a unique occasion to study coronal science. In fact, the region of the corona best observed from the ground at total solar eclipses is not available for view from any space coronagraphs. In addition, eclipse views boast of much higher quality than those obtained with ground-based coronagraphs. On 21 August 2017, the first total solar eclipse visible solely from what is now United States territory since long before George Washington's presidency will occur. This event, which will cross coast-to-coast for the first time in 99 years, will provide an opportunity not only for massive expeditions with state-of-the-art ground-based equipment, but also for observations from aloft in aeroplanes and balloons. This set of eclipse observations will again complement space observations, this time near the minimum of the solar activity cycle. This review explores the past decade of solar eclipse studies, including advances in our understanding of the corona and its coronal mass ejections as well as terrestrial effects. We also discuss some additional bonus effects of eclipse observations, such as recreating the original verification of the general theory of relativity.

Is an eclipse described in the Odyssey?

PubMed Central

Baikouzis, Constantino; Magnasco, Marcelo O.

2008-01-01

Plutarch and Heraclitus believed a certain passage in the 20th book of the Odyssey (“Theoclymenus's prophecy”) to be a poetic description of a total solar eclipse. In the late 1920s, Schoch and Neugebauer computed that the solar eclipse of 16 April 1178 B.C.E. was total over the Ionian Islands and was the only suitable eclipse in more than a century to agree with classical estimates of the decade-earlier sack of Troy around 1192–1184 B.C.E. However, much skepticism remains about whether the verses refer to this, or any, eclipse. To contribute to the issue independently of the disputed eclipse reference, we analyze other astronomical references in the Epic, without assuming the existence of an eclipse, and search for dates matching the astronomical phenomena we believe they describe. We use three overt astronomical references in the epic: to Boötes and the Pleiades, Venus, and the New Moon; we supplement them with a conjectural identification of Hermes's trip to Ogygia as relating to the motion of planet Mercury. Performing an exhaustive search of all possible dates in the span 1250–1115 B.C., we looked to match these phenomena in the order and manner that the text describes. In that period, a single date closely matches our references: 16 April 1178 B.C.E. We speculate that these references, plus the disputed eclipse reference, may refer to that specific eclipse. PMID:18577587

Lunar shadow eclipse prediction models for the Earth orbiting spacecraft: Comparison and application to LEO and GEO spacecrafts

NASA Astrophysics Data System (ADS)

Srivastava, Vineet K.; Kumar, Jai; Kulshrestha, Shivali; Srivastava, Ashutosh; Bhaskar, M. K.; Kushvah, Badam Singh; Shiggavi, Prakash; Vallado, David A.

2015-05-01

A solar eclipse occurs when the Sun, Moon and Earth are aligned in such a way that shadow of the Moon falls on the Earth. The Moon's shadow also falls on the Earth orbiting spacecraft. In this case, the alignment of the Sun, Moon, and spacecraft is similar to that of the Sun, Moon, and Earth but this phenomenon is often referred as a lunar eclipse falling on the spacecraft. Lunar eclipse is not as regular in terms of times of occurrence, duration, and depth as the Earth shadow eclipse and number of its occurrence per orbital location per year ranges from zero to four with an average of two per year; a spacecraft may experience two to three lunar eclipses within a twenty-four hour period [2]. These lunar eclipses can cause severe spacecraft operational problems. This paper describes two lunar shadow eclipse prediction models using a projection map approach and a line of intersection method by extending the Earth shadow eclipse models described by Srivastava et al. [10,11] for the Earth orbiting spacecraft. The attractive feature of both models is that they are much easier to implement. Both mathematical models have been simulated for two Indian low Earth orbiting spacecrafts: Oceansat-2, Saral-1, and two geostationary spacecrafts: GSAT-10, INSAT-4CR. Results obtained by the models compare well with lunar shadow model given by Escobal and Robertson [12], and high fidelity commercial software package, Systems Tool Kit (STK) of AGI.

Massive eclipsing binary candidates

NASA Technical Reports Server (NTRS)

Garrison, R. F.; Schild, R. E.; Hiltner, W. A.

1983-01-01

New UBV data are provided for 63 southern OB stars which are either identified in the survey by Garrison, Hiltner, and Schild as having double lines or are known from Wood et al. to be eclipsing binaries. Twenty of the stars are known eclipsing variables. Four stars, not previously known as eclipsing, have both spectroscopic evidence of duplicity and significant photometric variations. Several additional stars have a marginally significant spread in V magnitude.

2017 Total Solar Eclipse

NASA Image and Video Library

2017-08-21

The Moon is seen passing in front of the Sun during a solar eclipse from Ross Lake, Northern Cascades National Park, Washington on Monday, Aug. 21, 2017. A total solar eclipse swept across a narrow portion of the contiguous United States from Lincoln Beach, Oregon to Charleston, South Carolina. A partial solar eclipse was visible across the entire North American continent along with parts of South America, Africa, and Europe. Photo Credit: (NASA/Bill Ingalls)

2017 Total Solar Eclipse

NASA Image and Video Library

2017-08-21

The Sun is seen as it rises behind Jack Mountain head of the solar eclipse, Monday, Aug. 21, 2017, Ross Lake, Northern Cascades National Park, Washington. A total solar eclipse will sweep across a narrow portion of the contiguous United States from Lincoln Beach, Oregon to Charleston, South Carolina. A partial solar eclipse was visible across the entire North American continent along with parts of South America, Africa, and Europe. Photo Credit: (NASA/Bill Ingalls)

2017 Total Solar Eclipse

NASA Image and Video Library

2017-08-21

This composite image shows the progression of a partial solar eclipse over Ross Lake, in Northern Cascades National Park, Washington on Monday, Aug. 21, 2017. A total solar eclipse swept across a narrow portion of the contiguous United States from Lincoln Beach, Oregon to Charleston, South Carolina. A partial solar eclipse was visible across the entire North American continent along with parts of South America, Africa, and Europe. Photo Credit: (NASA/Bill Ingalls)

New Zealand Astronomy and the 9 September 1885 Total Solar Eclipse

NASA Astrophysics Data System (ADS)

Orchiston, Wayne; Rowe, Glen

The second half of the nineteenth century saw a blossoming of interest in solar eclipses as astronomers tried to establish whether the corona was a solar, lunar or terrestrial phenomenon, and as they investigated the nature of the corona, the chromosphere and prominences. Critical in these investigations were astronomy's newest allies: photography and spectroscopy. Photography was used with great effectiveness throughout the half century, but spectroscopy was first applied during the `Indian eclipse' of 1868. Thereafter, almost every total solar eclipse was subjected to scrutiny, the intensity of which depended upon the duration of the eclipse and the location of its path of totality. The first total solar eclipse visible from New Zealand following European settlement occurred on 9 September 1885, and attracted the attention of professional scientists and amateur astronomers. The centre of the path of totality extended from West Wanganui Inlet on the far northern reaches of the west coast of the South Island to Castle Point on the Wairarapa Coast, and a total eclipse was visible from population centres like Collingwood, Nelson, Picton, Wellington, Otaki, Palmerston North, Wanganui and throughout the Wairarapa. In this chapter we examine this eclipse, in the context of New Zealand astronomy and the international development of solar physics.

EE Cep observations requested for upcoming eclipse

NASA Astrophysics Data System (ADS)

Waagen, Elizabeth O.

2014-07-01

The AAVSO requests observations for the upcoming eclipse of EE Cephei, a long-period eclipsing variable. EE Cep has a period of 2,050 days, and shows strong variations in the eclipse light curve from one event to the next. Observations are needed to study the morphology of the upcoming eclipse, which will be used to better understand the shape of the eclipsing disk and how it precesses. Mid-eclipse is predicted to be August 23, 2014, but the early stages of the eclipse may begin as much as a month earlier. EE Cep is being observed by a number of amateur and professional astronomers using multiple telescopes at multiple wavelengths. Among these is a collaboration (see https://sites.google.com/site/eecep2014campaign/) headed by Cezary Galan at the Nicolaus Copernicus Astronomical Center in Poland; several individual AAVSO observers are already participating in this effort. The AAVSO is not currently a partner in that campaign, but all data submitted to the AAVSO will be publicly available. The AAVSO strongly encourages observers to begin following this star now, and to continue observations into October 2014 at least. Finder charts with sequence may be created using the AAVSO Variable Star Plotter (http://www.aavso.org/vsp). Observations should be submitted to the AAVSO International Database. See full Alert Notice for more details and observations.

Stellar Obliquity and Magnetic Activity of Planet-hosting Stars and Eclipsing Binaries Based on Transit Chord Correlation

NASA Astrophysics Data System (ADS)

Dai, Fei; Winn, Joshua N.; Berta-Thompson, Zachory; Sanchis-Ojeda, Roberto; Albrecht, Simon

2018-04-01

The light curve of an eclipsing system shows anomalies whenever the eclipsing body passes in front of active regions on the eclipsed star. In some cases, the pattern of anomalies can be used to determine the obliquity Ψ of the eclipsed star. Here we present a method for detecting and analyzing these patterns, based on a statistical test for correlations between the anomalies observed in a sequence of eclipses. Compared to previous methods, ours makes fewer assumptions and is easier to automate. We apply it to a sample of 64 stars with transiting planets and 24 eclipsing binaries for which precise space-based data are available, and for which there was either some indication of flux anomalies or a previously reported obliquity measurement. We were able to determine obliquities for 10 stars with hot Jupiters. In particular we found Ψ ≲ 10° for Kepler-45, which is only the second M dwarf with a measured obliquity. The other eight cases are G and K stars with low obliquities. Among the eclipsing binaries, we were able to determine obliquities in eight cases, all of which are consistent with zero. Our results also reveal some common patterns of stellar activity for magnetically active G and K stars, including persistently active longitudes.

Atmospheric boundary layer effects induced by the 20 March 2015 solar eclipse

NASA Astrophysics Data System (ADS)

Gray, Suzanne L.; Harrison, R. Giles

2016-04-01

The British Isles benefits from dense meteorological observation networks, enabling insights into the still-unresolved effects of solar eclipse events on the near-surface wind field. The near-surface effects of the solar eclipse of 20 March 2015 are derived through comparison of output from the Met Office's operational weather forecast model (which is ignorant of the eclipse) with data from two meteorological networks: the Met Office's land surface station (MIDAS) network and a roadside measurement network operated by Vaisala. Synoptic-evolution relative calculations reveal the cooling and increase in relative humidity almost universally attributed to eclipse events. In addition, a slackening of wind speeds by up to about 2 knots in already weak winds and backing in wind direction of about 20 degrees under clear skies across middle England are attributed to the eclipse event. The slackening of wind speed is consistent with the previously reported boundary layer stabilisation during eclipse events. Wind direction changes have previously been attributed to a large-scale `eclipse-induced cold-cored cyclone', mountain slope flows, and changes in the strength of sea breezes. A new explanation is proposed here by analogy with nocturnal wind changes at sunset and shown to predict direction changes consistent with those observed.

The Citizen CATE Experiment: High altitude cirrus cloud removal from eclipse data through use of Kalman filters.

NASA Astrophysics Data System (ADS)

Jensen, Logan; Citizen CATE Experiment 2017 Team

2018-01-01

The Citizen Continental America Telescopic Eclipse (CATE) Experiment was designed to fill in the current data gap for the solar corona from approximately 1 to 2.5 solar radii. Using the total solar eclipse, the project took advantage of the unique opportunity to study this region of the corona from 68 identical sites across the United States. Before the 2017 eclipse, image reduction pipelines and advanced processing techniques were researched and implemented using data that had been collected from the 2016 Indonesian eclipse as a test set. This would speed up the turnaround from data to science after the 2017 eclipse.When processing the 2016 eclipse data, cirrus clouds became apparent moving across the field of view. These would interfere with future processing goals for the data such as coronal filament tracing and polar plume measurements. As the clouds moved across the field they did not completely obscure any part of the image, instead they produced variable, moving absorption across the CATE field of view. This had the effect of creating a noisy signal for each pixel. A noise reduction procedure based on a Kalman filter was developed to effectively remove the clouds from the data. Initial results from the 2016 eclipse data are presented.

Eclipse-Free-Time Assessment Tool for IRIS

NASA Technical Reports Server (NTRS)

Eagle, David

2012-01-01

IRIS_EFT is a scientific simulation that can be used to perform an Eclipse-Free- Time (EFT) assessment of IRIS (Infrared Imaging Surveyor) mission orbits. EFT is defined to be those time intervals longer than one day during which the IRIS spacecraft is not in the Earth s shadow. Program IRIS_EFT implements a special perturbation of orbital motion to numerically integrate Cowell's form of the system of differential equations. Shadow conditions are predicted by embedding this integrator within Brent s method for finding the root of a nonlinear equation. The IRIS_EFT software models the effects of the following types of orbit perturbations on the long-term evolution and shadow characteristics of IRIS mission orbits. (1) Non-spherical Earth gravity, (2) Atmospheric drag, (3) Point-mass gravity of the Sun, and (4) Point-mass gravity of the Moon. The objective of this effort was to create an in-house computer program that would perform eclipse-free-time analysis. of candidate IRIS spacecraft mission orbits in an accurate and timely fashion. The software is a suite of Fortran subroutines and data files organized as a "computational" engine that is used to accurately predict the long-term orbit evolution of IRIS mission orbits while searching for Earth shadow conditions.

Period changes of the long-period cataclysmic binary EX Draconis

NASA Astrophysics Data System (ADS)

Pilarčík, L.; Wolf, M.; Dubovský, P. A.; Hornoch, K.; Kotková, L.

2012-03-01

The cataclysmic variable star EX Dra is a relatively faint but frequently investigated eclipsing dwarf nova. In total 35 new eclipses were measured photometrically as part of our long-term monitoring of interesting eclipsing systems. Using published and new mid-eclipse times obtained between 2004 and 2011 we constructed the observed-minus-calculated diagram. The current data present 21 years of period modulation with a semi-amplitude of 2.5 min. The eclipse timings show significant deviations from the best sinusoidal fit, which indicates that this ephemeris is not a complete description of the data. The fractional period change is roughly ΔP/P = 3 × 10-6.

Light curve solutions of the eccentric binaries KIC 10992733, KIC 5632781, KIC 10026136 and their out-of-eclipse variability

NASA Astrophysics Data System (ADS)

Kjurkchieva, Diana; Vasileva, Doroteya

2018-01-01

We determined the orbits and stellar parameters of three eccentric eclipsing binaries by light curve solutions of their Kepler data. KIC 10992733 and KIC 5632781 undergo total eclipses while KIC 10026136 reveals partial eclipses. The components of the targets are G and K stars. KIC 10992733 exhibited variations which were attributed to variable visibility of spot(s) on asynchronously rotating component. KIC 5632781 and KIC 1002613 reveal tidally-induced features at periastron, i.e. they might be considered as eclipsing heartbeat stars. The characteristics of the periastron features (shape, width and amplitude) confirm the theoretical predictions.

VizieR Online Data Catalog: OGLE eclipsing binaries in LMC (Wyrzykowski+, 2003)

NASA Astrophysics Data System (ADS)

Wyrzykowski, L.; Udalski, A.; Kubiak, M.; Szymanski, M.; Zebrun, K.; Soszynski, I.; Wozniak, P. R.; Pietrzynski, G.; Szewczyk, O.

2003-09-01

We present the catalog of 2580 eclipsing binary stars detected in 4.6 square degree area of the central parts of the Large Magellanic Cloud. The photometric data were collected during the second phase of the OGLE microlensing search from 1997 to 2000. The eclipsing objects were selected with the automatic search algorithm based on an artificial neural network. Basic statistics of eclipsing stars are presented. Also, the list of 36 candidates of detached eclipsing binaries for spectroscopic study and for precise LMC distance determination is provided. The full catalog is accessible from the OGLE Internet archive. (2 data files).

Conjunctive Faith: A Critique and Analysis from an Evangelical Perspective

DTIC Science & Technology

1990-06-01

Fowler regards those who practice radical monotheism as valuers of an inclusive, global community, practicing a type of universal faith that eclipses...Stages of Faith, 20. * 24 think. ,23 Niebuhr’s second type of faith relationship, which Fowler endorses, is henotheism. Niebuhr clothes henotheism...could sus- tain. In doing so, I failed to take seriously enough certain indications, which faith development categories actually make quite clear

GMRT discovery of PSR J1544+4937: An eclipsing black-widow pulsar identified with a Fermi-LAT source

DOE PAGES

Bhattacharyya, B.; Roy, J.; Ray, P. S.; ...

2013-07-29

Using the Giant Metrewave Radio Telescope, we performed deep observations to search for radio pulsations in the directions of unidentified Fermi-Large Area Telescope γ-ray sources. We report the discovery of an eclipsing black-widow millisecond pulsar, PSR J1544+4937, identified with the uncataloged γ-ray source FERMI J1544.2+4941. This 2.16 ms pulsar is in a 2.9 hr compact circular orbit with a very low mass companion (Mc > 0.017M ⊙). At 322 MHz this pulsar is found to be eclipsing for 13% of its orbit, whereas at 607 MHz the pulsar is detected throughout the low-frequency eclipse phase. Variations in the eclipse ingressmore » phase are observed, indicating a clumpy and variable eclipsing medium. Moreover, additional short-duration absorption events are observed around the eclipse boundaries. Finally, using the radio timing ephemeris we were able to detect γ-ray pulsations from this pulsar, confirming it as the source powering the γ-ray emission.« less

Initial Results of HamSCI Ham Radio 21 August 2017 Eclipse Ionospheric Experiments

NASA Astrophysics Data System (ADS)

Frissell, N. A.; Gerrard, A. J.; Vega, J. S.; Katz, J. D.; West, M. L.; Gunning, S. W.; Moses, M. L.; Miller, E. S.; Erickson, P. J.; Huba, J.; Silver, H. W.; Ceglia, F.; Smith, P.; Williams, R.; Shovkoplyas, A.; Earle, G. D.; Gerzoff, R.; Gladstone, P.; Reyer, S. E.; Ackermann, J. R.; Bern, D.; Rose, S. W.

2017-12-01

On 21 August 2017, a total solar eclipse will cause the shadow of the moon to traverse the United States from Oregon to South Carolina in just over 90 minutes. The sudden absence of sunlight due to the eclipse, especially solar UV and x-rays, provides an impulse function to the upper atmosphere that modifies the neutral dynamics, plasma concentrations, and related properties. Despite more than 60 years of research, questions remain regarding eclipse-induced ionospheric impacts. Ham radio operators' advanced technical skills and inherent interest in ionospheric science make the amateur radio community ideal for contributing to and and participating in large-scale ionospheric sounding experiments. We present initial results from three amateur radio experiments designed to study the 2017 total solar eclipse: the Solar Eclipse QSO Party (SEQP), the HF Wideband Recording Experiment, and the Eclipse Frequency Measurement Test (FMT). These experiments are coordinated by HamSCI, the Ham Radio Science Citizen Investigation, a citizen science organization that connects the amateur radio community to the professional space science research community for mutual benefit.

The (Almost) Unseen Total Eclipse of 1831

NASA Astrophysics Data System (ADS)

Bartky, Ian R.

2008-03-01

The total eclipse of August 1831 began at sunrise in Australia, swept across the western South Pacific Ocean, and ended at sunset in the central South Pacific. As a result of the eclipse's path over mostly uninhabited ocean, the region's sparse European (British) population, and near-useless local predictions of the event at Hobart and Sydney in almanacs sold to the general public, almost no one witnessed its passage. In an attempt to document the eclipse, journals of naive observers - those having no access to a prediction - were examined. Thus far, the sole record is in the Pitcairn Island Register Book. Considering the Pitcairners' extreme isolation and the rather modest partial eclipse that occurred there, the entry is a surprising one; however, it can be explained in terms of events associated with their initial removal to Tahiti in March 1831 followed by their return home in June. Further, an authoritative means to identify any issues associated with eclipse predictions compiled for private-sector almanacs came in 1833 when sweeping changes in the British Nautical Almanac's section on eclipses were instituted.

GMRT DISCOVERY OF PSR J1544+4937: AN ECLIPSING BLACK-WIDOW PULSAR IDENTIFIED WITH A FERMI-LAT SOURCE

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

Bhattacharyya, B.; Roy, J.; Gupta, Y.

2013-08-10

Using the Giant Metrewave Radio Telescope, we performed deep observations to search for radio pulsations in the directions of unidentified Fermi-Large Area Telescope {gamma}-ray sources. We report the discovery of an eclipsing black-widow millisecond pulsar, PSR J1544+4937, identified with the uncataloged {gamma}-ray source FERMI J1544.2+4941. This 2.16 ms pulsar is in a 2.9 hr compact circular orbit with a very low mass companion (M{sub c} > 0.017M{sub Sun }). At 322 MHz this pulsar is found to be eclipsing for 13% of its orbit, whereas at 607 MHz the pulsar is detected throughout the low-frequency eclipse phase. Variations in themore » eclipse ingress phase are observed, indicating a clumpy and variable eclipsing medium. Moreover, additional short-duration absorption events are observed around the eclipse boundaries. Using the radio timing ephemeris we were able to detect {gamma}-ray pulsations from this pulsar, confirming it as the source powering the {gamma}-ray emission.« less

Modeling Amateur Radio Soundings of the Ionospheric Response to the 2017 Great American Eclipse

NASA Astrophysics Data System (ADS)

Frissell, N. A.; Katz, J. D.; Gunning, S. W.; Vega, J. S.; Gerrard, A. J.; Earle, G. D.; Moses, M. L.; West, M. L.; Huba, J. D.; Erickson, P. J.; Miller, E. S.; Gerzoff, R. B.; Liles, W.; Silver, H. W.

2018-05-01

On 21 August 2017, a total solar eclipse traversed the continental United States and caused large-scale changes in ionospheric densities. These were detected as changes in medium- and high-frequency radio propagation by the Solar Eclipse QSO Party citizen science experiment organized by the Ham Radio Science Citizen Investigation (hamsci.org). This is the first eclipse-ionospheric study to make use of measurements from a citizen-operated, global-scale HF propagation network and develop tools for comparison to a physics-based model ionosphere. Eclipse effects were observed ±0.3 hr on 1.8 MHz, ±0.75 hr on 3.5 and 7 MHz, and ±1 hr on 14 MHz and are consistent with eclipse-induced ionospheric densities. Observations were simulated using the PHaRLAP raytracing toolkit in conjunction with the eclipsed SAMI3 ionospheric model. Model results suggest 1.8, 3.5, and 7 MHz refracted at h≥125 km altitude with elevation angles θ≥22°, while 14 MHz signals refracted at h < 125 km with elevation angles θ < 10°.

The Spot Variability and Related Brightness variations of the Solar Type PreContact W UMa Binary System V1001 Cas

NASA Astrophysics Data System (ADS)

Samec, Ronald George; Koenke, Sam S.; Faulkner, Danny R.

2015-08-01

A new classification of eclipsing binary has emerged, Pre Contact WUMa Binaries (PCWB’s, Samec et al. 2012). These solar-type systems are usually detached or semidetached with one or both components under filling their critical Roche lobes. They usually have EA or EB-type light curves (unequal eclipse depths, indicating components with substantially different temperatures). The accepted scenario for these W UMa binaries is that they are undergoing steady but slow angular momentum losses due to magnetic braking as stellar winds blow radially away on stiff bipolar field lines. These binaries are believed to come into stable contact and eventually coalesce into blue straggler type, single, fast rotating A-type stars (Guinan and Bradstreet,1988). High precision 2012 and 2009 light curves are compared for the very short period (~0.43d) Precontact W UMa Binary (PCWB), V1001 Cassiopeia. This is the shortest period PCWB found so far. Its short period, similar to the majority of W UMa’s, in contrast to its distinct Algol-type light curve, make it a very rare and interesting system. Our solutions of light curves separated by some three years give approximately the same physical parameters. However the spots radically change, in temperature, area and position causing a distinctive variation in the shape of the light curves. We conclude that spots are very active on this solar type dwarf system and that it may mimic its larger cousins, the RS CVn binaries.

Chemical Composition of RR Lyn - an Eclipsing Binary System with Am and λ Boo Type Components

NASA Astrophysics Data System (ADS)

Jeong, Yeuncheol; Yushchenko, Alexander V.; Doikov, Dmytry N.; Gopka, Vira F.; Yushchenko, Volodymyr O.

2017-06-01

High-resolution spectroscopic observations of the eclipsing binary system RR Lyn were made using the 1.8 m telescope at the Bohuynsan Optical Astronomical Observatory in Korea. The spectral resolving power was R = 82,000, with a signal to noise ratio of S/N > 150. We found the effective temperatures and surface gravities of the primary and secondary components to be equal to Teff = 7,920 & 7,210 K and log(g) = 3.80 & 4.16, respectively. The abundances of 34 and 17 different chemical elements were found in the atmospheric components. Correlations between the derived abundances with condensation temperatures and the second ionization potentials of these elements are discussed. The primary component is a typical metallic line star with the abundances of light and iron group elements close to solar values, while elements with atomic numbers Z > 30 are overabundant by 0.5-1.5 dex with respect to solar values. The secondary component is a λ Boo type star. In this type of stars, CNO abundances are close to solar values, while the abundance pattern shows a negative correlation with condensation temperatures.

Envelopes in eclipsing binary stars

NASA Technical Reports Server (NTRS)

Huang, S.

1972-01-01

Theoretical research on eclipsing binaries is presented. The specific areas of investigation are the following: (1) the relevance of envelopes to the study of the light curves of eclipsing binaries, (2) the disk envelope, and (3) the spherical envelope.

2017 Total Solar Eclipse Across America Promo

NASA Image and Video Library

2017-08-10

On Monday, August 21, 2017, all of North America will be treated to an eclipse of the sun. Anyone within the path of totality can see one of nature’s most awe inspiring sights - a total solar eclipse.

2017 Total Solar Eclipse

NASA Image and Video Library

2017-08-21

The Moon is seen passing in front of the Sun at the point of the maximum of the partial solar eclipse near Banner, Wyoming on Monday, Aug. 21, 2017. A total solar eclipse swept across a narrow portion of the contiguous United States from Lincoln Beach, Oregon to Charleston, South Carolina. A partial solar eclipse was visible across the entire North American continent along with parts of South America, Africa, and Europe. Photo Credit: (NASA/Joel Kowsky)

2017 Total Solar Eclipse

NASA Image and Video Library

2017-08-21

The Moon is seen as it starts passing in front of the Sun during a solar eclipse from Ross Lake, Northern Cascades National Park, Washington on Monday, Aug. 21, 2017. A total solar eclipse swept across a narrow portion of the contiguous United States from Lincoln Beach, Oregon to Charleston, South Carolina. A partial solar eclipse was visible across the entire North American continent along with parts of South America, Africa, and Europe. Photo Credit: (NASA/Bill Ingalls)

Eclipse cooling of selected lunar features

NASA Technical Reports Server (NTRS)

Shorthill, R. W.; Saari, J. M.; Baird, F. E.; Lecompte, J. R.

1970-01-01

Thermal measurements were made in the 10 to 12 micron band of the lunar surface during the total eclipse of December19, 1964. A normalized differential thermal contour map is included, showing the location of the thermal anomalies or hot spots on the disk and the eclipse cooling curves of 400 sites, of which more than 300 were hot spots. The eclipse cooling data is compared to a particulate thermophysical model of the soil.

