THE DISCOVERY OF THE YOUNGEST MOLECULAR OUTFLOW ASSOCIATED WITH AN INTERMEDIATE-MASS PROTOSTELLAR CORE, MMS-6/OMC-3

We present subarcsecond resolution HCN (4-3) and CO (3-2) observations made with the Submillimeter Array, toward an extremely young intermediate-mass protostellar core, MMS 6-main, located in the Orion Molecular Cloud 3 region (OMC-3). We have successfully imaged a compact molecular outflow lobe (approximate to 1000 AU) associated with MMS 6-main, which is also the smallest molecular outflow ever found in the intermediate-mass protostellar cores. The dynamical timescale of this outflow is estimated to be <= 100 yr. The line width dramatically increases downstream at the end of the molecular outflow (Delta v similar to 25 km s(-1)) and clearly shows the bow-shock-type velocity structure. The estimated outflow mass (approximate to 10(-4) M-circle dot) and outflow size are approximately two to four orders and one to three orders of magnitude smaller, respectively, while the outflow force (approximate to 10(-4) M-circle dot km s(-1) yr(-1)) is similar, compared to the other molecular outflows studied in OMC-2/3. These results show that MMS6-main is a protostellar core at the earliest evolutionary stage, most likely shortly after the second core formation.