Giant protostellar outflows revealed by infrared imaging

Abstract

We present new infrared data from a survey for embedded protostellar jets in the Orion A cloud. This survey makes use of the S(1) v = 1-0 line of molecular hydrogen at lambda = 2.12 mum to search for infrared jets deep inside the cloud and thus hidden from view at optical wavelengths. We present data on the three flows associated with the Herbig-Haro objects HH 43/38 & HH 64, HH 65, and the L1641-N giant flow. HH 43, HH 38 and HH 64 are part of one H_2 flow extending over at least 1.4 pc. We identify a deeply embedded 1.3 mm and IRAS source (HH 43 MMS1 = IRAS 05355-0709C) as the likely driving source, while the infrared source previously assumed to drive HH 43/38 (HH 43-IRS1 = IRAS 05357-0710) is seen to drive a smaller jet. The morphology of HH 43-IRS1 suggests that it is a star+disk system seen close to edge-on. We identify another large H_2 flow apparently comprising the L1641-S3 CO outflow and the redshifted lobe of the L1641-S CO outflow containing HH 65. This flow extends over at least 2.6 pc and appears strongly curved. It is driven by L1641-S3 IRS, a deeply embedded 1.3 mm and IRAS source (L1641-S3 MMS1 = IRAS 05375-0731). Finally, we have found some additional large H_2 features to the east of V 380 Ori and the HH 1/2 system, which probably outline another part of the L1641-N outflow. The molecular flow MB 20/21, which extends to the south from V 380 Ori, also appears to be a part of the L1641-N outflow.