Detection of two carbon-chain-rich cores: CB130-3 and L673-SMM4

Abstract

We have found two dense cores, CB130-3 and L673-SMM4, where the carbon-chain molecules are extremely abundant relative to NH3, during a survey observation of radio emission lines of CCS, HC3N, HC 5N, and NH3 toward dark cloud cores. Judging from the low NH3/CCS ratios, they are possible candidates for "Carbon-Chain- Producing Regions" (CCPRs) recognized as chemically young dark cloud cores. The deuterium fractionation ratios DNC/HN13C in CB130-3 and L673-SMM4 are found to be 1.28+0.27-0.05 and 1.96 +0.32-0.01, respectively, which are comparable to or slightly higher than those in CCPRs found previously. We suggest that the dense cores of CB130-3 and L673-SMM4 are analogous to CCPRs, but their chemical evolutionary phase would be slightly older than those of the dense cores in the Taurus region. © 2011. The American Astronomical Society. All rights reserved.