A survey for post-common-envelope binary stars using GALEX and SDSS photometry
Abstract
We report the first results of our programme to obtain multi-epoch radial velocity measurements of stars with a strong far-ultraviolet excess to identify post-common-envelope binaries (PCEBs). The targets have been identified using optical photometry from Sloan Digital Sky Survey (SDSS) DR4, ultraviolet photometry from Galaxy Evolution Explorer (GALEX) GR2 and proper motion information from SDSS DR5. We have obtained spectra at two or more epochs for 36 targets. Three of our targets show large radial velocity shifts (>50kms-1) on a time-scale of hours or days and are almost certainly PCEBs. For one of these targets (SDSSJ104234.77+644205.4) we have obtained further spectroscopy to confirm that this is a PCEB with an orbital period of 4.74h and semi-amplitude K = 165kms-1. Two targets are rapidly rotating K-dwarfs which appear to show small radial velocity shifts and have strong CaII H&K emission lines. These may be wind-induced rapidly rotating (WIRRing) stars. These results show that we can use GALEX and SDSS photometry to identify PCEBs that cannot be identified using SDSS photometry alone, and to identify new WIRRing stars. A more comprehensive survey of stars identified using the methods developed in this paper will lead to a much improved understanding of common envelope evolution.
Based on observations made with the Isaac Newton Telescope operated on the island of La Palma by the Isaac Newton Group in the Spanish Observatorio del Roque de los Muchachos of the Instituto de Astrofsica de Canarias. E-mail: pflm@astro.keele.ac.uk- Publication:
-
Monthly Notices of the Royal Astronomical Society
- Pub Date:
- December 2009
- DOI:
- 10.1111/j.1365-2966.2009.15594.x
- arXiv:
- arXiv:0908.2916
- Bibcode:
- 2009MNRAS.400.2012M
- Keywords:
-
- binaries: spectroscopic;
- stars: late-type;
- white dwarfs;
- ultraviolet: stars;
- Astrophysics - Solar and Stellar Astrophysics
- E-Print:
- 11 pages, 7 figures, accepted for publication in MNRAS