Extreme Helium Stars: Model Atmospheres and a NLTE analysis of BD+10°2179

Extreme helium stars are hydrogen‐deficient supergiants of spectral type A and B. They are believed to result from mergers in double degenerate systems, if one white dwarf is of C/O‐type and the other of He‐type. We calculate a new grid of model atmospheres accounting for metal line blanketing with ATLAS12 and compare it to the benchmark code STERNE. Synthetic spectra are calculated accounting for NLTE effects for many ions and applied to high‐quality optical spectra of the prototype extreme helium star BD+10°2179.© 2010 American Institute of Physics
17 European White Dwarf Workshop, Tubingen (Germany), 16-20 August 2010
info:eu-repo/semantics/published