$\beta$ Cephei Pulsations in the High-mass Eclipsing System CW Cephei

Abstract

CW Cep is an early B-type eclipsing binary with mass measurement precisions better than 1 \%. We report the discovery of pulsation signatures in the TESS time-series data of the system observed during Sectors 17 and 18. Our binary modeling indicates that the target star is a partially-eclipsing detached system with masses of 12.95 $M_{\odot }$ and 11.88 $M_{\odot }$ and radii of 5.52 $R_{\odot }$ and 5.09 $R_{\odot }$ in an eccentric orbit of $e$ = 0.0305. The distance to the eclipsing system, 928 $\pm$ 36 pc, is much more precise than the Gaia distance of 962 $\pm$ 453 pc. Applying multifrequency analyses to the residual light curve in the outside-eclipse part, we detected 13 significant signals in two frequency regions. Six frequencies below 1 day${}^{-1}$ appeared to be mostly orbital harmonic and combination terms, or sidelobes due to insufficient removal of the binary effects. In contrast, seven frequencies clustered around 2.73 day${}^{-1}$ and 5.34 day${}^{-1}$ could be considered $\beta$ Cep-type pulsations. Our results represent the second discovery of $\beta$ Cep pulsations present in double-lined eclipsing binaries with precise masses and, hence, CW Cep serves as an important test-bed for the asteroseismic modeling of high-mass stars.

arXiv comment15 pages, including 4 figures and 3 tables

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• Tidally Perturbed Oblique Pulsations in the Hierarchical Triple System V1031 Orionis
• Absolute Parameters of Young Stars: V Puppis
• Tidally Excited Modes and $\delta$ Scuti Pulsations in the Eclipsing Triple Star IM Persei