Discovery of new roAp pulsators in the UVES survey of cool magnetic Ap stars

TL;DR

This study used high-precision spectroscopic observations to discover new rapidly oscillating Ap stars among cool magnetic Ap stars, revealing pulsations undetectable by previous low-precision photometric surveys.

Contribution

The paper reports the discovery of new roAp stars using UVES spectroscopic data, demonstrating that high-precision spectroscopy can identify pulsations missed by photometry.

Findings

Discovered 3 new roAp stars with spectroscopic methods.

Confirmed pulsations in 2 known roAp stars.

Showed that low-precision photometry often misses pulsations.

Abstract

We have carried out a survey of short-period pulsations among a sample of carefully chosen cool Ap stars using time-resolved observations with the UVES spectrometer at the ESO 8-m VLT telescope. Here we report the discovery of pulsations with amplitudes 50-100 m/s and periods 7-12 min in HD132205, HD148593 and HD151860. These objects are therefore established as new rapidly oscillating Ap (roAp) stars. In addition, we independently confirm the presence of pulsations in HD69013, HD96237 and HD143487 and detect, for the first time, radial velocity oscillations in two previously known photometric roAp stars HD119027 and HD185256. At the same time, no pulsation variability is found for HD5823, HD178892 and HD185204. All of the newly discovered roAp stars were previously classified as non-pulsating based on the low-precision ground-based photometric surveys. This shows that such observations cannot be used to reliably distinguish between pulsating and non-pulsating stars and that all cool Ap stars may harbor p-mode pulsations of different amplitudes.