Evolution of the Dust Size Distribution of Comet 67P/Churyumov–Gerasimenko from 2.2 au to Perihelion

Marco Fulle 1 Francesco Marzari 2 V. Della Corte 3 Sonia Fornasier 4 H. Sierks 5 A. Rotundi 3, 6 C. Barbieri 2 Philippe L. Lamy 7 R. Rodrigo 8, 9 D. Koschny 10 H. Rickman 11, 12 H. U. Keller 13 J. J. López-Moreno 14 M. Accolla 15 J. Agarwal 5 M. F. A’hearn 16 N. Altobelli 17 M. Antonella Barucci 4 Jean-Loup Bertaux 18 I. Bertini 19 D. Bodewits 16 E. Bussoletti 6 L. Colangeli 20 M. Cosi 21 G. Cremonese 22 Jean-François Crifo 23 V. Da Deppo 24 B. Davidsson 12 S. Debei 25 M. De Cecco 26 F. Esposito 27 M. Ferrari 3 F. Giovane 28 B. Gustafson 29 S. F. Green 30 Olivier Groussin 7 E. Grün 31 P. Gutierrez 14 C. Güttler 5 M. L. Herranz 15 S. F. Hviid 32 W. Ip 33 S. L. Ivanovski 3 J. M. Jerónimo 14 Laurent Jorda 7 J. Knollenberg 32 R. Kramm 5 E. Kührt 32 M. Küppers 34 L. Lara 14 M. Lazzarin 2 M. R. Leese 30 A. C. López-Jiménez 14 F. Lucarelli 6 E. Mazzotta Epifani 35 J. A. M. Mcdonnell 30, 36 V. Mennella 27 A. Molina 37 R. Morales 14 F. Moreno 14 S. Mottola 32 G. Naletto 38, 19, 25 N. Oklay 5 J. L. Ortiz 14 E. Palomba 3 P. Palumbo 3, 6 J.-M. Perrin 39 F. J. M. Rietmeijer 40 J. Rodríguez 14 R. Sordini 3 N. Thomas 41 C. Tubiana 5 J.-B. Vincent 5 P. Weissman 42 K.-P. Wenzel 10 V. Zakharov 4 J. C. Zarnecki 8, 30
18 IMPEC - LATMOS
LATMOS - Laboratoire Atmosphères, Milieux, Observations Spatiales
23 HEPPI - LATMOS
LATMOS - Laboratoire Atmosphères, Milieux, Observations Spatiales
Abstract : The Rosetta probe, orbiting Jupiter-family comet 67P/Churyumov–Gerasimenko, has been detecting individual dust particles of mass larger than 10−10 kg by means of the GIADA dust collector and the OSIRIS Wide Angle Camera and Narrow Angle Camera since 2014 August and will continue until 2016 September. Detections of single dust particles allow us to estimate the anisotropic dust flux from 67P, infer the dust loss rate and size distribution at the surface of the sunlit nucleus, and see whether the dust size distribution of 67P evolves in time. The velocity of the Rosetta orbiter, relative to 67P, is much lower than the dust velocity measured by GIADA, thus dust counts when GIADA is nadir-pointing will directly provide the dust flux. In OSIRIS observations, the dust flux is derived from the measurement of the dust space density close to the spacecraft. Under the assumption of radial expansion of the dust, observations in the nadir direction provide the distance of the particles by measuring their trail length, with a parallax baseline determined by the motion of the spacecraft. The dust size distribution at sizes >1 mm observed by OSIRIS is consistent with a differential power index of −4, which was derived from models of 67P's trail. At sizes <1 mm, the size distribution observed by GIADA shows a strong time evolution, with a differential power index drifting from −2 beyond 2 au to −3.7 at perihelion, in agreement with the evolution derived from coma and tail models based on ground-based data. The refractory-to-water mass ratio of the nucleus is close to six during the entire inbound orbit and at perihelion.
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Article dans une revue
Astrophysical Journal, American Astronomical Society, 2016, 821 (1), 14 p. <10.3847/0004-637X/821/1/19>
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Contributeur : Catherine Cardon <>
Soumis le : vendredi 8 avril 2016 - 20:45:19
Dernière modification le : lundi 5 juin 2017 - 20:40:31

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Marco Fulle, Francesco Marzari, V. Della Corte, Sonia Fornasier, H. Sierks, et al.. Evolution of the Dust Size Distribution of Comet 67P/Churyumov–Gerasimenko from 2.2 au to Perihelion. Astrophysical Journal, American Astronomical Society, 2016, 821 (1), 14 p. <10.3847/0004-637X/821/1/19>. <insu-01300203>

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