The initial magnetic criticality of prestellar cores

Felix D Priestley*, Charles Yin, James Wurster

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review


Direct observational measurements of the magnetic field strength in prestellar cores typically find supercritical mass-to-flux ratios, suggesting that the magnetic field is insufficient to prevent gravitational collapse. These measurements suffer from significant uncertainties; an alternative approach is to utilize the sensitivity of prestellar chemistry to the evolutionary history, and indirectly constrain the degree of magnetic support. We combine non-ideal magnetohydrodynamic simulations of prestellar cores with time-dependent chemistry and radiative transfer modelling, producing synthetic observations of the model cores in several commonly-observed molecular lines. We find that molecules strongly affected by freeze-out, such as CS and HCN, typically have much lower line intensities in magnetically subcritical models compared to supercritical ones, due to the longer collapse timescales. Subcritical models also produce much narrower lines for all species investigated. Accounting for a range of core properties, ages and viewing angles, we find that supercritical models are unable to reproduce the distribution of CS and N2H+ line strengths and widths seen in an observational sample, whereas subcritical models are in good agreement with the available data. This suggests that despite presently having supercritical mass-to-flux ratios, prestellar cores form as magnetically subcritical objects.
Original languageEnglish
Article numberstac2107
Pages (from-to)5689–5697
JournalMonthly Notices of the Royal Astronomical Society
Issue number4
Early online date19 Aug 2022
Publication statusPublished - Oct 2022


  • Astrochemistry
  • MHD
  • Stars:formation
  • ISM: magnetic fields
  • ISM: molecules


Dive into the research topics of 'The initial magnetic criticality of prestellar cores'. Together they form a unique fingerprint.

Cite this