NOAO >   Observing Info >   Approved Programs >   2001A-0275

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Proposal Information for 2001A-0275


PI: Tom Williams, University of New Mexico, tw@as.unm.edu
Address: 800 Yale Ave, Albuquerque, NM 87131, USA

Title: Radial Velocity Variables in the PG Survey He-rich Hot Subdwarf O Stars

Abstract: The evolutionary status of the ``compact'' He-rich hot subdwarf O stars remains in limbo. Although a variety of plausible theoretical scenarios have been proposed to place the compact sdOs in a rational evolutionary context, none are as yet solidly established. The very few sdO masses that have been empirically determined do not meet with theoretical expectations for compact sdOs. This project is intended to identify the radial velocity variables in a sample of 25 sdO binary candidates. The candidate systems have been identified on the basis of either a near IR flux excess or an anomalous optical flux distribution. Candidates showing significant radial velocity variability will be subject to precision radial velocity studies to determine the orbital parameters and masses of compact sdOs, thereby substantially constraining their evolutionary history.


National Optical Astronomy Observatory, 950 North Cherry Avenue, P.O. Box 26732, Tucson, Arizona 85726, Phone: (520) 318-8000, Fax: (520) 318-8360



NOAO >   Observing Info >   Approved Programs >   2001A-0275

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