HH 111

HH 111 is a Herbig-Haro object in the L1617 dark cloud of the Orion B molecular cloud in the constellation of Orion. It is a prototype of a highly collimated optical jet sources. It shows several bow shocks and has a length of about 2.6 light-years (0.8 parsec).

HH 111 is about 1300 light years (400 parsec) distant from earth and the central source is IRAS 05491+0247, also called VLA 1. This source is the driving source of the jets and it is a class I protostar with a luminosity of about 25. This protostar is embedded in a 30 cloud core. The dynamical age of the complex is only 800 years. Near the central source an ammonia feature called NH3-S was found, which is a starless core with a turbulent interior induced by HH 111.

The jets move with a speed of 300 - 600 km/s and consist of a blueshifted component, which is bright in optical wavelengths and a redshifted faint counterjet. A second pair of bipolar jets, called HH 121 was discovered in the near-infrared at an angle of 61° compared to the HH 111 pair. This was taken as evidence for a system with multiple protostars.