Had I special: The Astronomical Contributions of the Herschel Family

НазваниеHad I special: The Astronomical Contributions of the Herschel Family
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Kepler Eclipsing Binary Stars: on the Origin of Contact Binaries and the Degree of Thermal Contact

Andrej Prsa1, E. F. Guinan1, S. Rucinski2, B. Kirk1, C. Villamil1
1Villanova University, 2University of Toronto, Canada.

Exhibit Hall

Contact binary stars (W UMa-type binaries) are one of most ubiquitous close binaries in our Galaxy. The components evolved into a system that shares a common envelope and features active mass transfer. Because of the components' proximity, orbital periods of these systems are short (2-18 hours) and the orbital velocities are large (100-300 km/s). It might be expected that contact binary envelopes are in thermal contact, yet the observations indicate otherwise. Further, the evolution of these stars is speculated to be due to either tidal/magnetic tightening of the orbit or to 3rd body interaction, yet to date there is no definitive consensus. Kepler holds great promise in resolving these puzzles since the ultra-high precision photometry allows us to model the target stars to unprecedented accuracy. In September 2010 we acquired high-resolution echelle spectra at the 4-m Mayall telescope (Kitt Peak, AZ) of 15 select contact binaries in the Kepler field at 5 phases distributed uniformly across the phase space. These observations provided us with the masses, projected semi-major axes, and center-of-mass radial velocities of program stars, and allowed us, in conjunction with the Kepler data, to completely characterize the absolute properties (masses, radii, temperatures, luminosities) of these prime W UMa-type binaries. Here we present a preliminary analysis of three select systems, KepIDs 8496820, 9392682, and 12305537, based on the public Kepler data and high-resolution spectroscopy. The final analysis of these and other stars will be supplemented with the proprietary Kepler data obtained through the Cycle II Guest Observer program 09-KEPLER09-0054, which we gratefully acknowledge. This work was funded in part by NSF/RUI grant AST-05-07542.


A Spectral and Lightcurve Study of 50+ Blue Stars from the Burrell-Optical-Kepler-Survey (BOKS)

Jared Lalmansingh1, S. Howell2, D. Walter1, J. Cash1, K. Mighell2
1South Carolina State University, 2National Optical Astronomy Observatory.

Exhibit Hall

BOKS used the 0.6 m Burrell-Schmidt telescope over a period of 40 nights and identified 54,687 stars between 14 < r < 19 in the Kepler Mission’s field of view. Its primary goal was to detect Jupiter-sized and Hot Jupiter (Period = 3 - 9 days) short-period exoplanets within the survey field as well as to compile high precision stellar variability data that the Kepler Mission can use for comparison purposes and to characterize the hundreds of other variable stars within the survey region.
We present the spectral classifications and light curve analysis of a sub-sample of 50+ blue stars within the BOKS field of view using BOKS lightcurve data and spectra from the Kitt Peak 2.1 meter telescope. The purpose of this study is to identify the variability of and provide characterization for the blue star population within the BOKS field.
Support for this work was provided by NOAO and the NSF PAARE program to South Carolina State University under award AST-0750814.


A Method for Determining Precise Phase Shifts of Eclipses in EB Systems: Detecting Substellar, Non-Transiting Third Bodies in Kepler Mission Eclipsing Binary Light Curves.

Robert W. Slawson1, L. R. Doyle1
1SETI Institute.

Exhibit Hall

A third body orbiting an eclipsing binary induces a small phase shift in the eclipses due to the light time effect as the binary system orbits about the three-body barycenter. The presence of the small third-body is revealed by a periodicity in the phase shifts consistent with a Keplerian orbit.
We present a cross-correlation method that benefits from the nearly continuously sampled light curves now becoming available from the Kepler mission. For the template, we use a model light curve of the binary system that is stationary in phase (dP/dt=0, dω/dt=0, ...). A window function slides in time along both the observed light curve and template selecting a region for cross-correlation and the phase shift as a function of time is determined from the peak in the resulting correlation function.
We examine the sensitivity limits, through numerical experiments, to the detection of substellar and planet sized masses in multi-year orbits about EBs from Kepler mission light curves.


Kepler Systems That Show Multiple Transiting Objects

Jason H. Steffen1, D. C. Fabrycky2, E. B. Ford3, M. J. Holman4, J. J. Lissauer5, D. Ragozzine4, W. F. Welsh6, Kepler Science Team
1Fermilab, 2UC Santa Cruz, 3University of Florida, 4Harvard CfA, 5NASA Ames, 6San Diego State University.

