Gravitational Collapse and Disk Formation in Magnetized Cores
arXiv:1411.6828 · doi:10.1007/978-3-662-44625-6_16
Abstract
We discuss the effects of the magnetic field observed in molecular clouds on the process of star formation, concentrating on the phase of gravitational collapse of low-mass dense cores, cradles of sunlike stars. We summarize recent analytic work and numerical simulations showing that a substantial level of magnetic field diffusion at high densities has to occur in order to form rotationally supported disks. Furthermore, newly formed accretion disks are threaded by the magnetic field dragged from the parent core during the gravitational collapse. These disks are expected to rotate with a sub-Keplerian speed because they are partially supported by magnetic tension against the gravity of the central star. We discuss how sub-Keplerian rotation makes it difficult to eject disk winds and accelerates the process of planet migration. Moreover, magnetic fields modify the Toomre criterion for gravitational instability via two opposing effects: magnetic tension and pressure increase the disk local stability, but sub-Keplerian rotation makes the disk more unstable. In general, magnetized disks are more stable than their nonmagnetic counterparts; thus, they can be more massive and less prone to the formation of giant planets by gravitational instability.
Chapter 16 in "Magnetic Fields in Diffuse Media", Springer-Verlag, eds. de Gouveia Dal Pino, E., Lazarian, A., Melioli, C
References in corpus (19)
- A High Order Godunov Scheme with Constrained Transport and Adaptive Mesh Refinement for Astrophysical MHD
- Magnetic Fields in the Formation of Sun-Like Stars
- Magnetic processes in a collapsing dense core. I Accretion and Ejection
- Halting Type I planet migration in non-isothermal disks
- Magnetic Braking and Protostellar Disk Formation: The Ideal MHD Limit
- The impact of magnetic fields on single and binary star formation
- Magnetically Regulated Star Formation in 3D: The Case of Taurus Molecular Cloud Complex
- Magnetic processes in a collapsing dense core. II Fragmentation. Is there a fragmentation crisis ?
- Gravitational collapse of magnetized clouds. I. Ideal MHD accretion flow
- Gravitational collapse of magnetized clouds II. The role of Ohmic dissipation
- Evolution of Magnetic Fields in High Mass Star Formation: Linking field geometry and collapse for the W51 e2/e8 cores
- Mean-Field Magnetohydrodynamics of Accretion Disks
- Three-fluid plasmas in star formation II. Momentum transfer rate coefficients
- Disk Formation Enabled by Enhanced Resistivity
- A Survey of OH Masers Towards High Mass Protostellar Objects
- Three-fluid plasmas in star formation I. Magneto-hydrodynamic equations
- Modeling the magnetic field in the protostellar source NGC 1333 IRAS 4A
- The Challenge of Sub-Keplerian Rotation for Disk Winds
- Ambipolar Diffusion in Molecular Cloud Cores and the Gravomagneto Catastrophe