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Pulsational and evolutionary analysis of the double-mode RR Lyrae star BS Com

Dékány, I. ; Kovács, G. ; Jurcsik, J. ; Szabó, R. ; Váradi, M. ; Sódor, Á. ; Posztobányi, K. ; Hurta, Zs ; Vida, K. ; Vityi, N. ; Szing, A.

In: Monthly Notices of the Royal Astronomical Society, 2008, vol. 386, no. 1, p. 521-530

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    Titre
    • Pulsational and evolutionary analysis of the double-mode RR Lyrae star BS Com
    Auteur
    • Dékány, I.. Konkoly Observatory, PO Box 67, H-1525 Budapest, Hungary
    • Kovács, G.. Konkoly Observatory, PO Box 67, H-1525 Budapest, Hungary
    • Jurcsik, J.. Konkoly Observatory, PO Box 67, H-1525 Budapest, Hungary
    • Szabó, R.. Konkoly Observatory, PO Box 67, H-1525 Budapest, Hungary
    • Váradi, M.. Observatoire de Genève, Université de Genève, CH-1290 Sauverny, Switzerland
    • Sódor, Á.. Konkoly Observatory, PO Box 67, H-1525 Budapest, Hungary
    • Posztobányi, K.. AEKI, KFKI Atomic Energy Research Institute, Thermohydraulic Department, PO Box 49, H-1525 Budapest 114, Hungary
    • Hurta, Zs. Eötvös University, Department of Astronomy, PO Box 32, H-1518 Budapest, Hungary
    • Vida, K.. Eötvös University, Department of Astronomy, PO Box 32, H-1518 Budapest, Hungary
    • Vityi, N.. Eötvös University, Department of Astronomy, PO Box 32, H-1518 Budapest, Hungary
    • Szing, A.. Department of Experimental Physics and Astronomical Observatory, University of Szeged, H-6720 Szeged, Dóm tér 9, Hungary
    Type de document
    • Postprint
    Langue
    • Inglese
    Publié dans
    • Monthly Notices of the Royal Astronomical Society, 2008, vol. 386, no. 1, p. 521-530. Blackwell Publishing Ltd
    Autre version électronique
    Identifiant OAI-PMH
    • oai:doc.rero.ch:297491
    Summary
    We derive the basic physical parameters of the field double-mode RR Lyrae star BS Com from its observed periods and the requirement of consistency between the pulsational and evolutionary constraints. By using the current solar-scaled horizontal branch evolutionary models of Pietrinferni et al. and our linear non-adiabatic purely radiative pulsational models, we get M/M⊙= 0.698 ± 0.004, log(L/L⊙) = 1.712 ± 0.005, Teff= 6840 ± 14 K, [Fe/H]=−1.67 ± 0.01, where the errors are standard deviations assuming uniform age distribution along the full range of uncertainty in age. The last two parameters are in a good agreement with the ones derived from the observed BVIC colours and the updated atlas9 stellar atmosphere models. We get Teff= 6842 ± 10 K, [Fe/H]=−1.58 ± 0.11, where the errors are purely statistical ones. It is remarkable that the derived parameters are nearly independent of stellar age at early evolutionary stages. Later stages, corresponding to the evolution towards the asymptotic giant branch, are most probably excluded because the required high temperatures are less likely to satisfy the constraints posed by the colours. We also show that our conclusions are only weakly sensitive to non-linear period shifts predicted by current hydrodynamical models