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Acceleration of individual, decimetre-sized aggregates in the lower coma of comet 67P/Churyumov-Gerasimenko

Agarwal, Jessica and A'Hearn, M. F. and Vincent, J.B. and Güttler, C. and Höfner, S. and Sierks, H. and Tubiana, C. and Barbieri, C. and Lamy, P. and Rodrigo, Rafael and Koschny, Detlef and Rickmann, H. and Barucci, M. A. and Bertaux, J.-L. and Bertini, I. and Boudreault, S. and Cremonese, G. and Da Deppo, V. and Davidsson, B. and Debei, S. and De Cecco, M. and Deller, J. and Fornasier, S. and Fulle, M. and Gicquel, A. and Groussin, O. and Gutierrez, P.J. and Hofmann, M. and Hviid, S. and Ip, W-H. and Jorda, L and Keller, H. U. and Knollenberg, J. and Kramm, J. R. and Kührt, E. and Küppers, Michael and Lara López, Luisa M. and Lazzarin, M. and Lopez Moreno, J. and Marzari, F. and Naletto, G. and Oklay, N. and Shi, X. and Thomas, N. (2016) Acceleration of individual, decimetre-sized aggregates in the lower coma of comet 67P/Churyumov-Gerasimenko. Monthly Notices of the Royal Astronomical Society. Oxford University Press. DOI: 10.1093/mnras/stw2179 ISSN 0035-8711

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Abstract

We present OSIRIS/NAC observations of decimetre-sized, likely ice-containing aggregates ejected from a confined region on the surface of comet 67P/Churyumov-Gerasimenko. The images were obtained in January 2016 when the comet was at 2 AU from the Sun out-bound from perihelion. We measure the acceleration of individual aggregates through a two-hour image series. Approximately 50% of the aggregates are accelerated away from the nucleus, and 50% towards it, and likewise towards either horizontal direction. The accelerations are up to one order of magnitude stronger than local gravity, and are most simply explained by the combined effect of gas drag accelerating all aggregates upwards, and the recoil force from asymmetric outgassing, either from rotating aggregates with randomly oriented spin axes and suffcient thermal inertia to shift the temperature maximum away from an aggregate’s subsolar region, or from aggregates with variable ice content. At least 10% of the aggregates will escape the gravity field of the nucleus and feed the comet’s debris trail, while others may fall back to the surface and contribute to the deposits covering parts of the northern hemisphere. The rocket force plays a crucial role in pushing these aggregates back towards the surface. Our observations show the future back fall material in the process of ejection, and provide the first direct measurement of the acceleration of aggregates in the innermost coma (< 2 km) of a comet, where gas drag is still significant.

