Observational Properties of 155 $\beta$ Cephei pulsating variable stars

TL;DR

This study identifies and characterizes 155 $eta$ Cephei pulsating stars using TESS and Gaia data, providing updated relations and insights into their pulsation properties, evolutionary status, and potential for asteroseismology.

Contribution

The paper presents the first large-scale identification and confirmation of 83 new BCEP stars, updating the luminosity-period relation and analyzing their pulsation and evolutionary characteristics.

Findings

155 BCEP stars identified and 83 confirmed as new.

Pulsation periods range from 0.06 to 0.31 days.

Stars are in the main-sequence phase with masses 7-20 $M_{\u00d7}$.

Abstract

$\beta$ Cephei pulsating variable (BCEP) stars are the most massive pulsating variable stars in the main sequence, exhibiting both p- and g-mode pulsations. In this study, we identified 155 BCEP stars or candidates using data from TESS and Gaia, of which 83 were first confirmed as BCEP stars. They have visual magnitudes ranging from 8 to 12 mag and effective temperatures between approximately 20,000 and 30,000 K, while the parallaxes of most targets are between 0.2 and 0.6 mas. The study indicates that these BCEP stars have pulsation periods ranging from 0.06 to 0.31 days, with amplitudes ranging from 0.1 to 55.8 mmag in the TESS band. Additionally, the number of BCEP stars increases as the pulsation amplitude decreases. These targets align with the distribution region of BCEP stars in the luminosity-period (L-P) and temperature-period (T-P) diagrams. We have updated the L-P relation of BCEP stars. The Hertzsprung-Russell (H-R) diagram indicates that these targets are in the main-sequence evolutionary phase, with masses ranging from 7 to 20 $M_{\odot}$ and luminosities between 2800 and 71,000 $L_{\odot}$. They are almost in the theoretical instability region of BCEP stars but as previously reported, this region at the low-mass end (red) is not filled. The distribution of the pulsation constant indicates that the dominant pulsation periods of BCEP stars consist mainly of low-order p-mode pulsations with a high proportion of radial fundamental modes. These BCEP stars are excellent objects for enhancing our understanding of the structure and evolution of massive stars through asteroseismology.