MAGNETIC FIELDS IN EARLY PROTOSTELLAR DISK FORMATION

Autor(es)

Gonzalez-Casanova, Diego F. ^[1] ; Lazarian, Alexander ^[1] ; Santos-Lima, Reinaldo ^[2]

Afiliação do(s) autor(es)

^[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

• Tipo de documento: Artigo Científico
• Fonte: ASTROPHYSICAL JOURNAL; v. 819, n. 2 MAR 10 2016.
• Citações Web of Science: 4

Resumo

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)

• Processo FAPESP: 13/15115-8 - Estudo de efeitos de plasma não-colisional: aplicação ao meio intra-aglomerado de galáxias
• Beneficiário: Reinaldo Santos de Lima
• Modalidade de apoio: Bolsas no Brasil - Pós-Doutorado