EC 11481-2303—a peculiar subdwarf OB star revisited
Abstract
EC 11481-2303 is a peculiar, hot, high-gravity pre-white dwarf. Previous optical spectroscopy revealed that it is a sdOB star with T eff=41 790 K, log g=5.84, and He/H = 0.014 by number. We present an on-going spectral analysis by means of non-LTE model-atmosphere techniques based on high-resolution, high-S/N optical (VLT-UVES) and ultraviolet (FUSE, IUE) observations. We are able to reproduce the optical and UV observations simultaneously with a chemically homogeneous NLTE model atmosphere with a significantly higher effective temperature and lower He abundance ( T eff=55 000 K, log g=5.8, and He/H=0.0025 by number). While C, N, and O appear less than 0.15 times solar, the iron-group abundance is strongly enhanced by at least a factor of ten.
- Publication:
-
Astrophysics and Space Science
- Pub Date:
- October 2010
- DOI:
- 10.1007/s10509-010-0304-3
- arXiv:
- arXiv:1001.5115
- Bibcode:
- 2010Ap&SS.329..133R
- Keywords:
-
- Stars: individual: EC 11481–2303;
- Stars: abundances;
- Stars: atmospheres;
- Stars: chemically peculiar;
- Subdwarfs;
- Astrophysics - Solar and Stellar Astrophysics
- E-Print:
- 8 pages, 11 figures