Complex asteroseismology of SX Phoenicis

TL;DR

This paper performs seismic analysis of SX Phoenicis to fit observed radial-mode frequencies and flux amplitudes, providing insights into stellar convection and atmospheric properties of this prototype variable star.

Contribution

It presents a seismic model of SX Phoenicis with specific parameters, offering new constraints on outer-layer convection in such stars.

Findings

Seismic model with mass 1.05 M_sun

Moderately effective convection with α_MLT ≈ 0.7

Microturbulent velocity around 8 km/s

Abstract

We present seismic analysis of the prototype SX Phoenicis that aims at fitting the two radial-mode frequencies and the corresponding values of the bolometric flux amplitude (the parameter $f$), whose empirical values are derived from multi-coulor photometric observations. Seismic model that meets these conditions is of low mass, $M=1.05 M_\odot$, has moderately effective convection in the outer layers, described by the mixing length parameter $\alpha_{\rm MLT} \approx 0.7$, and the microturbulent velocity in the atmospheres of about $\xi_{\rm t}\approx 8$km/s. Such seismic studies of stars like SX Phe are very important for deriving constraints on outer-layer convection, because the object is on the border between very effective and ineffective convection.