Summer fireworks on comet 67P

Jean-Baptiste Vincent (1) , Michael F. A'Hearn (2) , Zhong-Yi Lin (3) , Mohamed R. El-Maarry (4) , Maurizio Pajola (5, 6) , Holger Sierks (1) , Cesare Barbieri (7) , Philippe L. Lamy (8) , R. Rodrigo (9, 10) , Detlef Koschny (11) , Hans Rickman (12, 13) , Horst U. Keller (14) , Jessica Agarwal (1) , Maria A. Barucci (15) , Jean-Loup Bertaux (16) , Ivano Bertini (6) , S. Besse (17) , Dennis Bodewits (2) , Gabriele Cremonese (18) , Vania Da deppo (19) , Björn Davidsson (20) , S. Debei (21) , Mariolino De cecco (22) , J. Deller (1) , Sonia Fornasier (15) , Marco Fulle (23) , Adeline Gicquel (1) , Olivier Groussin (8) , Pedro J. Gutiérrez (24) , P. Gutiérrez-Marquez (1) , C. Güttler (1) , Sebastian Höfner (1, 14) , M. Hofmann (1) , Stubbe F. Hviid (25) , W.-H. Ip (26, 3) , L. Jorda (8) , Jörg Knollenberg (25) , G. Kovacs (27, 1) , J.-R. Kramm (1) , Ekkehard Kührt (25) , Michael Küppers (28) , L. M. Lara (24) , Monica Lazzarin (7) , J. J. Lopez moreno (24) , F. Marzari (7) , Matteo Massironi (29) , S. Mottola (25) , Giampiero Naletto (6, 19, 27) , Nilda Oklay (1) , F. Preusker (25) , F. Scholten (25) , X. Shi (1) , Nicholas Thomas (4) , Imre Toth (30, 8) , Cecilia Tubiana (1)

1 MPS - Max-Planck-Institut für Sonnensystemforschung
2 Department of Astronomy [College Park]
3 IANCU - Institute of Astronomy [Taiwan]
4 Physikalisches Institut [Bern]
5 ARC - NASA Ames Research Center
6 CISAS - Centro di Ateneo di Studi e Attività Spaziali “Giuseppe Colombo”
7 Dipartimento di Fisica e Astronomia "Galileo Galilei"
8 LAM - Laboratoire d'Astrophysique de Marseille
9 CAB - Centro de Astrobiologia [Madrid]
10 ISSI - International Space Science Institute [Bern]
11 ESTEC - European Space Research and Technology Centre
12 CBK - Space Research Centre of Polish Academy of Sciences
13 Department of Physics and Astronomy [Uppsala]
14 IGEP - Institut für Geophysik und Extraterrestrische Physik [Braunschweig]
15 LESIA - Laboratoire d'études spatiales et d'instrumentation en astrophysique
16 PLANETO - LATMOS
17 RSSD - Research and Scientific Support Department, ESTEC
18 OAPD - INAF - Osservatorio Astronomico di Padova
19 IFN - CNR Institute for Photonics and Nanotechnologies
20 JPL - Jet Propulsion Laboratory
21 Department of Industrial Engineering [Padova]
22 University of Trento [Trento]
23 OAT - INAF - Osservatorio Astronomico di Trieste
24 IAA - Instituto de Astrofísica de Andalucía
25 DLR Institut für Planetenforschung
26 Institute of Space Science [Taiwan]
27 DEI - Department of Information Engineering [Padova]
28 Operations Department (ESAC)
29 Dipartimento di Geoscienze [Padova]
30 Konkoly Observatory

During its two years mission around comet 67P/Churyumov-Gerasimenko, ESA's Rosetta spacecraft had the unique opportunity to follow closely a comet in the most active part of its orbit. Many studies have presented the typical features associated to the activity of the nucleus, such as localized dust and gas jets. Here we report on series of more energetic transient events observed during the three months surrounding the comet's perihelion passage in August 2015. We detected and characterized 34 outbursts with the Rosetta cameras, one every 2.4 nucleus rotation. We identified 3 main dust plume morphologies associated to these events: a narrow jet, a broad fan, and more complex plumes featuring both previous types together. These plumes are comparable in scale and temporal variation to what has been observed on other comets. We present a map of the outbursts source locations, and discuss the associated topography. We find that the spatial distribution sources on the nucleus correlates well with morphological region boundaries, especially in areas marked by steep scarps or cliffs. Outbursts occur either in the early morning or shortly after the local noon, indicating two potential processes: Morning outbursts may be triggered by thermal stresses linked to the rapid change of temperature; afternoon events are most likely related to the diurnal or seasonal heat wave reaching volatiles buried under the first surface layer. In addition, we propose that some events can be the result of a completely different mechanism, in which most of the dust is released upon the collapse of a cliff.

Keywords: Gerasimenko; comets: individual: 67P/Churyumov

Domains: Astrophysics [astro-ph]

Jean-Baptiste Vincent, Michael F. A'Hearn, Zhong-Yi Lin, Mohamed R. El-Maarry, Maurizio Pajola, et al.. Summer fireworks on comet 67P. Monthly Notices of the Royal Astronomical Society, 2016, 462 (suppl. 1), pp.S184-S194. ⟨10.1093/mnras/stw2409⟩. ⟨insu-01371064⟩