skip to main content
OSTI.GOV title logo U.S. Department of Energy
Office of Scientific and Technical Information

Title: OPTICAL TRANSIENTS FROM THE UNBOUND DEBRIS OF TIDAL DISRUPTION

Abstract

In the tidal disruption of a star by a black hole, roughly half of the stellar mass becomes bound and falls into the black hole, while the other half is ejected at high velocity. Several previous studies have considered the emission resulting from the accretion of bound material; we consider the possibility that the unbound debris may also radiate once it has expanded and become transparent. We show that the gradual energy input from hydrogen recombination compensates for adiabatic losses over significant expansion factors. The opacity also drops dramatically with recombination, and the internal energy can be radiated by means of a cooling-transparency wave propagating from the surface layers inward. The result is a brief optical transient occurring {approx} 1 week after disruption and lasting 3-5 days with peak luminosities of 10{sup 40}-10{sup 42} ergs s{sup -1}, depending on the mass of the disrupted star. These recombination powered transients should accompany the X-ray/ultraviolet flare from the accretion of bound material, and so may be a useful signature for discriminating tidal disruption events, especially for lower and intermediate mass black holes.

Authors:
;  [1]
  1. University of California, Santa Cruz, CA (United States)
Publication Date:
OSTI Identifier:
21448939
Resource Type:
Journal Article
Journal Name:
Astrophysical Journal
Additional Journal Information:
Journal Volume: 714; Journal Issue: 1; Other Information: DOI: 10.1088/0004-637X/714/1/155; Journal ID: ISSN 0004-637X
Country of Publication:
United States
Language:
English
Subject:
79 ASTROPHYSICS, COSMOLOGY AND ASTRONOMY; BLACK HOLES; HYDROGEN; LUMINOSITY; RADIANT HEAT TRANSFER; RECOMBINATION; STARS; ULTRAVIOLET RADIATION; ELECTROMAGNETIC RADIATION; ELEMENTS; ENERGY TRANSFER; HEAT TRANSFER; NONMETALS; OPTICAL PROPERTIES; PHYSICAL PROPERTIES; RADIATIONS

Citation Formats

Kasen, Daniel, and Ramirez-Ruiz, Enrico. OPTICAL TRANSIENTS FROM THE UNBOUND DEBRIS OF TIDAL DISRUPTION. United States: N. p., 2010. Web. doi:10.1088/0004-637X/714/1/155.
Kasen, Daniel, & Ramirez-Ruiz, Enrico. OPTICAL TRANSIENTS FROM THE UNBOUND DEBRIS OF TIDAL DISRUPTION. United States. https://doi.org/10.1088/0004-637X/714/1/155
Kasen, Daniel, and Ramirez-Ruiz, Enrico. 2010. "OPTICAL TRANSIENTS FROM THE UNBOUND DEBRIS OF TIDAL DISRUPTION". United States. https://doi.org/10.1088/0004-637X/714/1/155.
@article{osti_21448939,
title = {OPTICAL TRANSIENTS FROM THE UNBOUND DEBRIS OF TIDAL DISRUPTION},
author = {Kasen, Daniel and Ramirez-Ruiz, Enrico},
abstractNote = {In the tidal disruption of a star by a black hole, roughly half of the stellar mass becomes bound and falls into the black hole, while the other half is ejected at high velocity. Several previous studies have considered the emission resulting from the accretion of bound material; we consider the possibility that the unbound debris may also radiate once it has expanded and become transparent. We show that the gradual energy input from hydrogen recombination compensates for adiabatic losses over significant expansion factors. The opacity also drops dramatically with recombination, and the internal energy can be radiated by means of a cooling-transparency wave propagating from the surface layers inward. The result is a brief optical transient occurring {approx} 1 week after disruption and lasting 3-5 days with peak luminosities of 10{sup 40}-10{sup 42} ergs s{sup -1}, depending on the mass of the disrupted star. These recombination powered transients should accompany the X-ray/ultraviolet flare from the accretion of bound material, and so may be a useful signature for discriminating tidal disruption events, especially for lower and intermediate mass black holes.},
doi = {10.1088/0004-637X/714/1/155},
url = {https://www.osti.gov/biblio/21448939}, journal = {Astrophysical Journal},
issn = {0004-637X},
number = 1,
volume = 714,
place = {United States},
year = {Sat May 01 00:00:00 EDT 2010},
month = {Sat May 01 00:00:00 EDT 2010}
}