Micro-tidal disruption events by stellar compact objects and the production of ultra-long GRBs

Journal Article · Wed Jun 01 04:00:00 EDT 2016 · Astrophysical Journal

DOI:https://doi.org/10.3847/0004-637X/823/2/113· OSTI ID:22869041

Perets, Hagai B. ^[1]; Li, Zhuo ^[2]; Lombardi, Jr., James C.; Milcarek, Jr., Stephen R. ^[3]

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1. Physics Department, Technion—Israel Institute of Technology (Israel)
2. Department of Astronomy and Kavli Institute for Astronomy and Astrophysics, Peking University, Beijing (China)
3. Department of Physics, Allegheny College, Meadville, PA 16335 (United States)

We explore full/partial tidal disruption events (TDEs) of stars/planets by stellar compact objects (black holes (BHs) or neutron stars (NSs)), which we term micro-TDEs. Disruption of a star/planet with mass M {sub ⋆} may lead to the formation of a debris disk around the BH/NS. Efficient accretion of a fraction (f{sub acc}=0.1 of the debris may then give rise to bright, energetic, long (10{sup 3}–10{sup 4} s), X-ray/gamma-ray flares, with total energies of up to (f{sub acc}/0.1)×10{sup 52} (M{sub ⋆}/0.6 M{sub ⊙}) erg, possibly resembling ultra-long gamma-ray bursts (GRBs)/X-ray flashes (XRFs). The energy of such flares depends on the poorly constrained accretion processes. Significantly fainter flares might be produced if most of the disk mass is blown away through strong outflows. We suggest three dynamical origins for such disruptions. In the first, a star/planet is tidally disrupted following a close random encounter with a BH/NS in a dense cluster. We estimate the BH (NS) micro-TDE rates from this scenario to be a few ×10{sup −6} (a few ×10{sup −7}) yr{sup −1} per Milky Way galaxy. Another scenario involves the interaction of wide companions due to perturbations by stars in the field, likely producing comparable but lower rates. Finally, a third scenario involves a BH/NS that gains a natal velocity kick at birth, leading to a close encounter with a binary companion and the tidal disruption of that companion. Such events could be associated with a supernova, or even with a preceding GRB/XRF event, and would likely occur hours to days after the prompt explosion; the rates of such events could be larger than those obtained from the other scenarios, depending on the preceding complex binary stellar evolution.

• OSTI ID: 22869041
• Journal Information: Astrophysical Journal, Journal Name: Astrophysical Journal Journal Issue: 2 Vol. 823; ISSN ASJOAB; ISSN 0004-637X
• Country of Publication: United States
• Language: English

Related Subjects

79 ASTRONOMY AND ASTROPHYSICS
BINARY STARS
BLACK HOLES
COMPARATIVE EVALUATIONS
COSMIC GAMMA BURSTS
DISTURBANCES
GAMMA RADIATION
MASS
MILKY WAY
NEUTRON STARS
PERTURBATION THEORY
PLANETS
STAR EVOLUTION
X RADIATION
X-RAY FLUORESCENCE ANALYSIS