NOAO >   Observing Info >   Approved Programs >   2010B-0457

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Proposal Information for 2010B-0457


PI: Marie-Michele Limoges, Universite de Montreal, limoges@astro.umontreal.ca
Address: Physique, P.O. 6128, succ. centre-ville, 2900, boul. ??douard-Montpetit, Montreal, Quebec H3C 3J7, Canada

CoI: Sebastien Lepine, American Museum of Natural History
CoI: Pierre Bergeron, Universite de Montreal

Title: A continuing census of Galactic white dwarfs to 40 parsecs of the Sun

Abstract: We propose to obtain spectra for 170 new white dwarf candidates suspected to be within 40 parsecs of the Sun, as a continuation of our survey of white dwarfs in the Solar Neiborhood. Spectral analysis will confirm the white dwarf status and provide reliable distance estimates for all objects. The census of nearby white dwarfs is currently complete only to about 20 parsecs of the Sun, a volume which includes only a little over 100 white dwarfs. The main limitation of the current census is that it is largely based on follow-up investigations of stars with very large proper motion. Our own survey investigates stars down to a much smaller proper motion limit (40 mas/yr) which minimizes the kinematic bias and provides a statistically complete census of white dwarfs to a significantly larger distance. Our follow-up spectroscopic program, initiated in the past two semesters, strikingly demonstrates the effectiveness of our white dwarf selection method, with a sucess rate exceeding 96%. We have now obtained spectra for 65% of our initial list of 350 white dwarf candidates, and request additional nights to observe the remaining 170. In particular, our survey has been efficient in locating faint, cool white dwarfs, which will help in the study of the cool end of the white dwarf luminosity function. Finally, objects of great astrophysical interest were found, such as the very cool DQ LSPM J0902+2010, the highly magnetic PM I11322+2809, and the extremely contaminated DA+dM binary system PM I04586+6209. We expect additional objects of interest to show up in our extended program, from which we expect to obtain a near-complete census of white dwarfs to a distance of 40 parsecs.


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