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Discovery of spin-rate-dependent asteroid thermal inertia

Harris, Alan and Drube, Line (2016) Discovery of spin-rate-dependent asteroid thermal inertia. In: Bulletin of the American Astronomical Society, 48 (7), p. 312. AAS. American Astronomical Society, Division for Planetary Sciences (DPS)/EPSC meeting 2016, 16.-21. Okt. 2016, Pasadena, California.

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Official URL: https://aas.org/files/dps-epsc-abstract-book-final.pdf

Abstract

Knowledge of the surface thermal inertia of an asteroid can provide insight into surface structure: porous material has a lower thermal inertia than rock. Using WISE/NEOWISE data and our new asteroid thermal-inertia estimator we show that the thermal inertia of main-belt asteroids (MBAs) appears to increase with spin period. Similar behavior is found in the case of thermophysically-modeled thermal inertia values of near-Earth objects (NEOs). We interpret our results in terms of rapidly increasing material density and thermal conductivity with depth, and provide evidence that thermal inertia increases by factors of 10 (MBAs) to 20 (NEOs) within a depth of just 10 cm. On the basis of a picture of depth-dependent thermal inertia our results suggest that, in general, thermal inertia values representative of solid rock are reached some tens of centimeters to meters below the surface in the case of MBAs (the median diameter in our dataset = 24 km). In the case of the much smaller (km-sized) NEOs a thinner porous surface layer is indicated, with large pieces of solid rock possibly existing just a meter or less below the surface. These conclusions are consistent with our understanding from in-situ measurements of the surfaces of the Moon, and a few asteroids, and suggest a very general picture of rapidly changing material properties in the topmost regolith layers of asteroids. Our results have important implications for calculations of the Yarkovsky effect, including its perturbation of the orbits of potentially hazardous objects and those of asteroid family members after the break-up event. Evidence of a rapid increase of thermal inertia with depth is also an important result for studies of the ejecta-enhanced momentum transfer of impacting vehicles ("kinetic impactors") in planetary defense.

Item URL in elib:https://elib.dlr.de/107296/
Document Type:Conference or Workshop Item (Lecture)
Title:Discovery of spin-rate-dependent asteroid thermal inertia
Authors:
AuthorsInstitution or Email of AuthorsAuthors ORCID iD
Harris, AlanAlan.Harris (at) dlr.dehttps://orcid.org/0000-0001-8548-8268
Drube, LineLine.Drube (at) dlr.dehttps://orcid.org/0000-0003-2486-8894
Date:2016
Journal or Publication Title:Bulletin of the American Astronomical Society
Refereed publication:No
Open Access:Yes
Gold Open Access:No
In SCOPUS:No
In ISI Web of Science:No
Volume:48
Page Range:p. 312
Editors:
EditorsEmail
AAS, DPSUNSPECIFIED
Publisher:AAS
Status:Published
Keywords:Asteroid, near-Earth object, infrared observations, thermal inertia
Event Title:American Astronomical Society, Division for Planetary Sciences (DPS)/EPSC meeting 2016
Event Location:Pasadena, California
Event Type:international Conference
Event Dates:16.-21. Okt. 2016
Organizer:American Astronomical Society - DPS
HGF - Research field:Aeronautics, Space and Transport
HGF - Program:Space
HGF - Program Themes:Space Science and Exploration
DLR - Research area:Raumfahrt
DLR - Program:R EW - Erforschung des Weltraums
DLR - Research theme (Project):R - Vorhaben Planetary Evolution and Life
Location: Berlin-Adlershof
Institutes and Institutions:Institute of Planetary Research > Leitungsbereich PF
Deposited By: Harris, Prof. Alan
Deposited On:03 Nov 2016 08:50
Last Modified:31 Jul 2019 20:04

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