Tidal Disruptions of Mainsequence Stars. II. Simulation Methodology and Stellar Mass Dependence of the Character of Full Tidal Disruptions
Abstract
This is the second in a series of papers presenting the results of fully general relativistic simulations of stellar tidal disruptions in which the stars' initial states are realistic mainsequence models. In the first paper, we gave an overview of this program and discussed the principal observational implications of our work. Here we describe our calculational method, which includes a new method for calculating fully relativistic stellar selfgravity, and provide details about the outcomes of full disruptions, focusing on the stellar mass dependence of the outcomes for a black hole of mass 10^{6} M_{⊙}. We consider eight different stellar masses, from 0.15 M_{⊙} to 10 M_{⊙}. We find that, relative to the traditional orderofmagnitude estimate r_{t}, the physical tidal radius of lowmass stars (M_{⋆} ≲ 0.7 M_{⊙}) is larger by tens of percent, while for highmass stars (M_{⋆} ≳ 1 M_{⊙}) it is smaller by a factor of 22.5. The traditional estimate of the range of energies found in the debris is ≍1.4× too large for lowmass stars, but is a factor of ∼2 too small for highmass stars; in addition, the energy distribution for highmass stars has significant wings. For all stars undergoing tidal encounters, we find that mass loss continues for many stellar vibration times because the black hole's tidal gravity competes with the instantaneous stellar gravity at the star's surface until the star has reached a distance from the black hole ∼O(10)r_{t}.
 Publication:

The Astrophysical Journal
 Pub Date:
 December 2020
 DOI:
 10.3847/15384357/abb3cd
 arXiv:
 arXiv:2001.03502
 Bibcode:
 2020ApJ...904...99R
 Keywords:

 Black hole physics;
 Gravitation;
 General relativity;
 Hydrodynamics;
 Galaxy nuclei;
 Stellar dynamics;
 Supermassive black holes;
 159;
 661;
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 1963;
 609;
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 Astrophysics  High Energy Astrophysical Phenomena;
 Astrophysics  Astrophysics of Galaxies;
 Astrophysics  Solar and Stellar Astrophysics
 EPrint:
 19 pages, 10 figures, 3 tables, accepted for publication in ApJ, Supersedes arXiv:1907.11883