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51. Sub-millimeter observation of water vapor at 557GHz in Comet C/2002 T7 (LINEAR)

Author

Jacques Crovisier, Samuel Gulkis, Lucas Kamp, Margaret A. Frerking, Nicolas Biver, Mathieu Choukroun, Dominique Bockelée-Morvan, Stephen Keihm, Michael Janssen, Seungwon Lee, Mark Hofstadter, Paul von Allmen, Department of Materials Science and Engineering, Faculty of Engineering, Kyushu University, Fukuoka (DMS), Kyushu University [Fukuoka], Laboratoire d'études spatiales et d'instrumentation en astrophysique (LESIA), Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université Paris Diderot - Paris 7 (UPD7)-Centre National de la Recherche Scientifique (CNRS), Jet Propulsion Laboratory (JPL), NASA-California Institute of Technology (CALTECH), and Kyushu University

Subjects
Physics, [PHYS]Physics [physics], Comet, Rotational transition, Astronomy, Astronomy and Astrophysics, Radius, Astrophysics, 7. Clean energy, Full width at half maximum, Outgassing, 13. Climate action, Space and Planetary Science, Emission spectrum, [PHYS.ASTR]Physics [physics]/Astrophysics [astro-ph], Water vapor, ComputingMilieux_MISCELLANEOUS, Line (formation)
Abstract

We present sub-millimeter observations of the ground-state rotational transition (110–101) of water vapor from Comet C/2002 T7 (LINEAR) obtained with the MIRO instrument on the ESA Rosetta spacecraft (s/c) orbiter on April 30, 2004. At the time of the observations, the comet was at a distance of 0.63 AU from the Sun, 0.68 AU from the MIRO telescope, and about 7.5 days after its perihelion. The ground state rotation transition of ortho-water at 556.936 GHz was observed and integrated for ∼8 h using a frequency switched radiometer to provide short and long term stability. The MIRO beam size is 7.5 arcmin in terms of full width half maximum, corresponding to a radius of 1.1 × 105 km at the comet location. The observed signal line area of the water line spectrum is 4.3 ± 0.8 K km/s. Using a molecular excitation and radiation transfer model and assuming the spherically symmetric and constant radial expansion of gas in the coma, we estimate that the production rate of water is (1.0 ± 0.2) × 1030 molecules/s and the expansion velocity is 1.1 ± 0.2 km/s at the time of the MIRO observation. The present estimation of the water outgassing rate of the comet is in good agreement with other observation-based estimations when the outgassing rates with respect to the time after perihelion are compared. The Doppler-corrected center velocity of the observed line was red-shifted by 0.67 ± 0.13 km/s, of which only 0.18 km/s shift is explained by the model and attributed to a self-absorption effect. The potential sources of the additional red shift are discussed.

Published
2014
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52. [Untitled]

Author

R. N. Martin, Paul Hartogh, Joseph P. McMullin, W. L. Peters, Mark Hofstadter, and Christopher Jarchow

Subjects
Physics, Planetary science, Space and Planetary Science, Short Term Variability, Comet, Earth and Planetary Sciences (miscellaneous), Astronomy, Astronomy and Astrophysics, Coma (optics), Spatial variability, sense organs, Comet Hale–Bopp
Abstract

We observed submillimeter lines of H2CO and HCN in comet Hale-Bopp near perihelion. One of our goals was to search for short term variability. Our observations are suggestive, but not conclusive, of temporal and/or spatial changes in the coma's HCN/H2CO abundance ratio of ∼25%. If due to spatial variability, the ratio on the sunward side of the coma is enhanced over other regions. If due to temporal variability, we find the bulk ratio in the coma changed in less than 16 hours.

Published
1997
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53. Continuum and spectroscopic observations of asteroid (21) Lutetia at millimeter and submillimeter wavelengths with the MIRO instrument on the Rosetta spacecraft

Author

Thomas R. Spilker, L. W. Kamp, Stephen Keihm, Wing-Huen Ip, M. A. Janssen, Jacques Crovisier, Gerard Beaudin, N. Biver, Peter Schloerb, Emmanuel Lellouch, P. Encrenaz, Mark Hofstadter, Ingrid Mann, P. von Allmen, Samuel Gulkis, T. Encrenaz, C. Backus, Paul Hartogh, Paul R. Weissman, Sukhan Lee, Dominique Bockelée-Morvan, Laboratoire d'études spatiales et d'instrumentation en astrophysique (LESIA), Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université Paris Diderot - Paris 7 (UPD7)-Centre National de la Recherche Scientifique (CNRS), Laboratoire d'Etude du Rayonnement et de la Matière en Astrophysique (LERMA), École normale supérieure - Paris (ENS-PSL), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université de Cergy Pontoise (UCP), Université Paris-Seine-Université Paris-Seine-Centre National de la Recherche Scientifique (CNRS), and École normale supérieure - Paris (ENS Paris)

Subjects
Physics, [PHYS]Physics [physics], Radiometer, 010504 meteorology & atmospheric sciences, Spacecraft, business.industry, Northern Hemisphere, Astronomy, Astronomy and Astrophysics, 01 natural sciences, Regolith, 13. Climate action, Space and Planetary Science, Asteroid, 0103 physical sciences, Millimeter, business, [PHYS.ASTR]Physics [physics]/Astrophysics [astro-ph], 010303 astronomy & astrophysics, Southern Hemisphere, ComputingMilieux_MISCELLANEOUS, 0105 earth and related environmental sciences, Exosphere
Abstract

The European Space Agency's Rosetta spacecraft made a close flyby of asteroid (21) Lutetia on July 10, 2010. The spacecraft carries a dual-band radiometer/spectrometer instrument, named MIRO, which operates at 190 GHz (1.6 mm) and 560 GHz (0.5 mm). During the flyby, the MIRO instrument measured the temperature of Lutetia in both the northern and southern hemispheres. At the time of the flyby, the northern hemisphere was seasonally sun-lit and warmer than the southern hemisphere. Subsurface (depths from ∼2 mm to ∼2 cm) temperatures ranged from ∼200 K on the northern hemisphere to ∼60 K on the southern hemisphere. A lunar-like regolith – very low thermal inertia

Published
2012
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54. Uranus Pathfinder: exploring the origins and evolution of Ice Giant planets