VizieR Online Data Catalog: Kepler Mission. VII. Eclipsing binaries in DR3 (Kirk+, 2016)

NASA Astrophysics Data System (ADS)

Kirk, B.; Conroy, K.; Prsa, A.; Abdul-Masih, M.; Kochoska, A.; Matijevic, G.; Hambleton, K.; Barclay, T.; Bloemen, S.; Boyajian, T.; Doyle, L. R.; Fulton, B. J.; Hoekstra, A. J.; Jek, K.; Kane, S. R.; Kostov, V.; Latham, D.; Mazeh, T.; Orosz, J. A.; Pepper, J.; Quarles, B.; Ragozzine, D.; Shporer, A.; Southworth, J.; Stassun, K.; Thompson, S. E.; Welsh, W. F.; Agol, E.; Derekas, A.; Devor, J.; Fischer, D.; Green, G.; Gropp, J.; Jacobs, T.; Johnston, C.; Lacourse, D. M.; Saetre, K.; Schwengeler, H.; Toczyski, J.; Werner, G.; Garrett, M.; Gore, J.; Martinez, A. O.; Spitzer, I.; Stevick, J.; Thomadis, P. C.; Vrijmoet, E. H.; Yenawine, M.; Batalha, N.; Borucki, W.

2016-07-01

The Kepler Eclipsing Binary Catalog lists the stellar parameters from the Kepler Input Catalog (KIC) augmented by: primary and secondary eclipse depth, eclipse width, separation of eclipse, ephemeris, morphological classification parameter, and principal parameters determined by geometric analysis of the phased light curve. The previous release of the Catalog (Paper II; Slawson et al. 2011, cat. J/AJ/142/160) contained 2165 objects, through the second Kepler data release (Q0-Q2). In this release, 2878 objects are identified and analyzed from the entire data set of the primary Kepler mission (Q0-Q17). The online version of the Catalog is currently maintained at http://keplerEBs.villanova.edu/. A static version of the online Catalog associated with this paper is maintained at MAST https://archive.stsci.edu/kepler/eclipsing_binaries.html. (10 data files).

Monitoring a photovoltaic system during the partial solar eclipse of August 2017

NASA Astrophysics Data System (ADS)

Kurinec, Santosh K.; Kucer, Michal; Schlein, Bill

2018-05-01

The power output of a 4.85 kW residential photovoltaic (PV) system located in Rochester, NY is monitored during the partial solar eclipse of August 21, 2017. The data is compared with the data on a day before and on the same day, a year ago. The area of exposed solar disk is measured using astrophotography every 16 s of the eclipse. Global solar irradiance is estimated using the eclipse shading, time of the day, location coordinates, atmospheric conditions and panel orientation. A sharp decline, as expected in the energy produced is observed at the time of the peak of the eclipse. The observed data of the PV energy produced is related with the model calculations taking into account solar eclipse coverage and cloudiness conditions. The paper provides a cohesive approach of irradiance calculations and obtaining anticipated PV performance.

Fall 2011 Eclipse Season Begins

NASA Image and Video Library

2011-09-13

The Fall 2011 eclipse season started on September 11, 2011. Here is an AIA 304 image from 0658 UT. SDO has eclipse seasons twice a year near each equinox. For three weeks near midnight Las Cruces time (about 0700 UT) our orbit has the Earth pass between SDO and the Sun. These eclipses can last up to 72 minutes in the middle of an eclipse season. The current eclipse season started on September 11 and lasts until October 4. To read more about SDO go to: sdo.gsfc.nasa.gov/ Credit: NASA/GSFC/SDO NASA Goddard Space Flight Center enables NASA’s mission through four scientific endeavors: Earth Science, Heliophysics, Solar System Exploration, and Astrophysics. Goddard plays a leading role in NASA’s accomplishments by contributing compelling scientific knowledge to advance the Agency’s mission. Follow us on Twitter Like us on Facebook Find us on Instagram

SPECIAL SEMINAR - The NOTTE experiment, or how to become a Total Solar Eclipse chaser

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

None

2011-02-08

The NOTTE experiment (Neutrino Oscillations with Telescope during Total Eclipse) aims at searching for visible photons emitted through a possible radiative decay of solar neutrinos. The experiment and the expeditions organized by a group of physicists and astrophysicists from INFN and INAF Bologna hunting for Total Solar Eclipses from 1998 to 2006 wil be described. The results of observations performed during total solar eclipse expeditions in 2001 (Zambia) and 2006 (Sahara desert, Libya) are presented and a beautiful photo gallery will be shown. Other peculiar observations that can be made during a solar eclipse are also illustrated. The seminar willmore » be followed by a brief presentation of future camps for solar eclipse chasers and scientists organized in 2008 in Russia, Kazakhstan, China and Mongolia, in 2009 in Shanghai and on the Easter Island in 2010.« less

Clear-Sky Probability for the August 21, 2017, Total Solar Eclipse Using the NREL National Solar Radiation Database

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

Habte, Aron M; Roberts, Billy J; Kutchenreiter, Mark C

The National Renewable Energy Laboratory (NREL) and collaborators have created a clear-sky probability analysis to help guide viewers of the August 21, 2017, total solar eclipse, the first continent-spanning eclipse in nearly 100 years in the United States. Using cloud and solar data from NREL's National Solar Radiation Database (NSRDB), the analysis provides cloudless sky probabilities specific to the date and time of the eclipse. Although this paper is not intended to be an eclipse weather forecast, the detailed maps can help guide eclipse enthusiasts to likely optimal viewing locations. Additionally, high-resolution data are presented for the centerline of themore » path of totality, representing the likelihood for cloudless skies and atmospheric clarity. The NSRDB provides industry, academia, and other stakeholders with high-resolution solar irradiance data to support feasibility analyses for photovoltaic and concentrating solar power generation projects.« less

A Case Study in High Contrast Coronagraph for Planet Discovery: The Eclipse Concept and Support Laboratory Experience

NASA Technical Reports Server (NTRS)

Trauger, John T.

2005-01-01

Eclipse is a proposed NASA Discovery mission to perform a sensitive imaging survey of nearby planetary systems, including a survey for jovian-sized planets orbiting Sun-like stars to distances of 15 pc. We outline the science objectives of the Eclipse mission and review recent developments in the key enabling technologies. Eclipse is a space telescope concept for high-contrast visible-wavelength imaging and spectrophotometry. Its design incorporates a telescope with an unobscured aperture of 1.8 meters, a coronographic camera for suppression of diffracted light, and precise active wavefront correction for the suppression of scattered background light. For reference, Eclipse is designed to reduce the diffracted and scattered starlight between 0.33 and 1.5 arcseconds from the star by three orders of magnitude compared to any HST instrument. The Eclipse mission provides precursor science exploration and technology experience in support of NASA's Terrestrial Planet Finder (TPF) program.

Effects of the 2017 Solar Eclipse on HF Radio Propagation and the D-Region Ionosphere: Citizen Science Investigation

NASA Technical Reports Server (NTRS)

Fry, C. D.; Rawlins, L.; Krause, L. H.; Suggs, R. M.; McTernan, J. K.; Adams, M. L.; Gallagher, D. L.; Anderson, Scott; Allsbrooks, Robert IV

2017-01-01

August 21, 2017 provided a unique opportunity to investigate the effects of the total solar eclipse on high frequency (HF) radio propagation and ionospheric variability. In Marshall Space Flight Center's partnership with the US Space and Rocket Center (USSRC) and Austin Peay State University (APSU), we engaged students and citizen scientists in an investigation of the eclipse effects on the mid-latitude ionosphere. Activities included implementing and configuring software, monitoring the HF Amateur Radio frequency bands and collecting radio transmission data on days before, the day of, and days after the eclipse to build a continuous record of changing propagation conditions as the moon's shadow marched across the United States. Post-eclipse radio propagation analysis provided insights into ionospheric variability due to the eclipse. We report on results, interpretation, and conclusions of these investigations.

HATS-36b and 24 Other Transiting/Eclipsing Systems from the HATSouth-K2 Campaign 7 Program

NASA Astrophysics Data System (ADS)

Bayliss, D.; Hartman, J. D.; Zhou, G.; Bakos, G. Á.; Vanderburg, A.; Bento, J.; Mancini, L.; Ciceri, S.; Brahm, R.; Jordán, A.; Espinoza, N.; Rabus, M.; Tan, T. G.; Penev, K.; Bhatti, W.; de Val-Borro, M.; Suc, V.; Csubry, Z.; Henning, Th.; Sarkis, P.; Lázár, J.; Papp, I.; Sári, P.

2018-03-01

We report on the result of a campaign to monitor 25 HATSouth candidates using the Kepler space telescope during Campaign 7 of the K2 mission. We discover HATS-36b (EPIC 215969174b, K2-145b), an eccentric (e=0.105+/- 0.028) hot Jupiter with a mass of 3.216+/- 0.062 {M}{{J}} and a radius of 1.235+/- 0.043 {R}{{J}}, which transits a solar-type G0V star (V = 14.386) in a 4.1752-day period. We also refine the properties of three previously discovered HATSouth transiting planets (HATS-9b, HATS-11b, and HATS-12b) and search the K2 data for TTVs and additional transiting planets in these systems. In addition, we also report on a further three systems that remain as Jupiter-radius transiting exoplanet candidates. These candidates do not have determined masses, however pass all of our other vetting observations. Finally, we report on the 18 candidates that we are now able to classify as eclipsing binary or blended eclipsing binary systems based on a combination of the HATSouth data, the K2 data, and follow-up ground-based photometry and spectroscopy. These range in periods from 0.7 day to 16.7 days, and down to 1.5 mmag in eclipse depths. Our results show the power of combining ground-based imaging and spectroscopy with higher precision space-based photometry, and serve as an illustration as to what will be possible when combining ground-based observations with TESS data.

EC 10246-2707: an eclipsing subdwarf B + M dwarf binary

NASA Astrophysics Data System (ADS)

Barlow, B. N.; Kilkenny, D.; Drechsel, H.; Dunlap, B. H.; O'Donoghue, D.; Geier, S.; O'Steen, R. G.; Clemens, J. C.; LaCluyze, A. P.; Reichart, D. E.; Haislip, J. B.; Nysewander, M. C.; Ivarsen, K. M.

2013-03-01

We announce the discovery of a new eclipsing hot subdwarf B + M dwarf binary, EC 10246-2707, and present multicolour photometric and spectroscopic observations of this system. Similar to other HW Vir-type binaries, the light curve shows both primary and secondary eclipses, along with a strong reflection effect from the M dwarf; no intrinsic light contribution is detected from the cool companion. The orbital period is 0.118 507 9936 ± 0.000 000 0009 d, or about 3 h. Analysis of our time series spectroscopy reveals a velocity semi-amplitude of K1 = 71.6 ± 1.7 km s-1 for the sdB and best-fitting atmospheric parameters of Teff = 28 900 ± 500 K, log g = 5.64 ± 0.06 and log N(He)/N(H) = -2.5 ± 0.2. Although we cannot claim a unique solution from modelling the light curve, the best-fitting model has an sdB mass of 0.45 M⊙ and a cool companion mass of 0.12 M⊙. These results are roughly consistent with a canonical-mass sdB and M dwarf separated by a ˜ 0.84 R⊙. We find no evidence of pulsations in the light curve and limit the amplitude of rapid photometric oscillations to <0.08 per cent. Using 15 yr of eclipse timings, we construct an observed minus calculated (O - C) diagram but find no statistically significant period changes; we rule out |dot{P}| > 7.2 × 10^{-12}. If EC 10246-2707 evolves into a cataclysmic variable, its period should fall below the famous cataclysmic variable period gap.

Constraints on the atmospheric circulation and variability of the eccentric hot Jupiter XO-3b

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

Wong, Ian; Knutson, Heather A.; Cowan, Nicolas B.

We report secondary eclipse photometry of the hot Jupiter XO-3b in the 4.5 μm band taken with the Infrared Array Camera on the Spitzer Space Telescope. We measure individual eclipse depths and center of eclipse times for a total of 12 secondary eclipses. We fit these data simultaneously with two transits observed in the same band in order to obtain a global best-fit secondary eclipse depth of 0.1580% ± 0.0036% and a center of eclipse phase of 0.67004 ± 0.00013. We assess the relative magnitude of variations in the dayside brightness of the planet by measuring the size of themore » residuals during ingress and egress from fitting the combined eclipse light curve with a uniform disk model and place an upper limit of 0.05%. The new secondary eclipse observations extend the total baseline from one and a half years to nearly three years, allowing us to place an upper limit on the periastron precession rate of 2.9 × 10{sup –3} deg day{sup –1}— the tightest constraint to date on the periastron precession rate of a hot Jupiter. We use the new transit observations to calculate improved estimates for the system properties, including an updated orbital ephemeris. We also use the large number of secondary eclipses to obtain the most stringent limits to date on the orbit-to-orbit variability of an eccentric hot Jupiter and demonstrate the consistency of multiple-epoch Spitzer observations.« less

Repeatability and Accuracy of Exoplanet Eclipse Depths Measured with Post-cryogenic Spitzer

NASA Astrophysics Data System (ADS)

Ingalls, James G.; Krick, J. E.; Carey, S. J.; Stauffer, John R.; Lowrance, Patrick J.; Grillmair, Carl J.; Buzasi, Derek; Deming, Drake; Diamond-Lowe, Hannah; Evans, Thomas M.; Morello, G.; Stevenson, Kevin B.; Wong, Ian; Capak, Peter; Glaccum, William; Laine, Seppo; Surace, Jason; Storrie-Lombardi, Lisa

2016-08-01

We examine the repeatability, reliability, and accuracy of differential exoplanet eclipse depth measurements made using the InfraRed Array Camera (IRAC) on the Spitzer Space Telescope during the post-cryogenic mission. We have re-analyzed an existing 4.5 μm data set, consisting of 10 observations of the XO-3b system during secondary eclipse, using seven different techniques for removing correlated noise. We find that, on average, for a given technique, the eclipse depth estimate is repeatable from epoch to epoch to within 156 parts per million (ppm). Most techniques derive eclipse depths that do not vary by more than a factor 3 of the photon noise limit. All methods but one accurately assess their own errors: for these methods, the individual measurement uncertainties are comparable to the scatter in eclipse depths over the 10 epoch sample. To assess the accuracy of the techniques as well as to clarify the difference between instrumental and other sources of measurement error, we have also analyzed a simulated data set of 10 visits to XO-3b, for which the eclipse depth is known. We find that three of the methods (BLISS mapping, Pixel Level Decorrelation, and Independent Component Analysis) obtain results that are within three times the photon limit of the true eclipse depth. When averaged over the 10 epoch ensemble, 5 out of 7 techniques come within 60 ppm of the true value. Spitzer exoplanet data, if obtained following current best practices and reduced using methods such as those described here, can measure repeatable and accurate single eclipse depths, with close to photon-limited results.

Comparisons of Measurements and Modeling of Solar Eclipse Effects on VLF Transmissions

NASA Astrophysics Data System (ADS)

Eccles, J. V.; Rice, D. D.; Sojka, J. J.; Marshall, R. A.; Drob, D. P.; Decena, J. C.

2017-12-01

The solar eclipse of 2017 August 21 provides an excellent opportunity to examine Very Low Frequency (VLF) radio signal propagation through the path of the solar eclipse between Navy VLF transmitters and several VLF receivers. The VLF transmitters available for this study radio signal propagation study are NLK in Jim Creek, Washington (24.8 kHz, 192 kW, 48.20N, 121.90W), NML in LaMour, North Dakota (25.2 kHz, 500 kW 46.37N, 93.34W), and NAA in Cutler, Maine (24.0 kHz, 1000 kW, 44.65N, 67.29W). These VLF transmitters provide propagation paths to three VLF receivers at Utah State University (41.75N, 111.76W), Bear Lake Observatory (41.95N, 111.39W), Salt Lake City (40.76N, 111.89W) and one receiver in Boulder, Colorado (40.02N, 105.27W). The solar eclipse shadow will cross all propagations paths during the day and will modify the D region electron density within the solar shadow. The week prior to the solar eclipse will be used to generate a diurnal baseline of VLF single strength for each transmitter-receiver pair. These will be compared to the day of the solar eclipse to identify VLF propagation differences through the solar eclipse shawdow. Additionally, the electron density effects of the week prior and of the solar eclipse day will be modeled using the Data-Driven D Region (DDDR) model [Eccles et al., 2005] with a detailed eclipse solar flux mask. The Long-Wave Propagation Code and the HASEL RF ray-tracing code will be used to generate VLF signal strength for each measured propagation path through the days prior and the solar eclipse day. Model-measurement comparisons will be presented and the D region electron density effects of the solar eclipse will be examined. The DDDR is a time-dependent D region model, which makes it very suitable for the solar eclipse effects on the electron density for the altitude range of 36 to 130 km. Eccles J. V., R. D. Hunsucker, D. Rice, J. J. Sojka (2005), Space weather effects on midlatitude HF propagation paths: Observations and a data-driven D region model, Space Weather, 3, S01002, doi:10.1029/2004SW000094.

Io in Eclipse, Movie

NASA Technical Reports Server (NTRS)

2001-01-01

Glowing spots of hot lava and ethereal auroral emissions are highlighted against blackness in this sequence of 48 frames from NASA's Cassini spacecraft, which show Jupiter's moon Io in the darkness of the giant planet's shadow.

The sequence was recorded over a two-hour interval that spanned nearly an entire eclipse on Jan. 1, 2001. Although no sunlight shines on the moon during an eclipse, two types of glows can be seen. The bright points of light are the glows of hot lava from active volcanoes. The brightest is the volcano Pele, which appears to be erupting steadily despite its great intensity. To the right of Pele and slightly above it is a pair of bright spots associated with the volcano Pillan, the source of a major eruption in 1997. NASA's Galileo spacecraft and Hubble Space Telescope saw that 1997 eruption of Pillan dwarf the energy output from neighboring Pele, but Pillan's eruption has waned over the past 30 months to the pair of small hot spots seen here. Another volcano, seen below and to the right of Pele, varies on a time scale of days. This sequence of images illustrates the great variations in intensity and longevity of Io's volcanic eruptions.

The second type of glow seen on Io during eclipse is a set of faint, diffuse emissions due to atmospheric auroras. Similar to the aurora borealis and aurora australis on Earth, Io's auroras are caused by the collisions of charged particles with gases in Io's tenuous atmosphere. A faint ring encircles the moon, while brighter glows are concentrated near the moon's equator. These equatorial glows are seen here gradually shifting clockwise in location as the eclipse progresses, due to the changing orientation of Jupiter's magnetic field. This is a new result which confirms that these visible auroras, like their counterparts seen at ultraviolet wavelengths, are caused by electrical currents that flow between Io and Jupiter.

The original images were taken through a clear filter of Cassini's narrow-angle camera from a distance of over 10 million kilometers (6.3 million miles), with a resolution of 61 kilometers (40 miles) per pixel. The images have been cropped and processed to remove scattered light.

Cassini is a cooperative project of NASA, the European Space Agency and the Italian Space Agency. The Jet Propulsion Laboratory, a division of the California Institute of Technology in Pasadena, Calif., manages Cassini for NASA's Office of Space Science, Washington, D.C.

Analysis of partial-reflection data from the solar eclipse of 10 Jul. 1972. [ground-based experiment using vertical incident radio waves partially reflected from D region

NASA Technical Reports Server (NTRS)

Bean, T. A.; Bowhill, S. A.

1973-01-01

Partial-reflection data collected for the eclipse of July 10, 1972 as well as for July 9 and 11, 1972, are analyzed to determine eclipse effects on D-region electron densities. The partial-reflection experiment was set up to collect data using an on-line PDP-15 computer and DECtape storage. The electron-density profiles show good agreement with results from other eclipses. The partial-reflection programs were changed after the eclipse data collection to improve the operation of the partial-reflection system. These changes were mainly due to expanded computer hardware and have simplified the operations of the system considerably.

Impact Results From the Astronomers Without Borders Building on the Eclipse Education Program

NASA Astrophysics Data System (ADS)

Bartolone, L. M.; Simmons, M.; Nelson, A.; Kruse, B.

2017-12-01

Astronomers Without Borders "Building on the Eclipse Education Program" was its first to move beyond outreach, exploring how to impact science identity, attitudes towards STEM and inspire audiences to explore careers in STEM. Inspired by the eclipse, educators and scientists were brought together in an online community to support one another in learning about the Sun and light after audiences were inspired by the Total Solar Eclipse. The program also collected and analyzed data on participating groups in an attempt to have more information about audiences for the next total solar eclipse to cross the United States in 2024. Although we anticipate the program will be ongoing, preliminary results will be presented.

2017 Total Solar Eclipse

NASA Image and Video Library

2017-08-21

The Moon is seen passing in front of the Sun during a total solar eclipse on Monday, August 21, 2017 from onboard a NASA Gulfstream III aircraft flying 25,000 feet above the Oregon coast. A total solar eclipse swept across a narrow portion of the contiguous United States from Lincoln Beach, Oregon to Charleston, South Carolina. A partial solar eclipse was visible across the entire North American continent along with parts of South America, Africa, and Europe. Photo Credit: (NASA/Carla Thomas)

Total Eclipse From Onboard NASA's G-III Research Aircraft

NASA Image and Video Library

2017-09-13

As the 2017 solar eclipse approaches and enters totality, NASA Armstrong staff and NASA senior management share their excitement and first-hand experience from aboard NASA’s Armstrong Flight Research Center Gulfstream III aircraft. The G-III aircraft flew at 35,000 feet above the coast of Oregon during the 2017 total solar eclipse, capturing some of the very first views of the 2017 total solar eclipse as it made its way across the United States.

Effects Total Solar Eclipse to Nasty Behaviour of the Several Legume Plants as a Result Student Research

NASA Astrophysics Data System (ADS)

Anggraeni, S.; Diana, S.; Supriatno, B.

2017-09-01

Some group students of plant Physiology course have given task to do free inquiry. They investigated of the nasty behaviour of several legume plants in response to changes in light during the partial solar eclipse that occurred at March 9, 2016. The investigation carried out in UPI Bandung, West Java, Indonesia, which is in the penumbra region of a total solar eclipse with the location coordinates of latitude: -6.86105, longitude: 07.59071, S 6057’ 37.53553 “and E 107035’ 24.29141”. They were measuring the movement of opening leaves every ten minutes at the beginning of the start until the end of the eclipse compared with the behaviour without eclipsing. Influence is expressed by comparing the leaf opening movement (measured in the form of leaf angular) at the time of the eclipse with a normal day. Each group was observed for one plant of the legume, there are: Mimosa pudica, Bauhinia purpurea, Caesalpinia pulcherrima, and Arachis pintoi. The results showed that the changes in leaf angular in plants Mimosa pudica, Caesalpinia pulcherrima, and Arachis pintoi differently significant, except for Bauhinia purpurea. In conclusion, the total solar eclipse in the penumbra area affects the movement of some nasty legume plants. It is recommended to conduct a study of the nasty behaviour of legume plants in the area umbra in the path of a total solar eclipse.

Educational, scientific, tourist and outreach potential of the September 1, 2016 Annular Solar Eclipse in Tanzania

NASA Astrophysics Data System (ADS)

Tayabali Jiwaji, Noorali

2015-08-01

Tanzania will witness a major astronomical spectacle of an annular eclipse on September 1, 2016. The central part of the eclipse will pass through southern Tanzania, crossing national parks and game reserves such as Katavi and the world famous Selous. For the rest of Tanzania and neighbouring countries it will be a memorable event with large of the proportion of the Sun being covered up. The climate in Tanzania during September is cool and dry which will provide ideal viewing conditions. Solar eclipse events attract "eclipse chasers" from around the globe.Scientific interest in measuring the properties of the Sun and the effects of the eclipse on the atmosphere will allow local scientists to partner with leading scientists to gain valuable experience and knowledge.Local population's wonder and interest in eclipses can be exploited through public-private partnerships by encouraging students and local people to travel to the central path or to observe from their backyards. Large number of eclipse glasses can be manufactured cheaply using safe solar filters for supplying to students and general population in Tanzania and neigbouring countries. This will raise science awareness about the wonders of our Universe.When combined with the attraction of Tanzania's treasures in the north and the 16 tonne Mbozi meteorite in southern Tanzania, the touristic potential of this event can be exploited through tour packages and worldwide advertisements during the coming year.

Eclipsing binary stars with a δ Scuti component

NASA Astrophysics Data System (ADS)

Kahraman Aliçavuş, F.; Soydugan, E.; Smalley, B.; Kubát, J.

2017-09-01

Eclipsing binaries with a δ Sct component are powerful tools to derive the fundamental parameters and probe the internal structure of stars. In this study, spectral analysis of six primary δ Sct components in eclipsing binaries has been performed. Values of Teff, v sin I, and metallicity for the stars have been derived from medium-resolution spectroscopy. Additionally, a revised list of δ Sct stars in eclipsing binaries is presented. In this list, we have only given the δ Sct stars in eclipsing binaries to show the effects of the secondary components and tidal-locking on the pulsations of primary δ Sct components. The stellar pulsation, atmospheric and fundamental parameters (e.g. mass, radius) of 92 δ Sct stars in eclipsing binaries have been gathered. Comparison of the properties of single and eclipsing binary member δ Sct stars has been made. We find that single δ Sct stars pulsate in longer periods and with higher amplitudes than the primary δ Sct components in eclipsing binaries. The v sin I of δ Sct components is found to be significantly lower than that of single δ Sct stars. Relationships between the pulsation periods, amplitudes and stellar parameters in our list have been examined. Significant correlations between the pulsation periods and the orbital periods, Teff, log g, radius, mass ratio, v sin I and the filling factor have been found.

Discovery of deep eclipses in the cataclysmic variable IPHAS J051814.33+294113.0

NASA Astrophysics Data System (ADS)

Kozhevnikov, V. P.

2018-06-01

Performing the photometric observations of the cataclysmic variable IPHAS J051814.33+294113.0, we discovered very deep eclipses. The observations were obtained over 14 nights, had a total duration of 56 hours and covered one year. The large time span, during which we observed the eclipses, allowed us to measure the orbital period in IPHAS J051814.33+294113.0 with high precision, P_{orb}=0.20603098± 0.00000025 d. The prominent parts of the eclipses lasted 0.1± 0.01 phases or 30± 3 min. The depth of the eclipses was variable in the range 1.8-2.9 mag. The average eclipse depth was equal to 2.42± 0.06 mag. The prominent parts of the eclipses revealed a smooth and symmetric shape. We derived the eclipse ephemeris, which, according to the precision of the orbital period, has a formal validity time of 500 years. This ephemeris can be useful for future investigations of the long-term period changes. During the latter four observational nights in 2017 January, we observed the sharp brightness decrease of IPHAS J051814.33+294113.0 by 2.3 mag. This brightness decrease imitated the end of the dwarf nova outburst. However, the long-term light curve of IPHAS J051814.33+294113.0 obtained in the course of the Catalina Sky Survey during 8 years showed no dwarf nova outbursts. From this we conclude that IPHAS J051814.33+294113.0 is a novalike variable. Moreover, the sharp brightness decrease, which we observed in IPHAS J051814.33+294113.0, suggests that this novalike variable belongs to the VY Scl-subtype. Due to very deep eclipses, IPHAS J051814.33+294113.0 is suitable to study the accretion disc structure using eclipse mapping techniques. Because this novalike variable has the long orbital period, it is of interest to determine the masses of the stellar components from radial velocity measurements. Then, our precise eclipse ephemeris can be useful to the phasing of spectroscopic data.

Solar Activity and Motions in the Solar Chromosphere and Corona at the 2012 and 2013 Total and Annular Eclipses in the U.S., Australia, and Africa

NASA Astrophysics Data System (ADS)

Pasachoff, Jay M.; Babcock, B. A.; Davis, A. B.; Demianski, M.; Lucas, R.; Lu, M.; Dantowitz, R.; Rusin, V.; Saniga, M.; Seaton, D. B.; Gaintatzis, P.; Voulgaris, A.; Seiradakis, J. H.; Gary, D. E.; Shaik, S. B.

