The rapidly pulsating sdO star, SDSS J160043.6+074802.9 |
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| Authors: | C Rodríguez-López A E Lynas-Gray D Kilkenny J MacDonald A Moya C Koen P A Woudt D J Wium B Oruru E Zietsman |
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| Institution: | Laboratoire d'Astrophysique de Toulouse-Tarbes, Universitéde Toulouse, CNRS, Toulouse 31400, France;Departamento de Física Aplicada, Universidade de Vigo, Vigo 36310, Spain;Department of Physics, University of Oxford, Keble Road, Oxford OX1 3RH;Department of Physics, University of the Western Cape, Private Bag X17, Bellville, 7535 Cape, South Africa;Department of Physics and Astronomy, University of Delaware, Newark, DE 19716, USA;Departmento de Física Estelar, Instituto de Astrofísica de Andalucía-CSIC, Granada 18008, Spain;Department of Statistics, University of the Western Cape, Private Bag X17, Bellville, 7535 Cape, South Africa;Department of Astronomy, University of Cape Town, Private Bag X3, Rondebosch 7701, South Africa;National Astrophysics and Space Science Programme, Department of Physics, University of the Free State, Bloemfontein 9300, South Africa;Department of Mathematical Sciences, University of South Africa, UNISA 0003, South Africa |
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| Abstract: | A spectroscopic analysis of Sloan Digital Sky Survey (SDSS) J160043.6+074802.9, a binary system containing a pulsating subdwarf-O (sdO) star with a late-type companion, yields T eff= 70 000 ± 5000 K and log g = 5.25 ± 0.30 , together with a most likely type of K3 V for the secondary star. We compare our results with atmospheric parameters derived by Fontaine et al. and in the context of existing evolution models for sdO stars. New and more extensive photometry is also presented which recovers most, but not all, frequencies found in an earlier paper. Therefore, it seems probable that some pulsation modes have variable amplitudes. A non-adiabatic pulsation analysis of uniform metallicity sdO models show those having log g > 5.3 to be more likely to be unstable and capable of driving pulsation in the observed frequency range. |
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| Keywords: | stars: oscillations stars: individual: SDSS J160043 6+074802 9 |
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