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Non-LTE metal abundances in V652 Her and HD144941

N. Przybilla·M. F. Nieva·U. Heber·C. S. Jeffery
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Abstract

Two evolutionary scenarios are proposed for the formation of extreme helium stars: a post-AGB star suffering from a late thermal pulse, or the merger of two white dwarfs. An identification of the evolutionary channel for individual objects has to rely on surface abundances. We present preliminary results from a non-LTE analysis of CNO, Mg and S for two unique objects, V652 Her and HD144941. Non-LTE abundance corrections for these elements range from negligible values to ~0.7 dex. Non-LTE effects typically lead to systematic shifts in the abundances relative to LTE and reduce the uncertainties.

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N. Przybilla, M. F. Nieva, U. Heber, C. S. Jeffery. 2005-12-06. Non-LTE metal abundances in V652 Her and HD144941. https://arxiv.org/abs/astro-ph/0512153

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