Star Formation Signatures in the Condensation Downstream of Hh 80n

HH 80N is one of the Herbig-Haro objects that have associated quiescent dense clumps. We report CO and CS BIMA observations that reveal star formation within the HH 80N dense clump. The CO emission reveals clearly a bipolar molecular outflow centered on the dense clump. The CS emission traces a ring-like structure of radius ' 0.24 pc. The CS kinematics shows that the ring is collapsing with an infall speed of ∼ 0.6 km s−1. The required mass to produce the collapse is in agreement with previous ammonia observations of the 20 M core, which is embedded within the CS structure. However, we cannot discard that the ring structure is expanding driven by protostellar winds, if the CS abundance if unusually high and the CO momentum rate is much higher than that measured, due to inclination and optical depth effects. The properties of the molecular outflow and of the dense core suggest that it harbors a Class 0 object. There are also signatures of interaction of the HH 80/81/80N outflow with the dense gas. In particular it is possible that the HH 80/81/80N outflow has triggered or at least speed up the star formation in this region. Subject headings: ISM: individual (HH 80N) — ISM: jets and outflows — ISM: kinematics and dynamics — stars: formation