IRSV 1540-5413 : a born-again asymptotic giant branch star ?
Abstract
Photometric and spectroscopic observations of IRSV 1540-5413 are presented. This object is variable and shows photospheric TiO and CO absorption bands. Its circumstellar shell contains silicate grains, and an SiO maser emission is observed at 86 GHz. It does not show the H2O absorption band at 2 μm, nor OH maser emission at 1612 MHz although there are enough far-infrared photons to excite this transition at a detectable level. Its 1 - 100 μm broad band spectrum is bi-modal and can be understood in terms of a model in which mass loss decreased abruptly ≡150 years ago; mass loss rate was at that time ≡2×10-5M_sun;yr-1. It is conjectured that IRSV 1540-5413 is hydrogen deficient and could be a born-again asymptotic giant branch star.
- Publication:
-
Astronomy and Astrophysics
- Pub Date:
- May 1988
- Bibcode:
- 1988A&A...197..143L
- Keywords:
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- Asymptotic Giant Branch Stars;
- Late Stars;
- Masers;
- Planetary Nebulae;
- Star Formation;
- Stellar Mass Ejection;
- Astronomical Photometry;
- Infrared Astronomy;
- Stellar Evolution;
- Variable Stars;
- Astrophysics