Author

Abigail Rymer, S. Kemble, Elias Roussos, Sebastien Hess, Benoît Noyelles, Imke de Pater, Nick Sergis, Glyn Collinson, Stas Barabash, Ravit Helled, Jared Leisner, Chris S. Arridge, Nicholas A Teanby, Baptiste Cecconi, Andy F. Cheng, Norbert Krupp, Andrew Bacon, Joachim Saur, Yves Langevin, Andrew Fazakerley, Steve Miller, Jaques Gustin, Matthew S. Tiscareno, Christopher T. Russell, Mathieu Barthelemy, Nadine Nettelmann, Richard Holme, Philippe Zarka, Ingo Müller-Wodarg, Apostolos A. Christou, Andrew J. Coates, Robert Ebert, Thomas P. Andert, Olivier Mousis, Sandrine Vinatier, Paul M. Schenk, Gerald Schubert, Laurent Lamy, Michael Guest, Craig B. Agnor, Régis Courtin, Daniel Gautier, Jan-Erik Wahlund, Cesar Bertucci, Ulrich R. Christensen, Pontus Brandt, Javier Martin-Torres, Adam Masters, Don Banfield, Silvia Tellmann, Elizabeth P. Turtle, Matthew M. Hedman, Frank Sohl, Mark Hofstadter, Leigh N. Fletcher, Özgür Karatekin, Chris Paranicas, Kunio M. Sayanagi, Nicolas André, Agustín Sánchez-Lavega, Tom Stallard, Kevin H. Baines, Eric Quémerais, Martin Pätzold, Supriya Chakrabarti, Marina Galand, L. Peacocke, Pierre Henri, John F. Cooper, Gabriel Tobie, Marta Entradas, Nicholas Achilleos, Michele K. Dougherty, Renée Prangé, C. P. Chaloner, Henrik Melin, Geraint H. Jones, Jonathan J. Fortney, Edward C. Sittler, Mullard Space Science Laboratory (MSSL), University College of London [London] (UCL), School of Physics and Astronomy [London], Queen Mary University of London (QMUL), Centre d'étude spatiale des rayonnements (CESR), Université Toulouse III - Paul Sabatier (UT3), Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire Midi-Pyrénées (OMP), Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS), Jet Propulsion Laboratory (JPL), NASA-California Institute of Technology (CALTECH), Department of Atmospheric, Oceanic and Planetary Physics [Oxford] (AOPP), University of Oxford [Oxford], Laboratoire d'études spatiales et d'instrumentation en astrophysique (LESIA), Centre National de la Recherche Scientifique (CNRS)-Université Paris Diderot - Paris 7 (UPD7)-Observatoire de Paris, PSL Research University (PSL)-PSL Research University (PSL)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Pierre et Marie Curie - Paris 6 (UPMC), Institut d'astrophysique spatiale (IAS), Université Paris-Sud - Paris 11 (UP11)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS), Univers, Transport, Interfaces, Nanostructures, Atmosphère et environnement, Molécules (UMR 6213) (UTINAM), Université de Franche-Comté (UFC)-Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS), University of Rostock [Germany], Institute of Geophysics and Planetary Physics [Los Angeles] (IGPP), University of California [Los Angeles] (UCLA), University of California-University of California, Department of Physics and Astronomy [Leicester], University of Leicester, Cornell University, Laboratoire de Planétologie et Géodynamique UMR6112 (LPG), Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Université de Nantes - Faculté des Sciences et des Techniques, Université de Nantes (UN)-Université de Nantes (UN)-Université d'Angers (UA), Astrium [Stevenage], EADS - European Aeronautic Defense and Space, Department of Physics and Astronomy [UCL London], Universität der Bundeswehr München [Neubiberg], Swedish Institute of Space Physics [Uppsala] (IRF), Institut de Planétologie et d'Astrophysique de Grenoble (IPAG), Centre National d'Études Spatiales [Toulouse] (CNES)-Université Grenoble Alpes (UGA)-Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire des Sciences de l'Univers de Grenoble (OSUG), Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry])-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP)-Institut national de recherche en sciences et technologies pour l'environnement et l'agriculture (IRSTEA)-Université Joseph Fourier - Grenoble 1 (UJF)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Université Grenoble Alpes (UGA)-Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry])-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP)-Institut national de recherche en sciences et technologies pour l'environnement et l'agriculture (IRSTEA)-Université Joseph Fourier - Grenoble 1 (UJF)-Centre National de la Recherche Scientifique (CNRS), Instituto de Astronomía y Física del Espacio [Buenos Aires] (IAFE), Universidad de Buenos Aires [Buenos Aires] (UBA)-Consejo Nacional de Investigaciones Científicas y Técnicas [Buenos Aires] (CONICET), Johns Hopkins University Applied Physics Laboratory [Laurel, MD] (APL), Center for Space Physics [Boston] (CSP), Boston University [Boston] (BU), Max Planck Institute for Solar System Research (MPS), Max-Planck-Gesellschaft, Armagh Observatory [Armagh], NASA Goddard Space Flight Center (GSFC), Blackett Laboratory, Imperial College London, Southwest Research Institute [San Antonio] (SwRI), Department of Science and Technology Studies [London] (STS), University of California [Santa Cruz] (UCSC), University of California, Laboratoire de Physique Atmosphérique et Planétaire (LPAP), Université de Liège, Department of Earth and Space Sciences [Los Angeles], University of Colorado [Boulder], School of Environmental Sciences [Liverpool], University of Liverpool, Royal Observatory of Belgium [Brussels], University of Iowa [Iowa City], Centro de Astrobiologia [Madrid] (CAB), Instituto Nacional de Técnica Aeroespacial (INTA)-Consejo Superior de Investigaciones Científicas [Spain] (CSIC), Space Research Centre [Leicester], Fondation Universitaire Notre Dame de la Paix (FUNDP), Facultés Universitaires Notre-Dame de la Paix, Institut de Mécanique Céleste et de Calcul des Ephémérides (IMCCE), Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, PSL Research University (PSL)-PSL Research University (PSL)-Université de Lille-Centre National de la Recherche Scientifique (CNRS), Department of Astronomy [Berkeley], University of California [Berkeley], Rhenish Institute for Environmental Research (RIU), University of Cologne, HEPPI - LATMOS, Laboratoire Atmosphères, Milieux, Observations Spatiales (LATMOS), Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS), University of the Basque Country/Euskal Herriko Unibertsitatea (UPV/EHU), Institute for Geophysics and Meteorology [Köln] (IGM), Lunar and Planetary Institute [Houston] (LPI), Office for Space Research and Applications [Athens], Academy of Athens, DLR Institute of Planetary Research, German Aerospace Center (DLR), School of Earth Sciences [Bristol], University of Bristol [Bristol], Université de Toulouse (UT)-Université de Toulouse (UT)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire Midi-Pyrénées (OMP), Institut de Recherche pour le Développement (IRD)-Université Toulouse III - Paul Sabatier (UT3), Université de Toulouse (UT)-Université de Toulouse (UT)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Météo-France -Institut de Recherche pour le Développement (IRD)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Météo-France -Centre National de la Recherche Scientifique (CNRS), University of Oxford, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université Paris Diderot - Paris 7 (UPD7)-Centre National de la Recherche Scientifique (CNRS), Université Paris-Sud - Paris 11 (UP11)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Centre National d’Études Spatiales [Paris] (CNES), Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Université de Franche-Comté (UFC), Université Bourgogne Franche-Comté [COMUE] (UBFC)-Université Bourgogne Franche-Comté [COMUE] (UBFC), University of Rostock, University of California (UC)-University of California (UC), Cornell University [New York], Laboratoire de Planétologie et Géodynamique [UMR 6112] (LPG), Université d'Angers (UA)-Université de Nantes - UFR des Sciences et des Techniques (UN UFR ST), Université de Nantes (UN)-Université de Nantes (UN)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS), Institut de Planétologie et d'Astrophysique de Grenoble (IPAG ), Observatoire des Sciences de l'Univers de Grenoble (OSUG), Université Joseph Fourier - Grenoble 1 (UJF)-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP )-Institut national des