A Caltech Library Service

First results of Herschel-PACS observations of Neptune

Lellouch, E. and Lis, D. C. (2010) First results of Herschel-PACS observations of Neptune. Astronomy and Astrophysics, 518 . L152. ISSN 0004-6361.

PDF - Published Version
See Usage Policy.


Use this Persistent URL to link to this item:


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_4 at 120 μm. Numerous spectral features due to HD (R(0) and R(1)), H_(2)O, CH_4, 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^(-5), confirming the enrichment of Neptune in deuterium over the protosolar value (~2.1 × 10^(-5)); (iii) the CH_4 mixing ratio in the mid stratosphere is (1.5 ± 0.2) × 10^(-3), and CH_4 appears to decrease in the lower stratosphere at a rate consistent with local saturation, in agreement with the scenario of CH_4 stratospheric injection from Neptune's warm south polar region; (iv) the H_(2)O stratospheric column is (2.1 ± 0.5) × 10^(14) cm^(-2) but its vertical distribution is still to be determined, so the H_(2)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.

Item Type:Article
Related URLs:
URLURL TypeDescription
Lis, D. C.0000-0002-0500-4700
Additional Information:© 2010 ESO. Received 31 March 2010; Accepted 14 May 2010; Published online 16 July 2010. Herschel is an ESA space observatory with science instruments provided by European-led Principal Investigator consortia and with important participation from NASA. PACS has been developed by a consortium of institutes led by MPE (Germany) and including UVIE (Austria); KUL, CSL, IMEC (Belgium); CEA, OAMP (France); MPIA (Germany); IFSI, OAP/AOT, OAA/CAISMI, LENS, SISSA (Italy); IAC (Spain). This development has been supported by the funding agencies BMVIT (Austria), ESA-PRODEX (Belgium), CEA/CNES (France), DLR (Germany), ASI (Italy), and CICT/MCT (Spain). Additional funding support for some instrument activities has been provided by ESA. Data presented in this paper were analysed using “HIPE”, a joint development by the Herschel Science Ground Segment Consortium, consisting of ESA, the NASA Herschel Science Center, and the HIFI, PACS and SPIRE consortia. We are indebted to Bruno Bézard for important discussions on the HD and CH_4 line parameters.
Funding AgencyGrant Number
Bundesministerium für Verkehr, Innovation und Technologie (BMVIT)UNSPECIFIED
European Space Agency-PROgramme for the Development of scientific EXperiments (ESA-PRODEX) (Belgium)UNSPECIFIED
Commissariat à l’Energie Atomique (CEA)UNSPECIFIED
Deutsches Zentrum für Luft- und Raumfahrt (DLR)UNSPECIFIED
Agenzia Spaziale Italiana (ASI)UNSPECIFIED
Comisión Interministerial de Ciencia y Tecnología (CICYT)UNSPECIFIED
European Space Agency (ESA)UNSPECIFIED
Centre National d'Études Spatiales (CNES)UNSPECIFIED
Ministerio de Ciencia Y Tecnologia (MCYT)UNSPECIFIED
Subject Keywords:planets and satellites: atmospheres; planets and satellites: individual: Neptune; planets and satellites: composition; techniques: spectroscopic
Record Number:CaltechAUTHORS:20101123-112202778
Persistent URL:
Official Citation:First results of Herschel-PACS observations of Neptune E. Lellouch, P. Hartogh, H. Feuchtgruber, B. Vandenbussche, T. de Graauw, R. Moreno, C. Jarchow, T. Cavalié, G. Orton, M. Banaszkiewicz, M. I. Blecka, D. Bockelée-Morvan, J. Crovisier, T. Encrenaz, T. Fulton, M. Küppers, L. M. Lara, D. C. Lis, A. S. Medvedev, M. Rengel, H. Sagawa, B. Swinyard, S. Szutowicz, F. Bensch, E. Bergin, F. Billebaud, N. Biver, G. A. Blake, J. A. D. L. Blommaert, J. Cernicharo, R. Courtin, G. R. Davis, L. Decin, P. Encrenaz, A. Gonzalez, E. Jehin, M. Kidger, D. Naylor, G. Portyankina, R. Schieder, S. Sidher, N. Thomas, M. de Val-Borro, E. Verdugo, C. Waelkens, H. Walker, H. Aarts, C. Comito, J. H. Kawamura, A. Maestrini, T. Peacocke, R. Teipen, T. Tils and K. Wildeman A&A 518 L152 (2010) DOI: 10.1051/0004-6361/201014600
Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:20987
Deposited By: Jason Perez
Deposited On:23 Nov 2010 21:40
Last Modified:03 Oct 2019 02:18

Repository Staff Only: item control page