Oxo Crater on (1) Ceres: Geological History and the Role of Water-ice

Dwarf planet Ceres (∅ ∼ 940 km) is the largest object in the main asteroid belt. Investigations suggest that Ceres is a thermally evolved, volatile-rich body with potential geological activity, a body that was never completely molten, but one that possibly partially differentiated into a rocky core and an ice-rich mantle, and may contain remnant internal liquid water. Thermal alteration and the infall of exogenic material contribute to producing a (dark) carbonaceous chondritic-like surface containing ammoniated phyllosilicates. Here we report imaging and spectroscopic analyses of data on the bright Oxo crater derived from the Framing Camera and the Visible and Infrared Spectrometer on board the Dawn spacecraft. We confirm that the transitional complex crater Oxo (∅ ∼ 9 km) exhibits exposed surface water-ice. We show that this water-ice-rich material is associated exclusively with two lobate deposits at pole-facing scarps, deposits that also contain carbonates and admixed phyllosilicates. Due to Oxo’s location at −4802 m below the cerean reference ellipsoid and its very young age of only 190 ka (1σ: +100 ka, −70 ka), Oxo is predestined for ongoing water-ice sublimation.

[1]  C. Russell,et al.  Geomorphological evidence for ground ice on dwarf planet Ceres , 2017 .

[2]  F. G. Carrozzo,et al.  An investigation of the bluish material on Ceres , 2017 .

[3]  D. Crown,et al.  Evolution of Occator Crater on (1) Ceres , 2017 .

[4]  K. Matz,et al.  Timing of optical maturation of recently exposed material on Ceres , 2016 .

[5]  C. Russell,et al.  FC colour images of dwarf planet Ceres reveal a complicated geological history , 2016 .

[6]  N. Schorghofer.  Predictions of depth-to-ice on asteroids based on an asynchronous model of temperature, impact stirring, and ice loss , 2016 .

[7]  F. G. Carrozzo,et al.  Detection of local H2O exposed at the surface of Ceres , 2016, Science.

[8]  C. Russell,et al.  Cratering on Ceres: Implications for its crust and evolution , 2016, Science.

[9]  C. Russell,et al.  The geomorphology of Ceres , 2016, Science.

[10]  C. Russell,et al.  A partially differentiated interior for (1) Ceres deduced from its gravity field and shape , 2016, Nature.

[11]  R. Mugnuolo,et al.  Bright carbonate deposits as evidence of aqueous alteration on (1) Ceres , 2016, Nature.

[12]  R. Jaumann,et al.  Dawn arrives at Ceres: Exploration of a small, volatile-rich world , 2016, Science.

[13]  T. Kneissl,et al.  Planetary surface dating from crater size-frequency distribution measurements: Poisson timing analysis , 2016 .

[14]  C. Russell,et al.  Sublimation in bright spots on (1) Ceres , 2015, Nature.

[15]  R. Jaumann,et al.  Ammoniated phyllosilicates with a likely outer Solar System origin on (1) Ceres , 2015, Nature.

[16]  R. Stephens,et al.  Photometric properties of Ceres from telescopic observations using Dawn Framing Camera color filters , 2015, 1510.00387.

[17]  C. Russell,et al.  Exogenic olivine on Vesta from Dawn Framing Camera color data , 2015 .

[18]  O. Aharonson,et al.  Thermal stability of ice on Ceres with rough topography , 2015 .

[19]  T. Titus.  Ceres: Predictions for near‐surface water ice stability and implications for plume generating processes , 2015 .

[20]  Linda C. Kah,et al.  Gale crater and impact processes – Curiosity’s first 364 Sols on Mars , 2015 .

[21]  C. Russell,et al.  Detection of serpentine in exogenic carbonaceous chondrite material on Vesta from Dawn FC data , 2014 .

[22]  D. Teyssier,et al.  Localized sources of water vapour on the dwarf planet (1) Ceres , 2014, Nature.

[23]  James A. Skinner,et al.  Crater-based dating of geological units on Mars: methods and application for the new global geological map , 2013 .

[24]  V. Ansan,et al.  The origin and timing of fluvial activity at Eberswalde crater, Mars , 2012 .

[25]  Andreas Nathues,et al.  Color and Albedo Heterogeneity of Vesta from Dawn , 2012, Science.

[26]  Gregory Michael,et al.  Planetary surface dating from crater size–frequency distribution measurements: Spatial randomness and clustering , 2012 .

[27]  S. V. Gasselt,et al.  Map-projection-independent crater size-frequency determination in GIS environments—New software tool for ArcGIS , 2011 .

[28]  Robert O. Green,et al.  Thermal removal from near‐infrared imaging spectroscopy data of the Moon , 2011 .

[29]  G. Neukum,et al.  Planetary surface dating from crater size-frequency distribution measurements: Partial resurfacing events and statistical age uncertainty , 2010 .

[30]  M. Shepard,et al.  A test of the Hapke photometric model , 2007 .

[31]  Alan D. Howard,et al.  An intense terminal epoch of widespread fluvial activity on early Mars: 1. Valley network incision and associated deposits , 2005 .

[32]  C. Sotin,et al.  Ceres: Evolution and current state , 2005 .

[33]  R. Clark,et al.  The spectral reflectance of water-mineral mixtures at low temperatures. [observed on natural satellites and other solar system objects] , 1981 .

[34]  H. J. Moore,et al.  Standard techniques for presentation and analysis of crater size-frequency data , 1978 .