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Water production in comet 81P/Wild 2 as determined by Herschel/HIFI

de Val-Borro, M. and Lis, D. C. and Emprechtinger, M. and Blake, G. A. (2010) Water production in comet 81P/Wild 2 as determined by Herschel/HIFI. Astronomy and Astrophysics, 521 . Art. No. L50. ISSN 0004-6361.

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The high spectral resolution and sensitivity of Herschel/HIFI allows for the detection of multiple rotational water lines and accurate determinations of water production rates in comets. In this Letter we present HIFI observations of the fundamental 1_(10)–1_(01) (557 GHz) ortho and 1_(11)–0_(00) (1113 GHz) para rotational transitions of water in comet 81P/Wild 2 acquired in February 2010. We mapped the extent of the water line emission with five point scans. Line profiles are computed using excitation models which include excitation by collisions with electrons and neutrals and solar infrared radiation. We derive a mean water production rate of 1.0 × 10^(28) molecules s^(−1) at a heliocentric distance of 1.61 AU about 20 days before perihelion, in agreement with production rates measured from the ground using observations of the 18-cm OH lines. Furthermore, we constrain the electron density profile and gas kinetic temperature, and estimate the coma expansion velocity by fitting the water line shapes.

Item Type:Article
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URLURL TypeDescription DOIArticle
Lis, D. C.0000-0002-0500-4700
Blake, G. A.0000-0003-0787-1610
Additional Information:© 2010 ESO. Received 5 June 2010; Accepted 1 July 2010. Published online 01 October 2010. Herschel is an ESA space observatory with science instruments provided by European-led Principal Investigator consortia and with important participation from NASA. HIFI has been designed and built by a consortium of institutes and university departments from across Europe, Canada and the United States under the leadership of SRON Netherlands Institute for Space Research, Groningen, The Netherlands and with major contributions from Germany, France and the US. Consortium members are: Canada: CSA, U. Waterloo; France: CESR, LAB, LERMA, IRAM; Germany: KOSMA, MPIfR, MPS; Ireland, NUI Maynooth; Italy: ASI, IFSI-INAF, Osservatorio Astrofisico di Arcetri-INAF; The Netherlands: SRON, TUD; Poland: CAMK, CBK; Spain: Observatorio Astronómico Nacional (IGN), Centro de Astrobiología (CSIC-INTA). Sweden: Chalmers University of Technology – MC2, RSS & GARD, Onsala Space Observatory, Swedish National Space Board, Stockholm University – Stockholm Observatory; Switzerland: ETH Zürich, FHNW; USA: Caltech, JPL, NHSC. HIPE is 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. This development has been supported by national funding agencies: CEA, CNES, CNRS (France); ASI (Italy); DLR (Germany). Additional funding support for some instrument activities has been provided by ESA. Support for this work was provided by NASA through an award issued by JPL/Caltech. D.C.L. is supported by the NSF, award AST-0540882 to the Caltech Submillimeter Observatory. S.S., M.B. and M.I.B. are supported by the Polish Ministry of Education and Science (MNiSW).
Funding AgencyGrant Number
Ministerstwo Nauki i Szkolnictwa Wyższego (MNiSW)UNSPECIFIED
Subject Keywords:comets: individual: 81P/Wild 2; molecular processes; radiative transfer; submillimeter: general
Record Number:CaltechAUTHORS:20101216-105718851
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Official Citation:de Val-Borro, M., P. Hartogh, et al. (2010). "Water production in comet 81P/Wild 2 as determined by Herschel/HIFI." A&A 521: L50.
Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:21395
Deposited By: Tony Diaz
Deposited On:17 Dec 2010 17:57
Last Modified:03 Oct 2019 02:23

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