References - VPD0AJ
A FEROS survey of hot subdwarf stars
By: Stephane Vennes; Peter Nemeth and Adela Kawka
In: Open Astronomy - 2017 - Accepted - arXiv:1711.03341
Poster presentation: Eighth Meeting on Hot Subdwarf Stars and Related Objects, sdOB8, Kraków (Poland), July 9 - 15, 2017
(Astroserver project reference: VPD0AJ)
The poster presented at sdOB8.
We have initiated a small survey of twenty 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 extracted from our GALEX catalogue of hot subdwarf stars (Vennes et al., 2011; Nemeth et al., 2012). As expected (Kawka et al., 2015; Kupfer et al., 2015), the fraction of radial velocity variables is close to 50%, and, among these, we identified a long-period (62 d) sdO plus G III binary. This particular system should evolve into a close subdwarf plus white dwarf pair during the common envelope phase that follows the second ascent of the giant branch. Newly discovered systems also include short period binaries with periods ranging from 3.5 hours to 5 days and comprised of a hot subdwarf primary and a late-type companion seen in reflection, or a white dwarf companion. We present a preliminary model atmosphere analysis and a summary of results for representative objects in our sample.
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