Simulations of Magnetic Fields in Tidally-Disrupted Stars
Sep 26, 20166 pages
Published in:
- Astrophys.J.Lett. 834 (2017) 2, L19
- Published: Jan 12, 2017
e-Print:
- 1609.08160 [astro-ph.HE]
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Abstract: (IOP)
We perform the first magnetohydrodynamical simulations of tidal disruptions of stars by supermassive black holes. We consider stars with both tangled and ordered magnetic fields, for both grazing and deeply disruptive encounters. When the star survives disruption, we find its magnetic field amplifies by a factor of up to 20, but see no evidence for a self-sustaining dynamo that would yield arbitrary field growth. For stars that do not survive, and within the tidal debris streams produced in partial disruptions, we find that the component of the magnetic field parallel to the direction of stretching along the debris stream only decreases slightly with time, eventually resulting in a stream where the magnetic pressure is in equipartition with the gas. Our results suggest that the returning gas in most (if not all) stellar tidal disruptions is already highly magnetized by the time it returns to the black hole.Note:
- Accepted to ApJL. 7 pages, 4 figures
- black hole physics
- galaxies: active
- gravitation
References(51)
Figures(5)