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

Title: SOFT X-RAY TEMPERATURE TIDAL DISRUPTION EVENTS FROM STARS ON DEEP PLUNGING ORBITS

Abstract

One of the puzzles associated with tidal disruption event candidates (TDEs) is that there is a dichotomy between the color temperatures of a few × 10{sup 4} K for TDEs discovered with optical and UV telescopes and the color temperatures of a few × 10{sup 5}–10{sup 6} K for TDEs discovered with X-ray satellites. Here, we propose that high-temperature TDEs are produced when the tidal debris of a disrupted star self-intersects relatively close to the supermassive black hole, in contrast to the more distant self-intersection that leads to lower color temperatures. In particular, we note from simple ballistic considerations that greater apsidal precession in an orbit is the key to closer self-intersection. Thus, larger values of β, the ratio of the tidal radius to the pericenter distance of the initial orbit, are more likely to lead to higher temperatures of more compact disks that are super-Eddington and geometrically and optically thick. For a given star and β, apsidal precession also increases for larger black hole masses, but larger black hole masses imply a lower temperature at the Eddington luminosity. Thus, the expected dependence of the temperature on the mass of the black hole is non-monotonic. We find that in ordermore » to produce a soft X-ray temperature TDE, a deep plunging stellar orbit with β > 3 is needed and a black hole mass of ≲5 × 10{sup 6}M{sub ⊙} is favored. Although observations of TDEs are comparatively scarce and are likely dominated by selection effects, it is encouraging that both expectations are consistent with current data.« less

Authors:
;
Publication Date:
OSTI Identifier:
22518747
Resource Type:
Journal Article
Journal Name:
Astrophysical Journal Letters
Additional Journal Information:
Journal Volume: 812; Journal Issue: 2; Other Information: Country of input: International Atomic Energy Agency (IAEA); Journal ID: ISSN 2041-8205
Country of Publication:
United States
Language:
English
Subject:
79 ASTROPHYSICS, COSMOLOGY AND ASTRONOMY; ACCRETION DISKS; BLACK HOLES; DISTANCE; GALAXY NUCLEI; LUMINOSITY; MASS; ORBITS; PRECESSION; RELATIVISTIC RANGE; SATELLITES; SOFT X RADIATION; STARS; TELESCOPES

Citation Formats

Dai, Lixin, McKinney, Jonathan C., and Miller, M. Coleman, E-mail: cosimo@umd.edu. SOFT X-RAY TEMPERATURE TIDAL DISRUPTION EVENTS FROM STARS ON DEEP PLUNGING ORBITS. United States: N. p., 2015. Web. doi:10.1088/2041-8205/812/2/L39.
Dai, Lixin, McKinney, Jonathan C., & Miller, M. Coleman, E-mail: cosimo@umd.edu. SOFT X-RAY TEMPERATURE TIDAL DISRUPTION EVENTS FROM STARS ON DEEP PLUNGING ORBITS. United States. https://doi.org/10.1088/2041-8205/812/2/L39
Dai, Lixin, McKinney, Jonathan C., and Miller, M. Coleman, E-mail: cosimo@umd.edu. 2015. "SOFT X-RAY TEMPERATURE TIDAL DISRUPTION EVENTS FROM STARS ON DEEP PLUNGING ORBITS". United States. https://doi.org/10.1088/2041-8205/812/2/L39.
@article{osti_22518747,
title = {SOFT X-RAY TEMPERATURE TIDAL DISRUPTION EVENTS FROM STARS ON DEEP PLUNGING ORBITS},
author = {Dai, Lixin and McKinney, Jonathan C. and Miller, M. Coleman, E-mail: cosimo@umd.edu},
abstractNote = {One of the puzzles associated with tidal disruption event candidates (TDEs) is that there is a dichotomy between the color temperatures of a few × 10{sup 4} K for TDEs discovered with optical and UV telescopes and the color temperatures of a few × 10{sup 5}–10{sup 6} K for TDEs discovered with X-ray satellites. Here, we propose that high-temperature TDEs are produced when the tidal debris of a disrupted star self-intersects relatively close to the supermassive black hole, in contrast to the more distant self-intersection that leads to lower color temperatures. In particular, we note from simple ballistic considerations that greater apsidal precession in an orbit is the key to closer self-intersection. Thus, larger values of β, the ratio of the tidal radius to the pericenter distance of the initial orbit, are more likely to lead to higher temperatures of more compact disks that are super-Eddington and geometrically and optically thick. For a given star and β, apsidal precession also increases for larger black hole masses, but larger black hole masses imply a lower temperature at the Eddington luminosity. Thus, the expected dependence of the temperature on the mass of the black hole is non-monotonic. We find that in order to produce a soft X-ray temperature TDE, a deep plunging stellar orbit with β > 3 is needed and a black hole mass of ≲5 × 10{sup 6}M{sub ⊙} is favored. Although observations of TDEs are comparatively scarce and are likely dominated by selection effects, it is encouraging that both expectations are consistent with current data.},
doi = {10.1088/2041-8205/812/2/L39},
url = {https://www.osti.gov/biblio/22518747}, journal = {Astrophysical Journal Letters},
issn = {2041-8205},
number = 2,
volume = 812,
place = {United States},
year = {Tue Oct 20 00:00:00 EDT 2015},
month = {Tue Oct 20 00:00:00 EDT 2015}
}