title: Evolution of the outgassing of comet Hale-Bopp (C/1995 O1) from radio observations.
abstract: Spectra obtained from ground-based radio telescopes show the progressive release of CO, CH3OH, HCN, H2O (from OH), H2S, CS, H2CO, CH3CN, and HNC as comet Hale-Bopp (C/1995 01) approached the sun from 6.9 to 1.4 astronomical units (AU). The more volatile species were relatively more abundant in the coma far from the sun, but there was no direct correlation between overabundance and volatility. Evidence for H2O sublimation from icy grains was seen beyond 3.5 AU from the sun. The change from a CO-driven coma to an H2O-driven coma occurred at about 3 AU. The gas outflow velocity and temperature increased as Hale-Bopp approached the sun.
authors.affiliation: Observatoire de Paris-Meudon, F-92195 Meudon, France.
authors.forename: N
authors.initials: N
authors.lastname: Biver
authors.forename: D
authors.initials: D
authors.lastname: Bockelée-Morvan
authors.forename: P
authors.initials: P
authors.lastname: Colom
authors.forename: J
authors.initials: J
authors.lastname: Crovisier
authors.forename: J K
authors.initials: JK
authors.lastname: Davies
authors.forename: W R
authors.initials: WR
authors.lastname: Dent
authors.forename: D
authors.initials: D
authors.lastname: Despois
authors.forename: E
authors.initials: E
authors.lastname: Gérard
authors.forename: E
authors.initials: E
authors.lastname: Lellouch
authors.forename: H
authors.initials: H
authors.lastname: Rauer
authors.forename: R
authors.initials: R
authors.lastname: Moreno
authors.forename: G
authors.initials: G
authors.lastname: Paubert
mesh_terms: D002244:Carbon / Q000032:analysis; D002248:Carbon Monoxide / Q000032:analysis; D019443:Cosmic Dust; D005740:Gases; D006859:Hydrogen / Q000032:analysis; D007053:Ice; D019110:Meteoroids; D000432:Methanol / Q000032:analysis; D009584:Nitrogen / Q000032:analysis; D013057:Spectrum Analysis; D013696:Temperature; D014867:Water
chemical_list: D019443:Cosmic Dust; D005740:Gases; D007053:Ice; D014867:Water; D002244:Carbon; D002248:Carbon Monoxide; D006859:Hydrogen; D009584:Nitrogen; D000432:Methanol