Morphology and dynamics of the jets of comet 67P/Churyumov-Gerasimenko: Early-phase development^⋆

¹ Institute of Astronomy, National Central University, Chung-Li 32054, Taiwan
e-mail: zylin@astro.ncu.edu.tw
² Institute of Space Sciences, National Central University, Chung-Li 32054, Taiwan
³ Space Science Institute, Macau University of Science and Technology, Macau
⁴ Dept. of Earth Science, National Central University, Chung-Li 32054, Taiwan
⁵ Max-Planck Institut für Sonnensystemforschung, Justus-von-Liebig-Weg, 3, 37077 Göttingen, Germany
⁶ Instituto de Astrofísica de Andalucía (CSIC), c/Glorieta de la Astronomía, 18008 Granada, Spain
⁷ Department for Astronomy, University of Maryland, College Park, MD 20742-2421, USA
⁸ Department of Physics and Astronomy “G. Galilei”, University of Padova, Vic. Osservatorio 3, 35122 Padova, Italy
⁹ Centro di Ateneo di Studi ed Attivitá Spaziali “Giuseppe Colombo”, University of Padova, via Venezia 15, 35131 Padova, Italy
¹⁰ Aix Marseille Université, CNRS, LAM (Laboratoire d’Astro-physique de Marseille) UMR 7326, 13388, Marseille, France
¹¹ Centro de Astrobiologia (INTA-CSIC), European Space Agency (ESA), European Space Astronomy Centre (ESAC), PO Box 78, 28691 Villanueva de la Cañada, Madrid, Spain
¹² International Space Science Institute, Hallerstrasse 6, 3012 Bern, Switzerland
¹³ Research and Scientific Support Department, European Space Agency, 2201 Noordwijk, The Netherlands
¹⁴ PAS Space Reserch Center, Bartycka 18A, 00716 Warszawa, Poland
¹⁵ Institut für Geophysik und extraterrestrische Physik (IGEP), Technische Universität Braunschweig, 38106 Braunschweig, Germany
¹⁶ LESIA-Observatoire de Paris, CNRS, UPMC Univ Paris 06, Univ. Paris-Diderot, 5 place J. Janssen, 92195 Meudon Principal Cedex, France
¹⁷ LATMOS, CNRS/UVSQ/IPSL, 11 Boulevard d’Alembert, 78280 Guyancourt, France
¹⁸ INAF Osservatorio Astronomico di Padova, vic. dell’Osservatorio 5, 35122 Padova, Italy
¹⁹ CNR-IFN UOS Padova LUXOR, via Trasea 7, 35131 Padova, Italy
²⁰ Department of Physics and Astronomy, Uppsala University, Box 516, 75120 Uppsala, Sweden
²¹ Department of Industrial Engineering, University of Padova, via Venezia 1, 35131 Padova, Italy
²² University of Trento, via Sommarive 9, 38123 Trento, Italy
²³ INAF–Osservatorio Astronomico di Trieste, via Tiepolo 11, 34143 Trieste, Italy
²⁴ Deutsches Zentrum für Luft- und Raumfahrt (DLR), Institut für Planetenforschung, Rutherfordstrasse 2, 12489 Berlin, Germany
²⁵ Centre for Astrophysics and Planetary Science, School of Physical Sciences, The University of Kent, Canterbury CT2 7NH, UK
²⁶ Department of Information Engineering, University of Padova, via Gradenigo 6/B, 35131 Padova, Italy
²⁷ Physikalisches Institut der Universität Bern, Sidlerstr. 5, 3012 Bern, Switzerland

Received: 25 February 2015
Accepted: 8 June 2015

Abstract

Aims. The OSIRIS camera onboard the Rosetta spacecraft obtained close-up views of the dust coma of comet 67P. The jet structures can be used to trace their source regions and to examine the possible effect of gas-surface interaction.

Methods. We analyzed the wide-angle images obtained in the special dust observation sequences between August and September 2014. The jet features detected in different images were compared to study their time variability. The locations of the potential source regions of some of the jets are identified by ray tracing. We used a ring-masking technique to calculate the brightness distribution of dust jets along the projected distance.

Results. The jets detected between August and September 2014 mostly originated in the Hapi region. Morphological changes appeared over a timescale of several days in September. The brightness slope of the dust jets is much steeper than the background coma. This might be related to the sublimation or fragmentation of the emitted dust grains. Interaction of the expanding gas flow with the cliff walls on both sides of Hapi could lead to erosion and material down-fall to the nucleus surface.