Spectroscopic Mode Identification in Slowly Pulsating Subdwarf-B Stars

TL;DR

This paper introduces a new spectroscopic method for identifying pulsation modes in slowly pulsating subdwarf-B stars, demonstrating its effectiveness on synthetic data and applying it to a real star, HD 4539.

Contribution

The paper presents a novel spectroscopic mode identification technique and validates it with synthetic spectra before applying it to an actual star.

Findings

Successful identification of pulsation modes in synthetic spectra.

Application of the method to HD 4539 revealing its pulsation characteristics.

Enhanced understanding of non-radial pulsations in subdwarf-B stars.

Abstract

Mode identification is crucial for an asteroseismological study of any significance. Contrarily to spectroscopic techniques, methods such as period-fitting and multi-colour photometry do not provide a full reconstruction of non-radial pulsations. We present a new method of spectroscopic mode identification and test it on time-series of synthetic spectra appropriate for pulsating subdwarf-B stars. We then apply it to the newly discovered slowly pulsating subdwarf-B star HD 4539.