Time evolution of dust deposits in the Hapi region of comet 67P/Churyumov-Gerasimenko
| Autor: | D. Bodewits, Pamela Cambianica, Maurizio Pajola, Michael Küppers, Alice Lucchetti, Imre Toth, Holger Sierks, E. Frattin, Monica Lazzarin, Sonia Fornasier, F. La Forgia, E. Simioni, Giampiero Naletto, Luca Penasa, Pedro J. Gutiérrez, Gabriele Cremonese, Cecilia Tubiana, Marco Fulle, Matteo Massironi, Francesca Ferri, Francesco Marzari, J. B. Vincent, Stefano Mottola, H. U. Keller, Carsten Güttler, Cecilia Ceccarelli, Ivano Bertini, Ekkehard Kührt |
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| Přispěvatelé: | Laboratoire d'études spatiales et d'instrumentation en astrophysique (LESIA (UMR_8109)), Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Université de Paris (UP), German Centre for Air and Space Travel, Centre National de la Recherche Scientifique (France), Agenzia Spaziale Italiana, Ministerio de Ciencia, Innovación y Universidades (España), Government of Sweden |
| Jazyk: | angličtina |
| Rok vydání: | 2020 |
| Předmět: |
010504 meteorology & atmospheric sciences
Comet Astrophysics Atmospheric sciences comets: general / comets: individual: 67P/Churyumov-Gerasimenko / methods: data analysis / methods: numerical 7. Clean energy 01 natural sciences methods: numerical comets: general – comets: individual: 67P/Churyumov-Gerasimenko – methods: data analysis – methods: numerical individual: 67P/Churyumov-Gerasimenko [Comets] 0103 physical sciences data analysis [Methods] Comets: general Comets: individual: 67P/Churyumov-Gerasimenko Methods: data analysis Methods: numerical Ejecta Pebble 010303 astronomy & astrophysics Southern Hemisphere 0105 earth and related environmental sciences Physics [PHYS]Physics [physics] numerical [Methods] Accretion (meteorology) comets: general general [Comets] comets: individual: 67P/Churyumov-Gerasimenko Astronomy and Astrophysics Mass ratio methods: data analysis 13. Climate action Space and Planetary Science Erosion [PHYS.ASTR]Physics [physics]/Astrophysics [astro-ph] Mass fraction |
| Zdroj: | Astronomy and Astrophysics-A&A Astronomy and Astrophysics-A&A, EDP Sciences, 2020, 636, pp.A91. ⟨10.1051/0004-6361/202037485⟩ Digital.CSIC. Repositorio Institucional del CSIC instname |
| ISSN: | 0004-6361 |
| DOI: | 10.1051/0004-6361/202037485⟩ |
| Popis: | Aims. We provide a measurement of the seasonal evolution of the dust deposit erosion and accretion in the Hapi region of comet 67P/Churyumov-Gerasimenko with a vertical accuracy of 0.2-0.9 m. Methods. We used OSIRIS Narrow Angle Camera images with a spatial scale of lower than 1.30 m px-1 and developed a tool to monitor the time evolution of 22 boulder heights with respect to the surrounding dust deposit. The tool is based on the measurement of the shadow length projected by the boulder on the surrounding pebble deposit. Assuming the position of the boulders does not change during the observational period, boulder height variations provide an indication of how the thickness of the surrounding dust layer varies over time through erosion and accretion phenomena. Results. We measured an erosion of the dust deposit of 1.7 ± 0.2 m during the inbound orbit until 12 December, 2014. This value nearly balances the fallout from the southern hemisphere during perihelion cometary activity. During the perihelion phase, the dust deposit then increased by 1.4 ± 0.8 m. This is interpreted as a direct measurement of the fallout thickness. By comparing the erosion rate and dust volume loss rate at the Hapi region measured in the coma, the fallout represents ~96% in volume of the ejecta. The amount of the eroded pristine material from the southern hemisphere, together with its subsequent transport and fallout on the nucleus, led us to discuss the pristine water ice abundance in comet 67P. We determine that the refractory-to-ice mass ratio ranges from 6 to 110 in the perihelion-eroded pristine nucleus, providing a pristine ice mass fraction of (8 ± 7)% in mass. © 2020 ESO. OSIRIS was built by a consortium of the Max-Planck Institut fur Sonnensystemforschung, in Guttingen, Germany, CISAS University of Padova, Italy, the Laboratoire de Astrophysique de Marseille, France, the Instituto de Astrofisica de Andalucia, CSIC, Granada, Spain, the Research and Scientific Support Department of the European Space Agency, Noordwijk, The Netherlands, the Instituto Nacional de Tecnica Aeroespacial, Madrid, Spain, the Universidad Politechnica de Madrid, Spain, the Department of Physics and Astronomy of Uppsala University, Sweden, and the Institut fur Datentechnik und Kommunikationsnetze der Technischen Universitat Braunschweig, Germany. The support of the national funding agencies of Germany (DLR), France (CNES), Italy (ASI), Spain (MEC), Sweden (SNSB), and the ESA Technical Directorate is gratefully acknowledged. We thank the ESA teams at ESAC, ESOC and ESTEC for their work in support of the Rosetta mission. We made use of Arcgis 10.3.1 software together with the Matlab, Java, and ImageJ software to perform our analysis. I.T. acknowledges the support from project GINOP-2.3.2-15-2016-00003 "Cosmic effects and hazards". |
| Databáze: | OpenAIRE |
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