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| EPoS Contribution |
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PdBI subarcsecond observations of Class 0 protostars
Anaelle Maury ESO, Garching bei München, Germany | |
| The formation process of binary stars and multiple systems is poorly understood. The multiplicity rate of Class II pre-main-sequence stars and Class I protostars is well documented and known to be high (∼30% to 50% between ∼100 and 4000 AU). However, optical / near-infrared observations of Class I/Class II YSOs barely constrain the pristine properties of multiple systems, since dynamical evolution can quickly alter these properties during the protostellar phase. Therefore, determining the typical outcome of protostellar collapse and constraining models of binary formation by core fragmentation during collapse requires high-resolution millimeter continuum imaging of very young (Class 0) protostars observed at the beginning of the main accretion phase. We carried out a pilot high-resolution study of 5 Class 0 objects, using the most extended (A) configuration of the IRAM Plateau de Bure Interferometer (PdBI) at 1.3 mm. Our PdBI observations have a typical HPBW resolution ∼0.3" - 0.5" and rms continuum sensitivity ∼ 0.1 - 1 mJy/beam, which allow us to probe the multiplicity of Class 0 protostars down to separations a ∼50 AU and circumstellar mass ratios q ∼0.07. I'll show our observations suggests that the binary fraction in the ∼75 - 1000 AU range increases from the Class 0 to the Class I stage, and also seem to argue against purely hydrodynamic models of binary star formation. Finally, I'll briefly discuss possible alternative scenarios to reconcile the low multiplicity rate of Class 0 protostars on small scales with the higher binary fraction observed at later (e.g. Class I) evolutionary stages. | |
| Collaborators: Ph. Andre, CEA/Saclay - Service d'Astrophysique, France P. Hennebelle, ENS Paris, France F. Motte, EA/Saclay - Service d'Astrophysique, France D. Stamatellos, Cardiff University, Wales M. Bate, University of Exeter, UK A. Belloche, Max-Planck-Institut für Radioastronomie, Bonn, Germany G. Duchêne, University of California, Berkeley, USA A. Whitworth, Cardiff University, Wales |
Maury et al. 2010, accepted by A&A
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