NOAO > Observing Info > Approved Programs > 2009B-0365
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NOAO > Observing Info > Approved Programs > 2009B-0365 |
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PI: Richard Wade, Pennsylvania State University, wade@astro.psu.edu
Address: Astronomy Department, 525 Davey Lab, University Park, PA 16802, USA
Title: F dwarfs with hidden hot subdwarf companions
Abstract:
Theories of binary star evolution predict that an F dwarf star will
sometimes be paired with a hot subdwarf (an ``sdB'' star). This is an
essential prediction from theories that successfully account for
pairings of sdB stars with white dwarf or lower-mass stars, but the
F+sdB systems have not been observed before. The existence of such
objects needs to be demonstrated, and their space density in the disk of
the Galaxy needs to be determined. The distribution of orbital periods
of the F+sdB systems depends on the processes of mass transfer/loss and
angular momentum loss from the binary. Observations of F+sdB pairs
provide a new way to help test and improve binary population synthesis
(BPS) models, which are used throughout astrophysics to understand a
wide variety of exotic objects and to predict their numbers. Using
2MASS and GALEX archival data, it is possible to identify F stars
candidates with UV excesses (F+UVX). The 2.1m telescope with GoldCam
spectrograph will be used to classify these color-selected F+UVX
candidates on the MK system, reject interloping Algol systems and other
objects that mimic F-star colors, and develop a representative sample of
F+UVX stars that will be observed synoptically at high spectral
resolution to obtain spectroscopic orbits.
National Optical Astronomy Observatory, 950 North Cherry Avenue, P.O. Box 26732, Tucson, Arizona 85726, Phone: (520) 318-8000, Fax: (520) 318-8360
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NOAO > Observing Info > Approved Programs > 2009B-0365 |
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