Tidal disruption events on to stellar black holes in triples

Giacomo Fragione*, Nathan W.C. Leigh, Rosalba Perna, Bence Kocsis

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

8 Scopus citations

Abstract

Stars passing too close to a black hole can produce tidal disruption events (TDEs), when the tidal force across the star exceeds the gravitational force that binds it. TDEs have usually been discussed in relation to massive black holes that reside in the centres of galaxies or lurk in star clusters. We investigate the possibility that triple stars hosting a stellar black hole (SBH) may be sources of TDEs. We start from a triple system made up of three main-sequence stars and model the supernova (SN) kick event that led to the production of an inner binary comprised of an SBH. We evolve these triples with a high-precision N-body code and study their TDEs as a result of Kozai-Lidov oscillations. We explore a variety of distributions of natal kicks imparted during the SN event, various maximum initial separations for the triples, and different distributions of eccentricities. We show that the main parameter that governs the properties of the SBH-MS binaries that produce a TDE in triples is the mean velocity of the natal kick distribution. Smaller σ's lead to larger inner and outer semimajor axes of the systems that undergo a TDE, smaller SBH masses, and longer time-scales. We find that the fraction of systems that produce a TDE is roughly independent of the initial conditions, while estimate a TDE rate of 2.1 × 10−4-4.7 yr−1, depending on the prescriptions for the SBH natal kicks. This rate is almost comparable to the expected TDE rate for massive black holes.

Original languageEnglish (US)
Pages (from-to)727-737
Number of pages11
JournalMonthly Notices of the Royal Astronomical Society
Volume489
Issue number1
DOIs
StatePublished - Oct 11 2019

Keywords

  • Dynamics
  • Galaxies: kinematics and dynamics
  • Galaxy: kinematics
  • Stars: black holes
  • Stars: kinematics and dynamics

ASJC Scopus subject areas

  • Astronomy and Astrophysics
  • Space and Planetary Science

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