Item URL in elib:https://elib.dlr.de/108183/
Document Type:Article
Title:Acceleration of individual, decimetre-sized aggregates in the lower coma of comet 67P/Churyumov-Gerasimenko
Authors:
AuthorsInstitution or Email of AuthorsAuthors ORCID iD
Agarwal, Jessicamax-planck-institut für sonnensystemforschung, göttingen, germanyUNSPECIFIED
A'Hearn, M. F.university of maryland, department of astronomy, maryland, usaUNSPECIFIED
Vincent, J.B.max-planck-institut fuer sonnensystemforschung, germanyUNSPECIFIED
Güttler, C.max-planck-institut für sonnensystemforschungUNSPECIFIED
Höfner, S.max-planck-institut für sonnensystemforschung, göttingen, germanyUNSPECIFIED
Sierks, H.max-planck-institut für sonnensystemforschung, katlenburg-lindau, germanyUNSPECIFIED
Tubiana, C.max-planck-institut fuer sonnensystemforschung, germanyUNSPECIFIED
Barbieri, C.university of padova, padova, italyUNSPECIFIED
Lamy, P.laboratoire d'astronomie spatiale, marseille, franceUNSPECIFIED
Rodrigo, Rafaelinstituto de astrofisica de andaluciaUNSPECIFIED
Koschny, Detlefestec, the netherlandsUNSPECIFIED
Rickmann, H.Department of Physics and Astronomy, Uppsala University, SwedenUNSPECIFIED
Barucci, M. A.observatoire de paris, meudon, franceUNSPECIFIED
Bertaux, J.-L.laboratoire atmosphères, milieux, observations spatiales, cnrs/uvsq/upmc, 11 boulevard d’alembert, 78280 guyancourt, franceUNSPECIFIED
Bertini, I.dipartimento di astronomia, università di padova, padova, italyUNSPECIFIED
Boudreault, S.max-planck-institut für sonnensystemforschung, 37077 göttingen, germanyUNSPECIFIED
Cremonese, G.osservatorio astronomico, padova, italyUNSPECIFIED
Da Deppo, V.CNR-IFN UOS Padova LUXOR, ItalyUNSPECIFIED
Davidsson, B.astronomiska observatoriet, uppsala, swedenUNSPECIFIED
Debei, S.University of Trento, ItalyUNSPECIFIED
De Cecco, M.università di padova, center of studies and activities of space (cisas) "g.colombo", padova, italyUNSPECIFIED
Deller, J.mpsUNSPECIFIED
Fornasier, S.LESIA, Observatoire de Paris, CNRS, UPMC Univ, FranceUNSPECIFIED
Fulle, M.inaf - osservatorio astronomico di trieste, trieste, italyUNSPECIFIED
Gicquel, A.Max-Planck Institüt fur Sonnensystemforschung, Göttingen, GermanyUNSPECIFIED
Groussin, O.laboratoire d'astrophysique de marseille, franceUNSPECIFIED
Gutierrez, P.J.iaa-csic, granada, spainUNSPECIFIED
Hofmann, M.Max-Planck Institüt fur Sonnensystemforschung, Göttingen, GermanyUNSPECIFIED
Hviid, S.stubbe.hviid (at) dlr.deUNSPECIFIED
Ip, W-H.institute for space science, national central university, chung li, taiwanUNSPECIFIED
Jorda, Llam, marseilleUNSPECIFIED
Keller, H. U.max-planck-institut für sonnensystemforschung, katlenburg-lindauUNSPECIFIED
Knollenberg, J.joerg.knollenberg (at) dlr.deUNSPECIFIED
Kramm, J. R.max planck institute for solar systems research, katlenburg-lindau, germanyUNSPECIFIED
Kührt, E.ekkehard.kuehrt (at) dlr.deUNSPECIFIED
Küppers, Michaelmax-planck-institut für sonnensystemforschungUNSPECIFIED
Lara López, Luisa M.iaa-csic granada, spainUNSPECIFIED
Lazzarin, M.department of astronomy, university of paduaUNSPECIFIED
Lopez Moreno, J.instituto de astrofifica de andalucia-consejo superior de investigaciones cientificas, granada, spainUNSPECIFIED
Marzari, F.università di padova, departimento di fisica, padova, italyUNSPECIFIED
Naletto, G.università di padova, departimento di elettronica et informatica, padova, italyUNSPECIFIED
Oklay, N.max-planck-institut für sonnensystemforschungUNSPECIFIED
Shi, X.technical university berlin, germany ; shanghai astronomical observatory, shanghai, china,UNSPECIFIED
Thomas, N.max-planck-institut für aeronomie, katlenburg-lindauUNSPECIFIED
Date:2016
Journal or Publication Title:Monthly Notices of the Royal Astronomical Society
Refereed publication:Yes
Open Access:No
Gold Open Access:No
In SCOPUS:Yes
In ISI Web of Science:Yes
DOI :10.1093/mnras/stw2179
Publisher:Oxford University Press
ISSN:0035-8711
Status:Published
Keywords:comets: general comets: individual: 67P/Churyumov–Gerasimenko zodiacal dust
HGF - Research field:Aeronautics, Space and Transport
HGF - Program:Space
HGF - Program Themes:Space Science and Exploration
DLR - Research area:Raumfahrt
DLR - Program:R EW - Erforschung des Weltraums
DLR - Research theme (Project):R - Projekt ROSETTA Instrumente, R - Projekt ROSETTA Lander
Location: Berlin-Adlershof
Institutes and Institutions:Institute of Planetary Research > Asteroids and Comets
Deposited By: Schubert, Renate
Deposited On:24 Nov 2016 10:41
Last Modified:06 Sep 2019 15:17

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