2014/12/31 by Hajime Susa, Kentaro Doi, Kazuyuki Omukai · 2 citations
Physics and Astronomy · #Astro and Planetary Science #Astrophysics #Astrophysics and Star Formation Studies #Dissipation #Dissipative system #Dynamo #Ion #Ionization #Magnetic field #Magnetohydrodynamics #Metallicity #Physics #Star formation #Stars #Stellar, planetary, and galactic studies #astro-ph.SR
paper · pdf · doi:10.1088/0004-637x/801/1/13
13 pages, 7 figures, ApJ accepted
arxiv created 2014/12/31 · openalex publication_date 2015/02/25 · arxiv updated 2015/06/23 · openalex created_date 2025/10/10 · openalex updated_date 2026/08/05
We study the dissipation process of magnetic fields in the metallicity range 0–1 Z ☉ for contracting prestellar cloud cores. By solving non-equilibrium chemistry for important charged species, including charged grains, we evaluate the drift velocity of the magnetic-field lines with respect to the gas. We find that the magnetic flux dissipates in the density range 10 12 cm −3 ≲ n H ≲ 10 17 cm −3 for the solar-metallicity case at the scale of the core, which is assumed to be the Jeans scale. The dissipation density range becomes narrower for lower metallicity. The magnetic field is always frozen to the gas below metallicity ≲ 10 −7 –10 −6 Z ☉ , depending on the ionization rate by cosmic rays and/or radioactivity. With the same metallicity, the dissipation density range becomes wider for lower ionization rates. The presence of such a dissipative regime is expected to cause various dynamical phenomena in protostellar evolution such as the suppression of jet/outflow launching and the fragmentation of circumstellar disks depending on the metallicity.