Post-impact thermal structure and cooling timescales of Occator Crater on Asteroid 1 Ceres
File(s)1-s2.0-S0019103518300186-main.pdf (2.39 MB)
Accepted version
Author(s)
Type
Journal Article
Abstract
Occator crater is perhaps the most distinct surface feature observed by NASA's Dawn spacecraft on the Cerean surface. Contained within the crater are the highest albedo features on the planet, Cerealia Facula and Vinalia Faculae, and relatively smooth lobate flow deposits. We present hydrocode simulations of the formation of Occator crater, varying the water to rock ratio of our pre-impact Cerean surface. We find that at water to rock mass ratios up to 0.3, sufficient volumes of Occator's post-impact subsurface would be above the melting point of water to allow for the deposition of Faculae like deposits via impact-heat driven hydrothermal effusion of brines. This reservoir of hydrothermally viable material beneath the crater is composed of a mixture of impactor material and material uplifted from 10’s of kilometers beneath the pre-impact surface, potentially sampling a deep subsurface volatile reservoir. Using a conductive cooling model, we estimate that the lifetime of hydrothermal activity within such a system, depending on choice of material constants, is between 0.4 and 4 Myr. Our results suggest that impact heating from the Occator forming impact provides a viable mechanism for the creation of observed faculae, with the proviso that the faculae formed within a relatively short time window after the crater itself formed.
Date Issued
2019-03-01
Date Acceptance
2018-08-29
Citation
Icarus, 2019, 320, pp.110-118
ISSN
0019-1035
Publisher
Elsevier
Start Page
110
End Page
118
Journal / Book Title
Icarus
Volume
320
Copyright Statement
© 2018 Published by Elsevier Inc. This manuscript is licensed under the Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 International Licence http://creativecommons.org/licenses/by-nc-nd/4.0/.
Sponsor
Science and Technology Facilities Council (STFC)
Grant Number
ST/N000803/1
Subjects
Science & Technology
Physical Sciences
Astronomy & Astrophysics
Asteroid Ceres
Asteroids Impact Processes
HYDROCODE SIMULATION
WATER ICE
STRENGTH
SURFACE
DEPOSITS
IMPACTS
Astronomy & Astrophysics
0201 Astronomical and Space Sciences
0402 Geochemistry
0404 Geophysics
Publication Status
Published
Date Publish Online
2018-08-30