planets and satellites: atmospheres; planets and satellites: individual: Neptune; planets and satellites: composition; techniques: spectroscopic
Abstract :
[en] We report on the initial analysis of a Herschel-PACS full range spectrum of Neptune, covering the 51-220 μm range with a mean resolving power of ~3000, and complemented by a dedicated observation of CH[SUB]4[/SUB] at 120 μm. Numerous spectral features due to HD (R(0) and R(1)), H[SUB]2[/SUB]O, CH[SUB]4[/SUB], and CO are present, but so far no new species have been found. Our results indicate that (i) Neptune's mean thermal profile is warmer by ~3 K than inferred from the Voyager radio-occultation; (ii) the D/H mixing ratio is (4.5 ± 1) × 10[SUP]-5[/SUP], confirming the enrichment of Neptune in deuterium over the protosolar value (~2.1 × 10[SUP]-5[/SUP]); (iii) the CH[SUB]4[/SUB] mixing ratio in the mid stratosphere is (1.5 ± 0.2) × 10[SUP]-3[/SUP], and CH[SUB]4[/SUB] appears to decrease in the lower stratosphere at a rate consistent with local saturation, in agreement with the scenario of CH[SUB]4[/SUB] stratospheric injection from Neptune's warm south polar region; (iv) the H[SUB]2[/SUB]O stratospheric column is (2.1 ± 0.5) × 10[SUP]14[/SUP] cm[SUP]-2[/SUP] but its vertical distribution is still to be determined, so the H[SUB]2[/SUB]O external flux remains uncertain by over an order of magnitude; and (v) the CO stratospheric abundance is about twice the tropospheric value, confirming the dual origin of CO suspected from ground-based millimeter/submillimeter observations. Herschel is an ESA space observatory with science instruments provided by European-led Principal Investigator consortia and with important participation from NASA.
Disciplines :
Space science, astronomy & astrophysics
Author, co-author :
Lellouch, Emmanuel; LESIA, Observatoire de Paris, 5 place Jules Janssen, 92195 Meudon, France
Hartogh, Paul; Max-Planck-Institut für Sonnensystemforschung, Katlenburg-Lindau, Germany
Feuchtgruber, H.; Max-Planck-Institut für extraterrestrische Physik, Garching bei München, Germany
Vandenbussche, B.; Instituut voor Sterrenkunde, Katholieke Universiteit Leuven, Belgium
de Graauw, T.; SRON, Groningen, The Netherlands
Moreno, R.; LESIA, Observatoire de Paris, 5 place Jules Janssen, 92195 Meudon, France
Jarchow, C.; Max-Planck-Institut für Sonnensystemforschung, Katlenburg-Lindau, Germany
Cavalié, T.; Max-Planck-Institut für Sonnensystemforschung, Katlenburg-Lindau, Germany
Orton, G.; JPL, California Institute of Technology, Pasadena, USA
Banaszkiewicz, M.; Space Research Centre, Polish Academy of Science, Warszawa, Poland
Blecka, M. I.; Space Research Centre, Polish Academy of Science, Warszawa, Poland
Bockelée-Morvan, D.; LESIA, Observatoire de Paris, 5 place Jules Janssen, 92195 Meudon, France
Crovisier, J.; LESIA, Observatoire de Paris, 5 place Jules Janssen, 92195 Meudon, France
Encrenaz, T.; LESIA, Observatoire de Paris, 5 place Jules Janssen, 92195 Meudon, France
Fulton, T.; Blue Sky Spectroscopy Inc., Lethbridge, Alberta, Canada
Küppers, M.; European Space Astronomy Center, Madrid, Spain
Lara, L. M.; Instituto de Astrofísica de Andalucía (CSIC), Granada, Spain
Lis, D. C.; California Institute of Technology, Pasadena, USA
Medvedev, A. S.; Max-Planck-Institut für Sonnensystemforschung, Katlenburg-Lindau, Germany
Rengel, M.; Max-Planck-Institut für Sonnensystemforschung, Katlenburg-Lindau, Germany
Sagawa, H.; Max-Planck-Institut für Sonnensystemforschung, Katlenburg-Lindau, Germany
Swinyard, B.; Rutherford Appleton Laboratory, Oxfordshire, U K
Szutowicz, S.; Space Research Centre, Polish Academy of Science, Warszawa, Poland
Bensch, F.; Deutsches Zentrum für Luft- und Raumfahrt (DLR), Bonn, Germany
Bergin, E.; University of Michigan, Ann Arbor, USA
Billebaud, F.; Université de Bordeaux, Observatoire Aquitain des Sciences de l'Univers, CNRS, UMR 5804, Laboratoire d'Astrophysique de Bordeaux, France
Biver, N.; LESIA, Observatoire de Paris, 5 place Jules Janssen, 92195 Meudon, France
Blake, G. A.; JPL, California Institute of Technology, Pasadena, USA
Blommaert, J A D L; Instituut voor Sterrenkunde, Katholieke Universiteit Leuven, Belgium
Cernicharo, J.; Laboratorio de Astrofísica Molecular, CAB. INTA-CSIC, Spain
Courtin, R.; LESIA, Observatoire de Paris, 5 place Jules Janssen, 92195 Meudon, France
Davis, G. R.; Joint Astronomy Center, Hilo, USA
Decin, L.; Instituut voor Sterrenkunde, Katholieke Universiteit Leuven, Belgium
Encrenaz, P.; LERMA, Observatoire de Paris, and Univ. Pierre et Marie Curie, Paris, France
Gonzalez, A.; Max-Planck-Institut für Sonnensystemforschung, Katlenburg-Lindau, Germany
Jehin, Emmanuel ; Université de Liège - ULiège > Département d'astrophys., géophysique et océanographie (AGO) > Astrophysique et traitement de l'image
Kidger, M.; Herschel Science Centre, ESA Centre, Madrid, Spain
Naylor, D.; University of Lethbridge, Canada
Portyankina, G.; University of Bern, Switzerland
Schieder, R.; University of Cologne, Germany
Sidher, S.; Rutherford Appleton Laboratory, Oxfordshire, U K
Thomas, N.; University of Bern, Switzerland
de Val-Borro, M.; Max-Planck-Institut für Sonnensystemforschung, Katlenburg-Lindau, Germany
Verdugo, E.; Herschel Science Centre, ESA Centre, Madrid, Spain
Waelkens, C.; Instituut voor Sterrenkunde, Katholieke Universiteit Leuven, Belgium
Walker, H.; Rutherford Appleton Laboratory, Oxfordshire, U K
Aarts, Henri J.M.; SRON, Groningen, The Netherlands
Comito, C.; Max-Planck-Institut für Radioastronomie, Bonn, Germany
Kawamura, J. H.; JPL, California Institute of Technology, Pasadena, USA
Maestrini, A.; LERMA, Observatoire de Paris, and Univ. Pierre et Marie Curie, Paris, France
Peacocke, T.; Experimental Physics Department, National University of Ireland Maynooth, Co. Kildare. Ireland