sciences de l'Univers (INSU - CNRS)-Institut national de recherche en sciences et technologies pour l'environnement et l'agriculture (IRSTEA)-Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry])-Centre National de la Recherche Scientifique (CNRS)-Université Joseph Fourier - Grenoble 1 (UJF)-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP )-Institut national des sciences de l'Univers (INSU - CNRS)-Institut national de recherche en sciences et technologies pour l'environnement et l'agriculture (IRSTEA)-Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry])-Centre National de la Recherche Scientifique (CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS), Consejo Nacional de Investigaciones Científicas y Técnicas [Buenos Aires] (CONICET)-Universidad de Buenos Aires [Buenos Aires] (UBA), Max-Planck-Institut für Sonnensystemforschung = Max Planck Institute for Solar System Research (MPS), University of California [Santa Cruz] (UC Santa Cruz), University of California (UC), Royal Observatory of Belgium [Brussels] (ROB), Instituto Nacional de Técnica Aeroespacial (INTA)-Consejo Superior de Investigaciones Científicas [Madrid] (CSIC), Facultés Universitaires Notre Dame de la Paix (FUNDP), University of California [Berkeley] (UC Berkeley), HELIOS - LATMOS, Observatoire Midi-Pyrénées (OMP), Météo France-Centre National d'Études Spatiales [Toulouse] (CNES)-Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Météo France-Centre National d'Études Spatiales [Toulouse] (CNES)-Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Toulouse III - Paul Sabatier (UT3), Université Fédérale Toulouse Midi-Pyrénées, California Institute of Technology (CALTECH)-NASA, Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Observatoire des Sciences de l'Univers de Grenoble (OSUG), Université Joseph Fourier - Grenoble 1 (UJF)-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP )-Institut national des sciences de l'Univers (INSU - CNRS)-Institut national de recherche en sciences et technologies pour l'environnement et l'agriculture (IRSTEA)-Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry])-Centre National de la Recherche Scientifique (CNRS)-Université Joseph Fourier - Grenoble 1 (UJF)-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP )-Institut national des sciences de l'Univers (INSU - CNRS)-Institut national de recherche en sciences et technologies pour l'environnement et l'agriculture (IRSTEA)-Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry])-Centre National de la Recherche Scientifique (CNRS), Consejo Superior de Investigaciones Científicas [Madrid] (CSIC)-Instituto Nacional de Técnica Aeroespacial (INTA), Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Observatoire Midi-Pyrénées (OMP), Universität der Bundeswehr München [Neubiberg] = Bundeswehr University, Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry])-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP)-Institut national de recherche en sciences et technologies pour l'environnement et l'agriculture (IRSTEA)-Université Joseph Fourier - Grenoble 1 (UJF)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Université Grenoble Alpes (UGA)-Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry])-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP)-Institut national de recherche en sciences et technologies pour l'environnement et l'agriculture (IRSTEA)-Université Joseph Fourier - Grenoble 1 (UJF)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Université Grenoble Alpes (UGA)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS), Consejo Superior de Investigaciones Científicas [Spain] (CSIC)-Instituto Nacional de Técnica Aeroespacial (INTA), Centre National de la Recherche Scientifique (CNRS)-Université de Lille-Observatoire de Paris, Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ), Mullard Space Science Laboratory ( MSSL ), University College of London [London] ( UCL ), Queen Mary University of London ( QMUL ), Centre d'étude spatiale des rayonnements ( CESR ), Université Paul Sabatier - Toulouse 3 ( UPS ) -Institut national des sciences de l'Univers ( INSU - CNRS ) -Observatoire Midi-Pyrénées ( OMP ) -Centre National de la Recherche Scientifique ( CNRS ), Jet Propulsion Laboratory ( JPL ), NASA-California Institute of Technology ( CALTECH ), Department of Atmospheric, Oceanic and Planetary Physics [Oxford] ( AOPP ), Laboratoire d'études spatiales et d'instrumentation en astrophysique ( LESIA ), Université Pierre et Marie Curie - Paris 6 ( UPMC ) -Institut national des sciences de l'Univers ( INSU - CNRS ) -Observatoire de Paris-Université Paris Diderot - Paris 7 ( UPD7 ) -Centre National de la Recherche Scientifique ( CNRS ), Institut d'astrophysique spatiale ( IAS ), Université Paris-Sud - Paris 11 ( UP11 ) -Institut national des sciences de l'Univers ( INSU - CNRS ) -Centre National de la Recherche Scientifique ( CNRS ), Univers, Transport, Interfaces, Nanostructures, Atmosphère et environnement, Molécules ( UTINAM ), Institut national des sciences de l'Univers ( INSU - CNRS ) -Centre National de la Recherche Scientifique ( CNRS ) -Université de Franche-Comté ( UFC ), Institute of Geophysics and Planetary Physics [Los Angeles] ( IGPP ), University of California at Los Angeles [Los Angeles] ( UCLA ), Laboratoire de Planétologie et Géodynamique de Nantes ( LPGN ), Université de Nantes ( UN ) -Institut national des sciences de l'Univers ( INSU - CNRS ) -Centre National de la Recherche Scientifique ( CNRS ), Swedish Institute of Space Physics [Uppsala] ( IRF ), Institut de Planétologie et d'Astrophysique de Grenoble ( IPAG ), Observatoire des Sciences de l'Univers de Grenoble ( OSUG ), Université Joseph Fourier - Grenoble 1 ( UJF ) -Institut national des sciences de l'Univers ( INSU - CNRS ) -Centre National de la Recherche Scientifique ( CNRS ) -Université Grenoble Alpes ( UGA ) -Université Joseph Fourier - Grenoble 1 ( UJF ) -Institut national des sciences de l'Univers ( INSU - CNRS ) -Centre National de la Recherche Scientifique ( CNRS ) -Université Grenoble Alpes ( UGA ) -Centre National de la Recherche Scientifique ( CNRS ), Instituto de Astronomia y Fisica del Espacio ( IAFE ), Consejo Nacional de Investigaciones Científicas y Técnicas ( CONICET ) -Universidad de Buenos Aires [Buenos Aires], Johns Hopkins University Applied Physics Laboratory [Laurel, MD] ( APL ), Center for Space Physics [Boston] ( CSP ), Boston University [Boston] ( BU ), Max Planck Institute for Solar System Research ( MPS ), NASA Goddard Space Flight Center ( GSFC ), Southwest Research Institute [San Antonio] ( SwRI ), Department of Science and Technology Studies [London] ( STS ), University of California [Santa Cruz] ( UCSC ), Laboratoire de Physique Atmosphérique et Planétaire ( LPAP ), University of Colorado Boulder [Boulder], University of Iowa [Iowa], Centro de Astrobiologia [Madrid] ( CAB ), Instituto Nacional de Técnica Aeroespacial ( INTA ) -Consejo Superior de Investigaciones Científicas [Spain] ( CSIC ), Fondation Universitaire Notre Dame de la Paix ( FUNDP ), Institut de Mécanique Céleste et de Calcul des Ephémérides ( IMCCE ), Université Pierre et Marie Curie - Paris 6 ( UPMC ) -Institut national des sciences de l'Univers ( INSU - CNRS ) -Observatoire de Paris-Université de Lille-Centre National de la Recherche Scientifique ( CNRS ), Astronomy Department [Berkeley], Rhenish Institute for Environmental Research ( RIU ), Laboratoire Atmosphères, Milieux, Observations Spatiales ( LATMOS ), Université de Versailles Saint-Quentin-en-Yvelines ( UVSQ ) -Université Pierre et Marie Curie - Paris 6 ( UPMC ) -Institut national des sciences de l'Univers ( INSU - CNRS ) -Centre National de la Recherche Scientifique ( CNRS ) -Université de Versailles Saint-Quentin-en-Yvelines ( UVSQ ) -Université Pierre et Marie Curie - Paris 6 ( UPMC ) -Institut national des sciences de l'Univers ( INSU - CNRS ) -Centre National de la Recherche Scientifique ( CNRS ), University of the Basque Country/Euskal Herriko Unibertsitatea ( UPV/EHU ), Institute for Geophysics and Meteorology [Köln] ( IGM ), Lunar and Planetary Institute [Houston] ( LPI ), and German Aerospace Center ( DLR )

