The Process of Stellar Tidal Disruption by Supermassive Black Holes. The first pericenter passage

TL;DR

This paper reviews analytical and numerical models of stellar tidal disruption by supermassive black holes, focusing on the initial disruption process and its immediate aftermath, including various stellar and orbital scenarios.

Contribution

It provides a comprehensive overview of models from simple physics to advanced hydrodynamic simulations of stellar tidal disruption, highlighting recent developments and diverse disruption outcomes.

Findings

Disruption models range from simple to hydrodynamic simulations.

The initial disruption process is well-understood compared to later TDE stages.

Different stellar types and orbital parameters significantly affect debris fate.

Abstract

Tidal disruption events (TDEs) are among the brightest transients in the optical, ultraviolet, and X-ray sky. These flares are set into motion when a star is torn apart by the tidal field of a massive black hole, triggering a chain of events which is -- so far -- incompletely understood. However, the disruption process has been studied extensively for almost half a century, and unlike the later stages of a TDE, our understanding of the disruption itself is reasonably well converged. In this Chapter, we review both analytical and numerical models for stellar tidal disruption. Starting with relatively simple, order-of-magnitude physics, we review models of increasing sophistication, the semi-analytic ``affine formalism,'' hydrodynamic simulations of the disruption of polytropic stars, and the most recent hydrodynamic results concerning the disruption of realistic stellar models. Our review surveys the immediate aftermath of disruption in both typical and more unusual TDEs, exploring how the fate of the tidal debris changes if one considers non-main sequence stars, deeply penetrating tidal encounters, binary star systems, and sub-parabolic orbits. The stellar tidal disruption process provides the initial conditions needed to model the formation of accretion flows around quiescent massive black holes, and in some cases may also lead to directly observable emission, for example via shock breakout, gravitational waves or runaway nuclear fusion in deeply plunging TDEs.