On the interpretation of new late B- and early A-type periodic variable stars in NGC 3766

TL;DR

This paper explores the mysterious nature of newly discovered B- and A-type variable stars in NGC 3766, which challenge existing stellar pulsation models and cannot be explained by rotation or binarity, leaving their origin unresolved.

Contribution

It highlights the existence of variable stars in an unexplained region of the Hertzsprung-Russell diagram, questioning current stellar variability theories.

Findings

Standard pulsation models do not predict these stars' variability.

Rotational modulation and binarity cannot explain their light curves.

Their origin remains an open question.

Abstract

We investigate possible interpretations of the new periodic B- and A-type variable stars discovered in NGC 3766. They lie in the region of the Hertzsprung-Russell diagram between slowly pulsating B and delta Sct stars, a region where no pulsation is predicted by standard models of pulsating stars. We show that the two other possible causes of periodic light curve variations, rotational modulation and binarity, cannot provide a satisfactory explanation for all the properties observed in those stars either. The question of their origin is thus currently an open issue.