The Ultraviolet Variability of AY Ceti
Abstract
AY Cet is a single-line binary comprised of a spotted G5 III primary and a white dwarf secondary. The authors obtained a series of UV spectra with the IUE satellite on five different dates covering a substantial part of the optical cycle of the primary star. They found no evidence that the continuum or the Lyα absorption line of the secondary star varied. There were significant changes in the strengths of the UV emission lines, but the variations were only weakly correlated with either the orbital phase of the binary or the rotational phase of the primary. The UV emission lines were especially strong near maximum visual brightness at a time when the starspot(s) on the primary was least visible. The authors attribute the enhanced line emission to a flare event on the primary, most likely at a high-latitude site close to the pole of this star. The UV radiative losses of this flare were comparable with those of flares previously observed on the RS CVn variables λ And and HR 1099.
- Publication:
-
The Astronomical Journal
- Pub Date:
- December 1987
- DOI:
- 10.1086/114597
- Bibcode:
- 1987AJ.....94.1657S
- Keywords:
-
- Binary Stars;
- Spaceborne Astronomy;
- Stellar Spectrophotometry;
- Ultraviolet Spectra;
- Variable Stars;
- White Dwarf Stars;
- Emission Spectra;
- Iue;
- Line Spectra;
- Radiant Flux Density;
- Stellar Luminosity;
- Astrophysics;
- STARS: BINARIES;
- STARS: WHITE DWARFS;
- STARS: SUBDWARFS;
- ULTRAVIOLET: GENERAL;
- X-RAYS: SOURCES