We imaged two starless molecular cloud cores , TUKH083 and TUKH122 , in the Orion A giant molecular cloud in the CCS and ammonia ( NH _ { 3 } ) emission with the Very Large Array .
TUKH122 contains one NH _ { 3 } core “ TUKH122-n , ” which is elongated and has a smooth oval boundary .
Where observed , the CCS emission surrounds the NH _ { 3 } core .
This configuration resembles that of the N _ { 2 } H ^ { + } 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 ^ { -1 } ) in the NH _ { 3 } emission line and therefore dominated by thermal motions .
The smooth oval shape of the core boundary and narrow linewidth in NH _ { 3 } 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 ( \sim 2 M _ { \odot } ) .
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 \sim 30 M _ { \odot } ) turbulent parent core , while the L1544 NH _ { 3 } core is embedded in the 0.2 pc less-massive ( virial mass \sim 10 M _ { \odot } ) thermal parent core .
TUKH083 shows complicated distribution in NH _ { 3 } , but was not detected in CCS .
The CCS emission toward TUKH083 appears to be extended , and is resolved out in our interferometric observations .