OSIRIS observations of meter-sized exposures of H2O ice at the surface of 67P/Churyumov-Gerasimenko and interpretation using laboratory experiments

Pommerol, A., Thomas, N., El-Maarry, M.R., Pajola, M., Groussin, O., Auger, A.-T., Oklay, N., Fornasier, S., Feller, C., Davidsson, B., and others. (2015) OSIRIS observations of meter-sized exposures of H2O ice at the surface of 67P/Churyumov-Gerasimenko and interpretation using laboratory experiments. Astronomy and Astrophysics, 583 . pp. 1-16. ISSN 0004-6361. E-ISSN 1432-0746. (doi:10.1051/0004-6361/201525977) (The full text of this publication is not currently available from this repository. You may be able to access a copy if URLs are provided) (KAR id:52266)

The full text of this publication is not currently available from this repository. You may be able to access a copy if URLs are provided.
Official URL: http://dx.doi.org/10.1051/0004-6361/201525977

Abstract

Since OSIRIS started acquiring high-resolution observations of the surface of the nucleus of comet 67P/Churyumov-Gerasimenko, over one hundred meter-sized bright spots have been identified in numerous types of geomorphologic regions, but mostly located in areas receiving low insolation. The bright spots are either clustered, in debris fields close to decameter-high cliffs, or isolated without structural relation to the surrounding terrain. They can be up to ten times brighter than the average surface of the comet at visible wavelengths and display a significantly bluer spectrum. They do not exhibit significant changes over a period of a few weeks. All these observations are consistent with exposure of water ice at the surface of boulders produced by dislocation of the weakly consolidated layers that cover large areas of the nucleus. Laboratory experiments show that under simulated comet surface conditions, analog samples acquire a vertical stratification with an uppermost porous mantle of refractory dust overlaying a layer of hard ice formed by recondensation or sintering under the insulating dust mantle. The evolution of the visible spectrophotometric properties of samples during sublimation is consistent with the contrasts of brightness and color seen at the surface of the nucleus. Clustered bright spots are formed by the collapse of overhangs that is triggered by mass wasting of deeper layers. Isolated spots might be the result of the emission of boulders at low velocity that are redepositioned in other regions. Â© 2015 ESO.

Item Type:	Article
DOI/Identification number:	10.1051/0004-6361/201525977
Additional information:	Unmapped bibliographic data: C7 - A25 [EPrints field already has value set] LA - English [Field not mapped to EPrints] J2 - Astron. Astrophys. [Field not mapped to EPrints] AD - Physikalisches Institut, University of Bern, Sidlerstrasse 5, Bern, Switzerland [Field not mapped to EPrints] AD - CISAS, University of Padova, Padova, Italy [Field not mapped to EPrints] AD - Aix-Marseille UniversitÃ©, CNRS, LAM, 38 rue Frederic Joliot-Curie, Marseille, France [Field not mapped to EPrints] AD - Max-Planck-Institut fur Sonnensystemforschung, Justus-von-Liebig-Weg 3, Gottingen, Germany [Field not mapped to EPrints] AD - LESIA, CNRS, Univ. Paris-Diderot, 5 place J. Janssen, Meudon, France [Field not mapped to EPrints] AD - Department of Physics and Astronomy, Uppsala University, Uppsala, Sweden [Field not mapped to EPrints] AD - LATMOS, UVSQ, IPSL, 11 boulevard d'Alembert, Guyancourt, France [Field not mapped to EPrints] AD - Department of Physics and Astronomy, University of Padova, Vicolo dell'Osservatorio 3, Padova, Italy [Field not mapped to EPrints] AD - Deutsches Zentrum fur Luft-und Raumfahrt, Institut fur Planetenforschung, RutherfordstraÃ?e 2, Berlin, Germany [Field not mapped to EPrints] AD - Institut fur Geophysik und Extraterrestrische Physik, Technische Universitat Braunschweig, Mendelssohnstr. 3, Braunschweig, Germany [Field not mapped to EPrints] AD - University of Kent, School of Physical Sciences, Canterbury, Kent, United Kingdom [Field not mapped to EPrints] AD - Department of Information Engineering, University of Padova, via Gradenigo 6/B, Padova, Italy [Field not mapped to EPrints] AD - CNR, LUXOR, via Trasea 7, Padova, Italy [Field not mapped to EPrints] AD - International Space Science Institute, HallerstraÃ?e 6, Bern, Switzerland [Field not mapped to EPrints] AD - Centro de Astrobiologia, CSIC, INTA, Torrejon de Ardoz, Madrid, Spain [Field not mapped to EPrints] AD - Scientific Support Office, European Space Agency, Noordwijk, Netherlands [Field not mapped to EPrints] AD - PAS, Space Research Center, Bartycka 18A, Warszawa, Poland [Field not mapped to EPrints] AD - Department of Astronomy, University of Maryland, College Park, MD, United States [Field not mapped to EPrints] AD - INAF, Osservatorio Astronomico, vicolo dell'Osservatorio 5, Padova, Italy [Field not mapped to EPrints] AD - University of Trento, via Mesiano 77, Trento, Italy [Field not mapped to EPrints] AD - Department of Industrial Engineering, University of Padova, via Venezia 1, Padova, Italy [Field not mapped to EPrints] AD - INAF, Osservatorio Astronomico, via Tiepolo 11, Trieste, Italy [Field not mapped to EPrints] AD - CSIC, Granada, Spain [Field not mapped to EPrints] AD - National Central University, Graduate Institute of Astronomy, 300 Chung-Da Rd, Chung-Li, Taiwan [Field not mapped to EPrints] AD - Operations Department, European Space Astronomy Centre, ESA, Villanueva de la Canada, Madrid, Spain [Field not mapped to EPrints] AD - Institut fur Datentechnik und Kommunikationsnetze, TU Braunschweig, Hans-Sommer-Str. 66, Braunschweig, Germany [Field not mapped to EPrints] DB - Scopus [Field not mapped to EPrints]
Uncontrolled keywords:	Comets: general, Methods: laboratory: solid state, Techniques: image processing, Dust, Image processing, Sintering, 67p/churyumov-gerasimenko, Comets: general, High resolution observations, Laboratory experiments, Methods: laboratory, Techniques: image processing, Vertical stratification, Visible wavelengths, Ice
Subjects:	Q Science > QB Astronomy
Divisions:	Divisions > Division of Natural Sciences > Physics and Astronomy
Depositing User:	Stephen Lowry
Date Deposited:	08 Dec 2015 22:32 UTC
Last Modified:	17 Aug 2022 10:59 UTC
Resource URI:	https://kar.kent.ac.uk/id/eprint/52266 (The current URI for this page, for reference purposes)

University of Kent Author Information

Lowry, S.C..

Creator's ORCID:	https://orcid.org/0000-0002-5605-4329
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