EC 11481–2303—a peculiar subdwarf OB star revisited
Source: Astrophysics and Space Science, Volume 329, Numbers 1-2, October 2010 , pp. 133-139(7)
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.
Document Type: Research Article
Affiliations: 1: Institute for Astronomy and Astrophysics, Kepler Center for Astro and Particle Physics, Eberhard Karls University, Sand 1, 72076, Tübingen, Germany, Email: firstname.lastname@example.org 2: Institute for Astronomy and Astrophysics, Kepler Center for Astro and Particle Physics, Eberhard Karls University, Sand 1, 72076, Tübingen, Germany 3: Department of Physics and Astronomy, Johns Hopkins University, Baltimore, MD, 21218, USA
Publication date: October 2010