SuperWASP observations of pulsating Am stars

TL;DR

This study analyzed over 1600 Am stars using SuperWASP data and discovered that approximately 200 of them pulsate as delta Sct and gamma Dor stars, challenging previous assumptions about their variability.

Contribution

It is the first extensive survey revealing pulsations in a large sample of Am stars, providing new data for understanding stellar pulsation and atomic diffusion.

Findings

Around 200 Am stars are pulsating delta Sct and gamma Dor stars.

Pulsation amplitudes are generally low, often missed in previous studies.

The results constrain models of atmospheric convection in Am stars.

Abstract

We have studied over 1600 Am stars at a photometric precision of 1 mmag with SuperWASP photometric data. Contrary to previous belief, we find that around 200 Am stars are pulsating delta Sct and gamma Dor stars, with low amplitudes that have been missed in previous, less extensive studies. While the amplitudes are generally low, the presence of pulsation in Am stars places a strong constraint on atmospheric convection, and may require the pulsation to be laminar. While some pulsating Am stars have been previously found to be delta Sct stars, the vast majority of Am stars known to pulsate are presented in this paper. They will form the basis of future statistical studies of pulsation in the presence of atomic diffusion.