Projects per year
Abstract
We investigate the role of magnetic fields in the fragmentation of self-gravitating discs using 3D global ideal magnetohydrodynamic simulations performed with the PHANTOM smoothed particle hydrodynamics code. For initially toroidal fields, we find two regimes. In the first, where the cooling time is greater than five times the dynamical time, magnetic fields reduce spiral density wave amplitudes, which in turn suppresses fragmentation. This is the case even if the magnetic pressure is only a 10th of the thermal pressure. The second regime occurs when the cooling time is sufficiently short that magnetic fields cannot halt fragmentation.We find that magnetized discs produce more massive fragments, due to both the additional pressure exerted by the magnetic field and the additional angular momentum transport induced by Maxwell stresses. The fragments are confined to a narrower range of initial semimajor axes than those in unmagnetized discs. The orbital eccentricity and inclination distributions of unmagnetized and magnetized disc fragments are similar. Our results suggest that the fragmentation boundary could be at cooling times a factor of 2 lower than predicted by purely hydrodynamical models.
Original language | English |
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Pages (from-to) | 3406-3416 |
Number of pages | 11 |
Journal | Monthly Notices of the Royal Astronomical Society |
Volume | 466 |
Issue number | 3 |
Early online date | 20 Dec 2016 |
DOIs | |
Publication status | Published - Apr 2017 |
Keywords
- Accretion: accretion discs
- Stars: formation
- Quasars: supermassive black holes
- Planets and satellites: formation
- Magnetohydrodynamics (MHD)
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Dive into the research topics of 'On the fragmentation boundary in magnetized self-gravitating discs'. Together they form a unique fingerprint.Projects
- 1 Finished
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ERC ECOGAL: Star Formation and the Galax: ECOGAL
Bonnell, I. A. (PI)
1/05/12 → 30/04/17
Project: Standard