Sign on

SAO/NASA ADS Astronomy Abstract Service

· Find Similar Abstracts (with default settings below)
· Reads History
·
· Translate This Page
Title:
A Radial Velocity Study of Hot Subdwarf Stars with Composite Spectra
Authors:
Wade, Richard A.; Stark, M. A.
Affiliation:
AA(Penn State Univ), AB(Univ. Wyoming)
Publication:
2007 AAS/AAPT Joint Meeting, American Astronomical Society Meeting 209, id.151.01; Bulletin of the American Astronomical Society, Vol. 38, p.1102
Publication Date:
12/2006
Origin:
AAS
Bibliographic Code:
2006AAS...20915101W

Abstract

Many subdwarf B (sdB) stars have composite energy distributions and/or spectra. The companion is a G or K star in most cases. Subdwarf B stars have helium-burning cores near 0.5 solar masses and have very low mass hydrogen envelopes. How the hydrogen envelopes were lost, very near the time of core helium ignition, is of great interest. Many sdB stars that show a composite nature may have formed by Roche lobe overflow (RLOF). The resulting binaries should have orbital periods of order 3 5 y and orbital separations of 2 3 AU. We have selected fifteen moderately bright sdB stars with composite spectra, to monitor for radial velocity variations. We use the bench-mounted Medium Resolution Spectrograph on the Hobby Eberly Telescope. Since January 2005, we have acquired between 3 and 10 observations of each star, over baselines of six months or longer. If these systems were formed by RLOF, we expect to see measurable orbital acceleration in many of these systems over this time span, barring systematic bad luck with orbital phase or inclination. We will describe the status of the program and the findings to date.
Bibtex entry for this abstract   Preferred format for this abstract (see Preferences)
  New!

Find Similar Abstracts:

Use: Authors
Title
Abstract Text
Return: Query Results Return    items starting with number
Query Form
Database: Astronomy
Physics
arXiv e-prints