Herbig-Haro object

A Herbig-Haro object (HH or HHO) is a small, glowing nebula resulting from the collision of the plasma of a jet from a protostar with the surrounding ISM. They are found on the order of a parsec from the protostar. Sometimes a single such star has two HHs, from opposing jets. They are found in star-forming regions, often near Bok globules.