Séminaire - Star formation in global hierarchical gravitational collapse - Raul Naranjo (Site Buffon)

IMPMC, Salle des élèves, 2^e étage, 61 rue Buffon, Paris 5^e

Jeudi 28 février 2019 à 14 h 30

Raul Naranjo - post-Doctorant - IMPMC (équipe Cosmochimie)

Abstract

Molecular clouds have been generally considered to be dense virialized structures in the interstellar medium, supported by magnetic fields or turbulence, with relatively long free-fall times and collapsing only locally at the scale of their dense cores. In this picture, the dense cores start their lives as low-mass hydrostatic structures and somehow eventually become gravitationally unstable in order to form stars. However, this notion has been criticized by a number of authors. Moreover, recent observations have shown the ubiquity of filaments in molecular clouds, which in addition appear to be funneling gas to the dense cores.

In this talk, I will describe a scenario in which molecular clouds are considered in a state of hierarchical gravitational collapse, i.e., developing local centers (filaments and cores) of collapse throughout the whole cloud while the cloud itself is also collapsing, making equilibrium unnecessary at all stages prior to the formation of actual stars and explaining some of the observed features.