Disk Wind Feedback from High-mass Protostars. IV. Shock-ionized Jets
Artikel i vetenskaplig tidskrift, 2024

Massive protostars launch accretion-powered, magnetically collimated outflows, which play crucial roles in the dynamics and diagnostics of the star formation process. Here we calculate the shock heating and resulting free-free radio emission in numerical models of outflows of massive star formation within the framework of the Turbulent Core Accretion model. We postprocess 3D magnetohydrodynamic simulation snapshots of a protostellar disk wind interacting with an infalling core envelope, and calculate shock temperatures, ionization fractions, and radio free-free emission. We find heating up to ∼107 K and near-complete ionization in shocks at the interface between the outflow cavity and infalling envelope. However, line-of-sight averaged ionization fractions peak around ∼10%, in agreement with values reported from observations of massive protostar G35.20-0.74N. By calculating radio-continuum fluxes and spectra, we compare our models with observed samples of massive protostars. We find our fiducial models produce radio luminosities similar to those seen from low- and intermediate-mass protostars that are thought to be powered by shock ionization. Comparing to more massive protostars, we find our model radio luminosities are ∼10-100 times less luminous. We discuss how this apparent discrepancy either reflects aspects of our modeling related to the treatment of cooling of the post-shock gas or a dominant contribution in the observed systems from photoionization. Finally, our models exhibit 10 yr radio flux variability of ∼5%, especially in the inner 1000 au region, comparable to observed levels in some hypercompact H ii regions.


Emiko C. Gardiner

University of California

Jonathan Tan

Chalmers, Rymd-, geo- och miljövetenskap, Astronomi och plasmafysik

University of Virginia

Jan Staff

University of The Virgin Islands

Chalmers, Rymd-, geo- och miljövetenskap, Astronomi och plasmafysik

Jon P Ramsey

University of Virginia

Yichen Zhang

Shanghai Jiao Tong University

Kei E.I. Tanaka

Tokyo Institute of Technology

Astrophysical Journal

0004-637X (ISSN) 1538-4357 (eISSN)

Vol. 967 2 145


Meteorologi och atmosfärforskning

Astronomi, astrofysik och kosmologi

Annan fysik



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