Fundamental stellar parameters of three Kepler stars accurately constrained by lithium abundance and rotation

Department of Astronomy, Beijing Normal University, 100875 Beijing, PR China
e-mail: liukang@mail.bnu.edu.cn; bisl@bnu.edu.cn

Received: 18 December 2013
Accepted: 27 January 2014

Abstract

Aims. The lithium abundances of KIC 11395018 and KIC 10920273 are not compatible with the age of these stars, which is deduced by asteroseismology. To explain this phenomenon, we investigated the possible evolutionary status and performed a seismological analysis of the three stars KIC 11395018, KIC 10273246, and KIC 10920273.

Methods. Using the Yale Rotating Stellar Evolution Code (YREC), we constructed stellar models that include diffusion and extra-mixing caused by rotation. In addition to the general observed properties, we considered two constraints, the lithium abundance log   N(Li) and the rotational period P_rot.

Results. A set of stellar fundamental parameters is given by our rotating model for each star. We estimate the mass and age to be 1.24 ± 0.01  M_⊙ and 5.55 ± 0.20 Gyr for KIC 11395018, 1.19 ± 0.04 M_⊙ and 4.36 ± 0.29 Gyr for KIC 10273246, and 1.15 ± 0.03  M_⊙ and 5.68 ± 0.30 Gyr for KIC 10920273. Moreover, the lithium abundance of our rotating model of the three stars agrees well with the observation.

Conclusions. The consideration of lithium and the rotational period helped us in obtaining very precise estimates of the star.