Exhibit Hall

Exoplanetary systems that have multiple transiting planets provide unique and important insight into the formation, evolution, and dynamics of exoplanetary systems. Kepler has announced the discovery of a confirmed planetary system with multiple transiting planets (Kepler 9, Holman et al. 2010) as well as several candidate planetary systems that show multiple transiting objects (Steffen et al. 2010). Kepler 9 shows deviations from a constant period due to the ongoing dynamical interactions between the confirmed planets. From these transit timing variations (TTV) one can measure the planetary masses from the photometric data alone. The presence of several systems with multiple transiting candidates from the first quarter of data indicate that Kepler should continue to find systems with multiple transiting planets. Such systems will provide important, general information about the histories of planetary systems.


The Faring Behavior of G and K Dwarfs as Seen in the Kepler Q1 Data

Peiyuan Mao1, D. Soderblom2, R. Osten2, J. Valenti2
1Lafayette College, 2Space Telescope Science Institute.

Exhibit Hall

The white-light photometric observations from the Kepler mission are the first ever look at the behavior of solar-type stars at ultra-high precision, and the light curves made available in the “Q1” data release show many astrophysical phenomena. Especially evident in a small fraction of the G and K dwarfs are flaring events, with rapid rises and exponential decays. These flares have much greater energies and longer decay time-scales than even the largest solar flares, which would be undetectable given Kepler’s 30-minute observing cadence. Moreover, stars that exhibit flares tend to show several flares during the 33.5 day interval covered by the Q1 data. Aside from the Kepler data itself, little is known about these stars and what sets them apart from other Kepler targets with similar rotation periods and variability amplitudes. We will show examples of flares in the Kepler light curves, describe our detection technique, and present our initial findings on this phenomenon.


Parameterizing and Modeling Eclipsing Binaries in The Kepler Field Using Kepler Quarter 2 and 3 Data

Sean Morrison1, K. Mighell2, S. Howell2, D. Bradstreet3
1Appalachian State University, 2National Optical Astronomy Observatory, 3Eastern University.

Exhibit Hall

We present a preliminary analysis of Quarter 2 and Quarter 3 Kepler light curves for 56 eclipsing binary star systems from the Kepler Cycle 1 program 08-KEPLER08-0014, "A Calibration Study of Variable Stars in the Kepler Field" (PI: Mighell). We developed a C program to phase these long cadence (30 minute) data that determines the period and zero point with a typical precision of 0.0864 seconds for an orbital period of 1.019949 days. We have developed 3D models of the systems using Binary Maker 3 (BM3) by David Bradstreet. Spectra of 32 of the systems were obtained at the Kitt Peak National Observatory 2.1 m telescope using the GoldCam spectrometer. We have determined temperatures for some of the stars from the temperature ratios, based on the BM3 models, and the average temperatures for the spectral classifications of the stars which were derived from the 2.1-m spectra. The high photometric precision of the Kepler light curves allows us to identify significant star spots on a subset of the systems. Morrison was supported by the NOAO/KPNO Research Experiences for Undergraduates (REU) Program which is funded by the National Science Foundation Research Experiences for Undergraduates Program and the Department of Defense ASSURE program through Scientific Program Order No. 13 (AST-0754223) of the Cooperative Agreement No. AST-0132798 between the Association of Universities for Research in Astronomy (AURA) and the NSF.


Cross Matching of Available GALEX Objects with Kepler Targets at MAST

Myron Smith1, B. Shiao2, Kepler
1Computer Sciences Corp., 2Space Telescope Science Institute.

Exhibit Hall

The recent release of the GALEX Release 6 dataset includes 72 sky "tiles" overlapping some 60% of the Kepler Field of View. MAST (Multi-Mission Archive at Space Telescope Science Institute) has constructed a cross-match catalog of all matches of GALEX objects with 5" of the coordinates for objects in the Kepler Input Catalog (KIC) and vice-versa.
The results permit the addition of UV colors (near-UV and/or far-UV, centered at about 2300 Angstroms and 1500 Angstroms, respectively) to
the SDSS program's griz filters that the Kepler ground-based support photometric program emulated. Until now the absence of an ultraviolet filter for this ground survey of KIC objects has meant that it was not possible to clearly identify hot (OBA-type) objects. The addition of the GALEX UV magnitudes will address this deficiency. In addition, the (FUV-NUV) vectors for ISM reddening and stellar temperature are very different, allowing the former degeneracy of the two terms to be lifted. We exhibit on-line tools to enable users to obtain UV, griz, and 2MASS colors to aid in the search of targets and to investigate general distributions of objects in the KIC. We discuss completeness of the cross-match survey with the KIC catalog. We point out that the numbers of detections are primarily limited by the far-UV and near-UV effective apertures of GALEX.


