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Near Surface Properties of Martian Regolith Derived From InSight HP 3 ‐RAD Temperature Observations During Phobos Transits
Author(s) -
Mueller N.,
Piqueux S.,
Lemmon M.,
Maki J.,
Lorenz R. D.,
Grott M.,
Spohn T.,
Smrekar S. E.,
Knollenberg J.,
Hudson T. L.,
Krause C.,
Millour E.,
Forget F.,
Golombek M.,
Hagermann A.,
Attree N.,
Siegler M.,
Banerdt W. B.
Publication year - 2021
Publication title -
geophysical research letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.007
H-Index - 273
eISSN - 1944-8007
pISSN - 0094-8276
DOI - 10.1029/2021gl093542
Subject(s) - regolith , martian , mars exploration program , geology , astrobiology , atmospheric sciences , venus , thermal , impact crater , martian surface , thermal conductivity , geophysics , physics , thermodynamics
We use the Martian surface temperature response to Phobos transits observed next to the InSight lander in Elysium Planitia to constrain the thermal properties of the uppermost layer of regolith. Modeled transit lightcurves validated by solar panel current measurements are used to modify the boundary conditions of a 1D heat conduction model. We test several model parameter sets, varying the thickness and thermal conductivity of the top layer to explore the range of parameters that match the observed temperature response within its uncertainty both during the eclipse as well as the full diurnal cycle. The measurements indicate a thermal inertia (TI) of 10 3− 16 + 22Jm − 2K − 1s − 1 / 2in the uppermost layer of 0.2–4 mm, significantly smaller than the TI of 200 Jm − 2K − 1s − 1 / 2derived from the diurnal temperature curve. This could be explained by larger particles, higher density, or some or slightly higher amount of cementation in the lower layers.