2014-01-01

Our studies of the solar chromosphere and corona at the 2012 and 2013 eclipses shortly after cycle maximum 24 (2011/2012) of solar activity (see: http://www.swpc.noaa.gov/SolarCycle/) involved radio observations of the 2012 annular eclipse with the Jansky Very Large Array, optical observations of the 2012 total eclipse from Australia, optical observations of the 2013 annular eclipse from Tennant Creek, Australia, and the 3 November 2013 total solar eclipse from Gabon. Our observations are coordinated with those from solar spacecraft: Solar Dynamics Observatory AIA and HMI, Hinode XRT and SOT, SOHO LASCO and EIT, PROBA2 SWAP, and STEREO SECCHI. Our 2012 totality observations include a CME whose motion was observed with a 37-minute interval. We include first results from the expedition to Gabon for the 3 November 2013 eclipse, a summary of eclipse results from along the path of totality across Africa, and a summary of the concomitant spacecraft observations. The Williams College 2012 expeditions were supported in part by NSF grant AGS-1047726 from Solar Terrestrial Research/NSF AGS, and by the Rob Spring Fund and Science Center funds at Williams. The JVLA is supported by the NSF. The Williams College 2013 total-eclipse expedition was supported in part by grant 9327-13 from the Committee for Research and Exploration of the National Geographic Society. ML was also supported in part by a Grant-In-Aid of Research from the National Academy of Sciences, administered by Sigma Xi, The Scientific Research Society (Grant ID: G20120315159311). VR and MS acknowledge support for 2012 from projects VEGA 2/0003/13 and NGS-3139-12 of the National Geographic Society. We are grateful to K. Shiota (Japan) for kindly providing us with some of his 2012 eclipse coronal images. We thank Alec Engell (Montana State U) for assistance on site, and Terry Cuttle (Queensland Amateur Astronomers) for help with site arrangements. We thank Aram Friedman (Ansible Technologies), Michael Kentrianakis, and Nicholas Weber (Dexter Southfield School) for collaboration on imaging at the Australian total eclipse.

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

Kim, Chun-Hwey; Song, Mi-Hwa; Yoon, Jo-Na

A photometric study of BD And was made through the analysis of two sets of new BVR light curves. The light curves with migrating photometric waves outside eclipse show that BD And is a short-period RS CVn-type binary star. The analysis of all available timings reveals that the orbital period has varied in a strictly cyclical way with a period of 9.2 yr. The periodic variation most likely arises from the light-time effect due to a tertiary moving in a highly elliptical orbit (e {sub 3} = 0.76). The Applegate mechanism could not operate properly in the eclipsing pair. Themore » light curves were modeled with two large spots on the hotter star and a large third light amounting to about 14% of the total systemic light. BD And is a triple system: a detached binary system consisting of two nearly equal solar-type stars with an active primary star and a G6-G7 tertiary dwarf. The absolute dimensions of the eclipsing pair and tertiary components were determined. The three components with a mean age of about 5.8 Gyr are located at midpositions in main-sequence bands. The radius of the secondary is about 17% larger than that deduced from stellar models. The orbital and radiometric characteristics of the tertiary are intensively investigated. One important feature is that the mutual inclination between two orbits is larger than 60°, implying that Kozai cycles had occurred very efficiently in the past. The possible past and future evolutions of the BD And system, driven by KCTF and MBTF, are also discussed.« less

Towards a Fundamental Understanding of Short Period Eclipsing Binary Systems Using Kepler Data

NASA Astrophysics Data System (ADS)

Prsa, Andrej

Kepler's ultra-high precision photometry is revolutionizing stellar astrophysics. We are seeing intrinsic phenomena on an unprecedented scale, and interpreting them is both a challenge and an exciting privilege. Eclipsing binary stars are of particular significance for stellar astrophysics because precise modeling leads to fundamental parameters of the orbiting components: masses, radii, temperatures and luminosities to better than 1-2%. On top of that, eclipsing binaries are ideal physical laboratories for studying other physical phenomena, such as asteroseismic properties, chromospheric activity, proximity effects, mass transfer in close binaries, etc. Because of the eclipses, the basic geometry is well constrained, but a follow-up spectroscopy is required to get the dynamical masses and the absolute scale of the system. A conjunction of Kepler photometry and ground- based spectroscopy is a treasure trove for eclipsing binary star astrophysics. This proposal focuses on a carefully selected set of 100 short period eclipsing binary stars. The fundamental goal of the project is to study the intrinsic astrophysical effects typical of short period binaries in great detail, utilizing Kepler photometry and follow-up spectroscopy to devise a robust and consistent set of modeling results. The complementing spectroscopy is being secured from 3 approved and fully funded programs: the NOAO 4-m echelle spectroscopy at Kitt Peak (30 nights; PI Prsa), the 10- m Hobby-Eberly Telescope high-resolution spectroscopy (PI Mahadevan), and the 2.5-m Sloan Digital Sky Survey III spectroscopy (PI Mahadevan). The targets are prioritized by the projected scientific yield. Short period detached binaries host low-mass (K- and M- type) components for which the mass-radius relationship is sparsely populated and still poorly understood, as the radii appear up to 20% larger than predicted by the population models. We demonstrate the spectroscopic detection viability in the secondary-to-primary light ratio regime of ~1-2% for the circumbinary host system Kepler-16. Semi-detached binaries are ideal targets to study the dynamical processes such as mass flow and accretion, and the associated thermal processes such as intensity variation due to distortion of the lobe-filling component and material inflow collisions with accretion disks. Overcontact binaries are very abundant, yet their evolution and radiative properties are poorly understood and conflicting theories exist to explain their population frequency and structure. In addition, we will measure eclipse timing variations for all program binaries that attest to the presence of perturbing third bodies (stellar and substellar!) or dynamical interaction between the components. By a dedicated, detailed, manual modeling of these sets of targets, we will be able to use Kepler's ultra-high precision photometry to a rewarding scientific end. Thanks to the unprecedented quality of Kepler data, this will be a highly focused effort that maximizes the scientific yield and the reliability of the results. Our team has ample experience dealing with Kepler data (PI Prsa serves as chair of the Eclipsing Binary Working Group in the Kepler Science Team), spectroscopic follow-up (Co-Is Mahadevan and Bender both have experience with radial velocity instrumentation and large spectroscopic surveys), and eclipsing binary modeling (PI Prsa and Co-I Devinney both have a long record of theoretical and computational development of modeling tools). The bulk of funding we are requesting is for two postdoctoral research fellows to conduct this work at 0.5 FTE/year each, for the total of 2 years.

Observations of the eclipsing binary b Persei

NASA Astrophysics Data System (ADS)

Templeton, Matthew R.

2015-01-01

Dr. Robert Zavala (USNO-Flagstaff) et al. request V time-series observations of the bright variable star b Persei 7-21 January 2015 UT, in hopes of catching a predicted eclipse on January 15. This is a follow-up to the February 2013 campaign announced in Alert Notice 476, and will be used as a photometric comparison for upcoming interferometric observations with the Navy Precision Optical Interferometer (NPOI) in Arizona. b Per (V=4.598, B-V=0.054) is ideal for photoelectric photometers or DSLR cameras. Telescopic CCD observers may observe by stopping down larger apertures. Comparison and check stars assigned by PI: Comp: SAO 24412, V=4.285, B-V = -0.013; Check: SAO 24512, V=5.19, B-V = -0.05. From the PI: "[W]e wanted to try and involve AAVSO observers in a follow up to our successful detection of the b Persei eclipse of Feb 2013, AAVSO Alert Notice 476 and Special Notice 333. Our goal now is to get good time resolution photometry as the third star passes in front of the close ellipsoidal binary. The potential for multiple eclipses exists. The close binary has a 1.5 day orbital period, and the eclipsing C component requires about 4 days to pass across the close binary pair. The primary eclipse depth is 0.15 magnitude. Photometry to 0.02 or 0.03 mags would be fine to detect this eclipse. Eclipse prediction date (JD 2457033.79 = 2015 01 11 UT, ~+/- 1 day) is based on one orbital period from the 2013 eclipse." More information is available at PI's b Persei eclipse web page: http://inside.warren-wilson.edu/~dcollins/bPersei/. Finder charts with sequence may be created using the AAVSO Variable Star Plotter (https://www.aavso.org/vsp). Observations should be submitted to the AAVSO International Database. See full Alert Notice for more details and information on the targets.

Detection of the Secondary Eclipse of Exoplanet HAT P-11b

NASA Technical Reports Server (NTRS)

Barry, R. K.; Deming, L. D.; Bakos, G.; Harrington, J.; Madhusudhan, N.; Noyes, R.; Seager, S.

2010-01-01

We have successfully conducted secondary eclipse observations of exoplanet HAT-P-11b using the Spitzer Space Telescope. HAT-P-11b was, until very recently, the smallest transiting extrasolar planet yet found and one of only two known exo-Neptunes. We observed the system at 3.6 microns for a period of 22 hours centered on the anticipated secondary eclipse time, to detect the eclipse and determine its phase. Having detected the secondary eclipse, we are at present making a more focused series of observations in both the 3.6 and 4.5 micron bands to fully characterize it. HAT-P-11b has a period of 4.8878 days, radius of 0.422 RJ, mass of 0.081 MJ and semi-major axis 0.053 AU. Measurements of the secondary eclipse will serve to clarify two key issues; 1) the planetary brightness temperature and the nature of its atmosphere, and 2) the eccentricity of its orbit, with implications for its dynamical evolution. A precise determination of the orbit phase for the secondary eclipse will also be of great utility for Kepler observations of this system at visible wavelengths.

Boise State's Idaho Eclipse Outreach Program

NASA Astrophysics Data System (ADS)

Davis, Karan; Jackson, Brian

2017-10-01

The 2017 total solar eclipse is an unprecedented opportunity for astronomical education throughout the continental United States. With the path of totality passing through 14 states, from Oregon to South Carolina, the United States is expecting visitors from all around the world. Due to the likelihood of clear skies, Idaho was a popular destination for eclipse-chasers. In spite of considerable enthusiasm and interest by the general population, the resources for STEM outreach in the rural Pacific Northwest are very limited. In order to help prepare Idaho for the eclipse, we put together a crowdfunding campaign through the university and raised over $10,000. Donors received eclipse shades as well as information about the eclipse specific to Idaho. Idaho expects 500,000 visitors, which could present a problem for the many small, rural towns scattered across the path of totality. In order to help prepare and equip the public for the solar eclipse, we conducted a series of site visits to towns in and near the path of totality throughout Idaho. To maximize the impact of this effort, the program included several partnerships with local educational and community organizations and a focus on the sizable refugee and low-income populations in Idaho, with considerable attendance at most events.

Accuracy of lunar eclipse observations made by Jesuit astronomers in China.

NASA Astrophysics Data System (ADS)

Fatoohi, L. J.; Stephenson, F. R.

1996-02-01

The Jesuit astronomers observed numerous lunar eclipses at Beijing and summaries of their observations - made between 1644 and 1785 - are preserved. The various lunar eclipse measurements that the Jesuits made are compared with the results of present-day computation.

2017 Solar Eclipse Event

NASA Image and Video Library

2017-06-11

Former Spacelab 1 Mission scientist Rick Chappell views the August 21, 2017 solar eclipse with his wife. Chappell, a former associate director for science at Marshall and now a physics professor at Vanderbilt University in Nashville, joined a throng of Marshall personnel to marvel at the eclipse.

GK Dra: a delta Scuti Star in a New Eclipsing System Discovered by Hipparcos

NASA Astrophysics Data System (ADS)

Dallaporta, Sergio; Tomov, Toma; Zwitter, Tomaz; Munari, Ulisse

2002-09-01

GK Dra has been discovered by the Hipparcos mission as a 17 days eclipsing binary. We present here the first ground-based study of this star, based on extensive BV photoelectric photometry. We found a period of 9.974 days, equal depth primary and secondary eclipse (m=0.35 mag), no color variation in eclipse, and one of the components being a Sct star with an amplitude of 0.04 mag and a period of about 2.7 hours.

Determination of the Io heat flow. 1: Eclipse observations

NASA Technical Reports Server (NTRS)

Sinton, W. M.; Kaminski, C.

1983-01-01

The thermal emission from Io during eclipse by Jupiter yields data from which the total thermal flux from the volcanoes on the satellite surface can be estimated. Thermal infrared observations in spectral bands between 3.5 and 30 microns of five Io eclipse reappearances and one eclipse disappearance are reported and discussed. The thermal emission of the volcanoes which occurs almost all of the time was determined from the Io heat flux data. The thermal observations of Io are discussed with respect to previous thermophysical theories.

Preliminary Studies of Interacting Binaries From NURO Observations : V963 Cygni and GSC 1419 0091

NASA Astrophysics Data System (ADS)

Samec, R. G.; Jones, S. M.; Scott, T.; Branning, J.; Miller, J.; Faulkner, D. R.; Hawkins, N. C.

2005-12-01

We present preliminary analyses of V963 and V965 Cygni based on observations taken at the National Undergraduate Research Observatory (NURO). Our CCD observations were taken 07-12 March 2005 and 19-25 July 2004 by DRF,RGS, and NCH with the Lowell Observatory 31-inch reflector. Standard UBVRI filters were used. Preliminary light curve analyses and updated periodicity studies are presented for these variables. V963 Cyg (GSC 2656 1995,α (2000) = 19h 44m 04.92s, δ (2000) = +31 41 50.17) is a detached binary discovered by Wachmann (Ast Abh Ham St VI, #1, 1961). The eclipse depths are nearly equal, 0.78 and 0.67 magnitudes in in V in the primary and secondary eclipses, respectively, causing observers to MISTAKINGLY classify it as an Algol-type system. Thus the two stars are similar in temperature and the period has to be DOUBLED. The curves appear fairlysymmetrical with a depressed section following the primary eclipse in R and I about 0.2 phase units wide. In BVRI, 100 to 130 observations were taken along with 75 in U. We determined three new times of minimum light, two secondary eclipses, HJD Min II = 2453207.76857±0.00029d and 2453211.9540±0.0032d, and one primary eclipse HJD Min I = 2453209.86073±0.00095d. A corrected period and an improved ephemeris was computed using available times of minimum light: HJD Min I = 2453209.8616(±0.0011)d + 1.39466792(±0.00000019)*E. GSC 1419 0091 (Brh V132) [α (2000) = 10h 11m 59.152s,δ (2000) = +16 52 30.28] is an overcontact binary discovered by Klaus Bernhard (BAV, http://www.var-mo.de/star/brh_v132.htm). We took approximately 60-65 observations in each of B,V,R, and I. We determined four new times of minimum light: HJD Min I = 2453437.8293(±0.0003) and 2453441.8291(±0.0019), and HJD Min II = 2453437.6973(±0.0012) and 2453442.76317(±0.0005). We computed an improved ephemeris from all available times of minimum and low light: HJD Min I = 2452754.4733(±0.0030)d + 0.2667251*E(±0.0000011). The light curves show shallow eclipse amplitudes of 0.46 and 0.43 mags in B and V, respectively, and a time of constant light in the secondary eclipse of 31 m. We wish to thank the NURO for their allocation of observing time, as well as NASA and the American Astronomical Society for their support in paying for travel and publication expenses.

Properties OF M31. V. 298 eclipsing binaries from PAndromeda

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

Lee, C.-H.; Koppenhoefer, J.; Seitz, S.

2014-12-10

The goal of this work is to conduct a photometric study of eclipsing binaries in M31. We apply a modified box-fitting algorithm to search for eclipsing binary candidates and determine their period. We classify these candidates into detached, semi-detached, and contact systems using the Fourier decomposition method. We cross-match the position of our detached candidates with the photometry from Local Group Survey and select 13 candidates brighter than 20.5 mag in V. The relative physical parameters of these detached candidates are further characterized with the Detached Eclipsing Binary Light curve fitter (DEBiL) by Devor. We will follow up the detachedmore » eclipsing binaries spectroscopically and determine the distance to M31.« less

An ultraviolet investigation of the unusual eclipsing binary system FF AQR

NASA Technical Reports Server (NTRS)

Dorren, J. D.; Guinan, E. F.; Sion, E. M.

1982-01-01

A series of seven low dispersion IUE exposures in ultraviolet and wavelength regions obtained on December 6, 1981 during the eclipse of the subdwarf, during egress, and out of eclipse is analyzed. These observations and the binary phase at which they were made are shown on a schematic representation of the V-band light curve obtained in 1975. The depth in V is 0.15 mag. The circles are IUE V magnitudes from FES measures obtained during the observing run. They indicate an eclipse depth some 0.05 mag lower than expected, possibly due to difficulties with the color term in the FES calibration. The eclipse depths of Dworetsky in U, B and V were assumed in the calculations.

Interacting Winds in Eclipsing Symbiotic Systems - The Case Study of EG Andromedae

NASA Astrophysics Data System (ADS)

Calabrò, Emanuele

2014-03-01

We report the mathematical representation of the so called eccentric eclipse model, whose numerical solutions can be used to obtain the physical parameters of a quiescent eclipsing symbiotic system. Indeed the nebular region produced by the collision of the stellar winds should be shifted to the orbital axis because of the orbital motion of the system. This mechanism is not negligible, and it led us to modify the classical concept of an eclipse. The orbital elements obtained from spectroscopy and photometry of the symbiotic EG Andromedae were used to test the eccentric eclipse model. Consistent values for the unknown orbital elements of this symbiotic were obtained. The physical parameters are in agreement with those obtained by means of other simulations for this system.

Response of Cassava canopy to mid-day pseudo sunrise induced by solar eclipse.

PubMed

Latha, R; Murthy, B S

2013-07-01

Variations in CO(2) concentration over a cassava canopy were measured during a solar eclipse at Thiruvananthapuram, India. The analysis presented attempts to differentiate between the eclipse effect and the possible effect of thick clouds, taking CO(2) as a proxy for photosynthesis. CO(2) and water vapor were measured at a rate of 10 Hz, and radiation at 1 Hz, together with other meteorological parameters. A rapid reduction in CO(2) observed post-peak eclipse, due apparently to intense photosynthesis, appears similar to what happens at daybreak/post-sunrise. The increase in CO(2) (4 ppm) during peak eclipse, with radiation levels falling below the photosynthesis cut-off for cassava, indicates domination of respiration due to the light-limiting conditions.

Data Collection During the Great American Eclipse

NASA Astrophysics Data System (ADS)

Vernier, Dave

2017-12-01

I am lucky enough (and old enough) to have seen three total eclipses. About a year ago, I became aware of the total eclipse that was coming to the United States on August 21, 2017. Because I knew how exciting a total eclipse can be, I spent a lot of time encouraging people to travel to the zone of totality if they possibly could. I also encouraged teachers to turn this event into a STEM lesson by taking data. We asked teachers to join us in collecting data during the eclipse and to share it. The people collecting these data were either teachers or former teachers (like me). Many times, the sensors were mounted with duct tape and rubber bands, but we got some great data!

Response of Cassava canopy to mid-day pseudo sunrise induced by solar eclipse

NASA Astrophysics Data System (ADS)

Latha, R.; Murthy, B. S.

2013-07-01

Variations in CO2 concentration over a cassava canopy were measured during a solar eclipse at Thiruvananthapuram, India. The analysis presented attempts to differentiate between the eclipse effect and the possible effect of thick clouds, taking CO2 as a proxy for photosynthesis. CO2 and water vapor were measured at a rate of 10 Hz, and radiation at 1 Hz, together with other meteorological parameters. A rapid reduction in CO2 observed post-peak eclipse, due apparently to intense photosynthesis, appears similar to what happens at daybreak/post-sunrise. The increase in CO2 (4 ppm) during peak eclipse, with radiation levels falling below the photosynthesis cut-off for cassava, indicates domination of respiration due to the light-limiting conditions.

Reliability of the totality of the eclipse in AD 628 in Nihongi

NASA Astrophysics Data System (ADS)

Tanikawa, Kiyotaka; Soma, Mitsuru

It is generally accepted that the solar eclipse on April 10, 628 (the second day, the third month, the thirty-sixth year of Empress Suiko) recorded in Nihongi is not total but partial though it is written as a total eclipse. We argue for the record appealing to the contemporary total or near total eclipses in Chinese history books and Japanese occultation observation. If the value of the tidal term in the lunar longitude (the coefficient of T2 term) is different from the present value by about -2"/cy-2, then there disappears an apparent contradiction of ΔT around AD 600 derived from lunar and solar eclipses. Grazing occultation data are found to be useful.

ISAAC Photometric Comparison of ECLIPSE Jitter and the ORAC-DR Equivalent Recipe for ISAAC

NASA Astrophysics Data System (ADS)

Currie, M. J.

2005-12-01

Motivated by a request from astronomers demanding accurate and consistent infrared photometry, I compare the photometry and quality of mosaics generated by the ECLIPSE jitter task and the ORAC-DR JITTER_SELF_FLAT recipe in two fields. The current (v4.9.0) ECLIPSE produces photometry a few percent fainter than ORAC-DR; the systematic trend with magnitude seen in v4.4.1 is now removed. Random errors arising from poor flat-fielding are not resolved. ECLIPSE generates noisier mosaics; ORAC-DR has poorer bias removal in crowded fields and defaults to larger mosaics. ORAC-DR runs a few times slower than ECLIPSE, but its recipe development is measured in weeks, not years.

Crowd-Sourced Radio Science at Marshall Space Flight Center

NASA Technical Reports Server (NTRS)

Fry, C. D.; McTernan, J. K.; Suggs, R. M.; Rawlins, L.; Krause, L. H.; Gallagher, D. L.; Adams, M. L.

2018-01-01

August 21, 2017 provided a unique opportunity to investigate the effects of the total solar eclipse on high frequency (HF) radio propagation and ionospheric variability. In Marshall Space Flight Center's partnership with the US Space and Rocket Center (USSRC) and Austin Peay State University (APSU), we engaged citizen scientists and students in an investigation of the effects of an eclipse on the mid-latitude ionosphere. Activities included fieldwork and station-based data collection of HF Amateur Radio frequency bands and VLF radio waves before, during, and after the eclipse to build a continuous record of changing propagation conditions as the moon's shadow marched across the United States. Post-eclipse radio propagation analysis provided insights into ionospheric variability due to the eclipse.

Simulation of the 21 August 2017 Solar Eclipse Using the Whole Atmosphere Community Climate Model-eXtended

NASA Astrophysics Data System (ADS)

McInerney, Joseph M.; Marsh, Daniel R.; Liu, Han-Li; Solomon, Stanley C.; Conley, Andrew J.; Drob, Douglas P.

2018-05-01

We performed simulations of the atmosphere-ionosphere response to the solar eclipse of 21 August 2017 using the Whole Atmosphere Community Climate Model-eXtended (WACCM-X v. 2.0) with a fully interactive ionosphere and thermosphere. Eclipse simulations show temperature changes in the path of totality up to -3 K near the surface, -1 K at the stratopause, ±4 K in the mesosphere, and -40 K in the thermosphere. In the F region ionosphere, electron density is depleted by about 55%. Both the temperature and electron density exhibit global effects in the hours following the eclipse. There are also significant effects on stratosphere-mesosphere chemistry, including an increase in ozone by nearly a factor of 2 at 65 km. Dynamical impacts of the eclipse in the lower atmosphere appear to propagate to the upper atmosphere. This study provides insight into coupled eclipse effects through the entire atmosphere from the surface through the ionosphere.

Implications of the Secondary Eclipse of Exoplanet HAT-P-11b

NASA Technical Reports Server (NTRS)

Barry, Richard K.; Deming, L. D.; Bakos, G.; Harrington, J.; Madhusudhan, N.; Noyes, R.; Seager, S.

2010-01-01

We observed exoplanet HAT-P-11b and have successfully detected its secondary eclipse. We conducted observations using the Spitzer Space Telescope in the post-cryo mission at 3.6 microns for a period of 22 hours centered on the anticipated secondary eclipse time, to detect the eclipse and determine its phase. Having detected the secondary eclipse, we are at present making a more focused series of observations in both the 3.6 and 4.5 micron bands to fully characterize it. HAT-P-11b is one of only two known exo-Neptunes and has a period of 4.8878 days, radius of 0.422 RJ, mass of 0.081 MJ and semi-major axis 0.053 AU. Measurements of the secondary eclipse will serve to clarify two key issues; 1) the planetary brightness temperature and the nature of its atmosphere, and 2) the eccentricity of its orbit, with implications for its dynamical evolution. We discuss implications of these observations.

V380 Dra: New short-period totally eclipsing active binary

NASA Astrophysics Data System (ADS)

Özdarcan, O.

2014-02-01

In this study, first complete and standard BVR light curves and photometric analysis of the eclipsing binary system V380 Dra are presented. Photometric analysis result indicates that the system has components which are cool main sequence stars. In light and color curves, remarkable asymmetry is observed, especially after secondary minimum, which is believed to be a result of chromospheric activity in one or both components. O-C diagram of available small number of eclipse times, together with new eclipse timings in this work, exhibits no significant variation. Preliminary light curve solution shows that the secondary minimum is total eclipse. By using the advantage of total eclipse and mass-luminosity relation, it is found that the system has a possible mass ratio of q = 0.81. First estimation of masses and radii of primary and secondary components are M1 = 0.77 M⊙,M2 = 0.62 M⊙ and R1 = 0.93 R⊙,R2 = 0.77 R⊙, respectively.

Eclipse SteerTech liquid lenslet beam steering technology

NASA Astrophysics Data System (ADS)

Westfall, Raymond T.; Rogers, Stanley; Shannon, Kenneth C., III

2007-09-01

Eclipse SteerTech TM transmissive fluid state electrowetting technology has successfully demonstrated the ability to control the shape and position of a fluid lenslet. In its final form, the technology will incorporate a dual fluid lenslet approach capable of operating in extremely high acceleration environments. The beam steering system works on the principle of electro-wetting. A substrate is covered with a closely spaced array of, independently addressable, transparent, electrically conductive pixels utilizing Eclipse's proprietary EclipseTEC TM technology. By activating and deactivating selected EclipseTEC TM pixels in the proper sequence, the shape and position of fluid lenslets or arrays of lenslets can be dynamically changed at will. The position and shape of individual fluid lenslets may be accurately controlled on any flat, simply curved, or complex curved, transparent or reflective surface. The smaller the pixels the better control of the position and shape of the fluid lenslets. Information on the successful testing of the Eclipse SteerTech TM lenslet and discussion of its use in a de-centered lenslet array will be presented.

Solar Coronal Jets Extending to High Altitudes Observed during the 2017 August 21 Total Eclipse

NASA Astrophysics Data System (ADS)

Hanaoka, Yoichiro; Hasuo, Ryuichi; Hirose, Tsukasa; Ikeda, Akiko C.; Ishibashi, Tsutomu; Manago, Norihiro; Masuda, Yukio; Morita, Sakuhiro; Nakazawa, Jun; Ohgoe, Osamu; Sakai, Yoshiaki; Sasaki, Kazuhiro; Takahashi, Koichi; Toi, Toshiyuki

2018-06-01

Coronal jets, which extend from the solar surface to beyond 2 R ⊙, were observed in the polar coronal hole regions during the total solar eclipse on 2017 August 21. In a time-series of white-light images of the corona spanning 70 minutes taken with our multi-site observations of this eclipse, six jets were found as narrow structures upwardly ejected with an apparent speed of about 450 km s‑1 in polar plumes. On the other hand, extreme-ultraviolet (EUV) images taken with the Atmospheric Image Assembly of the Solar Dynamics Observatory show that all of the eclipse jets were preceded by EUV jets. Conversely, all the EUV jets whose brightnesses are comparable to ordinary soft X-ray jets and that occurred in the polar regions near the eclipse period, were observed as eclipse jets. These results suggest that ordinary polar jets generally reach high altitudes and escape from the Sun as part of the solar wind.

Time Series Observations of the 2015 Eclipse of b Persei (not beta Persei) (Abstract)

NASA Astrophysics Data System (ADS)

Collins, D. F.

