Observational asteroseismology of hot subdwarf stars

TL;DR

This paper reviews recent observational advances and methods in ground-based asteroseismology of hot subdwarf stars, focusing on overcoming challenges posed by their rapid pulsations and faintness.

Contribution

It summarizes recent observational results and discusses improvements in ground-based asteroseismology techniques for hot subdwarf stars.

Findings

Progress in observational methods for hot subdwarf asteroseismology.

Enhanced understanding of pulsation modes through multi-color photometry.

Challenges remain due to the stars' faintness and rapid pulsations.

Abstract

Hot subdwarf stars are particularly challenging for asteroseismology due to their rapid pulsation periods, intrinsic faintness and relative rarity both in the field and in clusters. These features have ensured that the preferred method of observation up to now has been white-light photometry, and all asteroseismological solutions to date have been made by model fitting of the frequency spectrum. Several attempts have been made to perform asteroseismology using time-resolved spectroscopy on the brightest of these stars, but with modest results. A few attempts at simultaneous multi-color photometry have also been made to identify modes with the amplitude ratio method. We will review the most recent observational results and progress in improving the observational methods for ground-based asteroseismology of these compact pulsators.