Subjects
Solar System, 010504 meteorology & atmospheric sciences, [PHYS.ASTR.EP]Physics [physics]/Astrophysics [astro-ph]/Earth and Planetary Astrophysics [astro-ph.EP], Ciencias Físicas, Uranus, [SDU.ASTR.EP]Sciences of the Universe [physics]/Astrophysics [astro-ph]/Earth and Planetary Astrophysics [astro-ph.EP], interior, Natural satellite, 7. Clean energy, 01 natural sciences, Astrobiology, Ice Giant, Orbiter, Neptune, Planet, 0103 physical sciences, 010303 astronomy & astrophysics, ICE GIANT, 0105 earth and related environmental sciences, Physics, [PHYS]Physics [physics], natural satellite, ice giants, Nice model, Giant planet atmosphere, Astronomy, Astronomy and Astrophysics, Planetary system, [ SDU.ASTR.EP ] Sciences of the Universe [physics]/Astrophysics [astro-ph]/Earth and Planetary Astrophysics [astro-ph.EP], Ring system, Dynamo, Astronomía, [ PHYS.ASTR.EP ] Physics [physics]/Astrophysics [astro-ph]/Earth and Planetary Astrophysics [astro-ph.EP], URANUS, 13. Climate action, Space and Planetary Science, Exploration of Uranus, Magnetosphere, GIANT PLANET ATMOSPHERE, [PHYS.ASTR]Physics [physics]/Astrophysics [astro-ph], ORBITER, CIENCIAS NATURALES Y EXACTAS, Ice giant
Abstract

The “Ice Giants” Uranus and Neptune are a different class of planet compared to Jupiter and Saturn. Studying these objects is important for furthering our understanding of the formation and evolution of the planets, and unravelling the fundamental physical and chemical processes in the Solar System. The importance of filling these gaps in our knowledge of the Solar System is particularly acute when trying to apply our understanding to the numerous planetary systems that have been discovered around other stars. The Uranus Pathfinder (UP) mission thus represents the quintessential aspects of the objectives of the European planetary community as expressed in ESA’s Cosmic Vision 2015–2025. UP was proposed to the European Space Agency’s M3 call for medium-class missions in 2010 and proposed to be the first orbiter of an Ice Giant planet. As the most accessible Ice Giant within the M-class mission envelope Uranus was identified as the mission target. Although not selected for this call the UP mission concept provides a baseline framework for the exploration of Uranus with existing low-cost platforms and underlines the need to develop power sources suitable for the outer Solar System. The UP science case is based around exploring the origins, evolution, and processes at work in Ice Giant planetary systems. Three broad themes were identified: (1) Uranus as an Ice Giant, (2) An Ice Giant planetary system, and (3) An asymmetric magnetosphere. Due to the long interplanetary transfer from Earth to Uranus a significant cruise-phase science theme was also developed. The UP mission concept calls for the use of a Mars Express/Rosetta-type platform to launch on a Soyuz–Fregat in 2021 and entering into an eccentric polar orbit around Uranus in the 2036–2037 timeframe. The science payload has a strong heritage in Europe and beyond and requires no significant technology developments. Fil: Arridge, Christopher S.. University College London; Estados Unidos Fil: Agnor, Craig B.. Queen Mary University of London; Reino Unido Fil: Andre, Nicolas. Centre National de la Recherche Scientifique; Francia Fil: Baines, Kevin H.. National Aeronautics And Space Administration; Estados Unidos Fil: Fletcher, Leigh N.. University of Oxford; Reino Unido Fil: Gautier, Daniel. Centre National de la Recherche Scientifique. Observatoire de Paris; Francia Fil: Hofstadter, Mark D.. National Aeronautics And Space Administration; Estados Unidos Fil: Jones, Geraint H.. University College London; Estados Unidos Fil: Lamy, Laurent. Centre National de la Recherche Scientifique. Observatoire de Paris; Francia Fil: Langevin, Yves. Centre National de la Recherche Scientifique; Francia Fil: Mousis, Olivier. Centre National de la Recherche Scientifique; Francia Fil: Nettelmann, Nadine. Universitat Rostock; Alemania Fil: Russell, Christopher T.. University of California at Los Angeles; Estados Unidos Fil: Stallard, Tom. University of Leicester; Reino Unido Fil: Tiscareno, Matthew S.. Cornell University; Estados Unidos Fil: Tobie, Gabriel. Centre de Recherche de Nantes; Francia Fil: Bacon, Andrew. Systems Engineering and Asssessment Ltd; Reino Unido Fil: Chaloner, Chris. Systems Engineering and Asssessment Ltd; Reino Unido Fil: Guest, Michael. Systems Engineering and Asssessment Ltd; Reino Unido Fil: Kemble, Steve. Astrium; Reino Unido Fil: Peacocke, Lisa. Astrium; Reino Unido Fil: Achilleos, Nicholas. University College London; Estados Unidos Fil: Andert, Thomas P.. Universität der Bundeswehr; Alemania Fil: Banfield, Don. Cornell University; Estados Unidos Fil: Barabash, Stas. Sweden Institute of Space Physics; Suecia Fil: Barthelemy, Matthieu. Universite Joseph Fourier; Francia Fil: Bertucci, Cesar. Consejo Nacional de Investigaciónes Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Instituto de Astronomía y Física del Espacio. - Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Instituto de Astronomía y Física del Espacio; Argentina Fil: Brandt, Pontus. University Johns Hopkins; Estados Unidos Fil: Cecconi, Baptiste. Centre National de la Recherche Scientifique. Observatoire de Paris; Francia Fil: Chakrabarti, Supriya. Boston University; Estados Unidos

