2014ApJ...789...83T

We imaged two starless molecular cloud cores, TUKH083 and TUKH122, in the Orion A giant molecular cloud in the CCS and NH₃ emission with the Very Large Array. TUKH122 contains one NH₃core "TUKH122-n," which is elongated and has a smooth oval boundary. Where observed, the CCS emission surrounds the NH₃core. This configuration resembles that of the N₂H⁺ and CCS distribution in the Taurus starless core L1544, a well-studied example of a dense prestellar core exhibiting infall motions. The linewidth of TUKH122-n is narrow (0.20 km/s) in the NH₃emission line and therefore dominated by thermal motions. The smooth oval shape of the core boundary and narrow linewidth in N₂H⁺ seem to imply that TUKH122-n is dynamically relaxed and quiescent. TUKH122-n is similar to L1544 in the kinetic temperature (10 K), linear size (0.03 pc), and virial mass (∼2 M_☉). Our results strongly suggest that TUKH122-n is on the verge of star formation. TUKH122-n is embedded in the 0.2 pc massive (virial mass ∼30 M_☉) turbulent parent core, while the L1544 NH₃ core is embedded in the 0.2 pc less-massive (virial mass ∼10 M_☉) thermal parent core. TUKH083 shows complicated distribution in NH₃, but was not detected in CCS. The CCS emission toward TUKH083 appears to be extended, and is resolved out in our interferometric observations.