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Post-periapsis pancakes: sustenance for self-gravity in tidal disruption events

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journal contribution
posted on 19.04.2016, 10:04 by E. R. Coughlin, Christopher James Nixon, M. C. Begelman, P. J. Armitage, D. J. Price
A tidal disruption event, which occurs when a star is destroyed by the gravitational field of a supermassive black hole, produces a stream of debris, the evolution of which ultimately determines the observational properties of the event. Here, we show that a post-periapsis caustic – a location where the locus of gas parcels comprising the stream would collapse into a two-dimensional surface if they evolved solely in the gravitational field of the hole – occurs when the pericentre distance of the star is of the order of the tidal radius of the hole. It is demonstrated that this ‘pancake’ induces significant density perturbations in the debris stream, and, for stiffer equations of state (adiabatic index γ ≳ 5/3), these fluctuations are sufficient to gravitationally destabilize the stream, resulting in its fragmentation into bound clumps. The results of our findings are discussed in the context of the observational properties of tidal disruption events.

History

Citation

Monthly Notices Of The Royal Astronomical Society, 2016, 455 (4), pp. 3612-3627 (16)

Author affiliation

/Organisation/COLLEGE OF SCIENCE AND ENGINEERING/Department of Physics and Astronomy

Version

VoR (Version of Record)

Published in

Monthly Notices Of The Royal Astronomical Society

Publisher

Oxford University Press (OUP)

issn

0035-8711

eissn

1365-2966

Acceptance date

23/10/2015

Copyright date

2015

Available date

19/04/2016

Publisher version

http://mnras.oxfordjournals.org/content/455/4/3612

Language

en