title: The presence of clathrates in comet 67P/Churyumov-Gerasimenko.
abstract: Cometary nuclei are considered to most closely reflect the composition of the building blocks of our solar system. As such, comets carry important information about the prevalent conditions in the solar nebula before and after planet formation. Recent measurements of the time variation of major and minor volatile species in the coma of the Jupiter family comet 67P/Churyumov-Gerasimenko (67P) by the ROSINA (Rosetta Orbiter Spectrometer for Ion and Neutral Analysis) instrument onboard Rosetta provide insight into the possible origin of this comet. The observed outgassing pattern indicates that the nucleus of 67P contains crystalline ice, clathrates, and other ices. The observed outgassing is not consistent with gas release from an amorphous ice phase with trapped volatile gases. If the building blocks of 67P were formed from crystalline ices and clathrates, then 67P would have agglomerated from ices that were condensed and altered in the protosolar nebula closer to the Sun instead of more pristine ices originating from the interstellar medium or the outskirts of the disc, where amorphous ice may dominate.
authors.affiliation: Department of Space Research, Southwest Research Institute, 6220 Culebra Road, San Antonio, TX 78238, USA.
authors.forename: Adrienn
authors.identifier: 0000-0002-7744-246X
authors.initials: A
authors.lastname: Luspay-Kuti
authors.affiliation: Aix Marseille Université, CNRS, LAM (Laboratoire d'Astrophysique de Marseille), UMR 7326, 13388 Marseille, France.
authors.forename: Olivier
authors.initials: O
authors.lastname: Mousis
authors.affiliation: Department of Space Research, Southwest Research Institute, 6220 Culebra Road, San Antonio, TX 78238, USA.; Physikalisches Institut, University of Bern, Sidlerstrasse 5, CH-3012 Bern, Switzerland.
authors.forename: Myrtha
authors.initials: M
authors.lastname: Hässig
authors.affiliation: Department of Space Research, Southwest Research Institute, 6220 Culebra Road, San Antonio, TX 78238, USA.; Department of Physics and Astronomy, University of Texas at San Antonio, 1 UTSA Circle, San Antonio, TX 78249, USA.
authors.forename: Stephen A
authors.identifier: 0000-0003-4101-7901
authors.initials: SA
authors.lastname: Fuselier
authors.affiliation: Cornell Center for Astrophysics and Planetary Science, Space Sciences Building Cornell University, Ithaca, NY 14853, USA.
authors.forename: Jonathan I
authors.initials: JI
authors.lastname: Lunine
authors.affiliation: CRPG-CNRS, Nancy-Université, 15 rue Notre Dame des Pauvres, 54501 Vandoeuvre-lès-Nancy, France.
authors.forename: Bernard
authors.initials: B
authors.lastname: Marty
authors.affiliation: Department of Space Research, Southwest Research Institute, 6220 Culebra Road, San Antonio, TX 78238, USA.; Department of Physics and Astronomy, University of Texas at San Antonio, 1 UTSA Circle, San Antonio, TX 78249, USA.
authors.forename: Kathleen E
authors.identifier: 0000-0001-8397-3315
authors.initials: KE
authors.lastname: Mandt
authors.affiliation: Physikalisches Institut, University of Bern, Sidlerstrasse 5, CH-3012 Bern, Switzerland.; Center for Space and Habitability, University of Bern, CH-3012 Bern, Switzerland.
authors.forename: Peter
authors.initials: P
authors.lastname: Wurz
authors.affiliation: Physikalisches Institut, University of Bern, Sidlerstrasse 5, CH-3012 Bern, Switzerland.
authors.forename: Martin
authors.identifier: 0000-0001-6549-3318
authors.initials: M
authors.lastname: Rubin
mesh_terms: D005118:Extraterrestrial Environment; D007053:Ice / Q000032:analysis*; D019110:Meteoroids; D016083:Planets; D016082:Solar System; D013729:Terpenes / Q000737:chemistry / Q000302:isolation & purification*
chemical_list: D007053:Ice; D013729:Terpenes; C575039:clathric acid
keywords: Space science; comets