paper

Partial, zombie, and full tidal disruption of stars by supermassive black holes

arXiv:2108.04242 · doi:10.3847/1538-4357/ac1bb8

Abstract

We present long-duration numerical simulations of the tidal disruption of stars modelled with accurate stellar structures and spanning a range of pericentre distances, corresponding to cases where the stars are partially and completely disrupted. We substantiate the prediction that the late-time power-law index of the fallback rate for full disruptions, while for partial disruptions---in which the central part of the star survives the tidal encounter intact---we show that . For the subset of simulations where the pericenter distance is close to that which delineates full from partial disruption, we find that a stellar core can reform after the star has been completely destroyed; for these events the energy of the zombie core is slightly positive, which results in late-time evolution from to . We find that self-gravity can generate an that deviates from by a small but significant amount for several years post-disruption. In one specific case with the stellar pericenter near the critical value, we find self-gravity also drives the re-collapse of the central regions of the debris stream into a collection of several cores while the rest of the stream remains relatively smooth. We also show that it is possible for the surviving stellar core in a partial disruption to acquire a circumstellar disc that is shed from the rapidly rotating core. Finally, we provide a novel analytical fitting function for the fallback rates that may also be useful in a range of contexts beyond TDEs.

21 pages, 12 figures, accepted for publication in ApJ

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