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Space Science Reviews

, 215:29 | Cite as

The Thermal, Mechanical, Structural, and Dielectric Properties of Cometary Nuclei After Rosetta

  • O. GroussinEmail author
  • N. Attree
  • Y. Brouet
  • V. Ciarletti
  • B. Davidsson
  • G. Filacchione
  • H.-H. Fischer
  • B. Gundlach
  • M. Knapmeyer
  • J. Knollenberg
  • R. Kokotanekova
  • E. Kührt
  • C. Leyrat
  • D. Marshall
  • I. Pelivan
  • Y. Skorov
  • C. Snodgrass
  • T. Spohn
  • F. Tosi
Article
Part of the following topical collections:
  1. Comets: Post 67P / Churyumov-Gerasimenko Perspectives

Abstract

The physical properties of cometary nuclei observed today relate to their complex history and help to constrain their formation and evolution. In this article, we review some of the main physical properties of cometary nuclei and focus in particular on the thermal, mechanical, structural and dielectric properties, emphasising the progress made during the Rosetta mission. Comets have a low density of \(480 \pm 220~\mbox{kg}\,\mbox{m}^{-3}\) and a low permittivity of 1.9–2.0, consistent with a high porosity of 70–80%, are weak with a very low global tensile strength \(<100\) Pa, and have a low bulk thermal inertia of \(0\mbox{--}60~\mbox{J}\,\mbox{K}^{-1}\,\mbox{m}^{-2}\,\mbox{s}^{-1/2}\) that allowed them to preserve highly volatiles species (e.g. CO, CO2, CH4, N2) into their interior since their formation. As revealed by 67P/Churyumov-Gerasimenko, the above physical properties vary across the nucleus, spatially at its surface but also with depth. The broad picture is that the bulk of the nucleus consists of a weakly bonded, rather homogeneous material that preserved primordial properties under a thin shell of processed material, and possibly covered by a granular material; this cover might in places reach a thickness of several meters. The properties of the top layer (the first meter) are not representative of that of the bulk nucleus. More globally, strong nucleus heterogeneities at a scale of a few meters are ruled out on 67P’s small lobe.

Keywords

Solar system Comets Rosetta Space mission 

Notes

Acknowledgements

This project has received funding from the European Union’s Horizon 2020 research and innovation programme under grant agreement no. 686709. This work was supported by the Swiss State Secretariat for Education, Research and Innovation (SERI) under contract number 16.0008-2. The opinions expressed and arguments employed herein do not necessarily reflect the official view of the Swiss Government. Yuri Skorov thanks the Deutsche Forschungsgemeinschaft (DFG) for support (grant SK 264/2).

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Copyright information

© Springer Nature B.V. 2019

Authors and Affiliations

  • O. Groussin
    • 1
    Email author
  • N. Attree
    • 1
    • 2
  • Y. Brouet
    • 3
  • V. Ciarletti
    • 4
  • B. Davidsson
    • 5
  • G. Filacchione
    • 6
  • H.-H. Fischer
    • 7
  • B. Gundlach
    • 8
  • M. Knapmeyer
    • 9
  • J. Knollenberg
    • 9
  • R. Kokotanekova
    • 10
    • 11
    • 12
  • E. Kührt
    • 9
  • C. Leyrat
    • 13
  • D. Marshall
    • 10
    • 14
  • I. Pelivan
    • 15
    • 9
  • Y. Skorov
    • 10
    • 8
  • C. Snodgrass
    • 11
    • 16
  • T. Spohn
    • 9
  • F. Tosi
    • 6
  1. 1.Aix Marseille Univ, CNRS, CNES, LAM, Laboratoire d’Astrophysique de MarseilleMarseilleFrance
  2. 2.Earth and Planetary Observation CentreUniversity of StirlingStirlingUK
  3. 3.Physics InstituteUniversity of BernBernSwitzerland
  4. 4.LATMOS/IPSL, UVSQ (Université Paris-Saclay), UPMC (Sorbonne Univ.)CNRSGuyancourtFrance
  5. 5.Jet Propulsion LaboratoryPasadenaUSA
  6. 6.INAF-IAPSIstituto di Astrofisica e Planetologia SpazialiRomeItaly
  7. 7.DLR Microgravity User Support CentreCologneGermany
  8. 8.Institut für Geophysik und extraterrestrische PhysikTechnische Universität BraunschweigBraunschweigGermany
  9. 9.DLR Institute of Planetary ResearchBerlinGermany
  10. 10.Max Planck Institute for Solar System ResearchGöttingenGermany
  11. 11.Planetary and Space Sciences, School of Physical SciencesThe Open UniversityMilton KeynesUK
  12. 12.European Southern ObservatoryGarching bei MünchenGermany
  13. 13.Laboratoire d’Etudes Spatiales et d’Instrumentation en Astrophysique (LESIA), Observatoire de Paris, CNRS, UPMCParis Diderot Observatoire de ParisMeudonFrance
  14. 14.Universität GöttingenGöttingenGermany
  15. 15.Helmholtz Centre Potsdam, GFZGerman Research Center For GeosciencesPotsdamGermany
  16. 16.Institute for Astronomy, Royal ObservatoryUniversity of EdinburghEdinburghUK

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