Modeling $\epsilon$ Eridani and asteroseismic tests of element diffusion

TL;DR

This study models the star $psilon$ Eridani considering helium and metal diffusion, using seismic data to refine its evolutionary status and demonstrate the significant impact of metal diffusion on stellar structure and oscillation frequencies.

Contribution

It introduces models of $psilon$ Eridani that incorporate element diffusion and uses asteroseismic analysis to assess their effects on stellar properties.

Findings

Metal diffusion significantly affects internal temperature and sound speed.

Diffused models suggest a younger age (~1 Gyr) than previous models.

Average large frequency spacing is about 194 μHz.

Abstract

Taking into account the helium and metal diffusion, we explore the possible evolutionary status and perform seismic analysis of MOST target: the star $\epsilon$ Eridani. We adopt the different input parameters to construct the models by fitting the available observational constraints: e.g., $T_{eff}$, $L$, $R$, $[Fe/H]$. From computation, we obtain the average large spacings of $\epsilon$ Eridani about $194\pm 1 \mu$Hz. The age of the diffused models has been found to be about 1 Gyr, which is younger than one determined previously by models without diffusion. We found that the effect of pure helium diffusion on the internal structure of the young low-mass star is slight, but the metal diffusion influence is obvious. The metal diffusion leads the models to have much higher temperature in the radiation interior, correspondingly the higher sound speed in the interior of the model, thereby the larger frequency and spacings.