T166 Ceres' Surface Composition as an Indication of Interior Evolution (Posters)

Monday, 26 September 2016
9:00 AM - 6:30 PM
Exhibit Hall E/F

MINERALOGY OF CERES' CONIRAYA QUADRANGLE

Paper number: T166-2
Program: Technical Sessions
Time: 9:00 AM – 6:30 PM

Authors

Abstract

After more than one year orbit around Ceres, Dawn spacecraft [1] covered large part of its surface, allowing for a global mineralogical mapping of the planet. The Ceres surface show the ubiquitous absorption bands at 2.7 and 3.05 μm related to Mg-phyllosilicates and NH4-phyllosilicates, respectively [2-3]. Quadrangle Ac-H-2 ‘Coniraya’ is one of four quadrangles in the northern hemisphere of the dwarf planet Ceres (21-66 °N and 0-90 °E).

By the spectral analysis of VIR [4] data, four peculiar craters have been identified within the quadrangle:

- Gaue is the freshest large impact crater [5]. Spectra of Gaue material display a decrease of the band depth (BD) at 3.05 μm indicating a lower presence of ammonium-phyllosilicates with respect the average terrain.

- Ikapati is another fresh crater with dozen small bright spots and ridges, inside and near the crater floor [5]. It is associated to a decrease of 2.7 and 3.05 μm BD, indicating a lower presence of phyllosilicates. Moreover, it presents bluer spectral slope, indicating larger grain size of the regolith and/or larger presence of bluish material with respect the average terrain.

- Ernutet crater spectra display lower 2.7 μm BD as Gaue and Ikapati, but larger 3.05 μm BD indicating a dehydration and larger amount of ammonium-phyllosilicates. Moreover, it shows redder spectral slope which can be explained by a smaller grain size and/or by a slightly different composition with respect the average terrain.

- Oxo crater, located between the Coniraya and the Fejokoo quadrangle, stands out by the additional presence of water ice features [6].

Acknowledgements

This work is supported by the Italian Space Agency (ASI). VIR was funded and coordinated by the Italian Space Agency, with the scientific leadership of the Institute for Space Astrophysics and Planetology, Italian National Institute for Astrophysics, Italy. Support of the Dawn Science, Instrument, and Operation Teams is gratefully acknowledged.

References

[1] Russell C. T. and Raymond, C.A., 2011, SSR 163, 3-23

[2] De Sanctis M. C. et al., 2015 Nature, 528, 241-244

[3] Ammannito E. et al., 2016 Science, in press

[4] De Sanctis M. C. et al., 2011, SSR 163, 329-369

[5] Pasckert J. H. et al., 2016 LPSC #1450

[6] Combe J-Ph. et al., 2016, LPSC #1820

Geological Society of America Abstracts with Programs. Vol. 48, No. 7

doi: 10.1130/abs/2016AM-282641

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