Abstract
We report on the analysis of high-resolution optical spectra for 77 subdwarf B (sdB) stars from the ESO Supernova Ia Progenitor Survey. Effective temperature, surface gravity, and photospheric helium abundance are determined simultaneously by spectral line profile fitting of hydrogen and helium lines, and are found to be in agreement with previous studies of sdB stars. Twenty four objects show spectral signs of a cool companion, being either companion absorption lines or a flux contribution at Hα. Five stars with relatively high luminosity show peculiar Hα profiles, possibly indicating stellar winds. Our results are compared to recent theoretical simulations by Han et al. [MNRAS, 341, 669] for the distribution in effective temperature and surface gravity, and are found to agree very well with these calculations. Finally, we present a binary system consisting of two helium-rich hot subdwarfs.
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Lisker, T., Heber, U., Napiwotzki, R. et al. Spectroscopic analysis of sdB stars from the ESO Supernova Ia Progenitor Survey. Astrophys Space Sci 291, 351–358 (2004). https://doi.org/10.1023/B:ASTR.0000044343.94946.51
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DOI: https://doi.org/10.1023/B:ASTR.0000044343.94946.51