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The collapse of a molecular cloud core to stellar densities using radiation non-ideal magnetohydrodynamics

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Wurster_2018_Collapse_of_molecular_MNRAS_1859.pdf (12.90Mb)
Date
04/2018
Author
Wurster, J.
Bate, Matthew R.
Price, Daniel J.
Keywords
Magnetic fields
MHD
Radiative transfer
Methods: numerical
Stars: formation
Stars: winds
Outflows
QA75 Electronic computers. Computer science
QB Astronomy
QC Physics
T-DAS
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Abstract
We present results from radiation non-ideal magnetohydrodynamics (MHD) calculations that follow the collapse of rotating, magnetized, molecular cloud cores to stellar densities. These are the first such calculations to include all three non-ideal effects: ambipolar diffusion, Ohmic resistivity, and the Hall effect. We employ an ionization model in which cosmic ray ionization dominates at low temperatures and thermal ionization takes over at high temperatures. We explore the effects of varying the cosmic ray ionization rate from ζcr = 10−10 to 10−16 s−1. Models with ionization rates ≳10−12 s−1 produce results that are indistinguishable from ideal MHD. Decreasing the cosmic ray ionization rate extends the lifetime of the first hydrostatic core up to a factor of 2, but the lifetimes are still substantially shorter than those obtained without magnetic fields. Outflows from the first hydrostatic core phase are launched in all models, but the outflows become broader and slower as the ionization rate is reduced. The outflow morphology following stellar core formation is complex and strongly dependent on the cosmic ray ionization rate. Calculations with high ionization rates quickly produce a fast (≈14 km s−1) bipolar outflow that is distinct from the first core outflow, but with the lowest ionization rate, a slower (≈3−4 km s−1) conical outflow develops gradually and seamlessly merges into the first core outflow.
Citation
Wurster , J , Bate , M R & Price , D J 2018 , ' The collapse of a molecular cloud core to stellar densities using radiation non-ideal magnetohydrodynamics ' , Monthly Notices of the Royal Astronomical Society , vol. 475 , no. 2 , pp. 1859-1880 . https://doi.org/10.1093/mnras/stx3339
Publication
Monthly Notices of the Royal Astronomical Society
Status
Peer reviewed
DOI
https://doi.org/10.1093/mnras/stx3339
ISSN
0035-8711
Type
Journal article
Rights
© 2018 The Author(s) Published by Oxford University Press on behalf of the Royal Astronomical Society. This work has been made available online in accordance with publisher policies or with permission. Permission for further reuse of this content should be sought from the publisher or the rights holder. This is the final published version of the work, which was originally published at https://doi.org/10.1093/mnras/stx3339
Collections
  • University of St Andrews Research
URL
https://arxiv.org/abs/1801.01126
URI
http://hdl.handle.net/10023/18746

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