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Thomas IR, Vandaele AC, Robert S, Neefs E, Drummond R, Daerden F, Delanoye S, Ristic B, Berkenbosch S, Clairquin R, Maes J, Bonnewijn S, Depiesse C, Mahieux A, Trompet L, Neary L, Willame Y, Wilque V, Nevejans D, Aballea L, Moelans W, De Vos L, Lesschaeve S, Van Vooren N, Lopez-Moreno JJ, Patel MR, Bellucci G. Optical and radiometric models of the NOMAD instrument part II: the infrared channels - SO and LNO. Opt Express 2016; 24:3790-3805. [PMID: 27333621 DOI: 10.1364/oe.24.003790] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/06/2023]
Abstract
NOMAD is a suite of three spectrometers that will be launched in 2016 as part of the joint ESA-Roscosmos ExoMars Trace Gas Orbiter mission. The instrument contains three channels that cover the IR and UV spectral ranges and can perform solar occultation, nadir and limb observations, to detect and map a wide variety of Martian atmospheric gases and trace species. Part I of this work described the models of the UVIS channel; in this second part, we present the optical models representing the two IR channels, SO (Solar Occultation) and LNO (Limb, Nadir and Occultation), and use them to determine signal to noise ratios (SNRs) for many expected observational cases. In solar occultation mode, both the SO and LNO channel exhibit very high SNRs >5000. SNRs of around 100 were found for the LNO channel in nadir mode, depending on the atmospheric conditions, Martian surface properties, and observation geometry.
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Cessateur G, Keyser JD, Maggiolo R, Gibbons A, Gronoff G, Gunell H, Dhooghe F, Loreau J, Vaeck N, Altwegg K, Bieler A, Briois C, Calmonte U, Combi MR, Fiethe B, Fuselier SA, Gombosi TI, Hässig M, Le Roy L, Neefs E, Rubin M, Sémon T. Photochemistry of forbidden oxygen lines in the inner coma of 67P/Churyumov-Gerasimenko. J Geophys Res Space Phys 2016; 121:804-816. [PMID: 27134807 PMCID: PMC4845638 DOI: 10.1002/2015ja022013] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/07/2015] [Revised: 12/01/2015] [Accepted: 12/24/2015] [Indexed: 06/04/2023]
Abstract
Observations of the green and red-doublet emission lines have previously been realized for several comets. We present here a chemistry-emission coupled model to study the production and loss mechanisms of the O(1S) and O(1D) states, which are responsible for the emission lines of interest for comet 67P/Churyumov-Gerasimenko. The recent discovery of O2 in significant abundance relative to water 3.80 ± 0.85% within the coma of 67P has been taken into consideration for the first time in such models. We evaluate the effect of the presence of O2 on the green to red-doublet emission intensity ratio, which is traditionally used to assess the CO2 abundance within cometary atmospheres. Model simulations, solving the continuity equation with transport, show that not taking O2 into account leads to an underestimation of the CO2 abundance within 67P, with a relative error of about 25%. This strongly suggests that the green to red-doublet emission intensity ratio alone is not a proper tool for determining the CO2 abundance, as previously suggested. Indeed, there is no compelling reason why O2 would not be a common cometary volatile, making revision of earlier assessments regarding the CO2 abundance in cometary atmospheres necessary. The large uncertainties of the CO2 photodissociation cross section imply that more studies are required in order to better constrain the O(1S) and O(1D) production through this mechanism. Space weather phenomena, such as powerful solar flares, could be used as tools for doing so, providing additional information on a good estimation of the O2 abundance within cometary atmospheres.
