The 1979-1980 eclipse of ZET Aur. II. The emission spectrum.
Abstract
UV observations using the IUE are employed to discuss the strength and changes of Zeta Aur between a second contact and mid-eclipse in 1979, the relative visibility of the supergiant's chromosphere as compared with the circumstellar (CS) nebular scattering of the B star photons, and the origin of the high speed CS components observed at all orbital phases. Agreement has been found for a spectoscopic radius of 200 solar radii and a 400 pc distance, and eclipse emission lines were recorded from 1238.9-2802.7 microns. An asymmetry in the Fe III lines at 46 plus or minus 15 km/sec was seen during eclipse and is taken to indicate downflowing material. The high speed wind flowing from the K supergiant is thought to expand homogeneously until encountering the B type main sequence star, where an accretion bow shock forms, and the smaller star's passage near the K star at periastron may cause local surface heating and subsequent high speed flows.
- Publication:
-
The Astrophysical Journal
- Pub Date:
- December 1981
- DOI:
- 10.1086/159504
- Bibcode:
- 1981ApJ...251..597S
- Keywords:
-
- Eclipsing Binary Stars;
- Emission Spectra;
- K Stars;
- Stellar Spectra;
- Zeta Aurigae Star;
- Ferric Ions;
- Iue;
- Shock Waves;
- Stellar Envelopes;
- Ultraviolet Spectra;
- Astrophysics