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An Astronomy GradNet Tech Talk: Searching for Eclipsing Binary Stars

An Astronomy GradNet Tech Talk: Searching for Eclipsing Binary Stars. Jonathan Devor, Ph.D. October 20, 2008. Stellar structure: understanding how stars work. Why Eclipsing Binaries?.

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An Astronomy GradNet Tech Talk: Searching for Eclipsing Binary Stars

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  1. An Astronomy GradNet Tech Talk:Searching for Eclipsing Binary Stars Jonathan Devor, Ph.D. October 20, 2008

  2. Stellar structure:understanding how stars work

  3. Why Eclipsing Binaries? • Eclipsing binaries provide the most direct and accurate method of measuring both the masses and radii of stars. • We need to know both the masses and radii of stars to constrain their structure. • This is especially needed to understand low-mass stars, which don’t conform well to currently stellar models.

  4. What are Eclipsing Binary Stars? EB = eclipsing binary LC = light curve Light curve Secondary eclipse Primary eclipse Out-of-eclipse “plateau” Animation from Wikipedia

  5. Eccentric orbit Circular and Eccentric Orbits Circular orbit a

  6. Outline • Where the data comes from- The multi-epoch photometric surveys • How I analyzed the data- The automated DEBiL/MECI pipeline • Results- Discovery of low-mass eclipsing binaries Testing tidal circularization theory Finding “abnormal” eclipsing binaries

  7. OGLE:The Optical Gravitational Lensing Experiment • Located at Las Campanas Observatory, Chile • 1.3m physical aperture • I-band photometric observations • Magnitude limit I < 19 • ~200 observations per LC, compiled over three years (1997-1999) • Analyzed 49 bulge fields, totaling 218,699 LCs Specs: The Warsaw Telescope Las Campanas Observatory, Chile OGLE website

  8. “It is a common situation nowadays that the ability to generate data far exceeds the ability to process it, and even more so, to comprehend it.” (Wozniak et al. 2002) Release all the data to the public Many discoveries, most of which had nothing to do with the original survey motivations (e.g. pulsating stars, transiting exoplanets, population statistics, irregular variables, eclipsing binaries, etc.)

  9. TrES/Sleuth – a robotic telescope TrES = Trans-atlantic Exoplanet Survey Specs: • Sleuth is one of three robotic telescopes in the TrES network. • Located at Palomar Obs., CA • 10 cm physical aperture • 30“ photometric aperture radius • r - band photometric observations • Magnitude limit r < 15 • Effective 9-minute cadence (5 x 90sec) • ~2000 observations per LC • Analyzed 10 fields, totaling 185,445 LCs http://solas.dnsalias.org/~ftod//tres/sleuth.html Large field / bright targets  easier to follow-up

  10. (Devor 2005)

  11. “Abnormal” Eclipsing Binaries P = 1.046 days P = 24.073 days P = 0.485 days P = 0.310 days P = 0.538 days (Devor et al. 2008)

  12. A Binary with Large Eclipse Timing Variations

  13. The Orbital Period Distribution (Devor 2005)

  14. The MECI Flow-Chart (Devor & Charbonneau 2006) The Yonsei-Yale theoretical isochrones Log Luminosity Main-sequence (Yi et al. 2001) LogTemperature

  15. (Devor & Charbonneau 2006)

  16. Testing MECI with Known Systems (Lacy et al. 2002) (Lacy et al. 2003) (Devor & Charbonneau 2006)

  17. Binary Mass-Mass Plot (Devor et al. 2008)

  18. TrES/PSST (LC) Lowell Obs., AZ TrES/Slueth (LC) Palomar Obs., CA NIRSPEC (RV) Mauna Kea, HI Georgi Mandushev Dave Charbonneau Francis O'Donovan Dave Charbonneau John Bailey Cullen Blake Dave Charbonneau Russel White HATNet (LC) Mauna Kea, HI & FLWO, AZ Gaspar Bakos TRES (RV) FLWO, AZ IAC80 (LC) Observatorio del Teide Canary Islands Gabor Furesz Doug Mink Andy Szentgyorgyi Bill Wyatt Markus Rabus MECI + DEBiL pipeline

  19. T-Lyr1-17236:A long-period low-mass EB [J. Devor, D. Charbonneau, G. Torres, C. H. Blake, R. White, M. Rabus, F. T. O'Donovan, G. Mandushev, G. Bakos, & A. Szentgyorgyi The Astrophysical Journal] (Devor et al., in press) P = 8.429441 ± 0.000033 days

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