Published
2012
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55. DSS-28: a novel wide bandwidth radio telescope devoted to educational outreach

Author

Sander Weinreb, G. Jones, William A. Imbriale, John G. Leflang, Lawrence Teitelbaum, Hamdi Mani, Mark Hofstadter, Thomas B. H. Kuiper, R. Dorcey, Stephen D Smith, Stepp, Larry M., Gilmozzi, Roberto, and Hall, Helen J.

Subjects
Physics, Digital signal processor, business.industry, Amplifier, Bandwidth (signal processing), Electrical engineering, Astrophysics::Instrumentation and Methods for Astrophysics, law.invention, Radio telescope, Telescope, Optics, law, Baseband, Goldstone Deep Space Communications Complex, business, Radio astronomy
Abstract

We have recently equipped the 34-meter DSS-28 radio telescope at the Goldstone Deep Space Communications Complex with a novel wide bandwidth radiometer and digital signal processor as part of the Goldstone Apple Valley Radio Telescope (GAVRT) educational outreach program operated by the Jet Propulsion Laboratory and the Lewis Center for Educational Research. The system employs a cryogenically cooled wide bandwidth quad-ridge feed and InP low noise amplifiers to achieve excellent noise performance from 2.7 to 14 GHz; a fractional bandwidth better than 4:1. Four independently tunable dual-polarization receivers each down-convert a 2 GHz block to baseband, providing access to 8 GHz of instantaneous bandwidth. A flexible FPGA-based signal processor has been constructed using CASPER FPGA hardware and tools to take advantage of this enormous bandwidth. This system demonstrates many of the enabling wide bandwidth technologies that will be crucial to maximizing the utility of future large centimeter-wavelength arrays, in particular the Square Kilometer Array. The GAVRT program has previously used narrow bandwidth total power radiometers to study flux variability of quasars and the outer planets. The versatility of DSS-28 will enable other projects including spectroscopy and SETI. Finally, the wide instantaneous bandwidth available makes this system uniquely suited for studying transient radio pulses. A configuration of the digital signal processor has been developed which provides the capability of recording a burst of raw baseband voltage data triggered by a real-time incoherent dedispersion system which is very sensitive to pulses from a known source, such as the Crab Nebula pulsar.

Published
2010

56. Ice sublimation and rheology: Implications for the Martian polar layered deposits

Author

Bruce C. Murray and Mark Hofstadter

Subjects
Martian, Space and Planetary Science, Coulee, Stratification (water), Astronomy and Astrophysics, Sublimation (phase transition), Martian polar ice caps, Surface layer, Mars Exploration Program, Petrology, Duricrust, Geology, Astrobiology
Abstract

It has been suggested that the Martian polar layered deposits are composed largely of water ice. If true, then sublimation and deformation creep of the ice are important processes. Simple models indicate that sublimation will occur at a rate inconsistent with current estimates of the deposit's age and Viking observations of the atmospheric water abundance, suggesting that when considering the formation, evolution, and structure of the deposits, one must include a mechanism by which sublimation is inhibited. A surface layer of dust seems the most likely possibility. Additionally, over the age of the deposits, flows of at least 1 km are expected. At Viking resolution (⩾150 m) no obvious flow features are observed. Assuming that Martian features would be similar to those that occur on the Earth, this limits the maximum flow rates possible and suggest the deposits need to be more than 90% ice or less than about 40% ice by volume. The Mars Observer spacecraft will be able to constrain the ice abundance further by both searching for flow features and clarifying the nature of the deposit's surface and near surface.

Published
1990
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57. Vertical motions in the Uranian atmosphere: an analysis of radio observations

Author

Duane O. Muhleman, Mark Hofstadter, and Glenn L. Berge

Subjects
Atmosphere, Wavelength, Infrared astronomy, Opacity, Space and Planetary Science, Atmospheric circulation, Uranus, Astronomy, Astronomy and Astrophysics, Span (engineering), Geology, Latitude
Abstract

The present, 6-cm radio map of Uranus indicates latitudinal features which may be due to vertical motions of the atmosphere. It appears in light of Voyager IR measurements as well as previously obtained radio data that these large-scale vertical motions, which have not undergone significant changes over the course of 8 years, extend from the 0.1- to the 45-bar levels; this span corresponds to a height of the order of 250 km. The latitudinal structures are believed to be primarily caused by horizontal variations of absorber abundances.

