Jets from young stars - The case of R Monocerotis

Abstract

Both components of a highly collimated bipolar outflow from the young star R Mon have been discovered, using the 2.2-m telescope of the Calar Alto Observatory (CAO). The reciprocal dispersion of the Cassegrain spectrograph was 26 A per mm near H-alpha with a resolution correponding to about 100 km/s. A coude spectrogram was also obtained with a p.a. of 350 deg through R Mon. The S II line emission regions at 6716 and 6731 A are situated in narrow extensions on the opposite sides of R Mon along a line joining R Mon and HH 39. The situation indicates that outflow to HH 39 is still occurring. The velocities measured for the two flow regions are -74 (+ or 10 km/s), and 168 (+ or - 10 km/s), respectively. It is argued that the flow collimation occurs within 2000 AU from the star.