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Affiliation(s)
- G. Cessateur
- Space Physics DivisionRoyal Belgian Institute for Space AeronomyBrusselsBelgium
| | - J. De Keyser
- Space Physics DivisionRoyal Belgian Institute for Space AeronomyBrusselsBelgium
- Center for Plasma AstrophysicsKatholieke Universiteit LeuvenHeverleeBelgium
| | - R. Maggiolo
- Space Physics DivisionRoyal Belgian Institute for Space AeronomyBrusselsBelgium
| | - A. Gibbons
- Space Physics DivisionRoyal Belgian Institute for Space AeronomyBrusselsBelgium
- Service de Chimie Quantique et PhotophysiqueUniversité Libre de BruxellesBrusselsBelgium
| | - G. Gronoff
- Science Directorate, Chemistry and Dynamics BranchNASA Langley Research CenterHamptonVirginiaUSA
- SSAIHamptonVirginiaUSA
| | - H. Gunell
- Space Physics DivisionRoyal Belgian Institute for Space AeronomyBrusselsBelgium
| | - F. Dhooghe
- Space Physics DivisionRoyal Belgian Institute for Space AeronomyBrusselsBelgium
| | - J. Loreau
- Service de Chimie Quantique et PhotophysiqueUniversité Libre de BruxellesBrusselsBelgium
| | - N. Vaeck
- Service de Chimie Quantique et PhotophysiqueUniversité Libre de BruxellesBrusselsBelgium
| | - K. Altwegg
- Physikalisches InstitutUniversity of BernBernSwitzerland
- Center for Space and HabitabilityUniversity of BernBernSwitzerland
| | - A. Bieler
- Physikalisches InstitutUniversity of BernBernSwitzerland
- Department of Climate and Space Sciences and EngineeringUniversity of MichiganAnn ArborMichiganUSA
| | - C. Briois
- Laboratoire de Physique et Chimie de l'Environnement et de l'EspaceUMR 7328 CNRS, Université dOrléansOrléansFrance
| | - U. Calmonte
- Physikalisches InstitutUniversity of BernBernSwitzerland
| | - M. R. Combi
- Department of Climate and Space Sciences and EngineeringUniversity of MichiganAnn ArborMichiganUSA
| | - B. Fiethe
- Institute of Computer and Network Engineering (IDA)TU BraunschweigBraunschweigGermany
| | - S. A. Fuselier
- Space Science DivisionSouthwest Research InstituteSan AntonioTexasUSA
- Department of Physics and AstronomyUniversity of Texas at San AntonioSan AntonioTexasUSA
| | - T. I. Gombosi
- Department of Climate and Space Sciences and EngineeringUniversity of MichiganAnn ArborMichiganUSA
| | - M. Hässig
- Physikalisches InstitutUniversity of BernBernSwitzerland
- Space Science DivisionSouthwest Research InstituteSan AntonioTexasUSA
| | - L. Le Roy
- Physikalisches InstitutUniversity of BernBernSwitzerland
| | - E. Neefs
- Engineering DivisionRoyal Belgian Institute for Space AeronomyBrusselsBelgium
| | - M. Rubin
- Physikalisches InstitutUniversity of BernBernSwitzerland
| | - T. Sémon
- Physikalisches InstitutUniversity of BernBernSwitzerland
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Hässig M, Altwegg K, Balsiger H, Bar-Nun A, Berthelier JJ, Bieler A, Bochsler P, Briois C, Calmonte U, Combi M, De Keyser J, Eberhardt P, Fiethe B, Fuselier SA, Galand M, Gasc S, Gombosi TI, Hansen KC, Jäckel A, Keller HU, Kopp E, Korth A, Kührt E, Le Roy L, Mall U, Marty B, Mousis O, Neefs E, Owen T, Rème H, Rubin M, Sémon T, Tornow C, Tzou CY, Waite JH, Wurz P. Cometary science. Time variability and heterogeneity in the coma of 67P/Churyumov-Gerasimenko. Science 2015; 347:aaa0276. [PMID: 25613892 DOI: 10.1126/science.aaa0276] [Citation(s) in RCA: 204] [Impact Index Per Article: 22.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/02/2022]
Abstract
Comets contain the best-preserved material from the beginning of our planetary system. Their nuclei and comae composition reveal clues about physical and chemical conditions during the early solar system when comets formed. ROSINA (Rosetta Orbiter Spectrometer for Ion and Neutral Analysis) onboard the Rosetta spacecraft has measured the coma composition of comet 67P/Churyumov-Gerasimenko with well-sampled time resolution per rotation. Measurements were made over many comet rotation periods and a wide range of latitudes. These measurements show large fluctuations in composition in a heterogeneous coma that has diurnal and possibly seasonal variations in the major outgassing species: water, carbon monoxide, and carbon dioxide. These results indicate a complex coma-nucleus relationship where seasonal variations may be driven by temperature differences just below the comet surface.