Published
1990
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58. Observations of deep convective clouds as stable reflected light standard for climate research: AIRS evaluation

Author

Hartmut H. Aumann, Mark Hofstadter, and Thomas S. Pagano

Subjects
Sunlight, Meteorology, Brightness temperature, Cloud cover, Atmospheric Infrared Sounder, Calibration, Environmental science, Physical oceanography, Radiometric calibration, Latitude, Remote sensing
Abstract

Changes of the order of 1%/decade or less are expected in the tropical ocean cloud amount due to global warming. Since the ocean is very dark in the visible and near infrared region of the spectrum, a change in the Earth reflectance is equivalent to a measure of the change in the cloud cover. A reliable measurement of such a small change in the visible requires a reference source which is much more stable than 1%/decade. A procedure is developed to use the sunlight reflected from Deep Convective Clouds (DCC) as a stable and readily available reference source for reflected light channels. The procedure uses the stability of the NIST traceable infrared radiometric calibration of the Atmospheric Infrared Sounder (AIRS) to create a stable DCC detection threshold, which assures a stable visible reflected reference signal. DCC are identified in the data as any IR footprint within ±30 degree latitude, where the brightness temperature in the 1231 cm -1 window channel is 210K or less. The 90%tile value of the observed visible signal is used as reference to minimize the effect of under-filling the footprint. Typically 2000 DCC are identified each day during the daylight part of the orbit. The stability uncertainty in the DCC reference signal measured from the first four years of AIRS data is 0.02%/year, i.e. 0.2%/decade. The stability of the procedure demonstrated with AIRS is thus already better than the 1%/decade expected change in the cloud amount due to global warming. Extrapolated from four years to the expected 12 year lifetime of AIRS the trend uncertainty on the DCC measurements should decrease to 0.06%/decade. A 12 year record of the Earth reflectance stabilized with the DCC would allow for a very sensitive test of a change in the cloud amount. AIRS was launched on the EOS Aqua spacecraft in May 2002 into a 705 km polar sun-synchronous orbit with accurately maintained 1:30 PM ascending node. Essentially un-interrupted data are freely available since September 2002. The DCC are included in the AIRS Calibration Data Subset (ACDS).

Published
2007
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59. Remote sensing of a comet at millimeter and submillimeter wavelengths from an orbiting spacecraft

Author

Mark Hofstadter, Gerard Beaudin, T. Koch, M. A. Janssen, Margaret A. Frerking, C. Backus, Emmanuel Lellouch, Nicolas Biver, Paul Hartogh, Mark Allen, Wing Ip, Duane O. Muhleman, Heike Rauer, L. W. Kamp, Ingrid Mann, Dominique Bockelée-Morvan, Jacques Crovisier, Samuel Gulkis, Peter Schloerb, Thomas R. Spilker, Didier Despois, Pierre Encrenaz, Physical Chemistry, Laboratoire d'études spatiales et d'instrumentation en astrophysique (LESIA), Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université Paris Diderot - Paris 7 (UPD7)-Centre National de la Recherche Scientifique (CNRS), Laboratoire d'astrodynamique, d'astrophysique et d'aéronomie de bordeaux (L3AB), Université Sciences et Technologies - Bordeaux 1-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS), Observatoire aquitain des sciences de l'univers (OASU), Laboratoire d'Astrophysique de Bordeaux [Pessac] (LAB), Université de Bordeaux (UB)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS), and Université Sciences et Technologies - Bordeaux 1 (UB)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)

Subjects
Comet, 67P/Churyumov–Gerasimenko, 02 engineering and technology, 01 natural sciences, 7. Clean energy, law.invention, Telescope, [PHYS.ASTR.CO]Physics [physics]/Astrophysics [astro-ph]/Cosmology and Extra-Galactic Astrophysics [astro-ph.CO], Orbiter, Optics, law, MIRO, Spacecraft instruments, 0103 physical sciences, Rosetta, 0202 electrical engineering, electronic engineering, information engineering, Comets, Spectral resolution, 010303 astronomy & astrophysics, Remote sensing, Physics, Radiometer, Spectrometer, [SDU.ASTR]Sciences of the Universe [physics]/Astrophysics [astro-ph], business.industry, Parabolic reflector, Astronomy, 020206 networking & telecommunications, Astronomy and Astrophysics, Space and Planetary Science, Millimeter, Submillimeter spectroscopy, business, millimeter spectrometer
Abstract

The ESA Rosetta Spacecraft, launched on March 2, 2004 with the ultimate destination being Comet 67P/Churyumov–Gerasimenko, carries a relatively small and lightweight millimeter–submillimeter spectrometer instrument, the first of its kind launched into deep space. The instrument, named Microwave Instrument for the Rosetta Orbiter (MIRO), consists of a 30-cm diameter, offset parabolic reflector telescope, which couples energy in the millimeter and submillimeter bands to two heterodyne receivers. Center-band operating frequencies are near 190 GHz (1.6 mm) and 562 GHz (0.5 mm). Broadband, total power continuum measurements can be made in both bands. A 4096-channel spectrometer with 44 kHz resolution is connected to the submillimeter receiver. The spectral resolution is sufficient to observe individual, thermally broadened spectral lines ( T ⩾10 K). The submillimeter radiometer/spectrometer is fixed tuned to measure four volatile species—CO, CH 3 OH, NH 3 and three isotopes of water, H 2 16 O, H 2 17 O and H 2 18 O. The MIRO experiment will use these species as probes of the physical conditions within the nucleus and coma. The basic quantities measured by MIRO are surface temperature, gas production rates and relative abundances, and velocity and excitation temperature of each species, along with their spatial and temporal variability. This information will be used to infer coma structure and outgassing processes, including the nature of the nucleus/coma interface.

Published
2007
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60. MIRO: Microwave Instrument for Rosetta Orbiter

Author

T. Koch, Margaret A. Frerking, Peter Schloerb, W-H. Ip, Christopher Jarchow, Paul Hartogh, E. Lellouch, Y. Salinas, Duane O. Muhleman, Dominique Bockelée-Morvan, Th. Encrenaz, R. Nowicki, N. Biver, E. Steinmetz, Mark Allen, A. Deschamps, Samuel Gulkis, P. J. Encrenaz, Didier Despois, Jacques Crovisier, J. M. Krieg, Heike Rauer, L. W. Kamp, Mark Hofstadter, M. A. Janssen, R. Irigoyen, Thomas R. Spilker, Ingrid Mann, Gerard Beaudin, P. C. Stek, M. Gheudin, C. Kahn, C. Backus, Laboratoire d'astrodynamique, d'astrophysique et d'aéronomie de bordeaux (L3AB), Université Sciences et Technologies - Bordeaux 1-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS), Observatoire aquitain des sciences de l'univers (OASU), Laboratoire d'Astrophysique de Bordeaux [Pessac] (LAB), and Université de Bordeaux (UB)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)

Subjects
010504 meteorology & atmospheric sciences, Comet, 01 natural sciences, law.invention, [PHYS.ASTR.CO]Physics [physics]/Astrophysics [astro-ph]/Cosmology and Extra-Galactic Astrophysics [astro-ph.CO], Telescope, Orbiter, Optics, law, MIRO, 0103 physical sciences, Rosetta, comets, 010303 astronomy & astrophysics, 0105 earth and related environmental sciences, Physics, Radiometer, [SDU.ASTR]Sciences of the Universe [physics]/Astrophysics [astro-ph], Spacecraft, Spectrometer, business.industry, Parabolic reflector, Astronomy and Astrophysics, submillimeter spectroscopy, Space and Planetary Science, Asteroid, business, spacecraft instruments
Abstract

