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arXiv · 1001.5115

EC 11481-2303 - A Peculiar Subdwarf OB Star Revisited

T. Rauch·K. Werner·J. W. Kruk
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Abstract

EC 11481-2303 is a peculiar, hot, high-gravity pre-white dwarf. Previous optical spectroscopy revealed that it is a sdOB star with an effective temperature (Teff) of 41790 K, a surface gravity 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 (Teff = 55000 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.

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T. Rauch, K. Werner, J. W. Kruk. 2010-01-28. EC 11481-2303 - A Peculiar Subdwarf OB Star Revisited. https://doi.org/10.1007/s10509-010-0304-3

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