MOLECULAR OUTFLOWS AND STAR-FORMATION IN THE HL-TAU STELLAR GROUP

(CO)-C-12(2-1) and (CO)-C-13(2-1) observations of the HL Tau/HH 30 reg ion are presented. These observations have high sensitivity and spatia l resolution, and allow a large scale study of the kinematics of the g as in this complex stellar group. The main result is that HL Tau drive s a powerful extended molecular outflow that has probably blown out of its parental core on its blueward side. The red part of the flow is c urrently pushing its way into the denser remaining core gas. The total mass of outflowing gas is of the order of 0.17 M. with 2/3 of this ma ss in the red part of the flow. The outflow rate is very high: 10(-5) M., a value consistent with FU Orionis accretion rates. We also propos e that the complex molecular outflow field that we have discovered is the result of several other molecular outflows that are possibly assoc iated with the optical jets in this stellar group. We deduce from our data that the current constitution of this group consists of 3.6 M. in gas and 2.0 M. in stars, implying a high star formation efficiency wh ich approaches 36%. We compute the gravitational energy of the core an d find that the HL Tau system probably remains bound in spite of its c urrent outflow activity.