Hirsch H, Heber U (2009)
Publication Status: Published
Publication Type: Conference contribution
Publication year: 2009
Book Volume: 172
Article Number: ARTN 012015
DOI: 10.1088/1742-6596/172/1/012015
Stroer et al. (2007) recently suggested a classification of sdOs according to supersolar and subsolar helium abundances, with only the helium-enriched stars showing signes of carbon and/or nitrogen in their optical spectra. We aim to derive reliable carbon and nitrogen abundances by fitting synthetic spectra to data obtained with the UVES spectrograph at ESO. Here we present our first results of the analysis of carbon abundances in hot subdwarf O stars. By constructing a grid of model atmospheres consisting of hydrogen, helium and carbon we were able to derive atmospheric parameters of nine carbon rich sdOs. We find log(N(C)/N(total)) up to ten times higher than the solar value, while the mean value for the effective temperature and the surface gravity is slightly lower than derived by helium-hydrogen models only. Surprisingly, we also find three fast rotators among our program stars.
APA:
Hirsch, H., & Heber, U. (2009). Carbon abundances of sdO stars from SPY.
MLA:
Hirsch, Heiko, and Ulrich Heber. "Carbon abundances of sdO stars from SPY." 2009.
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