EPoS Contribution
EPoS Contribution
Is disk formation a simple result of angular momentum conservation during the main accretion phase? Constraints from CALYPSO observations of Class 0 protostars

Anaelle Maury
CEA Saclay, Saclay, FR
One of the main challenges to the formation of stars is the angular momentum problem: the gas contained in a typical star-forming core must reduce its specific angular momentum by 5 to 10 orders of magnitude to form a typical star such as our Sun, or else centrifugal forces will soon balance gravity and prevent inflow, accretion and the growth of the protostellar embryo. Early analytical analysis proposed that the formation of large (r > 100 AU) centrifugally supported disks would allow to dissipate angular momentum and therefore solve the angular momentum problem. However, we still don't know how the angular momentum is distributed and evolves in protostellar envelopes during the youngest phases of low-mass star formation. From pilot observations, we recently argued that the small disk sizes at the Class 0 stage are in favor of a magnetically-regulated angular momentum scenario for the formation of low-mass protostars and their disks. I will present new insights obtained thanks to the detailed analysis of millimeter observations of protostellar envelopes probing the envelope density, structure and kinematics from the small scales (50 AU) to large scales (5000 AU) obtained with the Plateau de Bure interferometer (PdBI) and the IRAM 30m telescope in teh framework of the CALYPSO (Continuum and Line in Young Protostellar Objects) program. I will present the statistical results putting constraints on disk properties in our CALYPSO sample of Class 0 protostars. I will link those results to a few detailed examples of our modeling of angular momentum distribution in the youngest envelopes, to provide a few keys adressing wether angular momentum conservation during the main accretion phase is the sole process responsible for the properties of disks formed during the protostellar stage.
M. Gaudel, CEA Saclay, FR
S. Maret, IPAG, FR
A. Belloche, MPIfR, DE
Ph. Andre, CEA Saclay, FR
and the CALYPSO collaboration
Suggested Session: Disk Formation