Pulsating B and Be stars in the Magellanic Clouds

TL;DR

This study investigates the presence of pulsating B and Be stars in the Magellanic Clouds to test theoretical predictions about stellar instability at low metallicities, using a large sample of stars with well-measured parameters.

Contribution

It provides observational evidence of B-type pulsators in low-metallicity environments, challenging existing models that do not predict such instability strips at these metallicities.

Findings

Detection of short-term periodic variability in B and Be stars in the Magellanic Clouds.

Evidence supporting the existence of pulsating B-type stars at low metallicities.

Implications for stellar pulsation theories at different metallicity levels.

Abstract

Stellar pulsations in main-sequence B-type stars are driven by the $\kappa$-mechanism due to the Fe-group opacity bump. The current models do not predict the presence of instability strips in the B spectral domain at very low metallicities. As the metallicity of the Magellanic Clouds (MC) has been measured to be around $Z=0.002$ for the Small Magellanic Cloud (SMC) and $Z=0.007$ for the Large Magellanic Cloud (LMC), they constitute a very suitable objects to test these predictions. The aim of this work is to investigate the existence of B-type pulsators at low metallicities, searching for short-term periodic variability in a large sample of B and Be stars from the MC with accurately determined fundamental astrophysical parameters.