The European Space Agency Rosetta Spacecraft, launched on March 2, 2004 toward Comet 67P/Churyumov-Gerasimenko, carries a relatively small and lightweight millimeter-submillimeter spectrometer instrument, the first of its kind launched into deep space. The instrument will be used to study the evolution of outgassing water and other molecules from the target comet as a function of heliocentric distance. During flybys of the asteroids (2867) Steins and (21) Lutetia in 2008 and 2010 respectively, the instrument will measure thermal emission and search for water vapor in the vicinity of these asteroids. The instrument, named MIRO (Microwave Instrument for the Rosetta Orbiter), consists of a 30-cm diameter, offset parabolic reflector telescope followed by two heterodyne receivers. Center-band operating frequencies of the receivers are near 190 GHz (1.6 mm) and 562 GHz (0.5 mm). Broadband continuum channels are implemented in both frequency bands for the measurement of near surface temperatures and temperature gradients in Comet 67P/Churyumov-Gerasimenko and the asteroids (2867) Steins and (21) Lutetia. A 4096 channel CTS (Chirp Transform Spectrometer) spectrometer having 180 MHz total bandwidth and 44 kHz resolution is, in addition to the continuum channel, connected to the submillimeter receiver. The submillimeter radiometer/spectrometer is fixed tuned to measure four volatile species – CO, CH3OH, NH3 and three, oxygen-related isotopologues of water, H2 16O, H2 17O and H2 18O. The basic quantities measured with the MIRO instrument are surface temperature, gas production rates and relative abundances, and velocity and excitation temperature of each species, along with their spatial and temporal variability. This paper provides a short discussion of the scientific objectives of the investigation, and a detailed discussion of the MIRO instrument system.

Published
2007
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61. MIRO observations of subsurface temperatures of the nucleus of 67P/Churyumov-Gerasimenko

Author

Gerard Beaudin, Mathieu Choukroun, Christopher Jarchow, Nicolas Biver, Holger Sierks, Paul Hartogh, H. U. Keller, Mark Hofstadter, F. Peter Schloerb, Samuel Gulkis, Dominique Bockelée-Morvan, C. Leyrat, Stephen Keihm, Michael Janssen, Pierre Encrenaz, Jacques Crovisier, Robert Gaskell, Paul von Allmen, Wing-Huen Ip, Laurent Jorda, Emmanuel Lellouch, Ladislav Rezac, Seungwon Lee, Jet Propulsion Laboratory (JPL), NASA-California Institute of Technology (CALTECH), Laboratoire d'études spatiales et d'instrumentation en astrophysique (LESIA), Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université Paris Diderot - Paris 7 (UPD7)-Centre National de la Recherche Scientifique (CNRS), Laboratoire d'Etude du Rayonnement et de la Matière en Astrophysique (LERMA), École normale supérieure - Paris (ENS-PSL), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université de Cergy Pontoise (UCP), Université Paris-Seine-Université Paris-Seine-Centre National de la Recherche Scientifique (CNRS), Max-Planck-Institut für Sonnensystemforschung = Max Planck Institute for Solar System Research (MPS), Max-Planck-Gesellschaft, Institute of Astronomy [Taiwan] (IANCU), National Central University [Taiwan] (NCU), Laboratoire d'Astrophysique de Marseille (LAM), Aix Marseille Université (AMU)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS), Institut für Geophysik und Extraterrestrische Physik [Braunschweig] (IGEP), Technische Universität Braunschweig = Technical University of Braunschweig [Braunschweig], German Aerospace Center (DLR), École normale supérieure - Paris (ENS Paris), Max Planck Institute for Solar System Research (MPS), and Max-Planck-Institut für Sonnensystemforschung (MPS)

Subjects
Physics, Brightness, Astronomy and Astrophysics, Astrophysics, Latitude, law.invention, Orbiter, Wavelength, medicine.anatomical_structure, [SDU]Sciences of the Universe [physics], 13. Climate action, Space and Planetary Science, law, Brightness temperature, medicine, Sublimation (phase transition), Astrophysics::Earth and Planetary Astrophysics, [PHYS.ASTR]Physics [physics]/Astrophysics [astro-ph], Nucleus, Astrophysics::Galaxy Astrophysics, Microwave
Abstract

International audience; Observations of the nucleus of 67P/Churyumov-Gerasimenko in the millimeter-wave continuum have been obtained by the Microwave Instrument for the Rosetta Orbiter (MIRO). We present data obtained at wavelengths of 0.5 mm and 1.6 mm during September 2014 when the nucleus was at heliocentric distances between 3.45 and 3.27 AU. The data are fit to simple models of the nucleus thermal emission in order to characterize the observed behavior and make quantitative estimates of important physical parameters, including thermal inertia and absorption properties at the MIRO wavelengths. MIRO brightness temperatures on the irregular surface of 67P are strongly affected by the local solar illumination conditions, and there is a strong latitudinal dependence of the mean brightness temperature as a result of the seasonal orientation of the comet's rotation axis with respect to the Sun. The MIRO emission exhibits strong diurnal variations, which indicate that it arises from within the thermally varying layer in the upper centimeters of the surface. The data are quantitatively consistent with very low thermal inertia values, between 10-30 JK(-1) m(-2) s(-1/2), with the 0.5 mm emission arising from 1 cm beneath the surface and the 1.6 mm emission from a depth of 4 cm. Although the data are generally consistent with simple, homogeneous models, it is difficult to match all of its features, suggesting that there may be some vertical structure within the upper few centimeters of the surface. The MIRO brightness temperatures at high northern latitudes are consistent with sublimation of ice playing an important role in setting the temperatures of these regions where, based on observations of gas and dust production, ice is known to be sublimating.

