AAS 205th Meeting, 9-13 January 2005
Session 107 Binary Stars Including Theory and Activity
Poster, Wednesday, January 12, 2005, 9:20am-6:30pm, Exhibit Hall

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[107.13] Resolving Close White Dwarf + Red Dwarf Binaries with HST

D. W. Hoard, S. Wachter (SSC/IPAC/Caltech), J. Farihi (UCLA/Gemini Observatory)

We report the initial results from an ongoing Hubble Space Telescope/Advanced Camera for Surveys (ACS) snapshot survey of white dwarfs (WDs) with suspected close, low mass stellar (or substellar) companions. In terms of the inferred overall census of the content of the Galaxy, WDs are the most common type of stellar object next to low mass stars (i.e., red dwarfs) and brown dwarfs. WDs hold clues to their own past evolution from formation, through the main sequence, and beyond. Our target sample consists of 96 objects that are unresolved from the ground and are either (a) known or suspected WD + red dwarf binary stars, or (b) putative solitary WDs that show an infrared excess in data from the Two Micron All Sky Survey (2MASS). We are using ACS with the F814W filter (approximately I-band) to obtain images of these targets in order to resolve close companions with separations as small as 1-10 AU (for distances < 100 pc). This survey will allow us to empirically test binary star parameters in the post-AGB phase and begin to address the fundamental astrophysical question of how stellar evolution influences the observed distribution of binary star parameters (orbital separation, in particular, as well as possibly component masses).

This research was carried out at the Jet Propulsion Laboratory, California Institute of Technology, and uses data products from 2MASS, a joint project of the U. of Massachusetts and IPAC/Caltech, funded by NASA and the NSF. Support for Program number 10255 was provided by NASA through a grant from the Space Telescope Science Institute, which is operated by the Association of Universities for Research in Astronomy, Incorporated, under NASA contract NAS5-26555.

The author(s) of this abstract have provided an email address for comments about the abstract: hoard@ipac.caltech.edu

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© 2004. The American Astronomical Society.