The radius and mass of the close solar twin 18 Sco derived from asteroseismology and interferometry

TL;DR

This study combines asteroseismology and interferometry to precisely determine the radius and mass of the solar twin 18 Sco, providing valuable data for solar comparison.

Contribution

It presents the first combined asteroseismic and interferometric measurements of 18 Sco's physical characteristics, improving precision over previous estimates.

Findings

Large frequency separation: 134.4 μHz

Radius: 1.010 R_sun

Mass: 1.02 M_sun

Abstract

The growing interest in solar twins is motivated by the possibility of comparing them directly to the Sun. To carry on this kind of analysis, we need to know their physical characteristics with precision. Our first objective is to use asteroseismology and interferometry on the brightest of them: 18 Sco. We observed the star during 12 nights with HARPS for seismology and used the PAVO beam-combiner at CHARA for interferometry. An average large frequency separation $134.4\pm0.3$ $\mu$Hz and angular and linear radiuses of $0.6759 \pm 0.0062$ mas and $1.010\pm0.009$ R$_{\odot}$ were estimated. We used these values to derive the mass of the star, $1.02\pm0.03$ M$_{\odot}$.