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arXiv · 1711.03341

A FEROS Survey of Hot Subdwarf Stars

S. Vennes·P. Nemeth·A. Kawka
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Abstract

We have completed a survey of twenty-two ultraviolet-selected hot subdwarfs using the Fiber-fed Extended Range Optical Spectrograph (FEROS) and the 2.2-m telescope at La Silla. The sample includes apparently single objects as well as hot subdwarfs paired with a bright, unresolved companion. The sample was extracted from our GALEX catalogue of hot subdwarf stars. We identified three new short-period systems (P=3.5 hours to 5 days) and determined the orbital parameters of a long-period (P=62.66 d) sdO plus G III system. This particular system should evolve into a close double degenerate system following a second common envelope phase. We also conducted a chemical abundance study of the subdwarfs: Some objects show nitrogen and argon abundance excess with respect to oxygen. We present key results of this programme.

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S. Vennes, P. Nemeth, A. Kawka. 2017-11-09. A FEROS Survey of Hot Subdwarf Stars. https://arxiv.org/abs/1711.03341

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