Thermophysics of fractures on comet 67P/Churyumov-Gerasimenko
Sebastien Höfner
(1, 2)
,
Jean-Baptiste Vincent
(1)
,
Jürgen Blum
(2)
,
Björn J. R. Davidsson
(3, 4)
,
Holger Sierks
(1)
,
Mohamed Ramy El-Maarry
(5)
,
Jakob Deller
(1)
,
Marc Hofmann
(1)
,
Xuan Hu
(1, 2)
,
Maurizio Pajola
(6, 7)
,
Cesare Barbieri
(7)
,
Philippe Lamy
(8)
,
Rafael Rodrigo
(9, 10)
,
Detlief Koschny
(11)
,
Hans Rickman
(12)
,
Horst Uwe Keller
(2)
,
Michael A’hearn
(1, 13, 14)
,
Anne-Thérèse Auger
(8)
,
Maria Antonella Barucci
(15)
,
Jean-Loup Bertaux
(16)
,
Ivano Bertini
(7)
,
Dennis Bodewits
(13)
,
Gabriele Cremonese
(7)
,
Vania da Deppo
(7)
,
Stefano Debei
(7)
,
Mariolino de Cecco
(7)
,
Sonia Fornasier
(15)
,
Marco Fulle
(17)
,
Adeline Gicquel
(1)
,
O. Groussin
(8)
,
Pedro J. Gutierrez
(18)
,
Pablo Gutiérrez-Marqués
(1)
,
Carsten Güttler
(1)
,
Stubbe F. Hviid
(19)
,
Wing-Huen Ip
(20)
,
Laurent Jorda
(8)
,
Jörg Knollenberg
(19)
,
Gabor Kovacs
(1, 21)
,
Jörg Rainer Kramm
(1)
,
Ekkehard Kührt
(19)
,
Michael Küppers
(22)
,
Florangela La Forgia
(7)
,
Monica Lazzarin
(7)
,
José J. Lopez-Moreno
(18)
,
Francesco Marzari
(7)
,
Harald Michalik
(2)
,
R. Moissl-Fraund
(7)
,
Fernando Moreno
(18)
,
Stefano Mottola
(19)
,
Giampiero Naletto
(6, 7, 23)
,
Nilda Oklay
(1)
,
Frank Preusker
(19)
,
Frank Scholten
(19)
,
Xian Shi
(1)
,
Nicolas Thomas
(5)
,
Imre Toth
(8, 24)
,
Cécilia Tubiana
(1)
,
S. Zitzmann
(1)
1
MPS -
Max-Planck-Institut für Sonnensystemforschung = Max Planck Institute for Solar System Research
2 IGEP - Institut für Geophysik und Extraterrestrische Physik [Braunschweig]
3 Department of Physics and Astronomy [Uppsala]
4 JPL - Jet Propulsion Laboratory
5 Physikalisches Institut [Bern]
6 CISAS - Centro di Ateneo di Studi e Attività Spaziali “Giuseppe Colombo”
7 Dipartimento di Fisica e Astronomia "Galileo Galilei"
8 LAM - Laboratoire d'Astrophysique de Marseille
9 CAB - Centro de Astrobiologia [Madrid]
10 ISSI - International Space Science Institute [Bern]
11 RSSD - Research and Scientific Support Department, ESTEC
12 CBK - Space Research Centre of Polish Academy of Sciences
13 Department of Astronomy [College Park]
14 Akademie der Wissenschaften zu Göttingen
15 LESIA (UMR_8109) - Laboratoire d'études spatiales et d'instrumentation en astrophysique
16 PLANETO - LATMOS
17 OAT - INAF - Osservatorio Astronomico di Trieste
18 IAA - Instituto de Astrofísica de Andalucía
19 DLR Institut für Planetenforschung
20 Institute of Space Science [Taiwan]
21 MOMEI - Department of Mechatronics, Optics and Mechanical Engineering Informatics
22 ESAC - European Space Astronomy Centre
23 DEI - Department of Information Engineering [Padova]
24 Konkoly Observatory
2 IGEP - Institut für Geophysik und Extraterrestrische Physik [Braunschweig]
3 Department of Physics and Astronomy [Uppsala]
4 JPL - Jet Propulsion Laboratory
5 Physikalisches Institut [Bern]
6 CISAS - Centro di Ateneo di Studi e Attività Spaziali “Giuseppe Colombo”
7 Dipartimento di Fisica e Astronomia "Galileo Galilei"
8 LAM - Laboratoire d'Astrophysique de Marseille
9 CAB - Centro de Astrobiologia [Madrid]
10 ISSI - International Space Science Institute [Bern]
11 RSSD - Research and Scientific Support Department, ESTEC
12 CBK - Space Research Centre of Polish Academy of Sciences
