2020/11/16 by Abhay Pratap Yadav, Yadav, Abhay Pratap, Santosh Joshi +3
Earth and Planetary Sciences · Physics and Astronomy · #Astronomy and Astrophysical Research #FOS: Physical sciences #Geophysics and Gravity Measurements #Solar and Stellar Astrophysics (astro-ph.SR) #Stellar, planetary, and galactic studies
paper · pdf · doi:10.48550/arxiv.2011.08164
openalex publication_date 2020/11/16 · openalex created_date 2024/04/10 · openalex updated_date 2026/07/28
For the B-type supergiant κ Cassiopeiae (HD 2905) variabilities with periods between several hours and a few days have been observed both photometrically and spectroscopically. A recent study of this star by Simón-D'ıaz et al. (2018) has revealed variability with a dominant period of 2.7 days. To understand this variability, we present a linear non-adiabatic stability analysis with respect to radial perturbations for models of κ Cassiopeiae. Instabilities associated with the fundamental mode and the first overtone are identified for models with masses between 27 M\odot and 44 M\odot. For selected models, the instabilities are followed into the non-linear regime by numerical simulations. As a result, finite amplitude pulsations with periods between 3 and 1.8 days are found. The model with a mass of 34.5 M\odot exhibits a pulsation period of 2.7 days consistent with the observations. In the non-linear regime, the instabilities may cause a substantial inflation of the envelope.