title: Detection of acetylene in the infrared spectrum of comet Hyakutake.
abstract: Comets are rich in volatile materials, of which roughly 80% (by number) are water molecules. Considerable progress is being made in identifying the other volatile species, the abundances of which should enable us to determine whether comets formed primarily from ice-covered interstellar grains, or from material that was chemically processed in the early solar nebula. Here we report the detection of acetylene (C2H2) in the infrared spectrum of comet C/1996 B2 (Hyakutake). The estimated abundance is 0.3-0.9%, relative to water, which is comparable to the predicted solid-phase abundance in cold interstellar clouds. This suggests that the volatiles in comet Hyakotake may have come from ice-covered interstellar grains, rather than material processed in the accretion disk out of which the Solar System formed.
authors.affiliation: Jet Propulsion Laboratory, Pasadena, California 91109, USA.
authors.forename: T Y
authors.initials: TY
authors.lastname: Brooke
authors.forename: A T
authors.initials: AT
authors.lastname: Tokunaga
authors.forename: H A
authors.initials: HA
authors.lastname: Weaver
authors.forename: J
authors.initials: J
authors.lastname: Crovisier
authors.forename: D
authors.initials: D
authors.lastname: Bockelée-Morvan
authors.forename: D
authors.initials: D
authors.lastname: Crisp
mesh_terms: D000114:Acetylene / Q000032:analysis*; D019443:Cosmic Dust; D005118:Extraterrestrial Environment; D019110:Meteoroids; D013055:Spectrophotometry, Infrared
chemical_list: D019443:Cosmic Dust; D000114:Acetylene