The atmosphere of the peculiar binary system ET Andromedae.
Abstract
High spectral resolution, high signal-to-noise OHP spectra which cover the range from 4000A to 7500A were used to derive abundances for ET And. An extreme overabundance of silicon by nearly 100 times of the solar value corroborates the Si-star classification. We find also enhanced abundances for iron-peak and rare-earths elements, which is typical for this group of CP stars. The deficiency of He (1/30 of the solar value), and to a lesser extent of Mg and C, is remarkable. Based on an estimate for R/Rsun_, derived from geometric arguments, and the measured interstellar Nai lines we conclude that ET And probably still has not evolved significantly from the main sequence. We present arguments, why some earlier luminosity determinations seem to be incorrect.
- Publication:
-
Astronomy and Astrophysics
- Pub Date:
- February 1995
- Bibcode:
- 1995A&A...294..757K
- Keywords:
-
- Abundance;
- Binary Stars;
- Peculiar Stars;
- Rare Earth Elements;
- Silicon;
- Stellar Atmospheres;
- Stellar Composition;
- Line Spectra;
- Main Sequence Stars;
- Spectral Resolution;
- Stellar Evolution;
- Astrophysics;
- STARS: ET AND;
- STARS: ABUNDANCES;
- STARS: CHEMICALLY PECULIAR