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Affiliation(s)
- M Hässig
- Physikalisches Institut, University of Bern, Sidlerstrasse 5, CH-3012 Bern, Switzerland. Southwest Research Institute, 6220 Culebra Road, San Antonio, TX 78238, USA.
| | - K Altwegg
- Physikalisches Institut, University of Bern, Sidlerstrasse 5, CH-3012 Bern, Switzerland. Center for Space and Habitability (CSH), University of Bern, Sidlerstrasse 5, CH-3012 Bern, Switzerland
| | - H Balsiger
- Physikalisches Institut, University of Bern, Sidlerstrasse 5, CH-3012 Bern, Switzerland
| | - A Bar-Nun
- Department of Geosciences, Tel-Aviv University, Ramat-Aviv, Tel-Aviv, Israel
| | - J J Berthelier
- Laboratoire Atmosphères, Milieux, Observations Spatiales (LATMOS), Institute Pierre Simon Laplace (IPSL), Centre national de recherche scientifique (CNRS), Université Pierre et Marie Curie (UPMC), Université de Versailles Saint-Quentin-en-Yvelines (UVSQ), BP 102, UPMC, 4 Place Jussieu, F-75252 Paris Cedex 05, France
| | - A Bieler
- Physikalisches Institut, University of Bern, Sidlerstrasse 5, CH-3012 Bern, Switzerland. Department of Atmospheric, Oceanic and Space Sciences, University of Michigan, 2455 Hayward Street, Ann Arbor, MI 48109, USA
| | - P Bochsler
- Physikalisches Institut, University of Bern, Sidlerstrasse 5, CH-3012 Bern, Switzerland
| | - C Briois
- Laboratoire de Physique et Chimie de l'Environnement et de l'Espace (LPC2E), UMR 7328 CNRS - Université d'Orléans, France
| | - U Calmonte
- Physikalisches Institut, University of Bern, Sidlerstrasse 5, CH-3012 Bern, Switzerland
| | - M Combi
- Department of Atmospheric, Oceanic and Space Sciences, University of Michigan, 2455 Hayward Street, Ann Arbor, MI 48109, USA
| | - J De Keyser
- Belgian Institute for Space Aeronomy (BIRA-IASB), Ringlaan 3, B-1180 Brussels, Belgium. Center for Plasma Astrophysics, KULeuven, Celestijnenlaan 200D, 3001 Heverlee, Belgium
| | - P Eberhardt
- Physikalisches Institut, University of Bern, Sidlerstrasse 5, CH-3012 Bern, Switzerland
| | - B Fiethe
- Institute of Computer and Network Engineering (IDA), TU Braunschweig, Hans-Sommer-Straße 66, D-38106 Braunschweig, Germany
| | - S A Fuselier
- Southwest Research Institute, 6220 Culebra Road, San Antonio, TX 78238, USA
| | - M Galand
- Department of Physics, Imperial College London, Prince Consort Road, London SW7 2AZ, UK
| | - S Gasc
- Physikalisches Institut, University of Bern, Sidlerstrasse 5, CH-3012 Bern, Switzerland
| | - T I Gombosi
- Department of Atmospheric, Oceanic and Space Sciences, University of Michigan, 2455 Hayward Street, Ann Arbor, MI 48109, USA
| | - K C Hansen
- Department of Atmospheric, Oceanic and Space Sciences, University of Michigan, 2455 Hayward Street, Ann Arbor, MI 48109, USA
| | - A Jäckel
- Physikalisches Institut, University of Bern, Sidlerstrasse 5, CH-3012 Bern, Switzerland
| | - H U Keller
- Institute for Geophysics and Extraterrestrial Physics, Technische Universität (TU) Braunschweig, 38106 Braunschweig, Germany. German Aerospace Center, Institute of Planetary Research, Asteroids and Comets, Rutherfordstraße 2, 12489 Berlin, Germany
| | - E Kopp
- Physikalisches Institut, University of Bern, Sidlerstrasse 5, CH-3012 Bern, Switzerland
| | - A Korth
- Max-Planck-Institut für Sonnensystemforschung, Justus-von-Liebig-Weg 3, 37077 Göttingen, Germany
| | - E Kührt
- German Aerospace Center, Institute of Planetary Research, Asteroids and Comets, Rutherfordstraße 2, 12489 Berlin, Germany
| | - L Le Roy
- Center for Space and Habitability (CSH), University of Bern, Sidlerstrasse 5, CH-3012 Bern, Switzerland
| | - U Mall
- Max-Planck-Institut für Sonnensystemforschung, Justus-von-Liebig-Weg 3, 37077 Göttingen, Germany
| | - B Marty
