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Thermophysical modelling and parameter estimation of small Solar system bodies via data assimilation

Hamm, Maximilian and Pelivan, Ivanka and Grott, Matthias and de Wiljes, J. (2020) Thermophysical modelling and parameter estimation of small Solar system bodies via data assimilation. Monthly Notices of the Royal Astronomical Society, 496 (3), pp. 2776-2785. Oxford University Press. doi: 10.1093/mnras/staa1755. ISSN 0035-8711.

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Official URL: https://academic.oup.com/mnras/article/496/3/2776/5860286

Abstract

Deriving thermophysical properties such as thermal inertia from thermal infrared observations provides useful insights into the structure of the surface material on planetary bodies. The estimation of these properties is usually done by fitting temperature variations calculated by thermophysical models to infrared observations. For multiple free model parameters, traditional methods such as least-squares fitting or Markov chain Monte Carlo methods become computationally too expensive. Consequently, the simultaneous estimation of several thermophysical parameters, together with their corresponding uncertainties and correlations, is often not computationally feasible and the analysis is usually reduced to fitting one or two parameters. Data assimilation (DA) methods have been shown to be robust while sufficiently accurate and computationally affordable even for a large number of parameters. This paper will introduce a standard sequential DA method, the ensemble square root filter, for thermophysical modelling of asteroid surfaces. This method is used to re-analyse infrared observations of the MARA instrument, which measured the diurnal temperature variation of a single boulder on the surface of near-Earth asteroid (162173) Ryugu. The thermal inertia is estimated to be 295 ± 18 Jm −2 K −1 s −1/2 Jm−2K−1s−1/2⁠, while all five free parameters of the initial analysis are varied and estimated simultaneously. Based on this thermal inertia estimate the thermal conductivity of the boulder is estimated to be between 0.07 and 0.12,Wm −1 K −1 Wm−1K−1 and the porosity to be between 0.30 and 0.52. For the first time in thermophysical parameter derivation, correlations and uncertainties of all free model parameters are incorporated in the estimation procedure that is more than 5000 times more efficient than a comparable parameter sweep.

Item URL in elib:https://elib.dlr.de/136730/
Document Type:Article
Title:Thermophysical modelling and parameter estimation of small Solar system bodies via data assimilation
Authors:
AuthorsInstitution or Email of AuthorsAuthor's ORCID iD
Hamm, Maximilianmaximilian.hamm (at) dlr.deUNSPECIFIED
Pelivan, IvankaInstitute for Mathematics, University of Potsdam, GermanyUNSPECIFIED
Grott, MatthiasMatthias.Grott (at) dlr.deUNSPECIFIED
de Wiljes, J.Institute for Mathematics, University of Potsdam, Karl-Liebknecht-Str. 24-25, D-14476 Potsdam-Golm, GermanyUNSPECIFIED
Date:2020
Journal or Publication Title:Monthly Notices of the Royal Astronomical Society
Refereed publication:Yes
Open Access:Yes
Gold Open Access:No
In SCOPUS:Yes
In ISI Web of Science:Yes
Volume:496
DOI :10.1093/mnras/staa1755
Page Range:pp. 2776-2785
Publisher:Oxford University Press
ISSN:0035-8711
Status:Published
Keywords:MASCOT, Hayabusa 2, Ryugu, Asteroids, Thermal Inertia
HGF - Research field:Aeronautics, Space and Transport
HGF - Program:Space
HGF - Program Themes:Space Exploration
DLR - Research area:Raumfahrt
DLR - Program:R EW - Space Exploration
DLR - Research theme (Project):Project MASCOT Science and operation (old)
Location: Berlin-Adlershof
Institutes and Institutions:Institute of Planetary Research > Planetary Physics
Deposited By: Grott, Dr.rer.nat. Matthias
Deposited On:27 Oct 2020 07:48
Last Modified:27 Oct 2020 07:48

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