Kepler Light Curves of AGN

Michael T. Carini1, W. Welsh2
1Western Kentucky University, 2San Diego State University.

Exhibit Hall

The Kepler mission is observing the same region of the sky for its entire mission lifetime, allowing virtually uninterrupted optical observations of any object in its field of view. This provides the opportunity to obtain optical light curves of AGN of unprecedented duration and sampling. During cycle 1, we obtained observations of two bright AGN in the Kepler field of view: the Seyfert 1 galaxy ZW 229.015 and the Seyfert 2 galaxy IGR J19473+4452. We present the light curves of these sources and discuss their variability properties. Because the Kepler Pipeline is optimized for detecting transiting planets, not photometry of extended sources, we also discuss potential systematic problems and cautions one must have when interpreting these light curves.


Mining the Kepler Mission Database: Rotations, Starspots, Ages and Possible Tidal Interactions of Stars with Close-in Planets

Greg Feiden1, E. Guinan2, T. Boyajian3, Y. Kok4, O. Basturk5, A. Roberson6, I. Ribas7
1Dartmouth College, 2Villanova University, 3Georgia State University, 4University of Sydney, Australia, 5Ankara University, Turkey, 6Pennsylvania State University, 7Institut de Ciencies de l'Espai, Spain.

Exhibit Hall

The first public data release from the Kepler Space Telescope contained over 156,000 stars which had been monitored continuously for approximately 33 days. With continuous photometric monitoring and unprecedented ultra-high precision, the Kepler dataset is an splendid resource for investigating stellar rotation (and age) via starspots as well as for investigating starspot fractional coverage and distributions, starspot lifetime and differential rotation as a function of spectral type and rotation/age. Here, we narrowed our focus to the ~306 planetary candidates, mostly main sequence late F, G and K stars, released during June 2010 (see Boruki et al. 2010). This is an attractive data set for the study of starspots properties since these stars host transiting planets with orbital planes almost exactly aligned with our line-of-sight and will generally have the host stars' rotation axes perpendicular to the planetary orbital plane. Thus, the inclination of the star's rotation axis can be assumed known and should (in most cases) be at right angles to our line-of-sight. Using a Lomb-Scargle Periodogram analysis, we have extracted reliable rotation periods and spot coverages for stars which showed evidence for starspots. From the measured rotation periods, we were able to determine, empirically, the age of the stellar system (using Villanova rotation-age relations) and investigate the potential tidal evolution of the planet-star system. However, we found good evidence that rotation-age relations do not apply to stars that host short-period, Jupiter sized planets. The aforementioned stars show a definite tendency towards star-rotation-planet orbital synchronization. The initial results of this exploratory program will be discussed.
This project was initiated at the 2010 Sagan Exoplanet Summer Workshop hosted by NExScI at Caltech. We wish to thank NASA and the organizers of the workshop - in particular Dawn Gelino and Carolyn Brinkworth. EG wishes also to acknowledge support from NSF/RUI Grant AST-10-09903.


Piecing Together Planet Populations: How RV Super-Earth Frequency Predictions Measure up to Kepler’s Planet Candidates

Angie Wolfgang1, G. Laughlin1
1University of California, Santa Cruz.

Exhibit Hall

Based on the mass and period distributions of the super-Earths discovered by the Geneva Extrasolar Planet Search, there are expected to be planets less massive than Neptune orbiting a large fraction of main sequence stars in periods of 50 days or less. Expanding on this prediction, we employ a Monte Carlo method to create populations of super-Earths with varying compositions, mass distributions, and period distributions. We then compare the results of these simulations with the planet candidates announced by Kepler on June 15, 2010, calculating a statistical best fit to identify the radial velocity super-Earth population which is most likely to reproduce Kepler’s population of planet candidates.

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