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arXiv · 1209.5290

Herschel observations of B1-bS and B1-bN: two first hydrostatic core candidates in the Perseus star-forming cloud

Stefano Pezzuto·D. Elia·E. Schisano·F. Strafella·J. Di Francesco·S. Sadavoy·P. André·M. Benedettini·J. P. Bernard·A. M. di Giorgio·A. Facchini·M. Hennemann·T. Hill·V. Könyves·S. Molinari·F. Motte·Q. Nguyen-Luong·N. Peretto·M. Pestalozzi·D. Polychroni·K. L. J. Rygl·P. Saraceno·N. Schneider·L. Spinoglio·L. Testi·D. Ward-Thompson·G. J. White
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Abstract

We report far-IR Herschel observations obtained between 70 $\mu$m and 500 $\mu$m of two star-forming dusty condensations, B1-bS and B1-bN, in the B1 region of the Perseus star-forming cloud. In the Western part of the Perseus cloud, B1-bS is the only source detected in all of the 6 PACS and SPIRE photometric bands without being visible in the Spitzer map at 24 $\mu$m. B1-bN is clearly detected between 100 $\mu$m and 250 $\mu$m. We have fitted the spectral energy distributions of these sources to derive their physical properties, and find that a simple greybody model fails to reproduce the observed SEDs. At least a two-component model, consisting of a central source surrounded by a dusty envelope is required. The properties derived from the fit, however, suggest that the central source is not a Class 0 object. We then conclude that while B1-bS and B1-bN appear to be more evolved than a pre-stellar core, the best-fit models suggest that their central objects are younger than a Class 0 source. Hence, they may be good candidates to be examples of the first hydrostatic core phase. The projected distance between B1-bS and B1-bN is a few Jeans lengths. If their physical separation is close to this value, this pair would allow the mutual interactions between two forming stars at a very early stage of their evolution to be studied.

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Stefano Pezzuto, D. Elia, E. Schisano, F. Strafella, J. Di Francesco, S. Sadavoy, P. André, M. Benedettini, J. P. Bernard, A. M. di Giorgio, A. Facchini, M. Hennemann, T. Hill, V. Könyves, S. Molinari, F. Motte, Q. Nguyen-Luong, N. Peretto, M. Pestalozzi, D. Polychroni, K. L. J. Rygl, P. Saraceno, N. Schneider, L. Spinoglio, L. Testi, D. Ward-Thompson, G. J. White. 2012-09-24. Herschel observations of B1-bS and B1-bN: two first hydrostatic core candidates in the Perseus star-forming cloud. https://doi.org/10.1051/0004-6361/201219501

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