New Radio Sources and the Composite Structure of Component B in the Very Young Protostellar System IRAS 16293-2422

In this article we report high-resolution (~0.1''-0.3''), high-sensitivity (~50-100 mJy beam-1) Very Large Array 0.7 and 1.3 cm observations of the young stellar system IRAS 16293-2422 in r Ophiuchus. In the 0.7 cm image, component A to the southeast of the system looks like its usual binary self. In the new 1.3 cm image, however, component A2 appears to have split into two subcomponents located roughly symmetrically around the original position of A2. This change of morphology is likely the result of a recent bipolar ejection, one of the very first such events observed in a low-mass source. Also in component A, a marginal detection of 0.7 cm emission associated with the submillimeter component Ab is reported. If confirmed, this detection would imply that Ab is a relatively extended dusty structure, where grain coagulation may already have taken place. With an angular size increasing with frequency, and an overall spectral index of 2, the emission from component B to the northwest of the system is confirmed to be dominated by optically thick thermal dust emission associated with a fairly massive, nearly face-on, circumstellar disk. In the central region, however, we find evidence for a modest free-free contribution that originates in a structure elongated roughly in the east-west direction. We argue that this free-free component traces the base of the jet driving the large-scale bipolar flow at a position angle of about 110deg that has long been known to be powered by IRAS 16293-2422.