The Unusual, High-Mass Ratio Contact Binary VZ PISCIUM
Abstract
Radial-velocity curves have been determined for the short-period W UMa type binary VZ Psc using the cross-correlation method. These yield a mass ratio of 0.92 + or - 0.03, a value closer to unity than that reported for any other W UMa binary thus far. Strong Ca II H and K emission is associated with each component. A light-curve solution indicates a greatly overcontact configuration with a very large temperature difference between components, a combination that is difficult to understand physically. However, the inclination is very low and thus the light-curve parameters are not well determined. The system has a high space velocity and belongs kinematically to the old-disk population. The high mass ratio makes VZ Psfc a candidate for recent evolution into contact, which may relate to some of its unusual properties.
- Publication:
-
The Astronomical Journal
- Pub Date:
- February 1989
- DOI:
- 10.1086/115002
- Bibcode:
- 1989AJ.....97..532H
- Keywords:
-
- Binary Stars;
- Late Stars;
- Mass Ratios;
- Emission Spectra;
- Light Curve;
- Radial Velocity;
- Stellar Evolution;
- Astrophysics;
- STARS: W URSAE MAJORIS