dc.creatorSantos-Lima, R.
dc.creatorde Gouveia Dal Pino, E. M.
dc.creatorLazarian, A.
dc.date.accessioned2013-11-05T17:54:07Z
dc.date.accessioned2018-07-04T16:23:14Z
dc.date.available2013-11-05T17:54:07Z
dc.date.available2018-07-04T16:23:14Z
dc.date.created2013-11-05T17:54:07Z
dc.date.issued2012
dc.identifierASTROPHYSICAL JOURNAL, BRISTOL, v. 747, n. 1, supl. 1, Part 6, pp. 52-77, 36951, 2012
dc.identifier0004-637X
dc.identifierhttp://www.producao.usp.br/handle/BDPI/41811
dc.identifier10.1088/0004-637X/747/1/21
dc.identifierhttp://dx.doi.org/10.1088/0004-637X/747/1/21
dc.identifier.urihttp://repositorioslatinoamericanos.uchile.cl/handle/2250/1635164
dc.description.abstractThe formation of protostellar disks out of molecular cloud cores is still not fully understood. Under ideal MHD conditions, the removal of angular momentum from the disk progenitor by the typically embedded magnetic field may prevent the formation of a rotationally supported disk during the main protostellar accretion phase of low-mass stars. This has been known as the magnetic braking problem and the most investigated mechanism to alleviate this problem and help remove the excess of magnetic flux during the star formation process, the so-called ambipolar diffusion (AD), has been shown to be not sufficient to weaken the magnetic braking at least at this stage of the disk formation. In this work, motivated by recent progress in the understanding of magnetic reconnection in turbulent environments, we appeal to the diffusion of magnetic field mediated by magnetic reconnection as an alternative mechanism for removing magnetic flux. We investigate numerically this mechanism during the later phases of the protostellar disk formation and show its high efficiency. By means of fully three-dimensional MHD simulations, we show that the diffusivity arising from turbulent magnetic reconnection is able to transport magnetic flux to the outskirts of the disk progenitor at timescales compatible with the collapse, allowing the formation of a rotationally supported disk around the protostar of dimensions similar to 100 AU, with a nearly Keplerian profile in the early accretion phase. Since MHD turbulence is expected to be present in protostellar disks, this is a natural mechanism for removing magnetic flux excess and allowing the formation of these disks. This mechanism dismisses the necessity of postulating a hypothetical increase of the ohmic resistivity as discussed in the literature. Together with our earlier work which showed that magnetic flux removal from molecular cloud cores is very efficient, this work calls for reconsidering the relative role of AD in the processes of star and planet formation.
dc.languageeng
dc.publisherIOP PUBLISHING LTD
dc.publisherBRISTOL
dc.relationASTROPHYSICAL JOURNAL
dc.rightsCopyright IOP PUBLISHING LTD
dc.rightsclosedAccess
dc.subjectACCRETION, ACCRETION DISKS
dc.subjectDIFFUSION
dc.subjectISM MAGNETIC FIELDS
dc.subjectMAGNETOHYDRODYNAMICS (MHD)
dc.subjectSTARS FORMATION
dc.subjectTURBULENCE
dc.titleTHE ROLE OF TURBULENT MAGNETIC RECONNECTION IN THE FORMATION OF ROTATIONALLY SUPPORTED PROTOSTELLAR DISKS
dc.typeArtículos de revistas


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