Probing the parameter space of HD 49933: a comparison between global and local methods

TL;DR

This paper compares global and local methods for exploring the stellar parameter space of HD 49933 using seismic data, providing consistent estimates of its mass, age, and initial composition.

Contribution

It introduces two independent approaches—local minimization and MCMC—for determining stellar parameters, validating their consistency and error estimation techniques.

Findings

Consistent stellar parameters obtained: mass 1.1-1.2 M_solar, age ~3 Gyr, initial Z ~0.008.

Error ellipses described using SVD techniques, validated by MCMC.

Methods provide reliable estimates of stellar properties with quantified uncertainties.

Abstract

We present two independent methods for studying the global stellar parameter space (mass M, age, initial chemical composition X_0, Z_0) of HD 49933 with seismic data. Using a local minimization and an MCMC algorithm, we obtain consistent results for the determination of the stellar properties: M = 1.1 - 1.2 M_solar, Age ~ 3.0 Gyr, Z_0 ~ 0.008. A description of the error ellipses can be defined using Singular Value Decomposition techniques, and this is validated by comparing the errors with those from the MCMC method.