Hydrogen alpha observations of RS Canum Venaticorum stars. IV. Gas streams in RT Lacertae.
Abstract
H-alpha spectroscopy of RT Lac with extensive phase and time coverage presents evidence for intermittent gas flow in this semidetached RS CVn system. Observed line profiles have been compared to synthetic profiles formed from standard-star spectra combined after applying parameters as expected for the binary components. For some higher-resolution data, the standard-star spectra were fit to the object spectrum automatically by varying the standard-star radial velocities, relative brightnesses, and rotational broadening in search of the minimum mean-square residuals between the object and synthetic spectra. Differences between the observed and synthetic line profiles show both excess emission and excess absorption. The detached K1 component shows variable excess emission. The contact G9 component shows variable excess absorption near secondary eclipse (G9 in front). In one case, excess absorption appeared at a high negative velocity (-300 km/s from the G9 star). These observations suggest mass loss through the outer Lagrangian point (L2). Radii determined from v-sin i and the assumption of synchronous rotation are consistent with previously determined photometric values.
- Publication:
-
The Astronomical Journal
- Pub Date:
- March 1985
- DOI:
- 10.1086/113757
- Bibcode:
- 1985AJ.....90..499H
- Keywords:
-
- Binary Stars;
- Gas Dynamics;
- H Alpha Line;
- Mass Flow;
- Stellar Spectrophotometry;
- Variable Stars;
- Absorption Spectra;
- Emission Spectra;
- Interstellar Gas;
- Radial Velocity;
- Spectral Line Width;
- Stellar Luminosity;
- Stellar Rotation;
- Astrophysics