Velocity-resolved observations of water in Comet Halley

An infrared spectrum of comet Halley was recorded at the NASA Kuiper Airborne Observatory with an instrumental velocity resolution of 1.1 km s^-1. A total of thirteen emission lines in the 2.65 μm spectral region were assigned to neutral gaseous H₂O: ten in the 001-000 band and three in the "hot" 011-010 band. The positions and widths of these lines are functions of the gas velocity field in the coma. Provisional analysis indicates that the neutral gas outflow is widely dispersed about the nucleus. This spectroscopic picture is consistent with spacecraft images that show multiple jets releasing material into most of the Sunfacing hemisphere.