2016-06-01

(Abstract only) The bright (V = 4.6) ellipsoidal variable b Persei consists of a close non-eclipsing binary pair that shows a nearly sinusoidal light curve with a ~1.5 day period. This system also contains a third star that orbits the binary pair every 702 days. AAVSO observers recently detected the first ever optical eclipse of A-B binary pair by the third star as a series of snapshots (D. Collins, R. Zavala, J. Sanborn - AAVSO Spring Meeting, 2013); abstract published in Collins, JAAVSO, 41, 2, 391 (2013); b Per mis-printed as b Per therein. A follow-up eclipse campaign in mid-January 2015 recorded time-series observations. These new time-series observations clearly show multiple ingress and egress of each component of the binary system by the third star over the eclipse duration of 2 to 3 days. A simulation of the eclipse was created. Orbital and some astrophysical parameters were adjusted within constraints to give a reasonable fit to the observed light curve.

An Atlas of Far-ultraviolet Spectra of the Zeta Aurigae Binary 31 Cygni with Line Identifications

NASA Astrophysics Data System (ADS)

Hagen Bauer, Wendy; Bennett, Philip D.

2014-04-01

The ζ Aurigae system 31 Cygni (K4 Ib + B4 V) was observed by the FUSE satellite during total eclipse and at three phases during chromospheric eclipse. We present the coadded, calibrated spectra and atlases with line identifications. During total eclipse, emission from high ionization states (e.g., Fe III and Cr III) shows asymmetric profiles redshifted from the systemic velocity, while emission from lower ionization states (e.g., Fe II and O I) appears more symmetric and is centered closer to the systemic velocity. Absorption from neutral and singly ionized elements is detected during chromospheric eclipse. Late in chromospheric eclipse, absorption from the K star wind is detected at a terminal velocity of ~80 km s-1. These atlases will be useful for interpreting the far-UV spectra of other ζ Aur systems, as the observed FUSE spectra of 32 Cyg, KQ Pup, and VV Cep during chromospheric eclipse resemble that of 31 Cyg.

THE BERLIN EXOPLANET SEARCH TELESCOPE II CATALOG OF VARIABLE STARS. I. CHARACTERIZATION OF THREE SOUTHERN TARGET FIELDS

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

Fruth, T.; Cabrera, J.; Csizmadia, Sz.

2013-11-01

A photometric survey of three southern target fields with BEST II yielded the detection of 2406 previously unknown variable stars and an additional 617 stars with suspected variability. This study presents a catalog including their coordinates, magnitudes, light curves, ephemerides, amplitudes, and type of variability. In addition, the variability of 17 known objects is confirmed, thus validating the results. The catalog contains a number of known and new variables that are of interest for further astrophysical investigations, in order to, e.g., search for additional bodies in eclipsing binary systems, or to test stellar interior models. Altogether, 209,070 stars were monitoredmore » with BEST II during a total of 128 nights in 2009/2010. The overall variability fraction of 1.2%-1.5% in these target fields is well comparable to similar ground-based photometric surveys. Within the main magnitude range of R in [11, 17], we identify 0.67(3)% of all stars to be eclipsing binaries, which indicates a completeness of about one third for this particular type in comparison to space surveys.« less

Nationwide Eclipse Ballooning Project

NASA Astrophysics Data System (ADS)

Colman Des Jardins, Angela; Berk Knighton, W.; Larimer, Randal; Mayer-Gawlik, Shane; Fowler, Jennifer; Harmon, Christina; Koehler, Christopher; Guzik, Gregory; Flaten, James; Nolby, Caitlin; Granger, Douglas; Stewart, Michael

2016-05-01

The purpose of the Nationwide Eclipse Ballooning Project is to make the most of the 2017 rare eclipse event in four main areas: public engagement, workforce development, partnership development, and science. The Project is focused on two efforts, both student-led: online live video of the eclipse from the edge of space and the study of the atmospheric response to the eclipse. These efforts, however, involving more than 60 teams across the US, are challenging in many ways. Therefore, the Project is leveraging the NASA Space Grant and NOAA atmospheric science communities to make it a success. The first and primary topic of this poster is the NASA Space Grant supported online live video effort. College and high school students on 48 teams from 31 states will conduct high altitude balloon flights from 15-20 locations across the 8/21/2017 total eclipse path, sending live video and images from near space to a national website. Video and images of a total solar eclipse from near space are fascinating and rare. It’s never been done live and certainly not in a network of coverage across a continent. In addition to the live video to the web, these teams are engaged in several other science experiments as secondary payloads. We also briefly highlight the eclipse atmospheric science effort, where about a dozen teams will launch over one hundred radiosondes from across the 2017 path, recording an unprecedented atmospheric data sample. Collected data will include temperature, density, wind, humidity, and ozone measurements.

Safety assessment of continuous glass filaments used in eclipse.

PubMed

Swauger, J E; Foy, J W

2000-11-01

Eclipse is a cigarette that produces smoke by primarily heating, rather than burning, tobacco. The Eclipse heat source assembly employs a continuous filament glass mat jacket to insulate the heat source. The glass mat insulator is composed of continuous glass filaments and a binder. The purpose of this article is to address the potential toxicological significance of the continuous glass filaments under the conditions of intended use. Transfer data and the unique physical characteristics of the filaments demonstrate that significant exposure of the smoker will not occur. The available environmental survey data clearly demonstrate that Eclipse smokers are extremely unlikely to be exposed to continuous glass filaments at a level that represents a biologically significant increase over background exposure to glass fibers. The chemical composition of the continuous glass filaments used in Eclipse is generally similar to C-glass fiber compositions such as MMVF 11 that have failed to produce either tumors or fibrosis in chronic inhalation studies conducted in rats. In vitro dissolution data demonstrate that the continuous glass filaments used in Eclipse are more soluble than biologically active fibers such as rock wool (MMVF 21) or asbestos. However, the continuous glass filaments used in Eclipse were not as soluble in simulated extracellular lung fluid as representative C-glass fibers (MMVF 10 and MMVF 11). In brief, exposure of Eclipse smokers to continuous glass filaments is extremely unlikely to occur at a level that may be construed to be of biological significance.

Migrating Dari Clustergen Flite Text-to-Speech Voice from Desktop to Android

DTIC Science & Technology

2014-09-01

Fig. 2 Android SDK Manager included in Eclipse ........................................................................7 Fig. 3 Android C Compiler...9 Android Flite Engine project imported to Eclipse .............................................................15 Fig. 10 Main page of the...17 Fig. 13 Building “libttsflite.so” in Eclipse using NDK ...............................................................18 Fig. 14

Preparing for the Eclipse

ERIC Educational Resources Information Center

Hurst, Anna; Plummer, Julia; Gurton, Suzanne; Schatz, Dennis

2017-01-01

On August 21, 2017, sky gazers all across North America will experience a total solar eclipse, arguably the most breathtaking of all astronomical phenomena. The August eclipse is an ideal astronomical event to observe with young children because it allows them to observe a powerful and easily accessible astronomical phenomenon. Observing…

VizieR Online Data Catalog: Parameters of 529 Kepler eclipsing binaries (Kjurkchieva+, 2017)

NASA Astrophysics Data System (ADS)

Kjurkchieva, D.; Vasileva, D.; Atanasova, T.

2017-11-01

We reviewed the Kepler eclipsing binary catalog (Prsa et al. 2011, Cat. J/AJ/141/83; Slawson et al. 2011, Cat. J/AJ/142/160; Matijevic et al. 2012) to search for detached eclipsing binaries with eccentric orbits. (5 data files).

A possible additional body in eclipsing binary system HS 2231+2441

NASA Astrophysics Data System (ADS)

Vidmachenko, A. P.; Shliakhetska, Ya. O.; Romanyuk, Ya. O.

2016-12-01

Analysis of the light curves of eclipsing binary systems HS 2231+2441, obtained with the 36-cm telescope, is made. In processing the photometric data on eclipses by method of timing, obtained evidence for the existence of a third body in the system.

Observational Δν-ρ¯ Relation for δ Sct Stars using Eclipsing Binaries and Space Photometry

NASA Astrophysics Data System (ADS)

García Hernández, A.; Martín-Ruiz, S.; Monteiro, Mário J. P. F. G.; Suárez, J. C.; Reese, D. R.; Pascual-Granado, J.; Garrido, R.

2015-10-01

Delta Scuti (δ Sct) stars are intermediate-mass pulsators, whose intrinsic oscillations have been studied for decades. However, modeling their pulsations remains a real theoretical challenge, thereby even hampering the precise determination of global stellar parameters. In this work, we used space photometry observations of eclipsing binaries with a δ Sct component to obtain reliable physical parameters and oscillation frequencies. Using that information, we derived an observational scaling relation between the stellar mean density and a frequency pattern in the oscillation spectrum. This pattern is analogous to the solar-like large separation but in the low order regime. We also show that this relation is independent of the rotation rate. These findings open the possibility of accurately characterizing this type of pulsator and validate the frequency pattern as a new observable for δ Sct stars.

KIC 6048106: an Algol-type eclipsing system with long-term magnetic activity and hybrid pulsations - I. Binary modelling

NASA Astrophysics Data System (ADS)

Samadi Ghadim, A.; Lampens, P.; Jassur, M.

2018-03-01

The A-F-type stars and pulsators (δ Scuti-γ Dor) are in a critical regime where they experience a transition from radiative to convective transport of energy in their envelopes. Such stars can pulsate in both gravity and acoustic modes. Hence, the knowledge of their fundamental parameters along with their observed pulsation characteristics can help in improving the stellar models. When residing in a binary system, these pulsators provide more accurate and less model-dependent stellar parameters than in the case of their single counterparts. We present a light-curve model for the eclipsing system KIC 6048106 based on the Kepler photometry and the code PHOEBE. We aim to obtain accurate physical parameters and tough constraints for the stellar modelling of this intermediate-mass hybrid pulsator. We performed a separate modelling of three light-curve segments which show a distinct behaviour due to a difference in activity. We also analysed the Kepler Eclipse Time Variations (ETVs). KIC 6048106 is an Algol-type binary with F5-K5 components, a near-circular orbit and a 1.56-d period undergoing variations of the order of Δ P/P˜eq 3.60× 10^{-7} in 287 ± 7 d. The primary component is a main-sequence star with M1 = 1.55 ± 0.11 M⊙, R1 = 1.57 ± 0.12 R⊙. The secondary is a much cooler subgiant with M2 = 0.33 ± 0.07 M⊙, R2 = 1.77 ± 0.16 R⊙. Many small near-polar spots are active on its surface. The second quadrature phase shows a brightness modulation on a time-scale 290 ± 7 d, in good agreement with the ETV modulation. This study reveals a stable binary configuration along with clear evidence of a long-term activity of the secondary star.

The massive multiple system HD 64315

NASA Astrophysics Data System (ADS)

Lorenzo, J.; Simón-Díaz, S.; Negueruela, I.; Vilardell, F.; Garcia, M.; Evans, C. J.; Montes, D.

2017-10-01

Context. The O6 Vn star HD 64315 is believed to belong to the star-forming region known as NGC 2467, but previous distance estimates do not support this association. Moreover, it has been identified as a spectroscopic binary, but existing data support contradictory values for its orbital period. Aims: We explore the multiple nature of this star with the aim of determining its distance, and understanding its connection to NGC 2467. Methods: A total of 52 high-resolution spectra have been gathered over a decade. We use their analysis, in combination with the photometric data from All Sky Automated Survey and Hipparcos catalogues, to conclude that HD 64315 is composed of at least two spectroscopic binaries, one of which is an eclipsing binary. We have developed our own program to fit four components to the combined line shapes. Once the four radial velocities were derived, we obtained a model to fit the radial-velocity curves using the Spectroscopic Binary Orbit Program (SBOP). We then implemented the radial velocities of the eclipsing binary and the light curves in the Wilson-Devinney code iteratively to derive stellar parameters for its components. We were also able to analyse the non-eclipsing binary, and to derive minimum masses for its components which dominate the system flux. Results: HD 64315 contains two binary systems, one of which is an eclipsing binary. The two binaries are separated by 0.09 arcsec (or 500 AU) if the most likely distance to the system, 5 kpc, is considered. The presence of fainter companions is not excluded by current observations. The non-eclipsing binary (HD 64315 AaAb) has a period of 2.70962901 ± 0.00000021 d. Its components are hotter than those of the eclipsing binary, and dominate the appearance of the system. The eclipsing binary (HD 64315 BaBb) has a shorter period of 1.0189569 ± 0.0000008 d. We derive masses of 14.6 ± 2.3 M⊙ for both components of the BaBb system. They are almost identical; both stars are overfilling their respective Roche lobes, and share a common envelope in an overcontact configuration. The non-eclipsing binary is a detached system composed of two stars with spectral types around O6 V with minimum masses of 10.8 M⊙ and 10.2 M⊙, and likely masses ≈ 30 M⊙. Conclusions: HD 64315 provides a cautionary tale about high-mass star isolation and multiplicity. Its total mass is likely above 90M⊙, but it seems to have formed without an accompanying cluster. It contains one the most massive overcontact binaries known, a likely merger progenitor in a very wide multiple system. Based on observations obtained at the European Southern Observatory under programmes 078.D-0665(A), 082-D.0136 and 093.A-9001(A). Based on observations made with the Nordic Optical Telescope, operated on the island of La Palma jointly by Denmark, Finland, Iceland, Norway, and Sweden, in the Spanish Observatorio del Roque de los Muchachos of the Instituto de Astrofísica de Canarias.

Paper Moon: Simulating a Total Solar Eclipse

ERIC Educational Resources Information Center

Madden, Sean P.; Downing, James P.; Comstock, Jocelyne M.

2006-01-01

This article describes a classroom activity in which a solar eclipse is simulated and a mathematical model is developed to explain the data. Students use manipulative devices and graphing calculators to carry out the experiment and then compare their results to those collected in Koolymilka, Australia, during the 2002 eclipse.

2017 Solar Eclipse, Ames Research Center

NASA Image and Video Library

2017-08-21

Taking a break from his duties at the Ames Vertical Gun Range to look up at the eclipse over Ames Research Center in Mountain View Adam Parrish not only views but wears, on his forehead, the image of the 2017 Solar eclipse at 09:20:56 on August 21, 2017.

2017 Solar Eclipse Event

NASA Image and Video Library

2017-06-11

Former Spacelab 1 mission scientist Rick Chappell addresses Marshall team members during the Aug. 21 eclipse-watching event in Activities Building 4316. Chappell, a former associate director for science at Marshall and now a physics professor at Vanderbilt University in Nashville, joined a throng of Marshall personnel to marvel at the eclipse.

The Astronomical Almanac Online - Welcome

Science.gov Websites

(incl. eclipses) Time-Scales and Coordinate Systems Sun Moon Planets Natural Satellites Dwarf Planets version contains precise ephemerides of the Sun, Moon, planets, and satellites, data for eclipses and : Phenomena (incl. eclipses) Section B: Time-Scales and Coordinate Systems Section C: Sun Section D: Moon

Observing the 2017 Total Solar Eclipse from the Pisgah Astronomical Research Institute

NASA Astrophysics Data System (ADS)

Kirwan, Sean Matthew; Cline, J. Donald; Krochmal, Mark; Donald Cline, Mark Krochmal

2017-01-01

The Pisgah Astronomical Research Institute (PARI) is located directly under the path of totality of next year’s solar eclipse and possesses two 26m radio telescopes capable of interferometry at simultaneously at 2.3 GHz and 8.4 GHZ. PARI is preparing these radio telescopes for use by the astronomical community to observe solar eclipse. We will present the status of PARI’s radio telescopes and information on access for the eclipse. We will also present the status and availability of several optical telescopes.

Total Solar Eclipse: “Through The Eyes of NASA,” Part 4

NASA Image and Video Library

2017-08-21

During the eclipse, 14 states across the U.S. were in the path of totality and experienced more than two minutes of darkness in the middle of the day – with a partial eclipse viewable all across North America. The broadcast – Eclipse Across America: Through the Eyes of NASA – covered locations along the path of totality, from Oregon to South Carolina including public reactions from all ages. The eclipse’s long path over land provided a unique opportunity to study the Sun, Earth, Moon and their interaction.

Total Solar Eclipse: “Through The Eyes of NASA,” Part 3

NASA Image and Video Library

2017-08-21

During the eclipse, 14 states across the U.S. were in the path of totality and experienced more than two minutes of darkness in the middle of the day – with a partial eclipse viewable all across North America. The broadcast – Eclipse Across America: Through the Eyes of NASA – covered locations along the path of totality, from Oregon to South Carolina including public reactions from all ages. The eclipse’s long path over land provided a unique opportunity to study the Sun, Earth, Moon and their interaction.

A Smoothed Eclipse Model for Solar Electric Propulsion Trajectory Optimization

NASA Technical Reports Server (NTRS)

Aziz, Jonathan D.; Scheeres, Daniel J.; Parker, Jeffrey S.; Englander, Jacob A.

2017-01-01

Solar electric propulsion (SEP) is the dominant design option for employing low-thrust propulsion on a space mission. Spacecraft solar arrays power the SEP system but are subject to blackout periods during solar eclipse conditions. Discontinuity in power available to the spacecraft must be accounted for in trajectory optimization, but gradient-based methods require a differentiable power model. This work presents a power model that smooths the eclipse transition from total eclipse to total sunlight with a logistic function. Example trajectories are computed with differential dynamic programming, a second-order gradient-based method.

Lightcurve Analysis for Two Near-Earth Asteroids Eclipsed by the Earth's Shadow

NASA Astrophysics Data System (ADS)

Birtwhistle, Peter

2018-07-01

Photometry was obtained from Great Shefford Observatory of near-Earth asteroids 2012 XE54 in 2012 and 2016 VA in 2016 during close approaches. A superfast rotation period has been determined for 2012 XE54 and H-G magnitude system coefficients have been estimated for 2016 VA. While under observation, 2012 XE54 underwent a deep penumbral eclipse by the Earth's shadow and 2016 VA also experienced a total eclipse by the Earth's shadow. The dimming due to the eclipses is modeled taking into account solar limb darkening.

FUSE Observations of the Bright, Eclipsing Nova-like Cataclysmic Variable, UX UMa (FUSE 2000)

NASA Technical Reports Server (NTRS)

Long, Knox; Froning, Cynthia

2004-01-01

This was a project to study the disk and wind of the eclipsing nova-like variable UX UMa, in order to better define the wind geometry of the system, including the nature of the transition region between the disk photosphere and the supersonic wind. We proposed to use phase resolved spectroscopy of the system, taking advantage of the fact that UX UMa is an eclipsing system, to isolate different regions of the wind and to use a Monte Carlo radiative transfer code to simulate the spectra through the eclipse.

A perspective about the total solar eclipse observation from future space settlements and a review of Indonesian space researches

NASA Astrophysics Data System (ADS)

Sastradipradja, D.; Dwivany, F. M.; Swandjaja, L.

2016-11-01

Viewing astronomy objects from space is superior to that from Earth due to the absence of terrestrial atmospheric disturbances. Since decades ago, there has been an idea of building gigantic spaceships to live in, i.e., low earth orbit (LEO) settlement. In the context of solar eclipse, the presuming space settlements will accommodate future solar eclipse chasers (amateur or professional astronomers) to observe solar eclipse from space. Not only for scientific purpose, human personal observation from space is also needed for getting aesthetical mental impression. Furthermore, since space science indirectly aids solar eclipse observation, we will discuss the related history and development of Indonesian space experiments. Space science is an essential knowledge to be mastered by all nations.

The mid 19th and early 20th Century Pull of a Nearby Eclipse Shadow Path

NASA Astrophysics Data System (ADS)

Bonifácio, Vitor

2012-09-01

The unique observing conditions allowed by total solar eclipses made them a highly desirable target of 19th and early 20th century astronomical expeditions, particularly after 1842. Due to the narrowness of the lunar shadow at the Earth's surface this usually implied traveling to faraway locations with all the subsequent inconveniences, in particular, high costs and complex logistics. A situation that improved as travel became faster, cheaper and more reliable. The possibility to observe an eclipse in one's own country implied no customs, no language barriers, usually shorter travelling distances and the likely support of local and central authorities. The eclipse proximity also provided a strong argument to pressure the government to support the eclipse observation. Sometimes the scientific elite would use such high profile events to rhetorically promote broader goals. In this paper we will analyse the motivation, goals, negotiating strategies and outcomes of the Portuguese eclipse expeditions made between 1860 and 1914. We will focus, in particular, on the observation of the solar eclipses of 22 December 1870 and 17 April 1912. The former allowed the start-up of astrophysical studies in the country while the movie obtained at the latter led Francisco da Costa Lobo to unexpectedly propose a polar flattening of the Moon.

Acoustic Gravity Waves in the Ionosphere and Thermosphere During the 2017 Solar Eclipse

NASA Astrophysics Data System (ADS)

Lin, C. Y. T.; Deng, Y.

2017-12-01

During the 2017 solar eclipse, as the sudden cavity of solar radiation created by the lunar shadow moves across the United States on August 21, 2017, decreases in local IT temperature and density are expected. The average velocity of the total solar eclipse across the United States is 700 m/s. The forefront and wake of the lunar shadow are expected to induce acoustic gravity waves according to previous studies of atmosphere waves induced by traveling wave packets moving at different velocities. Meanwhile, moving toward the cross-track direction of the obscuration footprint, weaker transitions will likely create mesoscale to large-scale traveling disturbances. We will use the Global Ionosphere Thermosphere Model, a global circulation model solving for non-hydrostatic equations, with high-resolution settings to investigate the IT responses related to the acoustic-gravity wave perturbations during the 2017 solar eclipse. The simulation will be performed with a sub-degree resolution in longitude and latitude for 3 hours when the atmosphere of the North America sector is mostly obscured. The observable differences between the eclipsed and non-eclipsed scenarios will be examined in detail and be interpreted as consequences from the solar eclipse. We will investigate the evolution of waves during the event and establish a theoretical baseline for further comparisons with observations.

Variable Emittance Electrochromic Devices for Satellite Thermal Control

NASA Astrophysics Data System (ADS)

Demiryont, Hulya; Shannon, Kenneth C.

2007-01-01

An all-solid-state electrochromic device (ECD) was designed for electronic variable emissivity (VE) control. In this paper, a low weight (5g/m2) electrochromic thermal control device, the EclipseVEECD™, is detailed as a viable thermal control system for spacecraft outer surface temperatures. Discussion includes the technology's performance, satellite applications, and preparations for space based testing. This EclipseVEECD™ system comprises substrate/mirror electrode/active element/IR transparent electrode layers. This system tunes and modulates reflection/emittance from 5 μm to 15 μm region. Average reflectance/emittance modulation of the system from the 400 K to 250 K region is about 75%, while at room temperature (9.5 micron) reflectance/emittance is around 90%. Activation voltage of the EclipseVEECD™ is around ±1 Volt. The EclipseVEECD™ can be used as a smart thermal modulator for the thermal control of satellites and spacecraft by monitoring and adjusting the amount of energy emitted from the outer surfaces. The functionality of the EclipseVEECD™ was successfully demonstrated in vacuum using a multi-purpose heat dissipation/absorption test module, the EclipseHEAT™. The EclipseHEAT™ has been successfully flight checked and integrated onto the United States Naval Alchemy MidSTAR satellite, scheduled to launch December 2006.

Girl Scout Stars: Engaging Girl Scouts in the 2017 Total Eclipse

NASA Astrophysics Data System (ADS)

Harman, P. K.

2017-12-01

Reaching for the Stars: NASA Science for Girl Scouts (Girl Scout Stars) engages Girl Scouts in observing the 2017 eclipse. Three councils are host-sponsors of Girl Scout Total Eclipse Destinations,. Total Eclipse of the Heartland, sponsored by Girl Scouts of Southern Illinois, begins with planetarium, and science center visits in St. Louis, and transits to Carbondale for the eclipse. The Great Eclipse Adventure, sponsored by the Girl Scouts of the Missouri Heartland, features hands-on science activities led by Astronomy and Physics faculty and grad students at University of Missouri, Columbia, MO, and observing the eclipse at a camp nearby. Eyes to the Sky: A Once in a Lifetime Destination, by the Girl Scouts of South Carolina - Mountains to Midlands, visits a Challenger Center, a planetarium, and observatory, and culminates at Camp MaBak, Marietta, SC. Girl Scout Destinations are travel adventures, for individual girls ages 11 and older, that are inspiring, life-changing experiences. Destinations are determined via an application and review process by Girls Scouts of the USA. Girl Scout Stars also developed an Eclipse Activity Guide and kit box of materials, distributed the materials to 91 Girl Scout Councils, and delivered webinar training to councils. The eclipse materials enrich the girls' summer camp experiences with activities that promote understanding the Sun-Earth-Moon relationship, the solar system and safe eclipse viewing; and that feature science practices. Examples of the reach of the kit boxes are Girl Scouts of Montana and Wyoming Total Eclipse Event in Casper, WY, and the Girl Scouts of Northern California summer camps featuring the activities. In Girl Scouting, girls discover their skills, talents and what they care about; connect with other Girl Scouts and people in their community; and take action to change the world. This is called the Girl Scout Leadership Experience. With girl-led, hands on activities where girls can team up and work together - they successfully achieve the five leadership outcomes: Strong sense of self, positive values, challenge seeking, healthy relationships, and community problem solving. When girls exhibit these attitudes and skills, they become responsible, productive, caring, and engaged citizens. Successes in this context will be presented. Funded by NASA:NNX16AB90A.

A Coral Sea Rehearsal for the Eclipse Megamovie

NASA Astrophysics Data System (ADS)

Hudson, H. S.; Davey, A. R.; Ireland, J.; Jones, L.; Mcintosh, S. W.; Paglierani, R.; Pasachoff, J. M.; Peticolas, L. M.; Russell, R. M.; Suarez Sola, F. I.; Sutherland, L.; Thompson, M. J.

2012-12-01

The "Eclipse on the Coral Sea" - 13/14 November 2012 (GMT/Australia) - will have happened already. Our intention is to have used this opportunity as a trial run for the eclipse in 2017, which features 1.5 hours of totality across the whole width of the continental US. Conceived first and foremost as an education and public outreach activity, the plan is to engage the public in solar science and technology by providing a way for them to include images they have taken of the solar eclipse, into a movie representation of coronal evolution in time. This project will assimilate as much eclipse photography as possible from the public. The resulting movie(s) will cover all ranges of expertise, and at the basic smartphone or hand-held digital camera level, we expect to have obtained a huge number of images in the case of good weather conditions. The capability of modern digital technology to handle such a data flow is new. The basic purpose of this and the 2017 Megamovie observations is to explore this capability and its ability to engage people from many different communities in the solar science, astronomy, mathematics, and technology. The movie in 2017, especially, may also have important science impact because of the uniqueness of the corona as seen under eclipse conditions. In this presentation we will describe our smartphone application development (see the "Transit of Venus" app for a role model here). We will also summarize data acquisition via both the app and more traditional web interfaces. Although for the Coral Sea eclipse event we don't expect to have a movie product by the time of the AGU, for the 2017 event we do intend to assemble the heterogenous data into beautiful movies within a short space of time after the eclipse. These movies may have relatively low resolution but would extend to the base of the corona. We encourage participation in the 2012 observations, noting that no total eclipse, prior to 2017, will occur in a region with good infrastructure for extended observations. The National Center for Atmospheric Research is sponsored by the National Science Foundation. The Megamovie project is supported by NSF grant AGS-1247226, and JMP's eclipse work about the eclipses of 2012 is supported by NSF grant AGS-1047726.

The Moon's Moment in the Sun - Extending Public Engagement after the Total Solar Eclipse with International Observe the Moon Night

NASA Astrophysics Data System (ADS)

Bleacher, L.; Jones, A. P.; Wasser, M. L.; Petro, N. E.; Wright, E. T.; Ladd, D.; Keller, J. W.

