Post-perihelion photometry of dust grains in the coma of 67P Churyumov–Gerasimenko

Elisa Frattin 1, 2 Gabriele Cremonese 1 Emanuele Simioni 1, 3 Ivano Bertini 2 Monica Lazzarin 2 Theresa Ott 4 Esther Drolshagen 5 Florangela La Forgia 2 Holger Sierks 6 Cesare Barbieri 2 Philippe L. Lamy 7 Rafael Rodrigo 8, 9 Detlef Koschny 10 Hans Rickman 11, 12 Horst Uwe Keller 13 Jessica Agarwal 6 Michael A'Hearn 6, 14 Maria Antonella Barucci 15 Jean-Loup Bertaux 16 Vania Da Deppo 3 Björn Davidsson 12 Stafano Debei 17 Mariolino De Cecco 18 Jakob Deller 6 Sabrina Ferrari 19 Francesca Ferri 19 Sonia Fornasier 15 Marco Fulle 20 Adeline Gicquel 6 Olivier Groussin 7 Pedro J. Gutierrez 21 Carsten Güttler 6 Marc Hofmann 6 Stubbe F. Hviid 22 Wing-Huen Ip 23 Laurent Jorda 7 Jörg Knollenberg 22 J.-Rainer Kramm 6 Ekkehard Kührt 22 Michael Küppers 24 Luisa M. Lara 21 José J. Lopez Moreno 21 Alice Lucchetti 1, 19 Francesco Marzari 2 Matteo Massironi 25 Stefano Mottola 22 Giampiero Naletto 19, 3, 26 Nilda Oklay 6 Maurizio Pajola 19, 27 Luca Penasa 19 Xian Shi 6 Nicolas Thomas 28 Cécilia Tubiana 6 Jean-Baptiste Vincent 6
Abstract : We present a photometric analysis of individual dust grains in the coma of comet 67P/Churyumov–Gerasimenko using OSIRIS images taken from 2015 July to 2016 January. We analysed a sample of 555 taken during 18 d at heliocentric distances ranging between 1.25 and 2.04 au and at nucleocentric distances between 80 and 437 km. An automated method to detect the tracks was specifically developed. The images were taken by OSIRIS NAC in four different filters: Near-IR (882 nm), Orange (649 nm), FarOrange (649 nm) and Blue (480 nm). It was not always possible to recognize all the grains in the four filters, hence we measured the spectral slope in two wavelengths ranges: in the interval [480–649] nm, for 1179 grains, and in the interval [649–882] nm, for 746 grains. We studied the evolution of the two populations’ average spectral slopes. The data result scattered around the average value in the range [480–649] nm, while in the [649–882] nm we observe a slight decreasing moving away from the Sun as well as a slight increasing with the nucleocentric distance. A spectrophotometric analysis was performed on a subsample of 339 grains. Three major groups were defined, based on the spectral slope between [535–882] nm: (i) the steep spectra that may be related with organic material, (ii) the spectra with an intermediate slope, likely a mixture of silicates and organics and (iii) flat spectra that may be associated with a high abundance of water ice.
Type de document :
Article dans une revue
Monthly Notices of the Royal Astronomical Society, Oxford University Press (OUP): Policy P - Oxford Open Option A, 2017, 469 (Suppl_2), pp.S195 - S203. 〈10.1093/mnras/stx1395〉
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Soumis le : dimanche 13 août 2017 - 18:51:43
Dernière modification le : jeudi 9 novembre 2017 - 09:36:02

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Elisa Frattin, Gabriele Cremonese, Emanuele Simioni, Ivano Bertini, Monica Lazzarin, et al.. Post-perihelion photometry of dust grains in the coma of 67P Churyumov–Gerasimenko. Monthly Notices of the Royal Astronomical Society, Oxford University Press (OUP): Policy P - Oxford Open Option A, 2017, 469 (Suppl_2), pp.S195 - S203. 〈10.1093/mnras/stx1395〉. 〈insu-01574335〉

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