Millimeter observations of the HH 222 region

The HH 222 streamers in Orion and their associated non-thermal radio jet form a unique object, whose nature remains enigmatic. We have carried out a set of detailed millimeter observations around the non-thermal radio source in several transitions of the CO, (13)CO C(18)O and CS molecules. We find that the radio source is not associated with any molecular outflow nor located within a dense molecular core, and is therefore very unlikely to be a newborn star. The observations are in principle consistent with the radio source being a more evolved T Tauri star undergoing an energetic event, but it could also be an evolved object (an X-ray binary or a microquasar) accidentally passing through the large Orion cloud complex.