Spectral analysis of the O(He)-type central stars of the planetary nebulae K 1-27 and LoTr 4
Abstract
The four known O(He) stars are the only amongst the hottest post-AGB stars whose atmospheres are composed of almost pure helium. Thus, their evolution deviates from the hydrogen-deficient post-AGB evolutionary sequence of carbon-dominated stars like e.g. PG 1159 stars. The origin of the O(He) stars is still not explained. They might be either post-early AGB stars or the progeny of R Coronae Borealis stars. We present preliminary results of a non-LTE spectral analysis based on FUSE and HST/COS observations.
- Publication:
-
Planetary Nebulae: An Eye to the Future
- Pub Date:
- August 2012
- DOI:
- 10.1017/S1743921312012033
- Bibcode:
- 2012IAUS..283..482R
- Keywords:
-
- stars: abundances;
- stars: AGB and post-AGB;
- stars: atmospheres;
- stars: evolution;
- planetary nebulae: individual (K 1-27;
- LoTr 4)