title: Detection of local H2O exposed at the surface of Ceres.
abstract: The surface of dwarf planet Ceres contains hydroxyl-rich materials. Theories predict a water ice-rich mantle, and water vapor emissions have been observed, yet no water (H2O) has been previously identified. The Visible and InfraRed (VIR) mapping spectrometer onboard the Dawn spacecraft has now detected water absorption features within a low-illumination, highly reflective zone in Oxo, a 10-kilometer, geologically fresh crater, on five occasions over a period of 1 month. Candidate materials are H2O ice and mineral hydrates. Exposed H2O ice would become optically undetectable within tens of years under current Ceres temperatures; consequently, only a relatively recent exposure or formation of H2O would explain Dawn's findings. Some mineral hydrates are stable on geological time scales, but their formation would imply extended contact with ice or liquid H2O.
authors.affiliation: Bear Fight Institute, 22 Fiddler's Road, P.O. Box 667, Winthrop, WA 98862, USA. jean-philippe_combe@bearfightinstitute.com.
authors.forename: Jean-Philippe
authors.initials: JP
authors.lastname: Combe
authors.affiliation: Bear Fight Institute, 22 Fiddler's Road, P.O. Box 667, Winthrop, WA 98862, USA.
authors.forename: Thomas B
authors.initials: TB
authors.lastname: McCord
authors.affiliation: Istituto di Astrofisica e Planetologia Spaziali-Istituto Nazionale di Astrofisica, Rome, Italy.
authors.forename: Federico
authors.initials: F
authors.lastname: Tosi
authors.affiliation: Istituto di Astrofisica e Planetologia Spaziali-Istituto Nazionale di Astrofisica, Rome, Italy. Institute of Geophysics and Planetary Physics, University of California, Los Angeles, CA, USA.
authors.forename: Eleonora
authors.initials: E
authors.lastname: Ammannito
authors.affiliation: Istituto di Astrofisica e Planetologia Spaziali-Istituto Nazionale di Astrofisica, Rome, Italy.
authors.forename: Filippo Giacomo
authors.initials: FG
authors.lastname: Carrozzo
authors.affiliation: Istituto di Astrofisica e Planetologia Spaziali-Istituto Nazionale di Astrofisica, Rome, Italy.
authors.forename: Maria Cristina
authors.initials: MC
authors.lastname: De Sanctis
authors.affiliation: Istituto di Astrofisica e Planetologia Spaziali-Istituto Nazionale di Astrofisica, Rome, Italy.
authors.forename: Andrea
authors.initials: A
authors.lastname: Raponi
authors.affiliation: Lunar and Planetary Laboratory, Tucson, AZ, USA.
authors.forename: Shane
authors.initials: S
authors.lastname: Byrne
authors.affiliation: Lunar and Planetary Laboratory, Tucson, AZ, USA.
authors.forename: Margaret E
authors.initials: ME
authors.lastname: Landis
authors.affiliation: Institute of Geophysics and Planetary Physics, University of California, Los Angeles, CA, USA.
authors.forename: Kynan H G
authors.initials: KH
authors.lastname: Hughson
authors.affiliation: Jet Propulsion Laboratory, Pasadena, CA, USA.
authors.forename: Carol A
authors.initials: CA
authors.lastname: Raymond
authors.affiliation: Institute of Geophysics and Planetary Physics, University of California, Los Angeles, CA, USA.
authors.forename: Christopher T
authors.initials: CT
authors.lastname: Russell