Asteroseismic estimate of helium abundance of 16 Cyg A, B
1 Tata Institute of Fundamental Research, Homi Bhabha Road, Mumbai 400005, India
2 Centro de Astrofísica da Universidade do Porto, Rua das Estrelas, 4150–762 Porto, Portugal
3 Departamento de Física e Astronomia, Universidade do Porto, 4169–007 Porto, Portugal
4 Astronomy Department, Yale University, P. O. Box 208101, New Haven, CT 065208101, USA
5 Homi Bhabha Centre for Science Education, TIFR, V. N. Purav Marg, Mumbai 400088, India
6 Institut d’Astrophysique Spatiale, Université Paris XI-CNRS, F-91405 Orsay Cedex, France
7 School of Physics and Astronomy, University of Birmingham, B15 2TT, UK
8 Stellar Astrophysics Centre, Aarhus University, Ny Munkegade 120, DK-8000 Aarhus C, Denmark
9 Laboratoire AIM, CEA/DSM, CNRS, Université Paris Diderot, IRFU/SAp, Centre de Saclay, 91191 Gif-sur-Yvette Cedex, France
10 Space Science Institute, Boulder, CO 80301, USA
Published online: 23 September 2015
The helium ionization zone in a star leaves a characteristic signature on its oscillation frequencies, which can be used to estimate the helium content in the envelope of the star. We use the oscillation frequencies of 16 Cyg A and B, obtained using 2.5 years of Kepler data, to estimate the envelope helium abundance of these stars. We find the envelope helium abundance to lie in the range 0.231–0.251 for 16 Cyg A and 0.218–0.266 for 16 Cyg B.
© Owned by the authors, published by EDP Sciences, 2015
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