English

$\alpha$ Centauri A as a potential stellar model calibrator: establishing the nature of its core

Solar and Stellar Astrophysics 2018-06-06 v2

Abstract

Understanding the physical process responsible for the transport of energy in the core of α\alpha Centauri A is of the utmost importance if this star is to be used in the calibration of stellar model physics. Adoption of different parallax measurements available in the literature results in differences in the interferometric radius constraints used in stellar modelling. Further, this is at the origin of the different dynamical mass measurements reported for this star. With the goal of reproducing the revised dynamical mass derived by Pourbaix & Boffin, we modelled the star using two stellar grids varying in the adopted nuclear reaction rates. Asteroseismic and spectroscopic observables were complemented with different interferometric radius constraints during the optimisation procedure. Our findings show that best-fit models reproducing the revised dynamical mass favour the existence of a convective core (\gtrsim 70% of best-fit models), a result that is robust against changes to the model physics. If this mass is accurate, then α\alpha Centauri A may be used to calibrate stellar model parameters in the presence of a convective core.

Keywords

Cite

@article{arxiv.1805.09103,
  title  = {$\alpha$ Centauri A as a potential stellar model calibrator: establishing the nature of its core},
  author = {B. Nsamba and M. J. P. F. G. Monteiro and T. L. Campante and M. S. Cunha and S. G. Sousa},
  journal= {arXiv preprint arXiv:1805.09103},
  year   = {2018}
}

Comments

6 pages, 2 figures, 4 tables. Accepted for publication in Monthly Notices of the Royal Astronomical Society Letters