title: Detection of CO and Ethane in Comet 21P/Giacobini-Zinner: Evidence for Variable Chemistry in the Outer Solar Nebula.
abstract: Ethane and carbon monoxide were detected in a short-period comet of probable Kuiper Belt origin. Ethane is substantially less abundant compared with Hyakutake and Hale-Bopp, two comets from the giant-planet region of the solar nebula, suggesting a heliocentric gradient in ethane in precometary ices. It is argued that processing by X-rays from the young Sun may be responsible.
authors.initials: MJ
authors.lastname: Mumma
authors.initials: MA
authors.lastname: DiSanti
authors.lastname: Dello Russo N
authors.initials: K
authors.lastname: Magee-Sauer
authors.initials: TW
authors.lastname: Rettig