13 Department of Astronomy [College Park]
14 Akademie der Wissenschaften zu Göttingen
15 LESIA (UMR_8109) - Laboratoire d'études spatiales et d'instrumentation en astrophysique
16 PLANETO - LATMOS
17 OAT - INAF - Osservatorio Astronomico di Trieste
18 IAA - Instituto de Astrofísica de Andalucía
19 DLR Institut für Planetenforschung
20 Institute of Space Science [Taiwan]
21 MOMEI - Department of Mechatronics, Optics and Mechanical Engineering Informatics
22 ESAC - European Space Astronomy Centre
23 DEI - Department of Information Engineering [Padova]
24 Konkoly Observatory
Maurizio Pajola
- Function : Author
- PersonId : 767226
- ORCID : 0000-0002-3144-1277
Cesare Barbieri
- Function : Author
- PersonId : 881734
Vania da Deppo
- Function : Author
- PersonId : 763247
- ORCID : 0000-0001-6273-8738
Wing-Huen Ip
- Function : Author
- PersonId : 770404
- ORCID : 0000-0001-5368-386X
Laurent Jorda
- Function : Author
- PersonId : 746464
- IdHAL : laurent-jorda
- ORCID : 0000-0001-8735-3308
- IdRef : 180975161
Michael Küppers
- Function : Author
- PersonId : 757030
- ORCID : 0000-0002-5666-8582
Nicolas Thomas
- Function : Author
- PersonId : 757031
- ORCID : 0000-0002-0146-0071
Abstract
Context. The camera OSIRIS on board Rosetta obtained high-resolution images of the nucleus of comet 67P/Churyumov-Gerasimenko (67P). Great parts of the nucleus surface are composed of fractured terrain.
Aims. Fracture formation, evolution, and their potential relationship to physical processes that drive activity are not yet fully understood. Observed temperatures and gas production rates can be explained or interpreted with the presence of fractures by applying appropriate modelling methods.
Methods. We followed a transient thermophysical model approach that includes radiative, conductive, and water-ice sublimation fluxes by considering a variety of heliocentric distances, illumination conditions, and thermophysical properties for a set of characteristic fracture geometries on the nucleus of 67P. We computed diurnal temperatures, heat fluxes, and outgassing behaviour in order to derive and distinguish the influence of the mentioned parameters on fractured terrain.
Results. Our analysis confirms that fractures, as already indicated by former studies about concavities, deviate from flat-terrain topographies with equivalent properties, mostly through the effect of self-heating. Compared to flat terrain, illuminated cometary fractures are generally warmer, with smaller diurnal temperature fluctuations. Maximum sublimation rates reach higher peaks, and dust mantle quenching effects on sublimation rates are weaker. Consequently, the rough structure of the fractured terrain leads to significantly higher inferred surface thermal inertia values than for flat areas with identical physical properties, which might explain the range of measured thermal inertia on 67P.
Conclusions. At 3.5 AU heliocentric distance, sublimation heat sinks in fractures converge to maximum values >50 W / m2 and trigger dust activity that can be related mainly to H2O. Fractures are likely to grow through the erosive interplay of alternating sublimation and thermal fatigue.
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