Observational studies of intermediate-mass protostars with PdBI, 30m, and Herschel

Séminaire IPAG de Asunción Fuente (OAN, Madrid), jeudi 29 novembre 2012 à 11h00, IPAG seminar room

The common paradigm for the formation of low mass stars includes the spherical infall of a cloud core, the formation of a disk with a protostar at its centre, and a bipolar outflow emitted from the inner region of this disk/ protostar structure. Our understanding of the formation of high mass stars is not so mature, although it is clear that there are some significant differences between the low mass and high mass formation mechanisms, including the fact that massive stars are predominantly born in clusters where interactions between stars are important during the formation process. High mass stars are rare in the vicinity of the Sun which hinders us from high spatial resolution studies that would shed some light on the details of their formation. Intermediate-mass young stellar objects (IMs) share many characteristics with high-mass stars (clustering, PDRs) but their study presents an important advantage : many are located closer to the Sun (d -<1 kpc) and in less complex regions than massive star-forming regions, allowing to be studied at spatial scales down to 500 AU - 1000 AU. Recent observations of IM protostars using the Plateau de Bure Interferometer and Herschel are presented and discussed in the context of the massive star formation theories and state-of-art chemical models. The understanding of the formation of IM stars is interesting by itself, but also the natural step to progress in our comprehension of the formation of more massive stars.