Cataclysmic Variable Stars and the MDM Parallax Program
John Thorstensen
Dartmouth College

Cataclysmic variable (CV) stars are close binary systems in which a white dwarf accretes material from a non-giant companion. CVs show intriguing physical effects, and are also useful signposts for binary evolution. In this talk I'll quickly survey the types of CVs, and then discuss the CV research I've been pursuing (for 30 years now!) at MDM Observatory on Kitt Peak. Much of the work is spectroscopic, finding CV orbital periods, and discovering some interesting examples. The most unusual component of the work is a parallax program, started in the late 1990s, which has gone on to attract several collaborators (including your alumnus Sébastien Lépine). Although parallax measurements are fundamental to stellar astronomy, there are few practioners, so I'll describe the parallax procedures in some detail.

Date:	Jeudi, le 21 octobre 2010
Heure:	11:30
Lieu:	Université de Montréal
	Pavillon Roger-Gaudry, local D-460
Contact:	Pierre Bergeron