Investigating the role of magnetic fields in star formation using molecular line profiles

ABSTRACT Determining the importance of magnetic fields in star-forming environments is hampered by the difficulty of accurately measuring both field strength and gas properties in molecular clouds. We post-process three-dimensional non-ideal magnetohydrodynamic simulations of pre-stellar cores with...

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Bibliographic Details
Published inMonthly notices of the Royal Astronomical Society Vol. 504; no. 2; pp. 2381 - 2389
Main Authors Yin, Charles, Priestley, Felix D, Wurster, James
Format Journal Article
LanguageEnglish
Published Oxford University Press 01.06.2021
Subjects
MHD
stars: formation
ISM: molecules
astrochemistry
ISM: magnetic fields
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Summary:ABSTRACT Determining the importance of magnetic fields in star-forming environments is hampered by the difficulty of accurately measuring both field strength and gas properties in molecular clouds. We post-process three-dimensional non-ideal magnetohydrodynamic simulations of pre-stellar cores with a time-dependent chemical network, and use radiative transfer modelling to calculate self-consistent molecular line profiles. Varying the initial mass-to-flux ratio from subcritical to supercritical results in significant changes to both the intensity and shape of several observationally important molecular lines. We identify the peak intensity ratio of N2H+ to CS lines, and the CS J = 2–1 blue-to-red peak intensity ratio, as promising diagnostics of the initial mass-to-flux ratio, with N2H+/CS values of >0.6 (<0.2) and CS blue/red values of <3 (>5) indicating subcritical (supercritical) collapse. These criteria suggest that, despite presently being magnetically supercritical, L1498 formed from subcritical initial conditions.
ISSN:0035-8711
1365-2966
DOI:10.1093/mnras/stab1039