2025/03/18 by Bo Huang, Huang, Bo, J. M. Girart +33
Chemistry · Physics and Astronomy · #Astro and Planetary Science #Astrophysics and Star Formation Studies #Astrophysics of Galaxies (astro-ph.GA) #FOS: Physical sciences #Molecular Spectroscopy and Structure
paper · pdf · doi:10.48550/arxiv.2503.14726
openalex publication_date 2025/03/18 · openalex created_date 2025/10/10 · openalex updated_date 2026/07/28
The \em B-field Orion Protostellar Survey (BOPS) recently obtained polarimetric observations at 870 \rm μm towards 61 protostars in the Orion molecular clouds with ∼ 1′′ spatial resolution using the Atacama Large Millimeter/submillimeter Array. From the BOPS sample, we selected the 26 protostars with extended polarized emission within a radius of ∼ 6′′ (2400~au) around the protostar. This allows to have sufficient statistical polarization data to infer the magnetic field strength. The magnetic field strength is derived using the Davis-Chandrasekhar-Fermi method. The underlying magnetic field strengths are approximately 2.0~mG for protostars with a standard hourglass magnetic field morphology, which is higher than the values derived for protostars with rotated hourglass, spiral, and complex magnetic field configurations (\lesssim1.0~mG). This suggests that the magnetic field plays a more significant role in envelopes exhibiting a standard hourglass field morphology, and a value of \gtrsim2.0 mG would be required to maintain such a structure at these scales. Furthermore, most protostars in the sample are slightly supercritical, with mass-to-flux ratios \lesssim3.0. In particular, the mass-to-flux ratios for all protostars with a standard hourglass magnetic field morphology are lower than 3.0. However, these ratios do not account for the contribution of the protostellar mass, which means they are likely significantly underestimated.