Abstract
Mergers of binaries comprising compact objects can give rise to explosive transient events, heralding the birth of exotic objects that cannot be formed through single-star evolution. Using a large number of directN-body simulations,we explore the possibility that awhite dwarf (WD) is dynamically driven to tidal disruption by a stellar-mass black hole (BH) as a consequence of the joint effects of gravitational wave (GW) emission and Lidov-Kozai oscillations imposed by the tidal field of an outer tertiary companion orbiting the inner BH-WD binary.We explore the sensitivity of our results to the distributions of natal kick velocities imparted to the BH and WD upon formation, adiabatic mass loss, semimajor axes and eccentricities of the triples, and stellar-mass ratios.We find rates ofWD-tidal disruption events (TDEs) in the range 1.2×10-3 - 1.4 Gpc-3 yr-1 for z ≤ 0.1, rarer than stellar TDEs in triples by a factor of ∼3-30. The uncertainty in the TDE rates may be greatly reduced in the future using GW observations of Galactic binaries and triples with LISA. WD-TDEs may give rise to high-energy X-ray or gamma-ray transients of duration similar to long gamma-ray bursts but lacking the signatures of a core-collapse supernova, while being accompanied by a supernova-like optical transient that lasts for only days. WD-BH and WD-NS binaries will also emit GWs in the LISA band before the TDE. The discovery and identification of triple-induced WD-TDE events by future time domain surveys and/or GWs could enable the study of the demographics of BHs in nearby galaxies.
| Original language | English (US) |
|---|---|
| Pages (from-to) | 1061-1072 |
| Number of pages | 12 |
| Journal | Monthly Notices of the Royal Astronomical Society |
| Volume | 495 |
| Issue number | 1 |
| DOIs | |
| State | Published - 2020 |
Funding
G. F. thanks Seppo Mikkola for helpful discussions on the use of the code ARCHAIN. We thank our referee, Hagai Perets, for a con- structive and stimulating report. G. F. acknowledges support from a CIERA postdoctoral fellowship at Northwestern University. R. P. acknowledges support by NSF award AST-1616157. The Center for Computational Astrophysics at the Flatiron Institute is supported by the Simons Foundation. N. W. C. L. gratefully acknowledges a Fondecyt Iniciacion grant (#11180005). This work received funding from the European Research Council (ERC) under the European Union’s Horizon 2020 Programme for Research and Innovation ERC-2014-STG under grant agreement No. 638435 (GalNUC) and from the Hungarian National Research, Development, and Innovation Office under grant NKFIH KH-125675 (to B. K). B. D. M. acknowledges support by NASA through the Astrophysics Theory Program (grant number NNX17AK43G) and by the Simons Foundation (grant number 606260).
Keywords
- Galaxies: Kinematics and dynamics
- Stars: Black holes
- Stars: Kinematics and dynamics
- Stars: Supernovae: General
- Stars: white dwarfs
ASJC Scopus subject areas
- Astronomy and Astrophysics
- Space and Planetary Science