2017-12-01

2017 presented an amazing opportunity to engage the public in learning about lunar and space science, the motions of the Earth-Moon-Sun system, and NASA's fleet of space missions, beginning with the 2017 total solar eclipse on 21 August and continuing with International Observe the Moon Night (InOMN) on 28 October. On 21 August 2017, everyone in the continental United States had the opportunity to witness a solar eclipse, weather permitting, in total or partial form. The path of totality, in which the Sun was completely obscured from view by the Moon, stretched from Oregon to South Carolina. The Education and Communication Team of NASA's Lunar Reconnaissance Orbiter (LRO) worked to highlight the Moon, the "central player" in the total solar eclipse, in a variety of ways for the public. Efforts included collaborating with Minor League Baseball teams to host eclipse-viewing events along the path of totality, communicating the Moon's role in the eclipse through public engagement products, communicating about InOMN as an experiential opportunity beyond the eclipse, and more. InOMN is an annual event, during which everyone on Earth is invited to observe and learn about the Moon and its connection to planetary science, and to share personal and community connections we all have to the Moon [2, 3, 4 and references therein]. For viewers across the United States, the total solar eclipse of 21 August provided an exciting opportunity to watch a New Moon cross in front of the Sun, casting the viewer in shadow and providing amazing views of the solar corona. The public observed the Moon in a different part of its orbit, when reflected sunlight revealed a fascinating lunar landscape - and extended their excitement for space science - by participating in InOMN on 28 October. With InOMN taking place barely two months after the total solar eclipse, it offered an opportunity to sustain and grow public interest in lunar and space science generated by the eclipse. We will report on the results of our efforts to engage the public with these two events, and make recommendations for extending and sustaining the engagement of the public in preparation for the 2024 total solar eclipse.

NEWS: Eye safety and the solar eclipse

NASA Astrophysics Data System (ADS)

LeConte, David

1999-05-01

Total eclipses of the Sun are amongst nature's most magnificent spectacles, and offer the opportunity for an exceptional educational experience. Many people never see one in their lifetime, but it has been estimated that this August's eclipse will be seen by more people than any other. It would be a sadly lost opportunity if they were denied the experience because they fear a danger that is easily avoided. The dangers of eye damage are real and precautions need to be taken. Staring at the bright solar photosphere can cause temporary or permanent retinal damage. Since the retina has no pain receptors the observer can be unaware that the eye is being `cooked', and the damage may only become apparent several hours later. However, when the photosphere is completely blocked by the Moon during the brief period of totality (two minutes or less), it is quite safe to look directly. In fact, you will not otherwise see anything at all. It is a complex message to get across to the public, and especially to children, that protection is required during the partial phases but not during totality, and that those outside the path of totality require protection for the whole eclipse. The National Eclipse Group was established by PPARC in 1997 to coordinate educational activities, issue public information and give authoritative advice for the 1999 eclipse. It has published a Solar Eclipse Safety Code, which is available on the national eclipse web site (mentioned above). It advises that the safest way to view the Sun is indirectly, by projecting an image of the Sun with a `pinhole', mirror, binoculars or telescope. Most people, however, will wish to observe the eclipse directly. Sunglasses, photographic film, crossed polarizers, smoked glass and similar filters must not be used. The Safety Code states that the Sun may be viewed directly only through special filters made specifically for solar viewing. Such eclipse viewers are typically made of aluminized polyester film (often generically referred to as `aluminized Mylar') or polymer. Users should ensure that they are marked as having been supplied specifically for direct viewing of the Sun and carry the `CE' mark. To be awarded CE certification, the viewers must be tested in the visual, infrared and ultraviolet by Approved Bodies appointed by the Secretary of State for Trade and Industry, and they must pass a standard based on a specification prepared by Dr B Ralph Chou, University of Waterloo, Canada (see http://sunearth.gsfc.nasa.gov/eclipse/safety2.html). Any method of solar eclipse observation, whether direct or indirect, is not without its hazards. Severe eye damage can be caused, for example, by looking through a pinhole, rather than at the projected image, and will certainly result from looking through any optical instrument. Eclipse viewers should be placed over the eyes before looking up at the Sun and not removed until after looking away. Whatever method is used, children must be clearly instructed and closely supervised. Eclipse viewers are probably not appropriate for very young children. Descriptions of observing methods are in the activities packs for primary and secondary schools prepared by the Association for Astronomy Education and are available from CLEAPSS Schools Science Service and the National Eclipse Line (0345 600444).

GLANCING VIEWS OF THE EARTH: FROM A LUNAR ECLIPSE TO AN EXOPLANETARY TRANSIT

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

Garcia Munoz, A.; Barrena, R.; Montanes-Rodriguez, P.

2012-08-20

It has been posited that lunar eclipse observations may help predict the in-transit signature of Earth-like extrasolar planets. However, a comparative analysis of the two phenomena addressing in detail the transport of stellar light through the planet's atmosphere has not yet been presented. Here, we proceed with the investigation of both phenomena by making use of a common formulation. Our starting point is a set of previously unpublished near-infrared spectra collected at various phases during the 2008 August lunar eclipse. We then take the formulation to the limit of an infinitely distant observer in order to investigate the in-transit signaturemore » of the Earth-Sun system as being observed from outside our solar system. The refraction bending of sunlight rays that pass through Earth's atmosphere is a critical factor in the illumination of the eclipsed Moon. Likewise, refraction will have an impact on the in-transit transmission spectrum for specific planet-star systems depending on the refractive properties of the planet's atmosphere, the stellar size, and the planet's orbital distance. For the Earth-Sun system, at mid-transit, refraction prevents the remote observer's access to the lower {approx}12-14 km of the atmosphere and, thus, also to the bulk of the spectroscopically active atmospheric gases. We demonstrate that the effective optical radius of the Earth in-transit is modulated by refraction and varies by {approx}12 km from mid-transit to internal contact. The refractive nature of atmospheres, a property which is rarely accounted for in published investigations, will pose additional challenges to the characterization of Earth-like extrasolar planets. Refraction may have a lesser impact for Earth-like extrasolar planets within the habitable zone of some M-type stars.« less

THE VARYING LIGHT CURVE AND TIMINGS OF THE ULTRASHORT-PERIOD CONTACT BINARY KIC 9532219

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

Lee, Jae Woo; Hong, Kyeongsoo; Koo, Jae-Rim

2016-03-20

KIC 9532219 is a W UMa-type eclipsing binary with an orbital period of 0.1981549 days that is below the short-period limit (∼0.22 days) of the period distribution for contact binaries. The Kepler light curve of the system exhibits striking changes in both eclipse depths and light maxima. Applying third-body and spot effects, the light-curve synthesis indicates that the eclipsing pair is currently in a marginal contact stage with a mass ratio of q = 1.20, an orbital inclination of i = 66.°0, a temperature difference of T{sub 1}–T{sub 2} = 172 K, and a third light of l{sub 3} = 75.9%.more » To understand the light variations with time, we divided up the light curve into 312 segments and analyzed them separately. The results reveal that variation of eclipse depth is primarily caused by changing amounts of contamination due to the nearby star KIC 9532228 between the Kepler Quarters and that the variable O’Connell effect originates from the starspot activity on the less massive primary component. Based on our light-curve timings, a period study of KIC 9532219 indicates that the orbital period has varied as a combination of a downward parabola and a light-travel-time (LTT) effect due to a third body, which has a period of 1196 days and a minimum mass of 0.0892 M{sub ⊙} in an orbit of eccentricity 0.150. The parabolic variation could be a small part of a second LTT orbit due to a fourth component in a wider orbit, instead of either mass transfer or angular momentum loss.« less

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

Guo, Zhao; Gies, Douglas R.; Fuller, Jim, E-mail: guo@astro.gsu.edu, E-mail: gies@chara.gsu.edu, E-mail: jfuller@caltech.edu

KIC 3230227 is a short period (P  ≈ 7.0 days) eclipsing binary with a very eccentric orbit ( e  = 0.6). From combined analysis of radial velocities and Kepler light curves, this system is found to be composed of two A-type stars, with masses of M {sub 1} = 1.84 ± 0.18  M {sub ⊙}, M {sub 2} = 1.73 ± 0.17  M {sub ⊙} and radii of R {sub 1} = 2.01 ± 0.09  R {sub ⊙}, R {sub 2} = 1.68 ± 0.08 R {sub ⊙} for the primary and secondary, respectively. In addition to an eclipse, the binary light curve shows a brightening and dimming near periastron, making this a somewhat rare eclipsing heartbeat star system.more » After removing the binary light curve model, more than 10 pulsational frequencies are present in the Fourier spectrum of the residuals, and most of them are integer multiples of the orbital frequency. These pulsations are tidally driven, and both the amplitudes and phases are in agreement with predictions from linear tidal theory for l  = 2, m  = −2 prograde modes.« less

High-level magnetic activity nature of the eclipsing binary KIC 12418816

NASA Astrophysics Data System (ADS)

Dal, H. A.; Özdarcan, O.

2018-02-01

We present comprehensive spectroscopic and photometric analysis of the detached eclipsing binary KIC 12418816, which is composed of two very similar and young main-sequence stars of spectral type K0 on a circular orbit. Combining spectroscopic and photometric modelling, we find masses and radii of the components of 0.88 ± 0.06 M⊙ and 0.85 ± 0.02 R⊙ for the primary and 0.84 ± 0.05 M⊙ and 0.84 ± 0.02 R⊙ for the secondary. Both components exhibit narrow emission features superposed on the cores of the Ca II H and K lines, while H α and H β photospheric absoprtion is more completely infilled by broader emission. Very high precision Kepler photometry reveals remarkable sinusoidal light variation at out-of-eclipse phases, indicating strong spot activity, presumably on the surface of the secondary component. Spots on the secondary component appear to migrate towards decreasing orbital phase with a migration period of 0.72 ± 0.05 yr. Besides the sinusoidal variation, we detect 81 flares and find that both components possess flare activity. Our analysis shows that 25 flares out of 81 exhibit very high energies together with lower frequency, while the rest of them are very frequent but with lower energies.

V850 Cyg: An eclipsing binary with a giant γ Dor pulsator

NASA Astrophysics Data System (ADS)

Çakırlı, Ö.; Ibanoglu, C.; Sipahi, E.; Akan, M. C.

2017-04-01

We present new spectroscopic observations of the double-lined eclipsing binary V850 Cyg. The long-cadence photometric observations obtained by Kepler were analysed and combined with the analysis of radial velocities for deriving the absolute parameters of the components. Masses and radii were determined as Mp=1.601 ± 0.076 M⊙ and Rp=4.239 ± 0.076 R⊙, Ms=0.851 ± 0.053 M⊙ and Rs=5.054 ± 0.087 R⊙ for the components of V850 Cyg. We estimate an interstellar reddening of 0.28 ± 0.12 mag and a distance of 1040 ± 160 pc for the system. The measured rotational velocity of the secondary appears to lower than that of synchronize rotation. However its spectral lines are too weak to be measured the rotational velocity with reasonable accuracy. We have extracted the synthetic light curve from the observations and excluded the data within the eclipses for the frequency analysis. We obtained at least nine frequencies in the γ Dor regime. It seems that the primary component oscillates with a dominant period of about 1.152549 ± 0.000009 days. We also compare pulsational properties of the primary star of V850 Cyg with the γ Dor type pulsating components in other binaries.

Citizen Sky, Solving the Mystery of epsilon Aurigae

NASA Astrophysics Data System (ADS)

Turner, Rebecca; Price, A.; Kloppenborg, B.; Henden, A.

2010-01-01

Citizen Sky is a multi-year, NSF funded citizen science project involving the bright star eps Aur. The project was conceived by the IYA 2009 working group on Research Experiences for Students, Teachers, and Citizen-Scientists. Citizen Sky goes beyond simple observing to include a major data analysis component. The goal is to introduce the participant to the full scientific process from background research to paper writing for a peer-reviewed journal. It begins with a 10 Star Training Program of several types of binary and transient variable stars that are easy to observe from suburban locations with the naked eye. Participants then move on to monitoring the rare and mysterious 2009-2011 eclipse (already underway) of epsilon Aurigae. This object undergoes eclipses only every 27.1 years and each eclipse lasts nearly two years. The star is bright enough to be seen with the naked eye from most urban areas. Training will be provided in observing techniques as well as basic data analysis of photometric and visual datasets (light curve and period analysis). The project also involves two public workshops, one on observing (already held in August of 2009) and one on data analysis and scientific paper writing (to be held in 2010.) This project has been made possible by the National Science Foundation.

On a possible additional component in an eclipsing binary system HS 2231 + 2441

NASA Astrophysics Data System (ADS)

Vidmachenko, A. P.; Romanyuk, Ya. O.; Shliahetskaya, Ya. O.

2016-05-01

Timing method based on the registration period of variations of a periodic process, associated with the star. The study of stellar eclipsing binary system for a long time allows a series of several transits, depending on the orbital period of the satellite smaller. We present a photometric study of system of the type HW Vir HS 2231 + 2441. Photometric data processing was performed using C-MuniWin Version 1.2.30 program. The accuracy of values for each observation point is in the range 0,003...0,009m for different nights. The calculated ephemeris determined from the light curve by fitting of arc of minimums to the nuclei of primary and secondary eclipses. The amplitude of the periodic changes of minimums moments that arise from the orbital motion of a close pair of stars around the barycenter of the triple system, is less than 0.0008 days (1.15 minutes). It was found that the periodic variation of the orbital period can be explained by the gravitational influence of a third companion on the central binary system with an orbital period of about 97±10d. Periodogram analysis of the observational data series indicate also on the periodicity with values of 48±5d and 195±15d, but with substantially less reliably

New insight into the physics of atmospheres of early type stars

NASA Technical Reports Server (NTRS)

Lamers, H. J. G. L. M.

1981-01-01

The phenomenon of mass loss and stellar winds from hot stars are discussed. The mass loss rate of early type stars increases by about a factor of 100 to 1000 during their evolution. This seems incompatible with the radiation driven wind models and may require another explanation for the mass loss from early type stars. The winds of early type stars are strongly variable and the stars may go through active phases. Eclipses in binary systems by the stellar winds can be used to probe the winds. A few future IUE studies are suggested.

The solar type deep low mass-ratio contact binary V658 Lyr: Photometric solution and preliminary elements

NASA Astrophysics Data System (ADS)

Martignoni, M.; Barani, C.; Acerbi, F.

2018-07-01

We present the first light curve analysis of the eclipsing binary V658 Lyr. B, V and Ic photometric observations made from 2014 to 2017 of this W UMa-type binary star are collected, the complete light curves were obtained in 2015 (4 nights) and 2016 (11 nights) and are used for a detailed photometric analysis to determine orbital and physical parameters using the Wilson-Devinney code. The results obtained indicates that V658 Lyr is an A-type overcontact binary system with both components of spectral type (G2 + G4). Based on our 17 ToM the short orbital period of the eclipsing binary was confirmed and revised to P = 0.3302577 days. The orbital period was found to show a cyclic variations and a decrease rate of dP/dt = - 2.97 × 10 -7 days yr-1 , which can be interpreted as a mass transfer from the more massive component to the less massive one. We have not found an asymmetry of the light curves. The mass of the primary and secondary stars are calculated to be M1 = 1.18M⊙( ± 0.08) and M2 = 0.21M⊙( ± 0.01) indicating the primary to be underluminous for its mass and the secondary to be overluminous for its mass.

Ionospheric response over Europe during the solar eclipse of March 20, 2015

NASA Astrophysics Data System (ADS)

Hoque, Mohammed Mainul; Wenzel, Daniela; Jakowski, Norbert; Gerzen, Tatjana; Berdermann, Jens; Wilken, Volker; Kriegel, Martin; Sato, Hiroatsu; Borries, Claudia; Minkwitz, David

2016-10-01

The solar eclipse on March 20, 2015 was a fascinating event for people in Northern Europe. From a scientific point of view, the solar eclipse can be considered as an in situ experiment on the Earth's upper atmosphere with a well-defined switching off and on of solar irradiation. Due to the strong changes in solar radiation during the eclipse, dynamic processes were initiated in the atmosphere and ionosphere causing a measurable impact, for example, on temperature and ionization. We analyzed the behavior of total ionospheric ionization over Europe by reconstructing total electron content (TEC) maps and differential TEC maps. Investigating the large depletion zone around the shadow spot, we found a TEC reduction of up to 6 TEC units, i.e., the total plasma depletion reached up to about 50%. However, the March 20, 2015 eclipse occurred during the recovery phase of a strong geomagnetic storm and the ionosphere was still perturbed and depleted. Therefore, the unusual high depletion is due to the negative bias of up to 20% already observed over Northern Europe before the eclipse occurred. After removing the negative storm effect, the eclipse-induced depletion amounts to about 30%, which is in agreement with previous observations. During the solar eclipse, ionospheric plasma redistribution processes significantly affected the shape of the electron density profile, which is seen in the equivalent slab thickness derived by combining vertical incidence sounding (VS) and TEC measurements. We found enhanced slab thickness values revealing, on the one hand, an increased width of the ionosphere around the maximum phase and, on the other, evidence for delayed depletion of the topside ionosphere. Additionally, we investigated very low frequency (VLF) signal strength measurements and found immediate amplitude changes due to ionization loss at the lower ionosphere during the eclipse time. We found that the magnitude of TEC depletion is linearly dependent on the Sun's obscuration function. By modelling TEC depletion and knowing the Sun's obscuration function in advance, Global Navigation Satellite System (GNSS) operators may improve the broadcast ionospheric correction during a solar eclipse day.

Solar eclipses at high latitudes: ionospheric effects in the lower ionosphere

NASA Astrophysics Data System (ADS)

Cherniakov, S.

2017-12-01

The partial reflection facility of the Polar Geophysical Institute (the Tumanny observatory, 69.0N, 35.7E) has observed behavior of the high-latitude lower ionosphere during the 20 March 2015 total solar eclipse. There were several effects during the eclipse. At the heights of 60-80 km the ionosphere has shown the effect of a "short night", but at the higher altitudes local enhanced electron concentration had a wave-like form. Data received by the riometer of the Tumanny observatory have also shown wave-like behavior. The behavior can be explained by influence of acoustic-gravity waves which originated after cooling of the atmosphere during the lunar shadow supersonic movement, and transport processes during the eclipse. During the 21 August 2017 solar eclipse there was a substorm at the high latitudes. But after the end of the substorm in the region of the Tumanny observatory the observed amplitudes of the reflected waves had wave effects which could be connected with the coming waves from the region of the eclipse. The wave features were also shown in the behavior of the total electron content (TEC) of the lower ionosphere. During several solar eclipses it was implemented observations of lower ionosphere behavior by the partial reflection facility of the Tumanny observatory. The consideration of the lower ionosphere TEC had revealed common features in the TEC behavior during the eclipses. The photochemical theory of processes in the lower ionosphere is very complicated and up to now it is not completely developed. Therefore introduction of the effective coefficients determining the total speed of several important reactions has been widely adopted when modeling the D-region of the ionosphere. However, experimental opportunities for obtaining effective recombination coefficients are rather limited. One of the methods to estimate effective recombination coefficients uses the phenomenon of a solar eclipse. During solar eclipses at the partial reflection facility of the Tumanny observatory observations were carried out. It gave possibility to obtain the behavior of the electron concentration in time at the selected heights. Using the obtained experimental profiles, the effective recombination coefficients at the D-region heights of the ionosphere have been evaluated.

The Great American Eclipse Glasses Debacle of 2017

NASA Astrophysics Data System (ADS)

Tresch Fienberg, Richard; AAS Solar Eclipse Task Force

2018-01-01

In 2014, looking ahead to the “Great American” solar eclipse of 21 August 2017, the American Astronomical Society established the AAS Solar Eclipse Task Force to help prepare the public for a safe and enjoyable experience. We worked with NASA and several associations of eye-care professionals to come up a safety message that we could all stand behind. The gist of it was that it is perfectly safe to view totality without protection, but when any part of the Sun’s bright face is exposed, you must view through eclipse glasses or handheld viewers that meet the ISO 12312-2 international safety standard for filters for direct viewing of the Sun. We compiled a list of manufacturers whose products we knew to meet the standard (because we examined their test data) and posted it on our website. These manufacturers were all based in the US or Europe. A few weeks before the eclipse, reports surfaced of viewers purchased on Amazon.com labeled “Made in China” or that were obvious knock-offs of US manufacturers’ products. Amazon responded by suspending virtually all sales of eclipse viewers and recalling many of units already sold and shipped. Millions of people who’d bought eclipse glasses online, whether from legitimate sources or from bad actors, were unsure whether they could trust their purchases. We had to change our safety messaging: it was no longer sufficient to tell people to look for the ISO 12312-2 label, because that was being printed on Chinese-made glasses that hadn’t actually been shown to meet the standard. Instead, the only way to know that you had safe viewers was to know that you got them from a legitimate source — which meant we had to expand the list on our website to include every legitimate seller we could identify. Doing so required a monumental effort under intense time pressure. Thankfully there were few reports of eye injuries following the eclipse, but apparently many people who otherwise would have viewed the eclipse chose to skip it rather than risk observing through possibly unsafe filters. Could this unfortunate situation have been avoided? How can we prevent it from happening at future eclipses?

The Palomar Transient Factory Orion Project: Eclipsing Binaries and Young Stellar Objects

NASA Astrophysics Data System (ADS)

van Eyken, Julian C.; Ciardi, David R.; Rebull, Luisa M.; Stauffer, John R.; Akeson, Rachel L.; Beichman, Charles A.; Boden, Andrew F.; von Braun, Kaspar; Gelino, Dawn M.; Hoard, D. W.; Howell, Steve B.; Kane, Stephen R.; Plavchan, Peter; Ramírez, Solange V.; Bloom, Joshua S.; Cenko, S. Bradley; Kasliwal, Mansi M.; Kulkarni, Shrinivas R.; Law, Nicholas M.; Nugent, Peter E.; Ofek, Eran O.; Poznanski, Dovi; Quimby, Robert M.; Grillmair, Carl J.; Laher, Russ; Levitan, David; Mattingly, Sean; Surace, Jason A.

2011-08-01

The Palomar Transient Factory (PTF) Orion project is one of the experiments within the broader PTF survey, a systematic automated exploration of the sky for optical transients. Taking advantage of the wide (3fdg5 × 2fdg3) field of view available using the PTF camera installed at the Palomar 48 inch telescope, 40 nights were dedicated in 2009 December to 2010 January to perform continuous high-cadence differential photometry on a single field containing the young (7-10 Myr) 25 Ori association. Little is known empirically about the formation of planets at these young ages, and the primary motivation for the project is to search for planets around young stars in this region. The unique data set also provides for much ancillary science. In this first paper, we describe the survey and the data reduction pipeline, and present some initial results from an inspection of the most clearly varying stars relating to two of the ancillary science objectives: detection of eclipsing binaries and young stellar objects. We find 82 new eclipsing binary systems, 9 of which are good candidate 25 Ori or Orion OB1a association members. Of these, two are potential young W UMa type systems. We report on the possible low-mass (M-dwarf primary) eclipsing systems in the sample, which include six of the candidate young systems. Forty-five of the binary systems are close (mainly contact) systems, and one of these shows an orbital period among the shortest known for W UMa binaries, at 0.2156509 ± 0.0000071 days, with flat-bottomed primary eclipses, and a derived distance that appears consistent with membership in the general Orion association. One of the candidate young systems presents an unusual light curve, perhaps representing a semi-detached binary system with an inflated low-mass primary or a star with a warped disk, and may represent an additional young Orion member. Finally, we identify 14 probable new classical T-Tauri stars in our data, along with one previously known (CVSO 35) and one previously reported as a candidate weak-line T-Tauri star (SDSS J052700.12+010136.8).

Plasma flux and gravity waves in the midlatitude ionosphere during the solar eclipse of 20 May 2012

NASA Astrophysics Data System (ADS)

Chen, Gang; Wu, Chen; Huang, Xueqin; Zhao, Zhengyu; Zhong, Dingkun; Qi, Hao; Huang, Liang; Qiao, Lei; Wang, Jin

2015-04-01

The solar eclipse effects on the ionosphere are very complex. Except for the ionization decay due to the decrease of the photochemical process, the couplings of matter and energy between the ionosphere and the regions above and below will introduce much more disturbances. Five ionosondes in the Northeast Asia were used to record the midlatitude ionospheric responses to the solar eclipse of 20 May 2012. The latitude dependence of the eclipse lag was studied first. The foF2 response to the eclipse became slower with increased latitude. The response of the ionosphere at the different latitudes with the same eclipse obscuration differed from each other greatly. The plasma flux from the protonsphere was possibly produced by the rapid temperature drop in the lunar shadow to make up the ionization loss. The greater downward plasma flux was generated at higher latitude with larger dip angle and delayed the ionospheric response later. The waves in the foEs and the plasma frequency at the fixed height in the F layer are studied by the time period analytic method. The gravity waves of 43-51 min center period during and after the solar eclipse were found over Jeju and I-Cheon. The northward group velocity component of the gravity waves was estimated as ~108.7 m/s. The vertical group velocities between 100 and 150 km height over the two stations were calculated as ~5 and ~4.3 m/s upward respectively, indicating that the eclipse-induced gravity waves propagated from below the ionosphere.

Confirming Variability in the Secondary Eclipse Depth of the Super-Earth 55 Cancri e

NASA Astrophysics Data System (ADS)

Tamburo, P.; Mandell, A.; Deming, D.; Garhart, E.

2018-05-01

We present a reanalysis of five transit and eight eclipse observations of the ultrashort-period super-Earth 55 Cancri e observed using the Spitzer Space Telescope during 2011–2013. We use pixel-level decorrelation to derive accurate transit and eclipse depths from the Spitzer data, and we perform an extensive error analysis. We focus on determining possible variability in the eclipse data, as was reported in Demory et al. From the transit data, we determine updated orbital parameters, yielding T 0 = 2,455,733.0037 ± 0.0002, P = 0.7365454 ± 0.0000003 days, i = 83.5 ± 1.°3, and R p = 1.89 ± 0.05 R ⊕. Our transit results are consistent with a constant depth, and we conclude that they are not variable. We find a significant amount of variability between the eight eclipse observations and confirm agreement with Demory et al. through a correlation analysis. We convert the eclipse measurements to brightness temperatures, and generate and discuss several heuristic models that explain the evolution of the planet’s eclipse depth versus time. The eclipses are best modeled by a year-to-year variability model, but variability on shorter timescales cannot be ruled out. The derived range of brightness temperatures can be achieved by a dark planet with inefficient heat redistribution intermittently covered over a large fraction of the substellar hemisphere by reflective grains, possibly indicating volcanic activity or cloud variability. This time-variable system should be observable with future space missions, both planned (JWST) and proposed (i.e., ARIEL).

Molecular structure and conformations of para-methylbenzene sulfonamide and ortho-methylbenzene sulfonamide: gas electron diffraction and quantum chemical calculations study.

