Jets from young stars.

The discovery of four jetlike emission-line nebulosities associated with DG Tau, DG Tau B, HH 30, and HL Tau, and the confirmation of the IRS 5 jet in L1551 are reported. All these jets have typical lengths of 2-4 x 10 to the 16th cm and small opening angles of 5 deg-10 deg. The observations strongly suggest that these jets are due to a highly collimated mass outflow. Their collimation must take place at distances smaller than 3 x 10 to the 15th cm from the jet sources. Many CO outflows observed near low to medium luminosity sources (0.1-100 solar luminosities) may be driven by jets, similar to the newly discovered ones.