Speaker
Dr
Abhay Pratap Yadav
(University of Goettingen, Germany)
Description
Spectroscopic and photometric variabilities have been noticed in several stars. The cause and responsible mechanism for such variabilities are not yet properly understood. Among the possible origins, radial and non-radial pulsations have been proposed as a cause of these variabilities. With the help of linear stability analysis, we have found several strong instabilities in models of massive zero age main sequence and post main sequence stars. To find the final fate of the unstable models, we have followed the identified instabilities into the non-linear regime using an energy conservative numerical scheme for selected stellar models. Rearrangement of stellar structure, finite amplitude pulsations (with periods between few hours to several days) and surface eruptions have been noticed as the final consequences of these instabilities. In case of finite amplitude pulsations, our estimates for pulsationally driven mass-loss rates are of the order of 10^{-4} M_sun/year for few massive OB-type stars which can potentially affect the stellar evolution. Observations of massive-luminous stars such as luminous blue variables (LBVs) using BINA telescopes will provide a unique opportunity to test our theoretical predictions of linear stability analysis and non-linear numerical simulations.
Primary author
Dr
Abhay Pratap Yadav
(University of Goettingen, Germany)
Co-author
Dr
Santosh Joshi
(ARIES, Nainital)
