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Studying Binary Stars a Few Photons at a Time

Studying Binary Stars a Few Photons at a Time. Elliott Horch, CIS. Astronomy. Stars are. very. VERY. VERY. …cool. What do we want to know about stars?. How do they form? How much matter is needed? Are planets involved? How do stars work? Do they change? How long do they live?

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Studying Binary Stars a Few Photons at a Time

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  1. Studying Binary Stars a Few Photons at a Time • Elliott Horch, CIS

  2. Astronomy Stars are very VERY VERY …cool.

  3. What do we want to know about stars? • How do they form? How much matter is needed? Are planets involved? • How do stars work? • Do they change? How long do they live? • Why do they appear in groups sometimes? • What can they tell us about how the Galaxy formed?

  4. What’s going to help us out in answering those questions? • Mass • Luminosity (total light output) • Size (radius) • Surface Temperature • Age • Heavy Metal Content (“metallicity”) • etc.

  5. What do we think we know about stars? • Energy production mechanisms • Basic life cycle features • Pulsation • Spectral features

  6. What still confuses us? • Details, details… (Sigh.) • e.g. how to calibrate luminosities, etc?? • Neutrinos • Formation Processes • “Jumps” in HR diagram • etc.

  7. Masses and the “MLR” • Theory: Mass and luminosity are related. Our favorite star! 0 log(L/Lsun) 0 log(M/Msun)

  8. Reality: Large Uncertainties!

  9. Binary stars. Gravitation --> orbit. N q N N N N N N N N N N q r q r r r r r r r r r r Why are masses so hard to measure? Okay, well how? Scales? Ha! BUT: need SIZE of orbit, which means we need the distance.

  10. Why are distances so hard to measure? • Parallax Earth

  11. Our Home Galaxy

  12. Our Home Galaxy - The Comic Book Version Globular Clusters Disk Bulge Halo

  13. Two “Populations” • Population I: • Disk dwellers • metal rich • Population II: • Halo dwellers • metal poor MLR log(L/Lsun) Pop I 0 Pop II 0 log(M/Msun)

  14. Imaging Binary Stars • That *3$%%^*&$$% Atmosphere!! • Blurs out star images, can’t see both stars distinctly if they’re too close together. • Related to twinkling. • Telescopes and camera systems: the rest of the optical system. • Big telescopes can resolve closer pairs. • Need high-speed cameras to “freeze” the twinkling.

  15. Why the atmosphere is such a bummer... light Atmosphere Ground

  16. At Big Telescopes, Stars “Speckle” integrated image speckle images

  17. At Big Telescopes, Stars “Speckle” integrated image speckle images

  18. Speckling Binary Star t=0.00s t=0.05s t=0.10s t=0.15s

  19. Speckling Binary Star t=0.00s t=0.05s t=0.10s t=0.15s

  20. Speckling Binary Star t=0.00s t=0.05s t=0.10s t=0.15s

  21. Reminds me of...

  22. A “Close Binary” t=0.00s t=0.05s t=0.10s t=0.15s

  23. A “Close Binary” t=0.00s t=0.05s t=0.10s t=0.15s

  24. A “Close Binary” t=0.00s t=0.05s t=0.10s t=0.15s

  25. We can Beat the Atmosphere!! 1 arcsec speckle analysis long exposure

  26. KPNO The WIYN Telescope Kitt Peak, Arizona

  27. Inside the WIYN Dome

  28. Hipparcos (True) Binaries W98 W97 W99.89 W99.02 W99 H91 C95 H91

  29. Space Telescope FGSs single star signal double star x

  30. Koesters Prism

  31. FGS will help us study Pop II binaries. Orbits Masses Luminosities Pop II MLR !!!!!!! Better Ages and Distances to Glob. Clusters!!!! A Real FGS Transfer Function arcsec -0.8 0.8 Henry et al. (1999)

  32. Conclusions • Stars are interesting. • Star images taken at big telescopes “speckle.” • Interferometric imaging of binary stars helps us determine their masses and luminosities, which in turn helps us understand how they work. • Speckle imaging from the ground. • Fine Guidance Sensor data from the Hubble Space Telescope.

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