An observed lack of substructure in starless cores. II. super-jeans cores

We present SMA and CARMA continuum and spectral line observations of five dense cores located in the Perseus and Ophiuchus molecular clouds whose masses exceed their thermal Jeans masses. Three of these cores have previously been identified as being starless and two have been classified as being possibly protostellar. We find that one core is certainly protostellar. The other four cores, however, are starless and undetected in both C 18O and 1.3mm continuum emission. These four starless cores have flat density profiles out to at least 3c0.006pc, which is typical for starless cores in general. Density profiles predicted by some collapse models, especially in the early stages of infall, are consistent with our observations. Archival data reveal that these starless cores have significant non-thermal support against collapse, although they may still be unstable. \ua9 2012. The American Astronomical Society. All rights reserved.Peer reviewed: YesNRC publication: Ye