Published
2015
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62. Dark side of comet 67P/Churyumov-Gerasimenko in Aug.–Oct. 2014

Author

Wing-Huen Ip, Laurent Jorda, Christopher Jarchow, F. P. Schloerb, Holger Sierks, C. Leyrat, Pierre Encrenaz, Samuel Gulkis, Jacques Crovisier, M. A. Janssen, Mark Hofstadter, Emmanuel Lellouch, P. von Allmen, B. Gaskell, Sukhan Lee, Mathieu Choukroun, Paul Hartogh, Horst Uwe Keller, N. Biver, Dominique Bockelée-Morvan, Stephen Keihm, Ladislav Rezac, Gerard Beaudin, Laboratoire d'Astrophysique de Marseille (LAM), and Aix Marseille Université (AMU)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)

Subjects
Physics, Brightness, [SDU.ASTR]Sciences of the Universe [physics]/Astrophysics [astro-ph], Polar night, Astronomy, Astronomy and Astrophysics, Astrophysics, law.invention, Orbiter, 13. Climate action, Space and Planetary Science, law, Highly porous, Thermal, Radiative transfer, Polar, Millimeter
Abstract

International audience; The high obliquity (similar to 50 degrees) of comet 67P/Churyumov-Gerasimenko (67P) is responsible for a long-lasting winter polar night in the southern regions of the nucleus. We report observations made with the submillimeter and millimeter continuum channels of the Microwave Instrument onboard the Rosetta Orbiter (MIRO) of the thermal emission from these regions during the period August-October 2014. Before these observations, the southern polar regions had been in darkness for approximately five years. Subsurface temperatures in the range 25 50 K are measured. Thermal model calculations of the nucleus near-surface temperatures carried out over the orbit of 67P, coupled with radiative transfer calculations of the MIRO channels brightness temperatures, suggest that these regions have a thermal inertia within the range 10-60 Jm(-2) K-1 s(-0.5). Such low thermal inertia values are consistent with a highly porous, loose, regolith-like surface. These values are similar to those derived elsewhere on the nucleus. A large difference in the brightness temperatures measured by the two MIRO continuum channels is tentatively attributed to dielectric properties that differ significantly from the sunlit side, within the first few tens of centimeters. This is suggestive of the presence of ice(s) within the MIRO depths of investigation in the southern polar regions. These regions started to receive sunlight in May of 2015, and refinements of the shape model in these regions, as well as continuing MIRO observations of 67P, will allow refining these results and reveal the thermal properties and potential ice content of the southern regions in more detail.

Published
2015
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63. On-board calibration techniques and test results for the Atmospheric Infrared Sounder (AIRS)

Author

Hartmut H. Aumann, Margaret H. Weiler, Thomas S. Pagano, Denise Hagan, Kenneth Overoye, Steven E. Broberg, Thomas Hearty, Mark Hofstadter, and Steven L. Gaiser

Subjects
Spacecraft, Black body, business.industry, Infrared, Atmospheric Infrared Sounder, Near-infrared spectroscopy, Calibration, Environmental science, Orbital mechanics, business, Water vapor, Remote sensing
Abstract

The Atmospheric Infrared Sounder (AIRS) is a space based instrument developed for measurement of global atmospheric properties; primarily water vapor and temperature. AIRS is one of several instruments on board NASA's Earth Observing System Aqua spacecraft. AIRS operates in the 3.7 - 15.4 micron region and has 2378 infrared channels and 4 Vis/NIR channels. AIRS spatial resolution is 13.5 km from the orbit of 705 km and it scans ±49.5 degrees. AIRS has a set of on-board calibrators including a single infrared blackbody source, a parylene spectral calibration source, a space view and a Vis/NIR photometric calibrator. The on-board calibration subsystems are described along with a description of special test procedures for using them and results from several tests performed to date. Results are exceptional indicating that the instrument is performing better than expected.

Published
2002
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64. Exploring Uranus

Author

Laurent Lamy and Mark Hofstadter

Subjects
History, Uranus, General Earth and Planetary Sciences, Astronomy, Astrobiology
Published
2014
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65. Infrared Low-Cloud Detection

Author

Mark Hofstadter and Andrew Heidinger

Abstract

Traditional infrared cloud retrieval algorithms, such as the Chahine method or the CO2 Slicing technique (Chahine 1974, Smith 1968), rely on recognizing the temperature difference between the ground and the cloud tops. For a low-cloud, however, the temperature difference is small, making it indistinguishable from the surface. As part of our work for the Atmospheric Infrared Sounder (AIRS), to be flown on the EOS-PM platform, we are developing an improved technique for the detection of low-clouds. It is based upon observations of the depth of narrow water vapor lines in an atmospheric window region. Compared to traditional methods, there is an extra factor (the water vapor amount) making the signal from a cloudy column different than that from a clear column, which increases our sensitivity to low-clouds.

Published
1997
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66. Latitudinal variations of ammonia in the atmosphere of Uranus: An analysis of microwave observations

Author

Mark Hofstadter and Duane O. Muhleman

Subjects
Atmosphere, Wavelength, Materials science, Space and Planetary Science, Limb darkening, Brightness temperature, Uranus, Mixing ratio, Astronomy, Astronomy and Astrophysics, Atmosphere of Uranus, Astrophysics, Latitude
Abstract

A 2-cm wavelength VLA map of Uranus is found upon analysis to display strong limb darkening and a lack of symmetry about the subearth point, perhaps due to a latitudinally varying NH3 mixing ratio. The change in NH3 abundance occurs near -45 deg latitude, and the calculated NH3 molar mixing ratios in the 5-20 bar region average 4.9 + or - 0.7 x 10 to the -7th at -90 to -45 deg latitudes, and 1.3 + or - 0.4 x 10 to the -6th at -45 to -15 deg latitudes. The model is in agreement both with previous work indicating the depletion of ammonia relative to solar abundance and a preliminary analysis of 6-cm data.

Published
1989
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67. Future Missions to the Giant Planets that Can Advance Atmospheric Science Objectives

Author

Diego Turrini, Adam Masters, Chris S. Arridge, Leigh N. Fletcher, Amy Simon, Mark Hofstadter, and The Royal Society

Subjects
Engineering, 010504 meteorology & atmospheric sciences, Gas giant, Astronomy & Astrophysics, 01 natural sciences, Space exploration, law.invention, Astrobiology, Orbiter, law, Planet, 0201 Astronomical and Space Sciences, 0103 physical sciences, Astrophysics::Solar and Stellar Astrophysics, 010303 astronomy & astrophysics, 0105 earth and related environmental sciences, Spacecraft, business.industry, Astrophysics::Instrumentation and Methods for Astrophysics, Giant planet, Astronomy and Astrophysics, Planetary science, 13. Climate action, Space and Planetary Science, Physics::Space Physics, Astrophysics::Earth and Planetary Astrophysics, business, Ice giant
Abstract

Other papers in this special issue have discussed the diversity of planetary atmospheres and some of the key science questions for giant planet atmospheres to be addressed in the future. There are crucial measurements that can only be made by orbiters of giant planets and probes dropped into their atmospheres. To help the community be more effective developers of missions and users of data products, we summarize how NASA and ESA categorize their planetary space missions, and the restrictions and requirements placed on each category. We then discuss the atmospheric goals to be addressed by currently approved giant-planet missions as well as missions likely to be considered in the next few years, such as a joint NASA/ESA Ice Giant orbiter with atmospheric probe. Our focus is on interplanetary spacecraft, but we acknowledge the crucial role to be played by ground-based and near-Earth telescopes, as well as theoretical and laboratory work.

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