Astron. J., 151, 126-126 (2016/May-0)
Structural studies of eight bright rimmed clouds in the southern hemisphere.
SHARMA S., PANDEY A.K., BORISSOVA J., OJHA D.K., IVANOV V.D., OGURA K., KOBAYASHI N., KURTEV R., GOPINATHAN M. and YADAV R.K.
Abstract (from CDS):
We carried out deep- and wide-field near- and mid-infrared observations for a sample of eight bright-rimmed clouds (BRCs). Supplemented with the Spitzer archival data, we have identified and classified 44 to 433 young stellar objects (YSOs) associated with these BRCs. The Class I sources are generally located toward the places with higher extinction and are relatively closer to each other than the Class II sources, confirming that the young protostars are usually found in regions with denser molecular material. On the other hand the comparatively older population, Class II objects, are more randomly found throughout the regions, which can be due to their dynamical evolution. Using the minimal sampling tree analyses, we have extracted 13 stellar cores of eight or more members, which contain 60% of the total YSOs. The typical core is ∼0.6 pc in radii and somewhat elongated (aspect ratio of 1.45), of relatively low stellar density (surface density 60 pc-2), consisting of a small (35) number of YSOs of relatively young sources (66% Class I), and partially embedded (median AK=1.1 mag). But the cores show a wide range in their mass distribution (∼20 to 2400 M☉), with a median value of around 130 M☉. We found the star-formation efficiencies in the cores to be between 3% and 30% with an average of ∼14%, which agrees with the efficiencies needed to link the core mass function to the initial mass function. We also found a linear relation between the density of the clouds and the number of YSOs. The peaked nearest neighbor spacing distributions of the YSOs and the ratio of Jeans lengths to the YSO separations indicates a significant degree of non-thermally driven fragmentation in these BRCs.
© 2016. The American Astronomical Society. All rights reserved.
stars: formation - stars: pre-main sequence
VizieR on-line data:
<Available at CDS (J/AJ/151/126): table1.dat table3.dat table4.dat table5.dat>
Table 3: [SPB2016] SFO54 NNN (Nos 1-145), [SPB2016] SFO55 NN (Nos 1-96), [SPB2016] SFO64 NNN (Nos 1-165), [SPB2016] SFO65 NN (Nos 1-44), [SPB2016] SFO68 NNN (Nos 1-148), [SPB2016] SFO75 NNN (Nos 1-433), [SPB2016] SFO76 NN (Nos 1-60), [SPB2016] SFO79 NNN (Nos 1-256).
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