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Enceladus: Cassini observations and implications for the search for life

Parkinson, C. D. and Liang, M. C. and Hartman, H. and Hansen, C. J. and Tinetti, G. and Meadows, V. and Kirschvink, J. L. and Yung, Y. L. (2007) Enceladus: Cassini observations and implications for the search for life. Astronomy and Astrophysics, 463 (1). pp. 353-357. ISSN 0004-6361. https://resolver.caltech.edu/CaltechAUTHORS:PARaanda07

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Abstract

Aims. The recent Cassini discovery of water vapor plumes ejected from the south pole of the Saturnian satellite, Enceladus, presents a unique window of opportunity for the detection of extant life in our solar system. Methods. With its significant geothermal energy source propelling these plumes >80 km from the surface of the moon and the ensuing large temperature gradient with the surrounding environment, it is possible to have the weathering of rocks by liquid water at the rock/liquid interface. For the cases of the putatively detected salt-water oceans beneath the ice crusts of Europa and Callisto, an isolated subsurface ocean without photosynthesis or contact with an oxidizing atmosphere will approach chemical equilibrium and annihilate any ecosystems dependent on redox gradients unless there is a substantial alternative energy source. This thermodynamic tendency imposes severe constraints on any biota that is based on chemical energy. On Enceladus, the weathering of rocks by liquid water and any concomitant radioactive emissions are possible incipient conditions for life. If there is CO, CO2 and NH3 present in the spectra obtained from the plume, then this is possible evidence that amino acids could be formed at the rock/liquid interface of Enceladus. The combination of a hydrological cycle, chemical redox gradient and geochemical cycle give favorable conditions for life. Results. We discuss the search for signatures of these species and organics in the Cassini UVIS spectra of the plume and implications for the possible detection of life.


Item Type:Article
Related URLs:
URLURL TypeDescription
https://doi.org/10.1051/0004-6361:20065773DOIUNSPECIFIED
ORCID:
AuthorORCID
Parkinson, C. D.0000-0002-5722-2224
Liang, M. C.0000-0002-5294-9344
Kirschvink, J. L.0000-0001-9486-6689
Yung, Y. L.0000-0002-4263-2562
Additional Information:© ESO 2007. Received 7 June 2006 / Accepted 27 September 2006. We thank Xun Jiang for assistance with linear regression, Andy Ingersoll, G. Orzechowska, and David Stevenson for helpful discussions. We thank F. Tian for communication of results prior to publication. We thank R. West for helpful comments and D. Shemansky for sharing the photoabsorption cross-sections of HCN. This work was supported by NASA grant NASA5-13296 to California Institute of Technology. The research at the Jet Propulsion Laboratory (JPL), California Institute of Technology, was performed under contract with the National Aeronautics and Space Administration.
Subject Keywords:astrobiology -- planets and satellites: general -- planets and satellites: formation -- planets and satellites: individual: Saturn -- planets and satellites: individual: Enceladus -- solar system: general -- astrochemistry
Issue or Number:1
Record Number:CaltechAUTHORS:PARaanda07
Persistent URL:https://resolver.caltech.edu/CaltechAUTHORS:PARaanda07
Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:7778
Collection:CaltechAUTHORS
Deposited By: Lindsay Cleary
Deposited On:30 Jul 2007
Last Modified:24 Jan 2020 23:09

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