Multiepoch radio observations of the exciting sources of HH 212 and HH 119

Abstract

We present high angular resolution (similar to 0."3) Very Large Array observations at 3.5 ern toward the regions of the exciting sources of two Herbig-Haro systems, namely, HH 212 in Orion and HH 119 in B335. The observations were made at three different epochs to search for possible fast time variations in the sources (on a scale of one week to one month). In HH 212 we detected, averaging the observations of the three epochs, a faint object, at the expected position for the exciting source of the HH system. Comparison with other radio observations indicates that this source exhibits considerable time variation on a scale of years. In B335 we detected at each epoch the source previously reported by other authors and our results suggest that this object, a thermal radio jet, is variable on timescales of a month. We discuss possible explanations for this fast variability.