EPoS Contribution
EPoS Contribution
Recent Advances and Future Directions of the Role of Magnetic Fields in Protostar Formation: What Close Collaborations between Theorists and Observers Can Achieve in Dispelling Myths and Testing Theories

Telemachos Mouschovias
Departments of Physics and Astronomy, University of Illinois at Urbana-Champaign, Urbana, USA
  1. Cloud formation by the Parker instability, including phase transitions, has recently been shown to account for the masses, sizes and other properties of dense clouds.
  2. The data that were thought to have established the "universality of turbulence" (from galactic to sub-pc scales) have been reexamined and shown unambiguously (a) not to support such conclusion, and (b) to be in excellent quantitative agreement with the ambipolar-diffusion theory of protostar formation. They also show a systematic increase of the mass-to-flux ratio from envelopes to cores, as predicted by the ambipolar-diffusion theory.
  3. A semi-analytical calculation has determined the Core-IMF, based on ambipolar diffusion in self-gravitating molecular clouds. The prediction is in excellent quantitative agreement with observations.
  4. At higher densities, after a central protostellar core becomes opaque, several key features of the magnetically-controlled spasmodic-accretion predictions have been confirmed by observations.

  1. A collaborative effort has started with an observer colleague that will test predictions of the ambipolar-diffusion theory at densities greater than 10^6 cm-3. These predictions include density and velocity profiles as well as evolutionary timescales and the physical properties of protostellar disks.
  2. A different collaboration with another observer (involving clouds and cores at densities smaller than 10^6 cm-3) will explore the role of turbulence vs. MHD waves in explaining observed linewidths. It has already shown that "Larson's law" is a myth unsupported by properly analyzed data.
  3. Theoretical calculations, properly accounting for the role of magnetic fields and grains in a six-fluid system (neutral molecules, atomic and molecular ions, electrons, negatively-charged, positively-charged and neutral grains) are now under way aiming at understanding protoplanetary disks. Synthetic spectra will be produced and compared with high-resolution observations.