A MOLECULAR JET FROM LKH-ALPHA-234

The Herbig Be star LkHalpha 234 possesses both a molecular outflow and an optical jet. New CO J = 3-2 observations with 14'' resolution show that the redshifted CO outflow is collimated, with an axis opposite t he blueshifted optical jet. A narrow CO structure or '' CO jet '' is f ound, which terminates in a CO-bright spot coincident with the Herbig- Haro object HH 105. The CO bright spot/HH object is probably the worki ng surface of an unseen (because of extinction) shock-ionized jet, whe re the head of the jet encounters the ambient cloud gas. The CO jet ma y be ambient gas entrained by the postulated fast ionized jet. The qui escent gas in the region is found to contain a ridge or shell of CO em ission within which LkHalpha 234 is embedded. The ridge is very sharpl y bounded to the west by a molecular cavity, suggesting that the forma tion of LkHalpha 234 was caused by the shell formation event. Triggere d star formation is further supported by the detection of a warm CO cl ump in the ridge which has the narrow lines (FWHM = 2 km s-1), mass (2 M.) and density (10(5) cm-3) typical of prestellar cores. The tempera ture of this clump (63 K) is much higher than the less-than-or-equal-t o 10 K of most cores, so that it may contain an embedded luminous obje ct as a heat source.