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Airfall on Comet 67P/Churyumov–Gerasimenko

Davidsson, Björn J. R. and Birch, Samuel and Blake, Geoffrey A. and Bodewits, Dennis and Dworkin, Jason P. and Glavin, Daniel P. and Furukawa, Yoshihiro and Lunine, Jonathan I. and Mitchell, Julie L. and Nguyen, Ann N. and Squyres, Steve and Takigawa, Aki and Vincent, Jean-Baptiste and Zacny, Kris (2021) Airfall on Comet 67P/Churyumov–Gerasimenko. Icarus, 354 . Art. No. 114004. ISSN 0019-1035. doi:10.1016/j.icarus.2020.114004.

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We here study the transfer process of material from one hemisphere to the other (deposition of airfall material) on an active comet nucleus, specifically 67P/Churyumov–Gerasimenko. Our goals are to: 1) quantify the thickness of the airfall debris layers and how it depends on the location of the target area, 2) determine the amount of H₂O and CO₂ ice that are lost from icy dust assemblages of different sizes during transfer through the coma, and 3) estimate the relative amount of vapor loss in airfall material after deposition in order to understand what locations are expected to be more active than others on the following perihelion approach. We use various numerical simulations, that include orbit dynamics, thermophysics of the nucleus and of individual coma aggregates, coma gas kinetics and hydrodynamics, as well as dust dynamics due to gas drag, to address these questions. We find that the thickness of accumulated airfall material varies substantially with location, and typically is of the order 0.1–1 m. The airfall material preserves substantial amounts of water ice even in relatively small (cm–sized) coma aggregates after a rather long (12 h) residence in the coma. However, CO₂ is lost within a couple of hours even in relatively large (dm–sized) aggregates, and is not expected to be an important component in airfall deposits. We introduce reachability and survivability indices to measure the relative capacity of different regions to simultaneously collect airfall and to preserve its water ice until the next perihelion passage, thereby grading their potential of contributing to comet activity during the next perihelion passage.

Item Type:Article
Related URLs:
URLURL TypeDescription
Birch, Samuel0000-0002-4578-1694
Blake, Geoffrey A.0000-0003-0787-1610
Bodewits, Dennis0000-0002-2668-7248
Dworkin, Jason P.0000-0002-3961-8997
Glavin, Daniel P.0000-0001-7779-7765
Furukawa, Yoshihiro0000-0001-7241-530X
Lunine, Jonathan I.0000-0003-2279-4131
Mitchell, Julie L.0000-0002-2733-6466
Nguyen, Ann N.0000-0002-0442-1991
Takigawa, Aki0000-0002-0649-6997
Vincent, Jean-Baptiste0000-0001-6575-3079
Additional Information:© 2020 Published by Elsevier Inc. Received 13 January 2020, Revised 15 July 2020, Accepted 21 July 2020, Available online 1 August 2020. Parts of the research was carried out at the Jet Propulsion Laboratory, California Institute of Technology, under a contract with the National Aeronautics and Space Administration. We gratefully acknowledge JPL funding. Declaration of Competing Interest: None.
Funding AgencyGrant Number
Subject Keywords:67P/Churyumov–Gerasimenko; Comets, composition; Comets, dust; Comets, nucleus
Record Number:CaltechAUTHORS:20200803-102840214
Persistent URL:
Official Citation:Björn J.R. Davidsson, Samuel Birch, Geoffrey A. Blake, Dennis Bodewits, Jason P. Dworkin, Daniel P. Glavin, Yoshihiro Furukawa, Jonathan I. Lunine, Julie L. Mitchell, Ann N. Nguyen, Steve Squyres, Aki Takigawa, Jean-Baptiste Vincent, Kris Zacny, Airfall on Comet 67P/Churyumov–Gerasimenko, Icarus, Volume 354, 2021, 114004, ISSN 0019-1035, (
Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:104699
Deposited By: Tony Diaz
Deposited On:03 Aug 2020 17:55
Last Modified:16 Nov 2021 18:34

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