講演者: Maciej Konacki (Caltech, USA)
  題名: Precision radial velocities of double-lined spectroscopic binaries 
        and the search for extrasolar planets in binary stellar systems
  日時: ８月３日（水）16時から17時すぎ 
  場所: 自然３号館6階６０９ゼミ室





  
  A spectroscopic technique employing an iodine absorption cell (I_2) to superimpose a reference spectrum onto a stellar spectrum is currently the most widely adopted approach to obtain precision radial velocities (RVs) of solar-type stars. It has been used to detect ~80 extrasolar planets out of ~130 know. Yet in its original version, it only allows us to measure precise radial velocities of single stars. I will present a novel method employing an I_2 absorption cell that enables us to accurately determine radial velocities of both components of double-lined binaries. My data from the Keck~I telescope and HIRES spectrograph demonstrate that ~20 m/s radial velocity precision can be routinely obtained for "early" type double-lined binaries (F3-F8). For later type binaries, the precision reaches ~10 m/s. I will discuss my ongoing search for extrasolar planets in multiple stellar systems and the recent detection of a hot Jupiter in a close triple-star system HD188753. I will also discuss the application of the new technique to stellar astronomy. In particular, such RVs when combined with the interferometric data collected with the Palomar Testbed Interferometer can routinely produce masses of the binary components accurate at the level of 0.1 to 1.0 % and challenge modern models of stellar structure and evolution.




Suggested reading


(1) Konacki, M. 2005, "An extrasolar giant planet in a close triple star-system", Nature, 14 July



(2) Konacki, M. 2005, "Precision radial velocities of double-lined spectroscopi binaries with an iodine absorption cell", Astrophysical Journal, vol. 626, p. 431



(3) Konacki, M. & Lane, B.F. 2004, "The visual orbits of the spectroscopic binaries HD 6118 and HD 27483 from the Palomar Testbed Interferometer", Astrophysical Journal, vol. 610, p. 443