Herbig-Haro object in the constellation Orion
HH 222, (also known as the Waterfall Nebula and Orion Streamers),[1] is a prominent Herbig–Haro object located in the Orion molecular cloud complex. It is characterized by its elongated, cascade-like structure resembling a flowing waterfall, formed by ionized gas streams interacting with surrounding molecular clouds.[3][2][4][5]
HH 222 is a giant, curved filament of shocked gas, stretching in a sinuous path that evokes the appearance of cascading water. The structure converges toward a bright, non-thermal radio source in its upper left region, with fainter parallel streams enhancing the waterfall illusion. Spectroscopic analysis reveals high-velocity outflows, indicative of shock fronts where material reaches speeds of hundreds of km/s.[6][7][8]
The nebula is embedded in a dusty environment, with the surrounding L1641 cloud obscuring parts of its extent in optical wavelengths. Infrared and radio observations have been crucial for mapping its full morphology and kinematics.[8]
HH 222 is classified as a giant Herbig–Haro flow, arising from collimated outflows ejected by young, low-mass stars during their protostellar phase. Detailed studies in 2013 identified its origin in the quadruple star system V380 Orionis, a multiple system of young stars approximately 0.3 parsecs from the nebula's head.[8]