PubMed

Petrov, Vjacheslav M; Girichev, Georgiy V; Oberhammer, Heinz; Petrova, Valentina N; Giricheva, Nina I; Bardina, Anna V; Ivanov, Sergey N

2008-04-03

The molecular structure and conformational properties of para-methylbenzene sulfonamide (4-MBSA) and ortho-methylbenzene sulfonamide (2-MBSA) have been studied by gas electron diffraction (GED) and quantum chemical methods (B3LYP/6-311+G** and MP2/6-31G**). Quantum chemical calculations predict the existence of two conformers for 4-MBSA with the S-N bond perpendicular to the benzene plane and the NH2 group either eclipsing or staggering the S-O bonds of the SO2 group. Both conformers possess CS symmetry. The eclipsed form is predicted to be favored by DeltaE = 0.63 kcal/mol (B3LYP) or 1.00 kcal/mol (MP2). According to the calculations, the S-N bond in 2-MBSA can possess planar direction opposite the methyl group (phi(C2C1SN) = 180 degrees ) or nonplanar direction (phi(C2C1SN) approximately 60 degrees ). In both cases, the NH2 group can adopt eclipsed or staggered orientation, resulting in a total of four stable conformers. The nonplanar eclipsed conformer (C1 symmetry) and the planar eclipsed form (CS symmetry) are predicted to be favored. According to the GED analysis, the saturated vapor over solid 4-MBSA at T = 151(3) degrees C consists as mixture of the eclipsed (78(19) %) and staggered (22(19) %) forms. The saturated vapor over solid 2-MBSA at T = 157(3) degrees C consists as a mixture of the nonplanar eclipsed (69(11) %) and planar eclipsed (31(11) %) forms.

Meteorological effects of the solar eclipse of 20 March 2015: analysis of UK Met Office automatic weather station data and comparison with automatic weather station data from the Faroes and Iceland

PubMed Central

Penman, John; Jónsson, Trausti; Bigg, Grant R.; Björnsson, Halldór; Sjúrðarson, Sølvi; Hansen, Mads A.; Cappelen, John; Bryant, Robert G.

2016-01-01

Here, we analyse high-frequency (1 min) surface air temperature, mean sea-level pressure (MSLP), wind speed and direction and cloud-cover data acquired during the solar eclipse of 20 March 2015 from 76 UK Met Office weather stations, and compare the results with those from 30 weather stations in the Faroe Islands and 148 stations in Iceland. There was a statistically significant mean UK temperature drop of 0.83±0.63°C, which occurred over 39 min on average, and the minimum temperature lagged the peak of the eclipse by about 10 min. For a subset of 14 (16) relatively clear (cloudy) stations, the mean temperature drop was 0.91±0.78 (0.31±0.40)°C but the mean temperature drops for relatively calm and windy stations were almost identical. Mean wind speed dropped significantly by 9% on average during the first half of the eclipse. There was no discernible effect of the eclipse on the wind-direction or MSLP time series, and therefore we can discount any localized eclipse cyclone effect over Britain during this event. Similar changes in air temperature and wind speed are observed for Iceland, where conditions were generally clearer, but here too there was no evidence of an eclipse cyclone; in the Faroes, there was a much more muted meteorological signature. This article is part of the themed issue ‘Atmospheric effects of solar eclipses stimulated by the 2015 UK eclipse’. PMID:27550769

"And they told two friends...and so on": RJ Reynolds' viral marketing of Eclipse and its potential to mislead the public.

PubMed

Anderson, S J; Ling, P M

2008-08-01

To explore viral marketing strategies for Eclipse cigarettes used by the RJ Reynolds Company (Winston-Salem, North Carolina, USA). Analysis of previously secret tobacco industry documents and multimedia materials. The failure of RJ Reynolds' (RJR) 1988 "smokeless" cigarette, Premier, was in part due to widespread bad word of mouth about the product's flavour, quality and difficulty of use. In 1994 RJR introduced an updated version of Premier, the ostensibly "reduced risk" Eclipse cigarette. RJR developed viral marketing channels to promote Eclipse using (1) exploratory interviews to motivate consumers to spread the word about Eclipse prior to market release, (2) promotional videos featuring positive feedback from test group participants to portray majority consensus among triers, (3) "Tupperware"-like parties for Eclipse where participants received samples to pass around in their social circles and (4) the Eclipse website's bulletin board as a forum for potential users to discuss the brand in their own words. These strategies targeted the brand's likeliest adopters, recruited informal and credible representatives of the product unaffiliated with RJR, and controlled the information spread about the product. Viral marketing techniques may be particularly useful to promote new tobacco products such as Eclipse that have limited appeal and need a highly motivated audience of early adopters and acceptors. Such techniques help evade the mass rejection that could follow mass promotion, circumvent marketing restrictions, and allow tobacco companies to benefit from health claims made by consumers. Cigarette manufacturers must be held accountable for perceived health benefits encouraged by all promotional activities including viral marketing.

The Cluster AgeS Experiment (CASE). Variable Stars in the Field of the Globular Cluster M22

NASA Astrophysics Data System (ADS)

Rozyczka, M.; Thompson, I. B.; Pych, W.; Narloch, W.; Poleski, R.; Schwarzenberg-Czerny, A.

2017-09-01

The field of the globular cluster M22 (NGC 6656) was monitored between 2000 and 2008 in a search for variable stars. BV light curves were obtained for 359 periodic, likely periodic, and long-term variables, 238 of which are new detections. 39 newly detected variables, and 63 previously known ones are members or likely members of the cluster, including 20 SX Phe, 10 RRab and 16 RRc type pulsators, one BL Her type pulsator, 21 contact binaries, and 9 detached or semi-detached eclipsing binaries. The most interesting among the identified objects are V112 - a bright multimode SX Phe pulsator, V125 - a β Lyr type binary on the blue horizontal branch, V129 - a blue/yellow straggler with a W UMa-like light curve, located halfway between the extreme horizontal branch and red giant branch, and V134 - an extreme horizontal branch object with P=2.33 d and a nearly sinusoidal light curve. All four of them are proper motion members of the cluster. Among nonmembers, a P=2.83 d detached eclipsing binary hosting a δ Sct type pulsator was found, and a peculiar P=0.93 d binary with ellipsoidal modulation and narrow minimum in the middle of one of the descending shoulders of the sinusoid. We also collected substantial new data for previously known variables. In particular we revise the statistics of the occurrence of the Blazhko effect in RR Lyr type variables of M22.

The nature of EU Pegasi: An Algol-type binary with a δ Scuti-type component

NASA Astrophysics Data System (ADS)

Yang, Yuangui; Yuan, Huiyu; Dai, Haifeng; Zhang, Xiliang

2018-03-01

The comprehensive photometry and spectroscopy for the neglected eclipsing binary EU Pegasi are presented. We determine its spectral type to be A3V. With the W-D program, the photometric solution was deduced from the four-color light curves. The results imply that EU Peg is a detached binary with a mass ratio of q = 0.3105(± 0.0011), whose components nearly fill their Roche lobes. The low-amplitude pulsation occurs around the secondary eclipse, which may be attributed to the more massive component. Three frequencies are preliminarily explored by the Fourier analysis. The pulsating frequency at f1 = 34.1 c d-1 is a p-mode pulsation. The orbital period may be undergoing a secular decrease, superimposed by a cyclic variation. The period decreases at a rate of dP/dt = -7.34 ± 1.06 d yr-1, which may be attributed to mass loss from the system due to stellar wind. The cyclic oscillation, with Pmod = 31.0 ± 1.4 yr and A = 0.0054 ± 0.0010 d, may be caused by the light-time effect due to the assumed third body. With its evolution, the pulsating binary EU Peg will evolve from the detached configuration to the semi-detached case.

2017 Solar Eclipse Event

NASA Image and Video Library

2017-06-11

Marshall Space Flight Center employees view the August 21, 2017 solar eclipse at the center’s activities building. The Huntsville area experienced 97 percent occultation, nearly a complete blocking out of the sun by the orbit of Earth's moon. The next opportunity to view a solar eclipse in the eastern and central United States will occur in April 2024.

2017 Total Solar Eclipse

NASA Image and Video Library

2017-08-21

A total solar eclipse is seen on Monday, August 21, 2017 from onboard a NASA Armstrong Flight Research Center’s Gulfstream III 25,000 feet above the Oregon coast. A total solar eclipse swept across a narrow portion of the contiguous United States from Lincoln Beach, Oregon to Charleston, South Carolina. Photo Credit: (NASA/Carla Thomas)

Project Report ECLIPSE: European Citizenship Learning Program for Secondary Education

ERIC Educational Resources Information Center

Bombardelli, Olga

2014-01-01

This paper reports on a European project, the Comenius ECLIPSE project (European Citizenship Learning in a Programme for Secondary Education) developed by six European partners coordinated by the University of Trento in the years 2011-2014. ECLIPSE (co-financed by the EACEA--Education, Audiovisual and Culture Executive Agency) aims at developing,…

2017 Total Eclipse Viewing Tips - Narrated by George Takei

NASA Image and Video Library

2017-08-09

On Monday, August 21, 2017, all of North America will be treated to an eclipse of the sun. Anyone within the path of totality can see one of nature’s most awe inspiring sights - a total solar eclipse. This video, narrated by actor George Takei, provides a few viewing tips for the public.

Modeling transiting circumstellar disks: characterizing the newly discovered eclipsing disk system OGLE LMC-ECL-11893

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

Scott, Erin L.; Mamajek, Eric E.; Pecaut, Mark J.

2014-12-10

We investigate the nature of the unusual eclipsing star OGLE LMC-ECL-11893 (OGLE J05172127-6900558) in the Large Magellanic Cloud recently reported by Dong et al. The eclipse period for this star is 468 days, and the eclipses exhibit a minimum of ∼1.4 mag, preceded by a plateau of ∼0.8 mag. Spectra and optical/IR photometry are consistent with the eclipsed star being a lightly reddened B9III star of inferred age ∼150 Myr and mass ∼4 M {sub ☉}. The disk appears to have an outer radius of ∼0.2 AU with predicted temperatures of ∼1100-1400 K. We model the eclipses as being duemore » to either a transiting geometrically thin dust disk or gaseous accretion disk around a secondary object; the debris disk produces a better fit. We speculate on the origin of such a dense circumstellar dust disk structure orbiting a relatively old low-mass companion, and on the similarities of this system to the previously discovered EE Cep.« less

Suzaku Observation of the Dwarf Nova V893 Scorpii: The Discovery of a Partial X-Ray Eclipse

NASA Technical Reports Server (NTRS)

Mukai, Koji; Zietsman, E.; Still, M.

2008-01-01

V893 Sco is an eclipsing dwarf nova that had attracted little attention from X-ray astronomers until it was proposed as the identification of an RXTE all-sky slew survey (XSS) source. Here we report on the po inted X-ray observations of this object using Suzaku. We confirm V893 Sco to be X-ray bright, whose spectrum is highly absorbed for a dwar f nova. We have also discovered a partial X-ray eclipse in V893 Sco. This is the first time that a partial eclipse is seen in Xray light c urves of a dwarf nova. We have successfully modeled the gross features of the optical and X-ray eclipse light curves using a boundary layer geometry of the X-ray emission region. Future observations may lead to confirmation of this basic picture, and allow us to place tight co nstraints on the size of the X-ray emission region. The partial X-ray eclipse therefore should make V893 Sco a key object in understanding the physics of accretion in quiescent dwarf nova.

First X-ray Statistical Tests for Clumpy Torii Models: Constraints from RXTE monitoring of Seyfert AGN

NASA Astrophysics Data System (ADS)

Markowitz, A.

2015-09-01

We summarize two papers providing the first X-ray-derived statistical constraints for both clumpy-torus model parameters and cloud ensemble properties. In Markowitz, Krumpe, & Nikutta (2014), we explored multi-timescale variability in line-of-sight X-ray absorbing gas as a function of optical classification. We examined 55 Seyferts monitored with the Rossi X-ray Timing Explorer, and found in 8 objects a total of 12 eclipses, with durations between hours and years. Most clouds are commensurate with the outer portions of the BLR, or the inner regions of infrared-emitting dusty tori. The detection of eclipses in type Is disfavors sharp-edged tori. We provide probabilities to observe a source undergoing an absorption event for both type Is and IIs, yielding constraints in [N_0, sigma, i] parameter space. In Nikutta et al., in prep., we infer that the small cloud angular sizes, as seen from the SMBH, imply the presence of >10^7 clouds in BLR+torus to explain observed covering factors. Cloud size is roughly proportional to distance from the SMBH, hinting at the formation processes (e.g. disk fragmentation). All observed clouds are sub-critical with respect to tidal disruption; self-gravity alone cannot contain them. External forces (e.g. magnetic fields, ambient pressure) are needed to contain them, or otherwise the clouds must be short-lived. Finally, we infer that the radial cloud density distribution behaves as 1/r^{0.7}, compatible with VLTI observations. Our results span both dusty and non-dusty clumpy media, and probe model parameter space complementary to that for short-term eclipses observed with XMM-Newton, Suzaku, and Chandra.

KSC-00pp0092

NASA Image and Video Library

2000-01-20

Traveling west to east, the full moon, viewed from Merritt Island, Fla., at 10:35 p.m. EST, moves into the Earth's shadow during a lunar eclipse. Eclipses occur when the Sun, Earth and Moon line up. They are rare because the Moon usually passes above or below the imaginary line connecting Earth and the Sun. The Earth casts a shadow that the Moon can pass through -when it does, it is called a lunar eclipse. They can only occur when the moon is "full." During a total lunar eclipse the Moon takes on a dark red color because it is being lighted slightly by sunlight passing through the Earth's atmosphere and this light has the blue component preferentially scattered out (this is also why the sky appears blue from the surface of the Earth), leaving faint reddish light to illuminate the Moon during the eclipse

Total Solar Eclipse of 1997 March 9

NASA Technical Reports Server (NTRS)

Espenak, Fred; Anderson, Jay

1995-01-01

A total eclipse of the Sun will be visible from Asia and the Pacific Ocean on 1997 March 9. The path of the Moon's umbral shadow begins in eastern Kazakhstan and travels through Mongolia and eastern Siberia, where it swings northward to end at sunset in the Arctic Ocean. A partial eclipse will be seen within the much broader path of the Moon's penumbral shadow, which includes eastern Asia, the northern Pacific, and the northwest corner of North America. Detailed predictions for this event are presented and include besselian elements, geographic coordinates of the path of totality, physical ephemeris of the umbra, topocentric limb profile corrections, local circumstances for 280 cities, maps of the eclipse path, weather prospects, the lunar limb profile, and the sky during totality. Tips and suggestions are also given on how to safely view and photograph the eclipse.

PTF1 J191905.19+481506.2—A partially eclipsing AM CVn system discovered in the Palomar transient factory

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

Levitan, David; Groot, Paul J.; Prince, Thomas A.

2014-04-20

We report on PTF1 J191905.19+481506.2, a newly discovered, partially eclipsing, outbursting AM CVn system found in the Palomar Transient Factory synoptic survey. This is only the second known eclipsing AM CVn system. We use high-speed photometric observations and phase-resolved spectroscopy to establish an orbital period of 22.4559(3) minutes. We also present a long-term light curve and report on the normal and super-outbursts regularly seen in this system, including a super-outburst recurrence time of 36.8(4) days. We use the presence of the eclipse to place upper and lower limits on the inclination of the system and discuss the number of knownmore » eclipsing AM CVn systems versus what would be expected.« less

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

Groot, Paul J., E-mail: pgroot@astro.ru.nl

In eclipsing binaries the stellar rotation of the two components will cause a rotational Doppler beaming during eclipse ingress and egress when only part of the eclipsed component is covered. For eclipsing binaries with fast spinning components this photometric analog of the well-known spectroscopic Rossiter-McLaughlin effect can exceed the strength of the orbital effect. Example light curves are shown for a detached double white dwarf binary, a massive O-star binary and a transiting exoplanet case, similar to WASP-33b. Inclusion of the rotational Doppler beaming in eclipsing systems is a prerequisite for deriving the correct stellar parameters from fitting high-quality photometricmore » light curves and can be used to determine stellar obliquities as well as, e.g., an independent measure of the rotational velocity in those systems that may be expected to be fully synchronized.« less

G-III Aircraft from NASA Armstrong Provides Live TV Coverage of Solar Eclipse Across America

NASA Image and Video Library

2017-08-13

For the first time in 99 years, a total solar eclipse will cross the entire nation Monday, Aug. 21. A total solar eclipse occurs when the sun is completely obscured by the moon. The lunar shadow enters the United States near Lincoln City, Oregon, at 9:05 a.m. PDT. Totality, where the moon completely covers the sun, begins in Lincoln City around 10:16 a.m. PDT. During totality, there will be up to two and a half minutes of darkness. The G-III aircraft was modified with upgraded windows and communications equipment to enable high-definition video to be streamed to NASA TV during the eclipse enabling citizen science. The aircraft will be flying at 25,000 feet over the coast of Oregon, near Lincoln City during the eclipse on August 21, 2017.

2017 Total Solar Eclipse - ISS Transit - (NHQ201708210203)

NASA Image and Video Library

2017-08-21

2017 Total Solar Eclipse - ISS Transit - (NHQ201708210203) In this video captured at 1,500 frames per second with a high-speed camera, the International Space Station, with a crew of six onboard, is seen in silhouette as it transits the sun at roughly five miles per second during a partial solar eclipse, Monday, Aug. 21, 2017 near Banner, Wyoming. Onboard as part of Expedition 52 are: NASA astronauts Peggy Whitson, Jack Fischer, and Randy Bresnik; Russian cosmonauts Fyodor Yurchikhin and Sergey Ryazanskiy; and ESA (European Space Agency) astronaut Paolo Nespoli. A total solar eclipse swept across a narrow portion of the contiguous United States from Lincoln Beach, Oregon to Charleston, South Carolina. A partial solar eclipse was visible across the entire North American continent along with parts of South America, Africa, and Europe. Photo Credit: (NASA/Joel Kowsky)

Total Solar Eclipse of 2001 June 21

NASA Technical Reports Server (NTRS)

Espenak, Fred; Anderson, Jay

1999-01-01

On 2001 June 21, a total eclipse of the Sun will be visible from within a narrow corridor which traverses the Southern Hemisphere. The path of the Moon's umbral shadow begins in the South Atlantic, crosses southern Africa and Madagascar, and ends at sunset in the Indian Ocean. A partial eclipse will be seen within the much broader path of the Moon's penumbral shadow, which includes eastern South America and the southern two thirds of Africa. Detailed predictions for this event are presented and include besselian elements, geographic coordinates of the path of totality, physical ephemeris of the umbra, topocentric limb profile corrections, local circumstances for approximately 350 cities, maps of the eclipse path, weather prospects, the lunar limb profile and the sky during totality. Tips and suggestions are also given on how to safely view and photograph the eclipse.

What If It Rains on Your Eclipse? Planning Ahead for August 2017

NASA Astrophysics Data System (ADS)

Bartlett, Jennifer L.; Keohane, J.

2010-01-01

It was a dark and rainy morning, not far out of Shanghai, when we saw the 2009 July 22 total solar eclipse. Many of the Americans puttering around their equipment that morning, in hopes that the sky would clear enough to catch some of event they had traveled around the world to view, were already planning ahead for 2017 August 21, when a narrow strip of the United States will experience up to 2 minutes and 45 seconds of totality. For most people, a total solar eclipse is once in a lifetime event steeped in legend. If you are situated along this privileged corridor, you will have a wonderful opportunity for public outreach. But what if it rains? Historically, August is mostly sunny at the location of greatest eclipse, near Makanda, Illinois. Even with such favorable circumstances, having a rain plan will ensure you make the most of the occasion. First, the flexibility to relocate your program to take advantage of the most favorable weather would be ideal. If that is not a realistic option, include some protective gear with your equipment so that you can set up despite misty or drizzling conditions. Second, monitoring changing light levels and temperatures should be possible even under cloudy skies. Third, for some sites, changes in wildlife behavior may also be noticeable. If the weather is clear, such projects could enhance your program during the partial phases of the eclipse and provide enrichment materials for those unable to attend. While 2017 may still seem in the distant future to all but eclipse fanatics, some creativity and advance brainstorming will ensure that your outreach program shines during the event, even if the Sun does not cooperate. S. Bell (2009, pc.), HMNAO, provided the eclipse predictions. Additional information is available via USNO Eclipse Portal (http://www.eclipse.org.uk/eclbin/query_usno.cgi).

Spitzer secondary eclipses of Qatar-1b

NASA Astrophysics Data System (ADS)

Garhart, Emily; Deming, Drake; Mandell, Avi; Knutson, Heather; Fortney, Jonathan J.

2018-02-01

Aims: Previous secondary eclipse observations of the hot Jupiter Qatar-1b in the Ks band suggest that it may have an unusually high day side temperature, indicative of minimal heat redistribution. There have also been indications that the orbit may be slightly eccentric, possibly forced by another planet in the system. We investigate the day side temperature and orbital eccentricity using secondary eclipse observations with Spitzer. Methods: We observed the secondary eclipse with Spitzer/IRAC in subarray mode, in both 3.6 and 4.5 μm wavelengths. We used pixel-level decorrelation to correct for Spitzer's intra-pixel sensitivity variations and thereby obtain accurate eclipse depths and central phases. Results: Our 3.6 μm eclipse depth is 0.149 ± 0.051% and the 4.5 μm depth is 0.273 ± 0.049%. Fitting a blackbody planet to our data and two recent Ks band eclipse depths indicates a brightness temperature of 1506 ± 71 K. Comparison to model atmospheres for the planet indicates that its degree of longitudinal heat redistribution is intermediate between fully uniform and day-side only. The day side temperature of the planet is unlikely to be as high (1885 K) as indicated by the ground-based eclipses in the Ks band, unless the planet's emergent spectrum deviates strongly from model atmosphere predictions. The average central phase for our Spitzer eclipses is 0.4984 ± 0.0017, yielding e cos ω = -0.0028 ± 0.0027. Our results are consistent with a circular orbit, and we constrain e cos ω much more strongly than has been possible with previous observations. Tables of the lightcurve data are only available at the CDS via anonymous ftp to http://cdsarc.u-strasbg.fr (http://130.79.128.5) or via http://cdsarc.u-strasbg.fr/viz-bin/qcat?J/A+A/610/A55

Go Dark Charleston 2017: Preparing the Lowcountry of Charleston, SC for a Unique Celestial Event

NASA Astrophysics Data System (ADS)

Hall, C.; Runyon, C. R.; Royle, M. L.

2017-12-01

The August 2017 total solar eclipse will cross the United States, from Oregon to South Carolina, for the first time in almost 100 years. This awe-inspiring event occurs when the moon crosses between the Sun and the Earth, casting a shadow on Earth. Charleston, SC is the final point in this path before the eclipse heads offshore. As such, it provides an opportunity for Charlestonians to witness the grand finale of such an extraordinary celestial event. In collaboration, the Lowcountry Hall of Science and Math (LHSM) and the SC NASA Space Grant Consortium (SCSG) are working with entities across the state to help raise awareness among the general public to the uniqueness of this total solar eclipse. The team is delivering content-rich, hands-on professional development statewide to formal and informal educators, park rangers and city/county government personnel to ensure an understanding behind why we have eclipses as well as safety when viewing eclipses. Our team is working with community organizations, such as sports teams (i.e., Charleston Riverdogs Baseball, Charleston Battery Soccer), museums, aquariums, state and national parks, etc. to bring NASA scientists, engineers and educators together to deliver exciting community demonstrations before, during and after the day of the eclipse. The LHSM, working directly with the Aquarium and Charlestowne Landing State Park, are capturing animal behavior, specifically marine birds and wolves, during the eclipse. In addition, the team is working directly with College of Charleston undergraduates and two local high schools to launch high-altitude balloons to capture video and pictures, as well as, perform science experiments focusing on the eclipse. And finally, the LHSM through SCSG funding, is determining and documenting the extent of knowledge and cultural misconceptions surrounding solar eclipses within the greater Charleston community. In our session, the team will share the outcomes of these varied endeavors.

Living matter: the "lunar eclipse" phenomena.

PubMed

Korpan, Nikolai N

2010-01-01

The present investigations describe a unique phenomenon, namely the phenomenon of the "lunar eclipse", which has been observed and discovered by the author in living substance during the freeze-thawing processes in vivo using temperatures of various intensities and its cryosurgical response in animal experiment. Similar phenomena author has observed in nature, namely the total lunar eclipse and total solar eclipse. In this experimental study 76 animals (mongrel dogs) were investigated. A disc cryogenic probe was placed on the pancreas after the laparotomy. For cryosurgical exposure a temperature range of -40 degrees C, -80 degrees C, -120 degrees C and -180 degrees C was selected in contact with pancreas parenchyma. The freeze-thaw cycle was monitored by intraoperative ultrasound before, during and after cryosurgery. Each cryolesion was observed for one hour after thawing intraoperatively. Immediately after freezing, during the thawing process, the snow-white pancreas parenchyma, frozen hard to an ice block and resembling a full moon with a sharp demarcation line, gradually assumed a ruby-red shade and a hemispherical shape as it grew in size depend on reconstruction vascular circulation from the periphery to the center. This snow-white cryogenic lesion dissolved in the same manner in all animal tissues. The "lunar eclipse" phenomenon contributes to a fundamental understanding of the mechanisms of biological tissue damage during low temperature exposure in cryoscience and cryomedicine. Properties of the pancreas parenchyma response during the phenomenon of the "lunar eclipse" provide important insights into the mechanisms of damage and the formation of cryogenic lesion immediately after thawing in cryosurgery. Vascular changes and circulatory stagnation are commonly considered to be the main mechanism of biological tissue injury during low temperature exposure. The phenomenon of the "lunar eclipse" suggests that cryosurgery is the first surgical technique to use anti-angiogenesis with an immediately following cryoaponecrosis and cryoapoptosis in the treatment of malignant tumor. Both the "lunar eclipse" in vivo as well as the similar phenomena, namely the total moon and total solar lunar eclipses, are is part of living nature.

Eclipse Megamovie: Solar Discoveries, Education, and Outreach through Crowdsourcing 2017 Eclipse Images

NASA Astrophysics Data System (ADS)

Peticolas, L. M.; Hudson, H. S.; Martinez Oliveros, J. C.; Johnson, C.; Zevin, D.; Krista, L. D.; Bender, M.; Mcintosh, S. W.; Konerding, D.; Koh, J.; Pasachoff, J.; Lorimore, B.; Jiang, G.; Storksdieck, M.; Yan, D.; Shore, L.; Fraknoi, A.; Filippenko, A.

2016-12-01

Since 2011, a team of solar scientists, eclipse chasers, education and outreach professionals, and film makers have been working to explore the possibility of gathering images from the public during the 2017 eclipse across the United States, to be used for scientific research, education, and enhancing the public's experience of the eclipse. After years of testing the initial ideas, engaging new organizations, and exploring new technologies, our team has developed a blueprint for this project. There are three main goals for this effort: 1. to learn more about the dynamic non-equilibrium processes in the corona and lower atmosphere of the Sun, 2. to educate the public about space physics, 3. provide different levels of engagement opportunities for an interested public, and 4. to understand how these various levels of engagement with a major scientific phenomena allow people to develop deeper personal connections to Science, Technology, Engineering, and Mathematics (STEM). We will meet these goals by training 1000 volunteers to take scientifically valid images and donate the images to this project, while also allowing the general public to share their images as well. During the Aug 21, 2017 eclipse, we will analyze these images in real-time to produce public-generated movies showing the corona of the Sun during totality from thousands of people. These movies will be disseminated in near real-time (on the order of 10s of minutes) to other eclipse programs, news organizations, and to the general public. Meanwhile, images collected during and after the eclipse will be available to scientists and the public for research purposes. To further engage the public, video clips, film, and a documentary will be produced prior and after the event. A science education research team will work alongside the team to understand how the project supports deeper connections to the eclipse experience.

Observation of the total solar eclipse on 21 June 2001 in Zambia

NASA Astrophysics Data System (ADS)

Takahashi, Noritsugu; Yumoto, Kiyohumi; Ichimoto, Kiyoshi

2002-04-01

On 21 June 2001, path of totality in Angola, Zambia, Zimbabwe, Mozambique, and Madagascar in Africa. The Japan Scientific Observation Team, consisting primarily of the members of the Solar Eclipse Subcommittee of the Committee for International Collaboration in Astronomy of the Science Council of JAPAN, visited Lusaka in Zambia to observe the total solar eclipse. Blessed with fine weather, the observation was successful. The outline of the influence of solar eclipse on the terrestrial magnetism, polarization of the flash spectrum, and other observation data, as well as the way educational activities were carried out, are reported.