- Centre de Recherches Pétrographiques et Géochimiques (CRPG), 15 Rue Notre Dame des Pauvres, BP 20, 54501 Vandoeuvre lès Nancy, France
| | - O Mousis
- Aix Marseille Université, CNRS, LAM (Laboratoire d'Astrophysique de Marseille), UMR 7326, 13388, Marseille, France
| | - E Neefs
- Engineering Division, BIRA-IASB, Ringlaan 3, B-1180 Brussels, Belgium
| | - T Owen
- Institute for Astronomy, University of Hawaii, Honolulu, HI 96822, USA
| | - H Rème
- Université de Toulouse, Université Paul Sabathier (UPS), Observatoire de Midi-Pyrénées (OMP), Institut de Recherche en Astrophysique et Planétologie (IRAP), Toulouse, France. CNRS, IRAP, 9 Avenue du Colonel Roche, BP 44346, F-31028 Toulouse Cedex 4, France
| | - M Rubin
- Physikalisches Institut, University of Bern, Sidlerstrasse 5, CH-3012 Bern, Switzerland
| | - T Sémon
- Physikalisches Institut, University of Bern, Sidlerstrasse 5, CH-3012 Bern, Switzerland
| | - C Tornow
- German Aerospace Center, Institute of Planetary Research, Asteroids and Comets, Rutherfordstraße 2, 12489 Berlin, Germany
| | - C-Y Tzou
- Physikalisches Institut, University of Bern, Sidlerstrasse 5, CH-3012 Bern, Switzerland
| | - J H Waite
- Southwest Research Institute, 6220 Culebra Road, San Antonio, TX 78238, USA
| | - P Wurz
- Physikalisches Institut, University of Bern, Sidlerstrasse 5, CH-3012 Bern, Switzerland
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Bertaux JL, Vandaele AC, Korablev O, Villard E, Fedorova A, Fussen D, Quémerais E, Belyaev D, Mahieux A, Montmessin F, Muller C, Neefs E, Nevejans D, Wilquet V, Dubois JP, Hauchecorne A, Stepanov A, Vinogradov I, Rodin A, Bertaux JL, Nevejans D, Korablev O, Montmessin F, Vandaele AC, Fedorova A, Cabane M, Chassefière E, Chaufray JY, Dimarellis E, Dubois JP, Hauchecorne A, Leblanc F, Lefèvre F, Rannou P, Quémerais E, Villard E, Fussen D, Muller C, Neefs E, Van Ransbeeck E, Wilquet V, Rodin A, Stepanov A, Vinogradov I, Zasova L, Forget F, Lebonnois S, Titov D, Rafkin S, Durry G, Gérard JC, Sandel B. A warm layer in Venus' cryosphere and high-altitude measurements of HF, HCl, H2O and HDO. Nature 2008; 450:646-9. [PMID: 18046397 DOI: 10.1038/nature05974] [Citation(s) in RCA: 146] [Impact Index Per Article: 9.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2007] [Accepted: 05/22/2007] [Indexed: 11/09/2022]
Abstract
Venus has thick clouds of H2SO4 aerosol particles extending from altitudes of 40 to 60 km. The 60-100 km region (the mesosphere) is a transition region between the 4 day retrograde superrotation at the top of the thick clouds and the solar-antisolar circulation in the thermosphere (above 100 km), which has upwelling over the subsolar point and transport to the nightside. The mesosphere has a light haze of variable optical thickness, with CO, SO2, HCl, HF, H2O and HDO as the most important minor gaseous constituents, but the vertical distribution of the haze and molecules is poorly known because previous descent probes began their measurements at or below 60 km. Here we report the detection of an extensive layer of warm air at altitudes 90-120 km on the night side that we interpret as the result of adiabatic heating during air subsidence. Such a strong temperature inversion was not expected, because the night side of Venus was otherwise so cold that it was named the 'cryosphere' above 100 km. We also measured the mesospheric distributions of HF, HCl, H2O and HDO. HCl is less abundant than reported 40 years ago. HDO/H2O is enhanced by a factor of approximately 2.5 with respect to the lower atmosphere, and there is a general depletion of H2O around 80-90 km for which we have no explanation.
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Affiliation(s)
- Jean-Loup Bertaux
- Service d'Aéronomie du CNRS/IPSL, Verrières-le-Buisson 91371, France.
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