Partial tidal disruption of White Dwarfs in off-equatorial orbits around Kerr black holes

TL;DR

This study uses numerical simulations to analyze partial tidal disruption events of white dwarfs in off-equatorial orbits around Kerr black holes, revealing unique features influenced by black hole spin and WD rotation.

Contribution

It introduces a hybrid numerical scheme combining Kerr geodesics with Newtonian fluid dynamics to study off-equatorial TDEs, highlighting effects of black hole spin and initial WD rotation.

Findings

Black hole spin can enhance TDE features in off-equatorial orbits.

Observable quantities in TDEs are similar for equatorial and off-equatorial orbits.

Results likely extend to general TDE scenarios with spinning black holes.

Abstract

We present the results of a suite of numerical simulations using smoothed particle hydrodynamics to study partial tidal disruption events (TDEs) of white dwarfs (WDs) in off-equatorial orbits in intermediate mass spinning (Kerr) black hole backgrounds. We carry out this analysis for both parabolic and eccentric WD orbits and also take into account possible initial WD spins. Our objective here is to quantify the differences in variables like the mass of the self-bound core, the peak fallback rate of debris and gravitational wave signature in off-equatorial orbits compared to equatorial ones. The analysis is carried out using a hybrid numerical scheme, one which involves integrating the exact Kerr geodesics while adopting a Newtonian formalism for the stellar fluid dynamics, justified by our choice of simulation parameters. We find that the physics of TDEs in off-equatorial orbits present several interesting and novel features due to black hole spin, which in some cases enhances when coupled with the rotation of the WD. However, numerical values of observable quantities in TDEs involving off-equatorial orbits cannot possibly distinguish between such orbits from equatorial ones. We further comment on the genericness of our results and argue that these should extend to a general TDE scenario involving a spinning BH.