2017 Total Solar Eclipse

NASA Image and Video Library

2017-08-21

This composite image of seven pictures shows the progression of a partial solar eclipse near from Ross Lake, Northern Cascades National Park, Washington on Monday, Aug. 21, 2017. The second to the last frame shows the International Space Station, with a crew of six onboard, in silhouette as it transits the Sun at roughly five miles per second. A total solar eclipse swept across a narrow portion of the contiguous United States from Lincoln Beach, Oregon to Charleston, South Carolina. A partial solar eclipse was visible across the entire North American continent along with parts of South America, Africa, and Europe. Photo Credit: (NASA/Bill Ingalls)

The Great American Eclipse of 2017: An Outreach Opportunity and Challenge

NASA Astrophysics Data System (ADS)

Fraknoi, A.; Schatz, D.; Shore, L.

2015-11-01

This paper consists of notes for, and from, a standing-room only Special Interest Group discussion at the 2014 ASP Meeting regarding the total eclipse of the Sun visible from the U.S. in 2017. There was a great deal of interest in organizing in advance for this total eclipse, and there was considerable discussion of the kinds of efforts and partnerships that may be needed at the national and local levels. People who read this summary and are interested in helping with national eclipse education and outreach efforts can contact the first author.

Initial Results of Interdisciplinary Science Enabled by Eclipse 2017: NASA Perspective

NASA Astrophysics Data System (ADS)

Guhathakurta, M.

2017-12-01

The exceptionally long path over land of the August 21st total and partial solar eclipse provided an unprecedented opportunity for cross disciplinary studies of the sun, moon, Earth, and their interactions. NASA supported research using ground-based measurements, balloons and planes that "chased" the eclipse as well as data taken from a vast array of orbiting spacecraft, all of which helped scientists take continuous measurements of the sun and the effects of the eclipse on the ionosphere and Earth for relatively long periods of time. This talk will summarize some of the initial findings from these research.

The Optical Gravitational Lensing Experiment. Eclipsing Binary Stars in the Small Magellanic Cloud

NASA Astrophysics Data System (ADS)

Wyrzykowski, L.; Udalski, A.; Kubiak, M.; Szymanski, M. K.; Zebrun, K.; Soszynski, I.; Wozniak, P. R.; Pietrzynski, G.; Szewczyk, O.

2004-03-01

We present new version of the OGLE-II catalog of eclipsing binary stars detected in the Small Magellanic Cloud, based on Difference Image Analysis catalog of variable stars in the Magellanic Clouds containing data collected from 1997 to 2000. We found 1351 eclipsing binary stars in the central 2.4 square degree area of the SMC. 455 stars are newly discovered objects, not found in the previous release of the catalog. The eclipsing objects were selected with the automatic search algorithm based on the artificial neural network. The full catalog is accessible from the OGLE Internet archive.

Implementation of Bessel's method for solar eclipses prediction in the WRF-ARW model

NASA Astrophysics Data System (ADS)

Montornes, Alex; Codina, Bernat; Zack, John W.; Sola, Yolanda

2016-05-01

Solar eclipses are predictable astronomical events that abruptly reduce the incoming solar radiation into the Earth's atmosphere, which frequently results in non-negligible changes in meteorological fields. The meteorological impacts of these events have been analyzed in many studies since the late 1960s. The recent growth in the solar energy industry has greatly increased the interest in providing more detail in the modeling of solar radiation variations in numerical weather prediction (NWP) models for the use in solar resource assessment and forecasting applications. The significant impact of the recent partial and total solar eclipses that occurred in the USA (23 October 2014) and Europe (20 March 2015) on solar power generation have provided additional motivation and interest for including these astronomical events in the current solar parameterizations.Although some studies added solar eclipse episodes within NWP codes in the 1990s and 2000s, they used eclipse parameterizations designed for a particular case study. In contrast to these earlier implementations, this paper documents a new package for the Weather Research and Forecasting-Advanced Research WRF (WRF-ARW) model that can simulate any partial, total or hybrid solar eclipse for the period 1950 to 2050 and is also extensible to a longer period. The algorithm analytically computes the trajectory of the Moon's shadow and the degree of obscuration of the solar disk at each grid point of the domain based on Bessel's method and the Five Millennium Catalog of Solar Eclipses provided by NASA, with a negligible computational time. Then, the incoming radiation is modified accordingly at each grid point of the domain.This contribution is divided in three parts. First, the implementation of Bessel's method is validated for solar eclipses in the period 1950-2050, by comparing the shadow trajectory with values provided by NASA. Latitude and longitude are determined with a bias lower than 5 x 10-3 degrees (i.e., ~ 550 m at the Equator) and are slightly overestimated and underestimated, respectively. The second part includes a validation of the simulated global horizontal irradiance (GHI) for four total solar eclipses with measurements from the Baseline Surface Radiation Network (BSRN). The results show an improvement in mean absolute error (MAE) from 77 to 90 % under cloudless skies. Lower agreement between modeled and measured GHI is observed under cloudy conditions because the effect of clouds is not included in the simulations for a better analysis of the eclipse outcomes. Finally, an introductory discussion of eclipse-induced perturbations in the surface meteorological fields (e.g., temperature, wind speed) is provided by comparing the WRF-eclipse outcomes with control simulations.

The solar eclipse: a natural meteorological experiment

PubMed Central

2016-01-01

A solar eclipse provides a well-characterized reduction in solar radiation, of calculable amount and duration. This captivating natural astronomical phenomenon is ideally suited to science outreach activities, but the predictability of the change in solar radiation also provides unusual conditions for assessing the atmospheric response to a known stimulus. Modern automatic observing networks used for weather forecasting and atmospheric research have dense spatial coverage, so the quantitative meteorological responses to an eclipse can now be evaluated with excellent space and time resolution. Numerical models representing the atmosphere at high spatial resolution can also be used to predict eclipse-related changes and interpret the observations. Combining the models with measurements yields the elements of a controlled atmospheric experiment on a regional scale (10–1000 km), which is almost impossible to achieve by other means. This modern approach to ‘eclipse meteorology’ as identified here can ultimately improve weather prediction models and be used to plan for transient reductions in renewable electricity generation. During the 20 March 2015 eclipse, UK electrical energy demand increased by about 3 GWh (11 TJ) or about 4%, alongside reductions in the wind and photovoltaic electrical energy generation of 1.5 GWh (5.5 TJ). This article is part of the themed issue ‘Atmospheric effects of solar eclipses stimulated by the 2015 UK eclipse’. PMID:27550768

Analysis of Geomagnetic Field Variations during Total Solar Eclipses Using INTERMAGNET Data

NASA Astrophysics Data System (ADS)

KIM, J. H.; Chang, H. Y.

2017-12-01

We investigate variations of the geomagnetic field observed by INTERMAGNET geomagnetic observatories over which the totality path passed during a solar eclipse. We compare results acquired by 6 geomagnetic observatories during the 4 total solar eclipses (11 August 1999, 1 August 2008, 11 July 2010, and 20 March 2015) in terms of geomagnetic and solar ecliptic parameters. These total solar eclipses are the only total solar eclipse during which the umbra of the moon swept an INTERMAGNET geomagnetic observatory and simultaneously variations of the geomagnetic field are recorded. We have confirmed previous studies that increase BY and decreases of BX, BZ and F are conspicuous. Interestingly, we have noted that variations of geomagnetic field components observed during the total solar eclipse at Isla de Pascua Mataveri (Easter Island) in Chile (IPM) in the southern hemisphere show distinct decrease of BY and increases of BX and BZ on the contrary. We have found, however, that variations of BX, BY, BZ and F observed at Hornsund in Norway (HRN) seem to be dominated by other geomagnetic occurrence. In addition, we have attempted to obtain any signatures of influence on the temporal behavior of the variation in the geomagnetic field signal during the solar eclipse by employing the wavelet analysis technique. Finally, we conclude by pointing out that despite apparent success a more sophisticate and reliable algorithm is required before implementing to make quantitative comparisons.

CATE 2016 Indonesia: Image Calibration, Intensity Calibration, and Drift Scan

NASA Astrophysics Data System (ADS)

Hare, H. S.; Kovac, S. A.; Jensen, L.; McKay, M. A.; Bosh, R.; Watson, Z.; Mitchell, A. M.; Penn, M. J.

2016-12-01

The citizen Continental America Telescopic Eclipse (CATE) experiment aims to provide equipment for 60 sites across the path of totality for the United States August 21st, 2017 total solar eclipse. The opportunity to gather ninety minutes of continuous images of the solar corona is unmatched by any other previous eclipse event. In March of 2016, 5 teams were sent to Indonesia to test CATE equipment and procedures on the March 9th, 2016 total solar eclipse. Also, a goal of the trip was practice and gathering data to use in testing data reduction methods. Of the five teams, four collected data. While in Indonesia, each group participated in community outreach in the location of their site. The 2016 eclipse allowed CATE to test the calibration techniques for the 2017 eclipse. Calibration dark current and flat field images were collected to remove variation across the cameras. Drift scan observations provided information to rotationally align the images from each site. These image's intensity values allowed for intensity calibration for each of the sites. A GPS at each site corrected for major computer errors in time measurement of images. Further refinement of these processes is required before the 2017 eclipse. This work was made possible through the NSO Training for the 2017 Citizen CATE Experiment funded by NASA (NASA NNX16AB92A).

KMTNet Time-series Photometry of the Doubly Eclipsing Binary Stars Located in the Large Magellanic Cloud

NASA Astrophysics Data System (ADS)

Hong, Kyeongsoo; Koo, Jae-Rim; Lee, Jae Woo; Kim, Seung-Lee; Lee, Chung-Uk; Park, Jang-Ho; Kim, Hyoun-Woo; Lee, Dong-Joo; Kim, Dong-Jin; Han, Cheongho

2018-05-01

We report the results of photometric observations for doubly eclipsing binaries OGLE-LMC-ECL-15674 and OGLE-LMC-ECL-22159, both of which are composed of two pairs (designated A&B) of a detached eclipsing binary located in the Large Magellanic Cloud. The light curves were obtained by high-cadence time-series photometry using the Korea Microlensing Telescope Network 1.6 m telescopes located at three southern sites (CTIO, SAAO, and SSO) between 2016 September and 2017 January. The orbital periods were determined to be 1.433 and 1.387 days for components A and B of OGLE-LMC-ECL-15674, respectively, and 2.988 and 3.408 days for OGLE-LMC-ECL-22159A and B, respectively. Our light curve solutions indicate that the significant changes in the eclipse depths of OGLE-LMC-ECL-15674A and B were caused by variations in their inclination angles. The eclipse timing diagrams of the A and B components of OGLE-LMC-ECL-15674 and OGLE-LMC-ECL-22159 were analyzed using 28, 44, 28, and 26 new times of minimum light, respectively. The apsidal motion period of OGLE-LMC-ECL-15674B was estimated by detailed analysis of eclipse timings for the first time. The detached eclipsing binary OGLE-LMC-ECL-15674B shows a fast apsidal period of 21.5 ± 0.1 years.

Eclipses and Eye Safety

ERIC Educational Resources Information Center

Fulco, Charles

2017-01-01

The 2017 Total Solar Eclipse (TSE2017) will occur on August 21 in the continental United States, bringing totality to this area for the first time since 1979. The Moon's umbra will traverse from Oregon to South Carolina in about 90 minutes, bringing an eerie darkness to 14 states coast-to-coast and a partial eclipse to every part of the country…

Period analysis of the eclipsing binary AI Dra

NASA Astrophysics Data System (ADS)

Zasche, P.; Uhlář, R.; Svoboda, P.

2010-03-01

The eclipsing binary system AI Dra reveals changes of its orbital period. These variations could be described as a result of orbiting the eclipsing pair around a common center of mass with two unseen companions with the periods about 18 and 43 years together with a steady period increase. Fourteen new minima observations were carried out by the authors.

2017 Solar Eclipse Event

NASA Image and Video Library

2017-06-11

Marshall Space Flight Center employee, Phillip Domen, safely views the August 21, 2017 solar eclipse with his homemade viewing box. The Huntsville area experienced 97 percent occultation, nearly a complete blocking out of the sun by the orbit of Earth's moon. The next opportunity to view a solar eclipse in the eastern and central United States will occur in April 2024.

Get Ready for the Great American Eclipse!

ERIC Educational Resources Information Center

Fulco, Charles

2017-01-01

This year marks 38 years since any part of the continental United States was darkened by the Moon's umbral shadow. During this "eclipse drought," no U.S. residents except those on Hawaii's Big Island in 1991 have had the opportunity to observe totality without traveling abroad. The 2017 Total Solar Eclipse (TSE2017, August 21, 2017) is…

Countdown to the Great American Eclipse

ERIC Educational Resources Information Center

Fulco, Charles

2017-01-01

The Great American Total Solar Eclipse (TSE2017) will occur on August 21 this year--the first total solar eclipse in the continental United States since 1979. For many reasons, this is a scientific and educational milestone event of the highest magnitude that should not be missed by any teacher and student whether or not their school is in session…

Learning about Phases of the Moon and Eclipses: A Guide for Teachers and Curriculum Developers

ERIC Educational Resources Information Center

Kavanagh, Claudine; Agan, Lori; Sneider, Cary

2005-01-01

"National Science Education Standards" (1996), published by the National Research Council, recommends that students learn to explain Moon phases and eclipses by the time they graduate from eighth grade. It is clear from the research literature, however, that misconceptions about Moon phases and eclipses are widespread and resistant to change, even…

You're Blocking the Light

ERIC Educational Resources Information Center

Riddle, Bob

2005-01-01

Eclipses typically occur in pairs twice each year, and the second pair for this year will be this month, starting with an annular solar eclipse on October 3, and two weeks later a partial lunar eclipse on October 17. The path of annularity will travel from the North Atlantic Ocean to Spain, where the annular phase will last for more than four…

'Mars-shine'

NASA Technical Reports Server (NTRS)

2005-01-01

[figure removed for brevity, see original site] 'Mars-shine' Composite

NASA's Mars Exploration Rover Spirit continues to take advantage of favorable solar power conditions to conduct occasional nighttime astronomical observations from the summit region of 'Husband Hill.'

Spirit has been observing the martian moons Phobos and Deimos to learn more about their orbits and surface properties. This has included observing eclipses. On Earth, a solar eclipse occurs when the Moon's orbit takes it exactly between the Sun and Earth, casting parts of Earth into shadow. A lunar eclipse occurs when the Earth is exactly between the Sun and the Moon, casting the Moon into shadow and often giving it a ghostly orange-reddish color. This color is created by sunlight reflected through Earth's atmosphere into the shadowed region. The primary difference between terrestrial and martian eclipses is that Mars' moons are too small to completely block the Sun from view during solar eclipses.

Recently, Spirit observed a 'lunar' eclipse on Mars. Phobos, the larger of the two martian moons, was photographed while slipping into the shadow of Mars. Jim Bell, the astronomer in charge of the rover's panoramic camera (Pancam), suggested calling it a 'Phobal' eclipse rather than a lunar eclipse as a way of identifying which of the dozens of moons in our solar system was being cast into shadow.

With the help of the Jet Propulsion Laboratory's navigation team, the Pancam team planned instructions to Spirit for acquiring the views shown here of Phobos as it entered into a lunar eclipse on the evening of the rover's 639th martian day, or sol (Oct. 20, 2005) on Mars. This image is a time-lapse composite of eight Pancam images of Phobos moving across the martian sky. The entire eclipse lasted more than 26 minutes, but Spirit was able to observe only in the first 15 minutes. During the time closest to the shadow crossing, Spirit's cameras were programmed to take images every 10 seconds.

In the first three images, Phobos was in sunlight, moving toward the upper right. After a 100-second delay while Spirit's computer processed the first three images, the rover then took the fourth image, showing Phobos just starting to enter the darkness of the martian shadow. At that point, an observer sitting on Phobos and looking back toward the Sun would have seen a spectacular sunset! In the fifth image, Phobos appeared like a crescent, almost completely shrouded in darkness.

In the last three images, Phobos had slipped entirely into the shadow of Mars. However, as with our own Moon during lunar eclipses on Earth, it was not entirely dark. The small amount of light still visible from Phobos is a kind of 'Mars-shine' -- sunlight reflected through Mars' atmosphere and into the shadowed region.

Rover scientists took some images later in the sequence to try to figure out if this 'Mars-shine' made Phobos colorful while in eclipse, but they'll need more time to complete the analysis because the signal levels are so low. Meanwhile, they will use the information on the timing of the eclipse to refine the orbital path of Phobos. The precise position of Phobos will be important to any future spacecraft taking detailed pictures of the moon or landing on its surface. In the near future it might be possible for one of the rovers to take images of a 'Deimal' eclipse to learn more about Mars' other enigmatic satellite, Deimos, as well.

Effects of the 2017 Solar Eclipse on HF Radio Propagation and the D-Region Ionosphere: Citizen Science Investigation

NASA Astrophysics Data System (ADS)

Fry, C. D.; Adams, M.; Gallagher, D. L.; Habash Krause, L.; Rawlins, L.; Suggs, R. M.; Anderson, S. C.

2017-12-01

August 21, 2017 provided a unique opportunity to investigate the effects of the total solar eclipse on high frequency (HF) radio propagation and ionospheric variability. In Marshall Space Flight Center's partnership with the US Space and Rocket Center (USSRC) and Austin Peay State University (APSU), we engaged students and citizen scientists in an investigation of the eclipse effects on the mid-latitude ionosphere. The Amateur Radio community has developed several automated receiving and reporting networks that draw from widely-distributed, automated and manual radio stations to build a near-real time, global picture of changing radio propagation conditions. We used these networks and employed HF radio propagation modeling in our investigation. A Ham Radio Science Citizen Investigation (HamSCI) collaboration with the American Radio Relay League (ARRL) ensured that many thousands of amateur radio operators would be "on the air" communicating on eclipse day, promising an extremely large quantity of data would be collected. Activities included implementing and configuring software, monitoring the HF Amateur Radio frequency bands and collecting radio transmission data on days before, the day of, and days after the eclipse to build a continuous record of changing propagation conditions as the moon's shadow marched across the United States. Our expectations were the D-Region ionosphere would be most impacted by the eclipse, enabling over-the-horizon radio propagation on lower HF frequencies (3.5 and 7 MHz) that are typically closed during the middle of the day. Post-eclipse radio propagation analysis provided insights into ionospheric variability due to the eclipse. We report on results, interpretation, and conclusions of these investigations.

Evaluation of six TPS algorithms in computing entrance and exit doses.

PubMed

Tan, Yun I; Metwaly, Mohamed; Glegg, Martin; Baggarley, Shaun; Elliott, Alex

2014-05-08

Entrance and exit doses are commonly measured in in vivo dosimetry for comparison with expected values, usually generated by the treatment planning system (TPS), to verify accuracy of treatment delivery. This report aims to evaluate the accuracy of six TPS algorithms in computing entrance and exit doses for a 6 MV beam. The algorithms tested were: pencil beam convolution (Eclipse PBC), analytical anisotropic algorithm (Eclipse AAA), AcurosXB (Eclipse AXB), FFT convolution (XiO Convolution), multigrid superposition (XiO Superposition), and Monte Carlo photon (Monaco MC). Measurements with ionization chamber (IC) and diode detector in water phantoms were used as a reference. Comparisons were done in terms of central axis point dose, 1D relative profiles, and 2D absolute gamma analysis. Entrance doses computed by all TPS algorithms agreed to within 2% of the measured values. Exit doses computed by XiO Convolution, XiO Superposition, Eclipse AXB, and Monaco MC agreed with the IC measured doses to within 2%-3%. Meanwhile, Eclipse PBC and Eclipse AAA computed exit doses were higher than the IC measured doses by up to 5.3% and 4.8%, respectively. Both algorithms assume that full backscatter exists even at the exit level, leading to an overestimation of exit doses. Despite good agreements at the central axis for Eclipse AXB and Monaco MC, 1D relative comparisons showed profiles mismatched at depths beyond 11.5 cm. Overall, the 2D absolute gamma (3%/3 mm) pass rates were better for Monaco MC, while Eclipse AXB failed mostly at the outer 20% of the field area. The findings of this study serve as a useful baseline for the implementation of entrance and exit in vivo dosimetry in clinical departments utilizing any of these six common TPS algorithms for reference comparison.

“And they told two friends…and so on”: RJ Reynolds’ viral marketing of Eclipse and its potential to mislead the public

PubMed Central

Anderson, S J; Ling, P M

2010-01-01

Objective To explore viral marketing strategies for Eclipse cigarettes used by the RJ Reynolds Company (Winston-Salem, North Carolina, USA). Methods Analysis of previously secret tobacco industry documents and multimedia materials. Results The failure of RJ Reynolds’ (RJR) 1988 “smokeless” cigarette, Premier, was in part due to widespread bad word of mouth about the product’s flavour, quality and difficulty of use. In 1994 RJR introduced an updated version of Premier, the ostensibly “reduced risk” Eclipse cigarette. RJR developed viral marketing channels to promote Eclipse using (1) exploratory interviews to motivate consumers to spread the word about Eclipse prior to market release, (2) promotional videos featuring positive feedback from test group participants to portray majority consensus among triers, (3) “Tupperware”-like parties for Eclipse where participants received samples to pass around in their social circles and (4) the Eclipse website’s bulletin board as a forum for potential users to discuss the brand in their own words. These strategies targeted the brand’s likeliest adopters, recruited informal and credible representatives of the product unaffiliated with RJR, and controlled the information spread about the product. Conclusions Viral marketing techniques may be particularly useful to promote new tobacco products such as Eclipse that have limited appeal and need a highly motivated audience of early adopters and acceptors. Such techniques help evade the mass rejection that could follow mass promotion, circumvent marketing restrictions, and allow tobacco companies to benefit from health claims made by consumers. Cigarette manufacturers must be held accountable for perceived health benefits encouraged by all promotional activities including viral marketing. PMID:18332064

Eclipse 2017: Partnering with NASA MSFC to Inspire Students

NASA Technical Reports Server (NTRS)

Fry, Craig " Ghee" ; Adams, Mitzi; Gallagher, Dennis; Krause, Linda

2017-01-01

NASA's Marshall Space Flight Center (MSFC) is partnering with the U.S. Space and Rocket Center (USSRC), and Austin Peay State University (APSU) to engage citizen scientists, engineers, and students in science investigations during the 2017 American Solar Eclipse. Investigations will support the Citizen Continental America Telescopic Eclipse (CATE), Ham Radio Science Citizen Investigation(HamSCI), and Interactive NASA Space Physics Ionosphere Radio Experiments (INSPIRE). All planned activities will engage Space Campers and local high school students in the application of the scientific method as they seek to explore a wide range of observations during the eclipse. Where planned experiments touch on current scientific questions, the camper/students will be acting as citizen scientists, participating with researchers from APSU and MSFC. Participants will test their expectations and after the eclipse, share their results, experiences, and conclusions to younger Space Campers at the US Space & Rocket Center.

Chasing the shadows, a trip to spice island

NASA Astrophysics Data System (ADS)

Yamani, A.; Soegijoko, W.; Baskoro, A. A.; Satyaningsih, R.; Simatupang, F. M.; Maulana, F.; Suherli, J.; Syamara, R.; Canas, L.; Stevenson, T.; Oktariani, F.; Santosa, I.; Ariadi, F.; Carvalho, N.; Soegijoko, K.

2016-11-01

The 2016 Total Solar Eclipse provided us an opportunity to introduce astronomy to a much wider audience. The path of totality crossed the Indonesia from Sumatra to the Maluku Islands and ended its journey in the Pacific Ocean. Its path crossed over 4 major islands, 12 provinces and many cities. Most of the cities have minimum exposure to astronomy. langitselatan travelled to observe the eclipse and to do astronomy outreach at the eastern most island under the eclipse path. We chose Maba, a small village in East Halmahera, North Maluku as our site to observe the eclipse as well as conduct a workshop for teachers and students. The aim of the workshop is to introduce astronomy taking advantage of the eclipse as well as raise awareness and curiosity among students. In this paper, we will share a short report regarding the whole trip and event in Maba.

KSC-00pp0091

NASA Image and Video Library

2000-01-20

Traveling west to east, the full moon, viewed from Merritt Island, Fla., at 10:18 p.m. EST, begins moving into the Earth's shadow, at the start of a lunar eclipse. Eclipses occur when the Sun, Earth and Moon line up. They are rare because the Moon usually passes above or below the imaginary line connecting Earth and the Sun. The Earth casts a shadow that the Moon can pass through -when it does, it is called a lunar eclipse. They can only occur when the moon is "full." During a total lunar eclipse the Moon takes on a dark red color because it is being lighted slightly by sunlight passing through the Earth's atmosphere and this light has the blue component preferentially scattered out (this is also why the sky appears blue from the surface of the Earth), leaving faint reddish light to illuminate the Moon during the eclipse

KSC-00pp0094

NASA Image and Video Library

2000-01-20

Viewed from Merritt Island, Fla., at 11:25 p.m. EST, the full moon, traveling west to east, is nearly completely in the Earth's shadow, producing a lunar eclipse. Eclipses occur when the Sun, Earth and Moon line up. They are rare because the Moon usually passes above or below the imaginary line connecting Earth and the Sun. The Earth casts a shadow that the Moon can pass through -when it does, it is called a lunar eclipse. They can only occur when the moon is "full." During a total lunar eclipse the Moon takes on a dark red color because it is being lighted slightly by sunlight passing through the Earth's atmosphere and this light has the blue component preferentially scattered out (this is also why the sky appears blue from the surface of the Earth), leaving faint reddish light to illuminate the Moon during the eclipse

KSC-00pp0093

NASA Image and Video Library

2000-01-20

Viewed from Merritt Island, Fla., at 10:59 p.m. EST, the full moon, traveling west to east, is three-quarters of the way into the Earth's shadow during a lunar eclipse. Eclipses occur when the Sun, Earth and Moon line up. They are rare because the Moon usually passes above or below the imaginary line connecting Earth and the Sun. The Earth casts a shadow that the Moon can pass through -when it does, it is called a lunar eclipse. They can only occur when the moon is "full." During a total lunar eclipse the Moon takes on a dark red color because it is being lighted slightly by sunlight passing through the Earth's atmosphere and this light has the blue component preferentially scattered out (this is also why the sky appears blue from the surface of the Earth), leaving faint reddish light to illuminate the Moon during the eclipse

Total Solar Eclipse of 1999 August 11

NASA Technical Reports Server (NTRS)

Espenak, Fred; Anderson, Jay

1997-01-01

On 1999 August 11, a total eclipse of the Sun will be visible from within a narrow corridor which traverses the Eastern Hemisphere. The path of the Moon's umbral shadow begins in the Atlantic and crosses central Europe, the Middle East, and India, where it ends at sunset in the Bay of Bengal. A partial eclipse will be seen within the much broader path of the Moon's penumbral shadow, which includes northeastern North America, all of Europe, northern Africa, and the western half of Asia. Detailed predictions for this event are presented and include besselian elements, geographic coordinates of the path of totality, physical ephemeris of the umbra, topocentric limb profile corrections, local circumstances for approximately 1400 cities, maps of the eclipse path, weather prospects, the lunar limb profile, and the sky during totality. Tips and suggestions are also given on how to safely view and photograph the eclipse.

[Development of a Software for Automatically Generated Contours in Eclipse TPS].

