English

Classically and Asteroseismically constrained 1D Stellar Evolution Models of $\alpha$ Centauri A and B using Empirical Mixing Length Calibrations

Solar and Stellar Astrophysics 2018-09-19 v2

Abstract

The bright, nearby binary α\alpha Centauri provides an excellent laboratory for testing stellar evolution models, as it is one of the few stellar systems for which we have high-precision classical (mass, radius, luminosity) and asteroseismic (pp-mode) observations. Stellar models are created and fit to the classical and seismic observations of both stars by allowing for the free variation of convective mixing length parameter αMLT\alpha_{\text{MLT}}. This system is modeled using five different sets of assumptions about the physics governing the stellar models. There are 31 pairs of tracks (out of 150,000{\sim} 150,000 generated) which fit the classical, binary, and seismic observational constraints of the system within 3σ3\,\sigma. Models with each tested choice of input physics are found to be viable, but the optimal mixing lengths for Cen A and Cen B remain the same regardless of the physical prescription. The optimal mixing lengths are αMLT,A/α=0.932\alpha_{\text{MLT,A}} /\alpha_{\odot}= 0.932 and αMLT,B/α=1.095\alpha_{\text{MLT,B}}/\alpha_{\odot} = 1.095. That Cen A and Cen B require sub- and super-solar mixing lengths, respectively, to fit the observations is a trend consistent with recent findings, such as in Kervella et al. (2017), Joyce and Chaboyer (2018), and Viani et al. (2018). The optimal models find an age for α\alpha Centauri of 5.3±0.35.3 \pm 0.3 Gyr.

Keywords

Cite

@article{arxiv.1806.07567,
  title  = {Classically and Asteroseismically constrained 1D Stellar Evolution Models of $\alpha$ Centauri A and B using Empirical Mixing Length Calibrations},
  author = {M. Joyce and B. Chaboyer},
  journal= {arXiv preprint arXiv:1806.07567},
  year   = {2018}
}

Comments

accepted for publication in the Astrophysical Journal

R2 v1 2026-06-23T02:35:34.441Z