The discovery of rapid oscillations in the magnetic Ap stars HD69013 and HD96237

TL;DR

This paper reports the discovery of rapid pulsations in two magnetic Ap stars, HD69013 and HD96237, revealing new insights into their stellar oscillations through spectroscopic and photometric observations.

Contribution

It presents the first detection of short period pulsations in these specific Ap stars using high-resolution spectroscopy and photometry.

Findings

HD69013 exhibits pulsations with an 11.4-minute period and amplitudes over 200 m/s.

HD96237 shows pulsations near 13.6 minutes with amplitudes around 100 m/s.

Pulsations were confirmed through both spectroscopic and photometric data.

Abstract

We report the detection of short period variations in the stars HD69013 and HD96237. These stars possess large overabundances of rare earth elements and global magnetic fields, thus belong to the class of chemically peculiar Ap stars of the main sequence. Pulsations were found from analysis of high time resolution spectra obtained with the ESO Very Large Telescope using a cross correlation method for wide spectral bands, from lines belonging to rare earth elements and from the H alpha core. Pulsation amplitudes reach more than 200 m/s for some lines in HD69013 with a period of 11.4 min and about 100m/s in HD96237 with periods near 13.6 min. The pulsations have also been detected in photometric observations obtained at the South African Astronomical Observatory.