PubMed

Xie, Zhao; Hu, Jinyou; Zou, Lian; Zhang, Weisha; Zou, Yuxin; Luo, Kelin; Liu, Xiangxiang; Yu, Luxin

2015-03-01

The automatic generation of planning targets and auxiliary contours have achieved in Eclipse TPS 11.0. The scripting language autohotkey was used to develop a software for automatically generated contours in Eclipse TPS. This software is named Contour Auto Margin (CAM), which is composed of operational functions of contours, script generated visualization and script file operations. RESULTS Ten cases in different cancers have separately selected, in Eclipse TPS 11.0 scripts generated by the software could not only automatically generate contours but also do contour post-processing. For different cancers, there was no difference between automatically generated contours and manually created contours. The CAM is a user-friendly and powerful software, and can automatically generated contours fast in Eclipse TPS 11.0. With the help of CAM, it greatly save plan preparation time and improve working efficiency of radiation therapy physicists.

z'-BAND GROUND-BASED DETECTION OF THE SECONDARY ECLIPSE OF WASP-19b

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

Burton, J. R.; Watson, C. A.; Pollacco, D.

2012-08-01

We present the ground-based detection of the secondary eclipse of the transiting exoplanet WASP-19b. The observations were made in the Sloan z' band using the ULTRACAM triple-beam CCD camera mounted on the New Technology Telescope. The measurement shows a 0.088% {+-} 0.019% eclipse depth, matching previous predictions based on H- and K-band measurements. We discuss in detail our approach to the removal of errors arising due to systematics in the data set, in addition to fitting a model transit to our data. This fit returns an eclipse center, T{sub 0}, of 2455578.7676 HJD, consistent with a circular orbit. Our measurementmore » of the secondary eclipse depth is also compared to model atmospheres of WASP-19b and is found to be consistent with previous measurements at longer wavelengths for the model atmospheres we investigated.« less

Spectral changes in the zenith skylight during total solar eclipses.

PubMed

Hall, W N

1971-06-01

The relative spectral intensity of the zenith sky was measured with an optical scanning spectrometer at Nantucket Island, Massachusetts, during the total solar eclipse of 7 March 1970. The spectral ratios I(5100 A)/I(4300 A) and I(5900 A)/I(5100 A) at Nantucket remained unchanged for 96% or less obscuration of the sun by the moon. The results are compared with other recent relative spectral intensity measurements made during total solar eclipses. Comparison with other eclipse measurements for solar elevation angle at totality less than 45 degrees shows a blue color shift consistent with rayleigh scattering. Eclipses with solar elevation angles at totality greater than 45 degrees do not show consistent color shifts. This inconsistency may be due to difficulty in establishing a suitable reference spectrum for comparison with the spectral distribution of the zenith sky at totality. Selection of a suitable reference spectrum is discussed.

A new study of the interacting binary star V356 Sgr

NASA Technical Reports Server (NTRS)

Polidan, R. S.

1988-01-01

Results on V356 Sgr from IUE and Voyager ultraviolet (500 to 3200 A) observations obtained in 1986 and 1987, primarily during 2 total eclipses are presented. The eclipse of Aug. 15, 1986 was fully covered with IUE low dispersion images and 9 hr of Voyager UVS data. The eclipse of Mar. 25, 1987 was covered with IUE low dispersion images and 1 high dispersion SWP image. During both eclipses the total strength of the emission lines is found to be invariant. An uneclipsed UV continuum is detected at wavelengths shorter than 1500 A. The high dispersion SWP spectrum reveals that the emission lines are extremely broad, almost symmetrical emissions with weak, slightly blue shifted absorption components. No evidence of carbon, C I, C II, C III, or C IV, is seen in the emission or absorption spectrum of V356 Sgr in eclipse. Models for this binary system are presented.

Ionospheric wave signature of the American solar eclipse on 21 August 2017 in Europe

NASA Astrophysics Data System (ADS)

Verhulst, Tobias G. W.; Stankov, Stanimir M.

2018-05-01

A total solar eclipse occurred on 21 August 2017, with the path of totality starting over the North Pacific Ocean, crossing North-America and ending over the Mid-Atlantic Ocean slightly North of the equator. As a result, a partial solar eclipse was observed as far away as the Western Europe. The ionospheric observatory in Dourbes, Belgium, was right on the edge of the partial eclipse and was exposed for a very short period of only few minutes just before the local sunset. High-resolution ionospheric measurements were carried out at the observatory with collocated digital ionosonde and GNSS receivers. The data analysis revealed a clear wave-like pattern in the ionosphere that can be seen arriving before the local onset of the eclipse. The paper details the analysis and provides a possible explanation of the observed phenomenon.

Simulation of the August 21, 2017 Solar Eclipse Using the Whole Atmosphere Community Climate Model - eXtended (WACCM-X)

NASA Astrophysics Data System (ADS)

McInerney, J. M.; Liu, H.; Marsh, D. R.; Solomon, S. C.; Vitt, F.; Conley, A. J.

2017-12-01

The total solar eclipse of August 21, 2017 transited the entire continental United States. This presented an opportunity for model simulation of eclipse effects on the lower atmosphere, upper atmosphere, and ionosphere. The Community Earth System Model (CESM), v2.0, now includes a functional version of the Whole Atmosphere Community Climate Model - eXtended (WACCM-X) that has a fully interactive ionosphere and thermosphere. WACCM-X, with a model top up to 700 kilometers, is an atmospheric component of CESM and is being developed at the National Center for Atmospheric Research in Boulder, Colorado. Here we present results from simulations using this model during a total solar eclipse. This not only gives insights into the effects of the eclipse through the entire atmosphere from the surface through the ionosphere/thermosphere, but also serves as a validation tool for the model.

March 7, 1970 solar eclipse investigation

NASA Technical Reports Server (NTRS)

Accardo, C. A.

1972-01-01

Studies from rockets directed toward establishing the solar X-ray fluxes during the 7 March 1970 total eclipse over the North American continent are reported. A map of the eclipse path is presented. The measured absorption profiles for the residual X-rays are useful in establishing their contribution to the D and E region ionization during the eclipse. The studies were performed with two Nike-Apache payloads launched over Wallops Island, Virginia. In addition to three X-ray detectors in the 1 to 8A, 8 to 20A and 44 to 60A bands, there was included in the payloads two additional experiments. These were an electric field experiment and an epithermal photoelectron experiment. The X-ray instrumentation, payload description, flight circumstances and finally, the X-ray results obtained are described. The various computer codes employed for the purpose of reducing the telemetered data as well as the eclipse codes are included.

The Planetary and Eclipse Oil Paintings of Howard Russell Butler

NASA Astrophysics Data System (ADS)

Pasachoff, Jay M.; Olson, R. M.

2013-10-01

The physics-trained artist Howard Russell Butler (1856-1934) has inspired many astronomy students through his planetary and eclipse paintings that were long displayed at the Hayden Planetarium in New York, the Fels Planetarium at the Franklin Institute in Philadelphia, and the Buffalo Museum of Science. We discuss not only the eclipse triptychs (1918, 1923, and 1925) at each of those institutions but also his paintings of Mars as seen from Phobos and from Deimos (with landscapes of those moons in the foreground depicted in additional oils hung at Princeton University) and the Earth from our Moon. We also describe his involvement with astronomy and his unique methodology that allowed him to surpass the effects then obtainable with photography, as well as his inclusion in a U.S. Naval Observatory eclipse expedition in 1918, as well as his auroral, solar-prominence, and 1932-eclipse paintings.

Period Variations of the Eclipsing Binary Systems T LMi and VX Lac

NASA Astrophysics Data System (ADS)

Yılmaz, M.; İzci, D. D.; Gümüş, D.; Özavci, İ.; Selam, S. O.

2015-07-01

We present a period analysis of the two Algol-type eclipsing binary systems T LMi and VX Lac using all available times of minimum in the literature, as well as new minima obtained at the Ankara University Kreiken Observatory. The period analysis of T LMi suggests mass transfer between the components and also a third body that is dynamically bound to the binary system. The analysis of VX Lac also suggests mass transfer between the components, and the presence of a third and a fourth body under the assumption of a Light-Time Effect. In addition, the periodic variation of VX Lac was examined under the hypothesis of magnetic activity, and the corresponding parameters were derived. We report here the orbital parameters for both systems, along with the ones related to mass transfer, and those for the third and fourth bodies.

THE ARAUCARIA PROJECT: ON THE TIP OF THE RED GIANT BRANCH DISTANCE DETERMINATION TO THE MAGELLANIC CLOUDS

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

Górski, Marek; Gieren, Wolfgang; Catelan, Márcio

2016-06-01

We present a precise optical and near-infrared determination of the tip of the red giant branch (TRGB) brightness in the Large and Small Magellanic Clouds (respectively, LMC and SMC). The commonly used calibrations of the absolute magnitude of the TRGB lead to an overestimation of the distance to the LMC and SMC in the K band, and an underestimation of the distance in the optical I band for both galaxies. Reported discrepancies are at the level of 0.2 mag, with respect to the very accurate distance determinations to both MCs based on late-type eclipsing binaries. The differential distances between themore » LMC and SMC obtained in the J and K bands, and for the bolometric brightness are consistent with each other, and with the results obtained from eclipsing binaries and other distance indicators.« less

Kottamia 74-inch telescope discovery of the new eclipsing binary 2MASS J20004638 + 0547475.: First CCD photometry and light curve analysis

NASA Astrophysics Data System (ADS)

Darwish, M. S.; Shokry, A.; Saad, S. M.; El-Sadek, M. A.; Essam, A.; Ismail, M.

2017-05-01

A CCD photometric study is presented for the eclipsing binary system 2MASS J20004638 + 0547475. Observations of the system were obtained in the V, R and I colours with the 2Kx2K CCD attached to 1.88 m Kottamia Optical Telescope. New times of light minimum and new ephemeris were obtained. The V, R and I light curves were analyzed using the PHOEBE 0.31 program to determine geometrical and physical parameters of the system. The results show that 2MASS J20004638 + 0547475, is A-Type WUMa and is an overcontact binary with high fill-out factor = 69%. The current evolutionary status of the system indicates that the primary component lies very close to the main sequence while the secondary is evolved. The asymmetric maxima were studied and a modeling of the hot spot parameters is given.

Determination of the axial rotation rate using apsidal motion for early-type eclipsing binaries

NASA Astrophysics Data System (ADS)

Khaliullin, Kh. F.; Khaliullina, A. I.

2007-11-01

Because the modern theory of stellar structure and evolution has a sound observational basis, we can consider that the apsidal parameters k2 computed in terms of this theory correctly reflect the radial density distribution in stars of different masses and spectral types. This allows us to address the problem of apsidal motion in close binary systems in a new way. Unlike the traditional approach, in this paper we use the observed apsidal periods Uobs to estimate the angular axial velocities of components, ωr, at fixed model values of k2. We use this approach to analyse the observational data for 28 eclipsing systems with known Uobs and early-type primaries (M >= 1.6 Msolar or Te >= 6000 K). We measure the age of the system in units of the synchronization time, t/tsyn. Our analysis yielded the following results. (i) There is a clear correlation between ωr/ωsyn and t/tsyn: the younger a star, the higher the angular velocity of its axial rotation in units of ωsyn, the angular velocity at pseudo-synchronization. This correlation is more significant and obvious if the synchronization time, tsyn, is computed in terms of the Zahn theory. (ii) This observational fact implies that the synchronization of early-type components in close binary systems continues on the main sequence. The synchronization times for the inner layers of the components (i.e. those that are responsible for apsidal motion) are about 1.6 and 3.1 dex longer than those predicted by the theories of Zahn and Tassoul, respectively. The average initial angular velocities (for the zero-age main sequence) are equal to ω0/ωsyn ~ 2.0. The dependence of the parameter E2 on stellar mass probably needs to be refined in the Zahn theory. (iii) Some components of the eclipsing systems of the sample studied show radially differential axial rotation. This is consistent with the Zahn theory, which predicts that the synchronization starts at the surface, where radiative damping of dynamical tides occurs, and develops toward the interior. Therefore, one would expect the inner parts of young double early-type stars to rotate faster than the outer parts.

Artificial Intelligence in Astronomy

NASA Astrophysics Data System (ADS)

Devinney, E. J.; Prša, A.; Guinan, E. F.; Degeorge, M.

2010-12-01

From the perspective (and bias) as Eclipsing Binary researchers, we give a brief overview of the development of Artificial Intelligence (AI) applications, describe major application areas of AI in astronomy, and illustrate the power of an AI approach in an application developed under the EBAI (Eclipsing Binaries via Artificial Intelligence) project, which employs Artificial Neural Network technology for estimating light curve solution parameters of eclipsing binary systems.

“Total Eclipse Preview Show”, Total Solar Eclipse: “Through The Eyes of NASA,” Part 1

NASA Image and Video Library

2017-08-21

On Monday, Aug. 21, NASA provided coast-to-coast coverage of the solar eclipse across America – featuring views of the phenomenon from unique vantage points, including from the ground, from aircraft, and from spacecraft including the ISS, during a live broadcast seen on NASA Television and the agency’s website.

Eclipse Megamovie 2017: A Citizen Science Project

NASA Astrophysics Data System (ADS)

Johnson, C.; Koh, J.; Konerding, D.; Peticolas, L. M.; Hudson, H. S.; Martinez Oliveros, J. C.; Zevin, D.

2017-12-01

The 2017 total solar eclipse presents an amazing opportunity for education and science outreach due to the breadth and reach of this astronomical event. The Eclipse Megamovie project looks to create organize a citizen science effort to capture images of the eclipse as it crosses the US and stitch these photos together into a continuous look at the corona. A collaboration between Google, UC Berkeley, and many other universities and amateur astronomy networks, this project looks to leverage the different strenghts of these organizations and capitalize on this rare outreach opportunity. We're excited to present the results of the project and a review of how things went.

Lunar Eclipse

NASA Image and Video Library

2003-11-09

In this lunar eclipse viewed from Merritt Island, Fla., the full moon takes on a dark red color because it is being lighted slightly by sunlight passing through the Earth's atmosphere. This light has the blue component preferentially scattered out (this is also why the sky appears blue from the surface of the Earth), leaving faint reddish light to illuminate the Moon. Eclipses occur when the Sun, Earth and Moon line up. They are rare because the Moon usually passes above or below the imaginary line connecting Earth and the Sun. The Earth casts a shadow that the Moon can pass through - when it does, it is called a lunar eclipse.

Solar Eclipse Education and Outreach Activities at APSU

NASA Astrophysics Data System (ADS)

Smith, J. Allyn; Buckner, Spencer L.; Adams, Mitzi; Meisch, Karen; Sudbrink, Don; Wright, Amy; Adams, Angela; Fagan, Ben

2018-01-01

The path of totality for the 21 August 2017 total solar eclipse passed directly over the APSU campus in north-central Tennessee. We discuss our public outreach and education efforts, both on campus and in the community, and present results and lessons learned from this event. We reached nearly 20,000 people via our efforts and hosted nearly 3000 viewers on campus on eclipse day. We also present our science activities and early results from those. On the whole, this event could be viewed as a large success for the university and the region, and the experiences will guide us in our efforts as we plan future eclipse activities.

Eclipsing binary stars in the era of massive surveys First results and future prospects

NASA Astrophysics Data System (ADS)

Papageorgiou, Athanasios; Catelan, Márcio; Ramos, Rodrigo Contreras; Drake, Andrew J.

2017-09-01

Our thinking about eclipsing binary stars has undergone a tremendous change in the last decade. Eclipsing binary stars are one of nature's best laboratories for determining the fundamental physical properties of stars and thus for testing the predictions of theoretical models. Some of the largest ongoing variable star surveys include the Catalina Real-time Transient Survey (CRTS) and the VISTA Variables in the Vía Láctea survey (VVV). They both contain a large amount of photometric data and plenty of information about eclipsing binaries that wait to be extracted and exploited. Here we briefly describe our efforts in this direction.

Spectrophotometry of Epsilon Aur, 3295-8880 A

NASA Technical Reports Server (NTRS)

Lockwood, G. W.; Thompson, D. T.; Lutz, B. L.; Sowell, J.

1985-01-01

Spectrophotometric scans were obtained at 8 A resolution from 3295 to 8880 A on twenty nights before, during, and after the recent eclipse of epsilon Aurigae, beginning with a pre-eclipse observation on 5 March 1982 U.T. The observations were reduced to absolute flux using the standard stars 109 Vir or xi(2) Ceti. The data confirm that the eclipse is essentially gray over the entire visible spectrum, as others have noted from broadband photometry. High resolution echellograms (450 to 6700 A) made through mid-eclipse and the scans show changes in the equivalent widths of H alpha, Na D, and O I as large as a factor of two.

The 1982-1984 Eclipse of Epsilon Aurigae

NASA Technical Reports Server (NTRS)

Stencel, R. E. (Editor)

1985-01-01

A workshop proceedings concerned with the new data collected during the 1982-1984 eclipse period of the 27-year system Epsilon Aurigae is presented. This binary star has been a classic problem in astrophysics because the opaque eclipsing object is nonstellar, and probably disk shaped. Invited papers concerning the history of the system, optical, infrared and ultraviolet photometry, optical polarimetry and ultraviolet spectroscopy are included. An invited paper concerning comprehensive theoretical interpretation in the context of stellar evolution also is included. The information collected herein is unparalleled in scope and will remain a standard reference until the next eclipse cycle in the year 2009 A.D., in all probability.

The orbital and superhump periods of the deeply eclipsing dwarf nova SDSS J150240.98+333423.9

NASA Astrophysics Data System (ADS)

Shears, J.; Campbell, T.; Foote, J.; Garrett, R.; Hager, T.; Mack Julian, W.; Kemp, J.; Masi, G.; Miller, I.; Patterson, J.; Richmond, M.; Ringwald, F.; Roberts, G.; Ruiz, J.; Sabo, R.; Stein, W.

2011-04-01

During 2009 July we observed the first confirmed superoutburst of the eclipsing dwarf nova SDSS J150240.98+333423.9 using CCD photometry. The outburst amplitude was at least 3.9 magnitudes and it lasted at least 16 days. Superhumps having up to 0.35 mags peak-to-peak amplitude were present during the outburst, thereby establishing it to be a member of the SU UMa family. The mean superhump period during the first 4 days of the outburst was Psh= 0.06028(19)d, although it increased during the outburst with dPsh/dt= +2.8(1.0)?10^-4. The orbital period was measured as Porb= 0.05890946(5)d from times of eclipses measured during outburst and quiescence. Based on the mean superhump period, the superhump period excess was e= 0.023(3). The FWHM eclipse duration declined from a maximum of 10.5 min at the peak of the outburst to 3.5 min later in the outburst. The eclipse depth increased from ~0.9 mag to 2.1 mag over the same period. Eclipses in quiescence were 2.7 min in duration and 2.8 mag deep.

Impact of the 2017 Solar Eclipse on Smart Grid

NASA Astrophysics Data System (ADS)

Reda, I.; Andreas, A.; Sengupta, M.; Habte, A.

2017-12-01

With the increasing interest in using solar energy as a major contributor to renewable energy utilization, and with the focus on using smart grids to optimize the use of electrical energy based on demand and resources from different locations, arises the need to know the Moon position in the sky with respect to the Sun. When a solar eclipse occurs, the Moon disk might totally or partially shade the Sun disk, which can affect the irradiance level from the sun disk, consequently, a resource on the grid is affected. The Moon position can then provide the smart grid users with information about potential total or partial solar eclipse at different locations in the grid, so that other resources on the grid can be directed where this might be needed when such phenomena occurs. At least five solar eclipses occur yearly at different locations on earth, they can last three hours or more depending on the location, which can have devastating effects on the smart grid users. On August 21, 2017 a partial solar eclipse will occur at the National Renewable Energy Laboratory in Golden, Colorado, USA. The solar irradiance will be measured during the eclipse and compared to the data generated by a model for validation.

Flexible transparent electrode

NASA Astrophysics Data System (ADS)

Demiryont, Hulya; Shannon, Kenneth C., III; Moorehead, David; Bratcher, Matthew

2011-06-01

This paper presents the properties of the EclipseTECTM transparent conductor. EclipseTECTM is a room temperature deposited nanostructured thin film coating system comprised of metal-oxide semiconductor elements. The system possesses metal-like conductivity and glass-like transparency in the visible region. These highly conductive TEC films exhibit high shielding efficiency (35dB at 1 to 100GHz). EclipseTECTM can be deposited on rigid or flexible substrates. For example, EclipseTECTM deposited on polyethylene terephthalate (PET) is extremely flexible that can be rolled around a 9mm diameter cylinder with little or no reduction in electrical conductivity and that can assume pre-extension states after an applied stress is relieved. The TEC is colorless and has been tailored to have high visible transmittance which matches the eye sensitivity curve and allows the viewing of true background colors through the coating. EclipseTECTM is flexible, durable and can be tailored at the interface for applications such as electron- or hole-injecting OLED electrodes as well as electrodes in flexible displays. Tunable work function and optical design flexibility also make EclipseTECTM well-suited as a candidate for grid electrode replacement in next-generation photovoltaic cells.

Stellar background observation during Total Solar Eclipse March 9th 2016

NASA Astrophysics Data System (ADS)

Mumtahana, Farahhati; Timur Jaelani, Anton; Muhamad, Johan; Sutastio, Heri

2016-11-01

We report observation and an early analysis of stellar background from total solar eclipse in Ternate, Indonesia. The eclipse phenomena which occurred on March, 9th 2016 was observed with certain portable instruments in order to obtain the stars behind the Sun in particular field of view and resolution. From our observation site in Ternate city, solar eclipse occurred in the late morning when the weather was unfortunately cloudy. However, during the darkness of totality, we obtained several point source objects between the gaps of the moving clouds and we suspected them as very faint stars due to their appearance in several frames. Those so called stars have been identified and measured with respect to their positions toward the center of the Sun. The main purpose of this research is to revisit strong lensing calculation of the Sun during total solar eclipse by measuring the deflection angle of the background stars as it had been calculated by Einstein and proved by Eddington at a total solar eclipse in 1919. To accomplish this aim, we need to conduct another observation to measure position of the same stars in the next period when those stars appear in the night sky.

On the period determination of ASAS eclipsing binaries

NASA Astrophysics Data System (ADS)

Mayangsari, L.; Priyatikanto, R.; Putra, M.

2014-03-01

Variable stars, or particularly eclipsing binaries, are very essential astronomical occurrence. Surveys are the backbone of astronomy, and many discoveries of variable stars are the results of surveys. All-Sky Automated Survey (ASAS) is one of the observing projects whose ultimate goal is photometric monitoring of variable stars. Since its first light in 1997, ASAS has collected 50,099 variable stars, with 11,076 eclipsing binaries among them. In the present work we focus on the period determination of the eclipsing binaries. Since the number of data points in each ASAS eclipsing binary light curve is sparse, period determination of any system is a not straightforward process. For 30 samples of such systems we compare the implementation of Lomb-Scargle algorithm which is an Fast Fourier Transform (FFT) basis and Phase Dispersion Minimization (PDM) method which is non-FFT basis to determine their period. It is demonstrated that PDM gives better performance at handling eclipsing detached (ED) systems whose variability are non-sinusoidal. More over, using semi-automatic recipes, we get better period solution and satisfactorily improve 53% of the selected object's light curves, but failed against another 7% of selected objects. In addition, we also highlight 4 interesting objects for further investigation.

Perception of Solar Eclipses Captured by Art Explains How Imaging Misrepresented the Source of the Solar Wind

PubMed Central

2015-01-01

The visible corona revealed by the natural phenomenon of solar eclipses has been studied for 150 years. A turning point has been the discovery that the true spatial distribution of coronal brightness can neither be seen nor imaged on account of its unprecedented dynamic range. Howard Russell Butler (1856–1934), the painter of solar eclipses in the early 20th century, possessed the extraordinary skill of painting from memory what he saw for only a brief time. His remarkable but forgotten eclipse paintings are, therefore, ideal for capturing and representing best the perceptual experience of the visible corona. Explained here is how by bridging the eras of visual (late 19th century) and imaging investigations (since the latter half of the 20th century), Butler’s paintings reveal why white-light images misled researching and understanding the Sun’s atmosphere, the solar wind. The closure in understanding solar eclipses through the convergence of perception, art, imaging, science and the history of science promises to enrich the experience of viewing and photographing the first solar eclipse of the 21st century in the United States on 21st August 2017. PMID:27551356

Perception of Solar Eclipses Captured by Art Explains How Imaging Misrepresented the Source of the Solar Wind.

PubMed

Woo, Richard

2015-12-01

The visible corona revealed by the natural phenomenon of solar eclipses has been studied for 150 years. A turning point has been the discovery that the true spatial distribution of coronal brightness can neither be seen nor imaged on account of its unprecedented dynamic range. Howard Russell Butler (1856-1934), the painter of solar eclipses in the early 20th century, possessed the extraordinary skill of painting from memory what he saw for only a brief time. His remarkable but forgotten eclipse paintings are, therefore, ideal for capturing and representing best the perceptual experience of the visible corona. Explained here is how by bridging the eras of visual (late 19th century) and imaging investigations (since the latter half of the 20th century), Butler's paintings reveal why white-light images misled researching and understanding the Sun's atmosphere, the solar wind. The closure in understanding solar eclipses through the convergence of perception, art, imaging, science and the history of science promises to enrich the experience of viewing and photographing the first solar eclipse of the 21st century in the United States on 21st August 2017.

Changes in surface solar UV irradiances and total ozone during the solar eclipse of August 11, 1999

NASA Astrophysics Data System (ADS)

Zerefos, C. S.; Balis, D. S.; Meleti, C.; Bais, A. F.; Tourpali, K.; Kourtidis, K.; Vanicek, K.; Cappellani, F.; Kaminski, U.; Colombo, T.; Stübi, R.; Manea, L.; Formenti, P.; Andreae, M. O.

2000-11-01

During the solar eclipse of August 11, 1999, intensive measurements of UV solar irradiance and total ozone were performed at a number of observatories located near the path of the Moon's shadow. At the Laboratory of Atmospheric Physics (LAP) of the Aristotle University of Thessaloniki, Greece, global and direct spectra of UV solar irradiances (285-365 nm) were recorded with a double monochromator, and erythemal irradiances were measured with broadband pyranometers. In addition, higher-frequency measurements of global and direct irradiances at six UV wavelengths were performed with a single Brewer spectrophotometer. Total ozone measurements were also performed with Dobson and Brewer spectrophotometers at Hradec Kralove (Czech Republic), Ispra (Italy), Sestola (Italy), Hohenpeissenberg (Germany), Bucharest (Romania), Arosa (Switzerland), and Thessaloniki (Greece). From the spectral UV measurements the limb darkening effect of the solar disk was tentatively quantified from differences of measured solar spectral irradiances at the peak of the eclipse (near to limb conditions) and before the eclipse. Two blackbody curves were fit to the preeclipse and peak eclipse spectra, which have shown a difference in effective temperatures of about 165°K between the limb and the whole of the solar disk. The limb darkening effect is larger at the shorter UV wavelengths. The ratio of the diffuse to direct solar irradiances during the eclipse shows that the diffuse component is reduced much less compared to the decline of the direct solar irradiance at the shorter wavelengths. Moreover, a 20-min oscillation of erythemal UV-B solar irradiance was observed before and after the time of the eclipse maximum under clear skies, indicating a possible 20-min fluctuation in total ozone, presumably caused by the eclipse-induced gravity waves. This work also shows that routine total ozone measurements with a Brewer or a Dobson spectrophotometer should be used with caution during a solar eclipse. This is because the diffuse light increases by more than 30% with respect to the direct solar radiation, increasing more at the shorter wavelength side of the UV spectrum. This plausible mechanism introduces an artificial decrease in total ozone during solar eclipse of more than 30 Dobson units (DU), which is confirmed by all Brewer and Dobson measurements. Changes in total ozone cited earlier in the refereed literature have not been confirmed in the present study.