Low-mass star-formation in the Ophiuchus Main Cloud
CEA, Paris, FR
|The Ophiuchus Molecular Cloud is a well documented star-forming cloud located ~140 pc from the Sun. It is therefore an excellent laboratory for dense core search and classification. Harbouring low-mass star formation, its protostellar population have been studied for about three decades from the near infrared to the millimeter and radio range. As part of the Herschel Gould Belt Survey, extensive submillimeter images of the Ophiuchus Main Cloud were produced and a deep census of both prestellar cores and young protostars was obtained using the multi-scale, multi-wavelength source extraction algorithm, getsources. About 200 candidates gravitationally bound prestellar cores were detected. They are primarily found in high column density filamentary structures above AV~7, which is an important result in a region not previously known to be filamentary. Based on these data we discuss the properties of the prestellar core mass function (CMF) as well as its variations in the various clumps of the cloud. The peak of the prestellar CMF appears to be close to 0.3 Solar masses in Ophiuchus. Conceptually, the low-mass end of the prestellar CMF is populated by pre-brown dwarf cores, the prototype of which is Oph-B11, a 20 Jovian masses object identified with SCUBA and IRAM. Our Herschel census of dense cores in Ophiuchus contains a few other candidate ultra low-mass cores under the hydrogen-burning limit (0.08 Msol) which will be discussed.
|Caption: Herschel column density map of L1688. The white lines trace the filaments detected with DisPerse (Sousbie 2011). Most prestellar cores are formed along these lines, in the densest filaments.
P. Andre, CEA, FR
Vera Könyves, CEA, FR
A. Men'shchikov, CEA, FR