Observational Properties of 155 O- and B-type Massive Pulsating Stars

Abstract

Abstract O- and B-type (OB-type) pulsating stars are important objects for studying the structure and evolution of massive stars through asteroseismology. A large amount of data from various sky surveys provides an unprecedented opportunity to search for and study this kind of variable star. We identify 155 OB-type pulsating stars or candidates, including 38 Oe/Be stars or candidates, from the data observed by TESS, LAMOST, and Gaia, which are almost new. Among the 155 objects, 87 samples are identified as slowly pulsating B (SPB) stars including 37 objects with pure low-frequency and 50 objects with both low- and high-frequency pulsation, and 14 samples are identified as β Cephei pulsating variable (BCEP) stars with both low- and high-frequency pulsation. An H-R diagram shows that these SPB and BCEP stars are mainly located in their instability regions and in the evolutionary stage of the main sequence with mass ranges of 2.5–20 M ⊙ and 7–20 M ⊙, respectively. Two special objects show Fourier spectra similar to BCEP stars but with different positions in H-R, period–temperature (P-T), and period–luminosity (P-L) diagrams. Meanwhile, 52 other targets are identified as candidates of OB-type pulsating stars. We also derive the preliminary results of the P-L relation for SPB and BCEP stars, respectively. This work also indicates that in addition to the H-R diagram, the P-T and P-L diagrams are also very useful for the classification of SPB and BCEP stars. Further detailed analysis of these objects can dramatically increase our understanding of the theories of evolution and structure for massive OB-type pulsating stars.