Evgeni Grishin

Stellar triples on the edge

Most of the stars are in bound binaries, and the number of stellar companions increases with stellar mass. We study the complex dynamics of stellar triples and their coupling to stellar evolution. We examine how the orbital evolution affects the inner binary’s stellar evolution and interaction and estimate the rates for stellar mergers, collisions and observable transients. For massive compact stellar triples, we find that a significant fraction could merge either on the main sequence or after the inner binary has collapsed into binary black-holes, generating a gravitational-wave merger event. For low and intermediate-mass stars, we find that wide stellar triples could be perturbed by the galactic tide and acquire extremely highly-eccentric orbits. In turn, stellar inspirals and collisions could dominate the collisional field population in generating field blue stragglers, proto-cataclysmic variables and double red-giant collisions and contribute to double white-dwarf collisions and type Ia Supernova progenitors.