title: Ethyl alcohol and sugar in comet C/2014 Q2 (Lovejoy).
abstract: The presence of numerous complex organic molecules (COMs; defined as those containing six or more atoms) around protostars shows that star formation is accompanied by an increase of molecular complexity. These COMs may be part of the material from which planetesimals and, ultimately, planets formed. Comets represent some of the oldest and most primitive material in the solar system, including ices, and are thus our best window into the volatile composition of the solar protoplanetary disk. Molecules identified to be present in cometary ices include water, simple hydrocarbons, oxygen, sulfur, and nitrogen-bearing species, as well as a few COMs, such as ethylene glycol and glycine. We report the detection of 21 molecules in comet C/2014 Q2 (Lovejoy), including the first identification of ethyl alcohol (ethanol, C2H5OH) and the simplest monosaccharide sugar glycolaldehyde (CH2OHCHO) in a comet. The abundances of ethanol and glycolaldehyde, respectively 5 and 0.8% relative to methanol (0.12 and 0.02% relative to water), are somewhat higher than the values measured in solar-type protostars. Overall, the high abundance of COMs in cometary ices supports the formation through grain-surface reactions in the solar system protoplanetary disk.
authors.affiliation: LESIA (Laboratoire d'Etudes Spatiales et d'Instrumentation en Astrophysique), Observatoire de Paris, PSL Research University, CNRS, UPMC, Université Paris-Diderot, 5 place Jules Janssen, F-92195 Meudon, France.
authors.forename: Nicolas
authors.initials: N
authors.lastname: Biver
authors.affiliation: LESIA (Laboratoire d'Etudes Spatiales et d'Instrumentation en Astrophysique), Observatoire de Paris, PSL Research University, CNRS, UPMC, Université Paris-Diderot, 5 place Jules Janssen, F-92195 Meudon, France.
authors.forename: Dominique
authors.initials: D
authors.lastname: Bockelée-Morvan
authors.affiliation: LESIA (Laboratoire d'Etudes Spatiales et d'Instrumentation en Astrophysique), Observatoire de Paris, PSL Research University, CNRS, UPMC, Université Paris-Diderot, 5 place Jules Janssen, F-92195 Meudon, France.
authors.forename: Raphaël
authors.initials: R
authors.lastname: Moreno
authors.affiliation: LESIA (Laboratoire d'Etudes Spatiales et d'Instrumentation en Astrophysique), Observatoire de Paris, PSL Research University, CNRS, UPMC, Université Paris-Diderot, 5 place Jules Janssen, F-92195 Meudon, France.
authors.forename: Jacques
authors.initials: J
authors.lastname: Crovisier
authors.affiliation: LESIA (Laboratoire d'Etudes Spatiales et d'Instrumentation en Astrophysique), Observatoire de Paris, PSL Research University, CNRS, UPMC, Université Paris-Diderot, 5 place Jules Janssen, F-92195 Meudon, France.
authors.forename: Pierre
authors.initials: P
authors.lastname: Colom
authors.affiliation: LERMA (Laboratoire d'Etudes du Rayonnement et de la Matière en Astrophysique et Atmosphères), Observatoire de Paris, PSL Research University, CNRS, Sorbonne Universités, UPMC Univ. Paris 06, 61 av. de l'Observatoire, F-75014, Paris, France. ; Cahill Center for Astronomy and Astrophysics 301-17, California Institute of Technology, Pasadena, CA 91125, USA.
authors.forename: Dariusz C
authors.initials: DC
authors.lastname: Lis
authors.affiliation: Stockholm Observatory, AlbaNova University Center, SE-106 91 Stockholm, Sweden.
authors.forename: Aage
authors.initials: A
authors.lastname: Sandqvist
authors.affiliation: IRAM (Institut de Radioastronomie Millimétrique), 300 rue de la Piscine, F-38406 Saint Martin d'Hères, France.
authors.forename: Jérémie
authors.initials: J
authors.lastname: Boissier
authors.affiliation: LAB (Laboratoire d'Astrophysique de Bordeaux), University of Bordeaux, CNRS, UMR 5804, 2 rue de l'Observatoire, F-33271 Floirac, France.
authors.forename: Didier
authors.initials: D
authors.lastname: Despois
authors.affiliation: Astrochemistry Laboratory, NASA Goddard Space Flight Center, Greenbelt, MD 20771, USA.
authors.forename: Stefanie N
authors.initials: SN
authors.lastname: Milam
keywords: astronomy; comets; complex organic molecules; space science