title: Cometary science. Subsurface properties and early activity of comet 67P/Churyumov-Gerasimenko.
abstract: Heat transport and ice sublimation in comets are interrelated processes reflecting properties acquired at the time of formation and during subsequent evolution. The Microwave Instrument on the Rosetta Orbiter (MIRO) acquired maps of the subsurface temperature of comet 67P/Churyumov-Gerasimenko, at 1.6 mm and 0.5 mm wavelengths, and spectra of water vapor. The total H2O production rate varied from 0.3 kg s(-1) in early June 2014 to 1.2 kg s(-1) in late August and showed periodic variations related to nucleus rotation and shape. Water outgassing was localized to the "neck" region of the comet. Subsurface temperatures showed seasonal and diurnal variations, which indicated that the submillimeter radiation originated at depths comparable to the diurnal thermal skin depth. A low thermal inertia (~10 to 50 J K(-1) m(-2) s(-0.5)), consistent with a thermally insulating powdered surface, is inferred.
authors.affiliation: Jet Propulsion Laboratory/California Institute of Technology, 4800 Oak Grove Drive, Pasadena, CA 91109, USA. samuel.gulkis@jpl.nasa.gov.
authors.forename: Samuel
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authors.lastname: Gulkis
authors.affiliation: Jet Propulsion Laboratory/California Institute of Technology, 4800 Oak Grove Drive, Pasadena, CA 91109, USA.
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authors.affiliation: Jet Propulsion Laboratory/California Institute of Technology, 4800 Oak Grove Drive, Pasadena, CA 91109, USA.
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authors.affiliation: LERMA, Observatoire de Paris, PSL Research University, UPMC Université Paris 06, CNRS, UMR8112, F-75014 Paris, France.
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authors.affiliation: LESIA-Observatoire de Paris, CNRS, UPMC, Université Paris-Diderot, 5 place Jules Janssen, 92195 Meudon, France.
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authors.affiliation: LESIA-Observatoire de Paris, CNRS, UPMC, Université Paris-Diderot, 5 place Jules Janssen, 92195 Meudon, France.
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authors.affiliation: Jet Propulsion Laboratory/California Institute of Technology, 4800 Oak Grove Drive, Pasadena, CA 91109, USA.
authors.forename: Mathieu
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authors.lastname: Choukroun
authors.affiliation: LESIA-Observatoire de Paris, CNRS, UPMC, Université Paris-Diderot, 5 place Jules Janssen, 92195 Meudon, France.
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authors.affiliation: Department of Physics and Astronomy, Uppsala University, Box 516, SE-75120 Uppsala, Sweden.
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authors.affiliation: LERMA, Observatoire de Paris, PSL Research University, UPMC Université Paris 06, CNRS, UMR8112, F-75014 Paris, France.
authors.forename: Pierre
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authors.affiliation: LESIA-Observatoire de Paris, CNRS, UPMC, Université Paris-Diderot, 5 place Jules Janssen, 92195 Meudon, France.
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authors.lastname: Encrenaz
authors.affiliation: Jet Propulsion Laboratory/California Institute of Technology, 4800 Oak Grove Drive, Pasadena, CA 91109, USA.
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authors.affiliation: Max-Planck-Institut für Sonnensystemforschung, Justus-von-Liebig-Weg 3, 37077 Göttingen, Germany.
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authors.affiliation: Jet Propulsion Laboratory/California Institute of Technology, 4800 Oak Grove Drive, Pasadena, CA 91109, USA.
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authors.affiliation: National Central University, Jhongli, Taoyuan City 32001, Taiwan.
authors.forename: Wing-Huen
authors.initials: WH
authors.lastname: Ip
authors.affiliation: Jet Propulsion Laboratory/California Institute of Technology, 4800 Oak Grove Drive, Pasadena, CA 91109, USA.
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authors.lastname: Janssen
authors.affiliation: Max-Planck-Institut für Sonnensystemforschung, Justus-von-Liebig-Weg 3, 37077 Göttingen, Germany.
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authors.affiliation: Jet Propulsion Laboratory/California Institute of Technology, 4800 Oak Grove Drive, Pasadena, CA 91109, USA.
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authors.affiliation: Jet Propulsion Laboratory/California Institute of Technology, 4800 Oak Grove Drive, Pasadena, CA 91109, USA.
authors.forename: Seungwon
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authors.affiliation: LESIA-Observatoire de Paris, CNRS, UPMC, Université Paris-Diderot, 5 place Jules Janssen, 92195 Meudon, France.
authors.forename: Emmanuel
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authors.affiliation: LESIA-Observatoire de Paris, CNRS, UPMC, Université Paris-Diderot, 5 place Jules Janssen, 92195 Meudon, France.
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authors.affiliation: Max-Planck-Institut für Sonnensystemforschung, Justus-von-Liebig-Weg 3, 37077 Göttingen, Germany.
authors.forename: Ladislav
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authors.lastname: Rezac
authors.affiliation: University of Massachusetts, 619 Lederle Graduate Research Tower, Amherst, MA 01003, USA. Jet Propulsion Laboratory/California Institute of Technology, 4800 Oak Grove Drive, Pasadena, CA 91109, USA.
authors.forename: F Peter
authors.initials: FP
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authors.affiliation: Jet Propulsion Laboratory/California Institute of Technology, 4800 Oak Grove Drive, Pasadena, CA 91109, USA.
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authors.lastname: Spilker