Astrophys. J., Suppl. Ser., 131, 249-271 (2000/November-0)
Tracing the mass during low-mass star formation. I. Submillimeter continuum observations.
SHIRLEY Y.L., EVANS II N.J., RAWLINGS J.M.C. and GREGERSEN E.M.
Abstract (from CDS):
We have obtained 850 and 450 µm continuum maps of 21 low-mass cores with SEDs ranging from pre-protostellar to Class I (18 K<Tbol<370 K), using SCUBA at the JCMT. In this paper we present the maps, radial intensity profiles, and photometry. Pre-protostellar cores do not have power-law intensity profiles, whereas the intensity profiles of Class 0 and Class I sources can be fitted with power laws over a large range of radii. A substantial number of sources have companion sources within a few arcminutes (two out of five pre-protostellar cores, nine out of 16 Class 0/I sources). The mean separation between sources is 10,800 AU. The median separation is 18,000 AU including sources without companions as a lower limit. The mean value of the spectral index between 450 and 850 µm is 2.8±0.4, with pre-protostellar cores having slightly lower spectral indices (2.5±0.4). The mean mass of the sample, based on the dust emission in a 120" aperture, is 1.1±0.9 M☉. For the sources fitted by power-law intensity distributions (Iν(b)/Iν(0)=(b/b0)m), the mean value of m is 1.52±0.45 for Class 0 and I sources at 850 µm and 1.44±0.25 at 450 µm. Based on a simple analysis, assuming the emission is in the Rayleigh-Jeans limit and that Td(r)∝r–0.4, these values of m translate into power-law density distributions (n∝r–p) with p∼2.1. However, we show that this result may be changed by more careful consideration of effects such as beam size and shape, finite outer radii, more realistic Td(r), and failure of the Rayleigh-Jeans approximation.
Stars: Formation - Stars: Low-Mass, Brown Dwarfs - Submillimeter
Table 1: [SER2000] LNNNNWW, [SER2000] LNNNNW, [SER2000] LNNNNA, [SER2000] LNNNN, [SER2000] BNNN, [SER2000] CBNNN, [SER2000] SSV NN, N=19.
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