Bayesian inference of stellar parameters based on 1D stellar models coupled with 3D envelopes. (arXiv:1910.04200v1 [astro-ph.SR])

Bayesian inference of stellar parameters based on 1D stellar models coupled with 3D envelopes. (arXiv:1910.04200v1 [astro-ph.SR])
<a href="http://arxiv.org/find/astro-ph/1/au:+Jorgensen_A/0/1/0/all/0/1">Andreas Christ S&#xf8;lvsten J&#xf8;rgensen</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Angelou_G/0/1/0/all/0/1">George C. Angelou</a>

Stellar models utilising one-dimensional (1D), heuristic theories of
convection fail to adequately describe the energy transport in superadiabatic
layers. The improper modelling leads to well-known discrepancies between
observed and predicted oscillation frequencies for stars with convective
envelopes. Recently, three-dimensional (3D) hydrodynamic simulations of stellar
envelopes have been shown to facilitate a realistic depiction of superadiabatic
convection in 1D stellar models. The resulting structural changes of the
boundary layers have been demonstrated to impact not only the predicted
oscillation spectra but evolution tracks as well. In this paper, we quantify
the consequences that the change in boundary conditions has for stellar
parameter estimates of main-sequence stars. For this purpose, we investigate
two benchmark stars, Alpha Centauri A and B, using Bayesian inference. We show
that the improved treatment of turbulent convection makes the obtained 1D
stellar structures nearly insensitive to the mixing length parameter. By using
3D simulations in 1D stellar models, we hence overcome the degeneracy between
the mixing length parameter and other stellar parameters. By lifting this
degeneracy, the inclusion of 3D simulations has the potential to yield more
robust parameter estimates. In this way, a more realistic depiction of
superadiabatic convection has important implications for any field that relies
on stellar models, including the study of the chemical evolution of the Milky
Way Galaxy and exoplanet research.

Stellar models utilising one-dimensional (1D), heuristic theories of
convection fail to adequately describe the energy transport in superadiabatic
layers. The improper modelling leads to well-known discrepancies between
observed and predicted oscillation frequencies for stars with convective
envelopes. Recently, three-dimensional (3D) hydrodynamic simulations of stellar
envelopes have been shown to facilitate a realistic depiction of superadiabatic
convection in 1D stellar models. The resulting structural changes of the
boundary layers have been demonstrated to impact not only the predicted
oscillation spectra but evolution tracks as well. In this paper, we quantify
the consequences that the change in boundary conditions has for stellar
parameter estimates of main-sequence stars. For this purpose, we investigate
two benchmark stars, Alpha Centauri A and B, using Bayesian inference. We show
that the improved treatment of turbulent convection makes the obtained 1D
stellar structures nearly insensitive to the mixing length parameter. By using
3D simulations in 1D stellar models, we hence overcome the degeneracy between
the mixing length parameter and other stellar parameters. By lifting this
degeneracy, the inclusion of 3D simulations has the potential to yield more
robust parameter estimates. In this way, a more realistic depiction of
superadiabatic convection has important implications for any field that relies
on stellar models, including the study of the chemical evolution of the Milky
Way Galaxy and exoplanet research.

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