NEW THEORETICAL ADVANCES:
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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.
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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.
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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.
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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.
FUTURE DIRECTIONS:
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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.
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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.
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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.
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