Asteroseismic study of the red giant ε Ophiuchi

We test the possible evolutionary tracks of stars with various masses (1.8 M,1.9 M,2.0 M,2.1 M,2.2 M)and metallicities Z(0.008,0.010, 0.012),including both models with and without convective core overshooting.At a given mass and metallicity,the models with a larger overshoot predict a larger radius...

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Veröffentlicht in:Research in astronomy and astrophysics 2010-12 (12), p.1265-1274
1. Verfasser: Shao-Lan Bi Ling-Huai Li Yan-Ke Tang Ning Gai
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Sprache:eng
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Zusammenfassung:We test the possible evolutionary tracks of stars with various masses (1.8 M,1.9 M,2.0 M,2.1 M,2.2 M)and metallicities Z(0.008,0.010, 0.012),including both models with and without convective core overshooting.At a given mass and metallicity,the models with a larger overshoot predict a larger radius and age of the star.Based on the observed frequency of oscillations and the position of Oph on the H-R diagram,we obtain two distinct better-fitting models:the solutions with mass M=1.9 M favor a radius in the range 10.55±0.03 R with an age of 1.01±0.08 Gyr;the solutions with mass M=2.0 M favor a radius in the range 10.74±0.03 R with an age of 0.95±0.11 Gyr.Furthermore,we investigate the influence of overshooting on the internal structure and the pulsation properties,and find that increasing the convective core overshoot significantly decreases non-radial mode inertia,while also increasing the mode amplitude.Therefore,the estimation of stellar mass and age might be modified by convective core penetration.
ISSN:1674-4527
2397-6209
DOI:10.1088/1674-4527/10/12/007