On the Evolution of Eccentric Ellipsoidal Variables 

by Dr Piotr Kołaczek-Szymański 

University of Liège, Belgium 

Abstract 

Currently, we know that stellar binarity is a common phenomenon, particularly important for massive stars whose evolutionary tracks are predominantly affected by the presence of a (nearby) companion. Moreover, a significant fraction of binary systems at various stages of their evolution is characterized by eccentric orbits, either due to their relatively young age or eccentricity-pumping mechanisms. Hence, the close investigation of eccentric binary systems is crucial for the verification of various tidal interaction theories that greatly influence our predictions of the evolution of these objects. During the seminar, I will focus on eccentric ellipsoidal variables (EEVs), occasionally dubbed as "heartbeat stars"), tidally excited oscillations and their impact on the evolution of EEVs. Additionally, I will discuss other effects associated with the periastron passages that can mimic EEVs, such as massive systems with stellar wind collisions.