NOAO > Observing Info > Approved Programs > 2010A-0167
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NOAO > Observing Info > Approved Programs > 2010A-0167 |
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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: Early F dwarfs with hidden hot subdwarf companions
Abstract:
Theories of binary star evolution predict that an early 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 only a
few F+sdB systems have been studied previously. Their space density in
the disk of the Galaxy needs to be determined. The distribution of
orbital periods of the F+sdB systems, which depends on the processes of
mass transfer/loss and angular momentum loss from the binary, needs to
be established. 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 early F star 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. For a sample of stars that can be observed
synoptically throughout the year and be of use to other observers, the
entire range of RA needs to be included; this proposal for 2010A
complements a similar proposal which has been awarded time in 2009B, to
provide the necessary MK classifications and other validation in the
remaining RA range.
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 > 2010A-0167 |
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