Star formation in Bok globules and low-mass clouds. IV. Herbig-Haro objects in B335.

An Hα emission knot, discovered by Vrba et al. (1986) in the Bok globule B335, is here confirmed as a bona fide Herbig-Haro object, HH 119B. In addition, two more HH objects have been found, all of which form a highly collimated HH complex emanating from the embedded far-infrared source. The axis of the HH-flow coincides with that of the molecular outflow. HH 119B is a low-excitation object, whereas HH 119A, formed as a bow shock further away from the source, has higher excitation. Both are located in the red lobe of the molecular outflow. HH 119C is situated near the opposite edge of the Bok globule, in the blue lobe of the outflow. The proper motions of HH 119B and C have been measured, and show that the Herbig-Haro objects move away from the source in opposite directions along the bipolar molecular outflow with a velocity of about 200 km s^-1, at an assumed distance of 250 pc. This chain of HH-objects suggests that the embedded energy-source has experienced several outbursts, the most recent of which were approximately 350 and 850 years ago. The authors relate these outbursts to FU Orionis type eruptions due to accretion events in a circumstellar disk.