Special TAPIR Seminar

Friday, August 25, 2023
2:00pm to 3:00pm
Add to Cal
Online and In-Person Event
Exploring the remains of stars disrupted by stellar black holes
Pavan Vynatheya, Graduate Student, Stellar Department, Max Planck Institut für Astrophysik (MPA), Garching,

In person: 370 Cahill -- To Join via Zoom: 864 8902 5566

ABSTRACT: In the centers of dense star clusters, close encounters between stars and compact objects are likely to occur. We study tidal disruption events of main sequence (MS) stars by stellar-mass black holes (termed micro-TDEs). Micro-TDEs can shed light on the processes occurring in the centre of globular clusters, including being an avenue in the mass growth of stellar-mass BHs and altering stellar trajectories. Using a suite of hydrodynamics simulations of partial micro-TDEs of realistic MS stars with the moving-mesh code AREPO, we examined the dependence of the properties of the remnant on the mass and age of the original star, the impact parameter, and the black hole mass. In particular, we focused on post-disruption orbital parameters and spins of the remnant, and the bound and unbound masses. Notably, depending on the initial conditions, the remnant star can become bound (eccentric) or unbound (hyperbolic) to the black hole. Hyperbolic orbits arise when the star's central density is relatively low and the black hole mass is high. We find that more evolved MS stars lose lesser mass than less evolved MS stars for the same impact parameter. The black hole also provides a torque to the remnant star that increases its specific spin angular momentum, but the gain in spin is less in cases where mass loss is significant. We provide best-fit analytical formulae for these parameters that can be incorporated into globular cluster codes to improve their accuracies.

For more information, please contact JoAnn Boyd by phone at 626-395-4280 or by email at [email protected].