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(Reference retrieved automatically from Web of Science through information on FAPESP grant and its corresponding number as mentioned in the publication by the authors.)

MAGNETIC FIELDS IN EARLY PROTOSTELLAR DISK FORMATION

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Author(s):
Gonzalez-Casanova, Diego F. [1] ; Lazarian, Alexander [1] ; Santos-Lima, Reinaldo [2]
Total Authors: 3
Affiliation:
[1] Univ Wisconsin, Dept Astron, 475 N Charter St, Madison, WI 53706 - USA
[2] Univ Sao Paulo, Inst Astron Geofis & Ciencias Atmosfer, R Matao 1226, BR-05508090 Sao Paulo, SP - Brazil
Total Affiliations: 2
Document type: Journal article
Source: ASTROPHYSICAL JOURNAL; v. 819, n. 2 MAR 10 2016.
Web of Science Citations: 4
Abstract

We consider formation of accretion disks from a realistically turbulent molecular gas using 3D MHD simulations. In particular, we analyze the effect of the fast turbulent reconnection described by the Lazarian \& Vishniac model for the removal of magnetic flux from a disk. With our numerical simulations we demonstrate how the fast reconnection enables protostellar disk formation resolving the so-called ``magnetic braking catastrophe.{''} In particular, we provide a detailed study of the dynamics of a 0.5. M-circle dot protostar and the formation of its disk for up to several thousands years. We measure the evolution of the mass, angular momentum, magnetic field, and turbulence around the star. We consider effects of two processes that strongly affect the magnetic transfer of angular momentum, both of which are based on turbulent reconnection: the first, ``reconnection diffusion,{''} removes the magnetic flux from the disk; the other involves the change of the magnetic field's topology, but does not change the absolute value of the magnetic flux through the disk. We demonstrate that for the first mechanism, turbulence causes a magnetic flux transport outward from the inner disk to the ambient medium, thus decreasing the coupling of the disk to the ambient material. A similar effect is achieved through the change of the magnetic field's topology from a split monopole configuration to a dipole configuration. We explore how both mechanisms prevent the catastrophic loss of disk angular momentum and compare both above turbulent reconnection mechanisms with alternative mechanisms from the literature. (AU)

FAPESP's process: 13/15115-8 - Study of collisionless plasma effects: application to the turbulent intracluster medium of galaxies
Grantee:Reinaldo Santos de Lima
Support type: Scholarships in Brazil - Post-Doctorate