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Catalogue POP – Notice individuelle de publication

Lin Zhong-Yi, Knollenberg Jörg, Vincent Jean-Baptiste, A'Hearn M. F., Ip W., Sierks Holger, Barbieri Cesare, Lamy Philippe, Rodrigo Rafael, Koschny Detlef, Rickman Hans, Keller Horst Uwe, Mottola Stefano, Bodewits Dennis, Agarwal Jessica, Barucci Maria Antonella, Bertaux Jean-Loup, Bertini Ivano, Cremonese Gabriele, Deller Jakob, Da Deppo Vania, Davidsson Björn, Debei Stefano, De Cecco M., Fornasier Sonia, Fulle Marco, Groussin Olivier, Gutierrez Pedro J., Güttler Carsten, Hofmann M., Hviid Stubbe F., Jorda Laurent, Kovacs Gabor, Kramm Rainer, Kührt Ekkehard, Küppers Michael, Lai I.-L., Lara Luisa M., Lazzarin Monica, Lee Jui-Chi, López-Moreno José J., Marzari Francesco, Naletto Giampiero, Oklay Nilda, Ott Thomas, Drolshagen E., Shi X., Thomas Nicholas, Tubiana Cecilia

Investigating the physical properties of outbursts on comet 67P/Churyumov-Gerasimenko

Monthly notices of the Royal Astronomical Society, 2017, vol. 469, pp. S731-S740

Référence DOI : 10.1093/mnras/stx2768
Référence ADS : 2017MNRAS.469S.731L

Résumé :

Cometary outbursts on several comets have been observed both by ground-based telescopes and by in situ instruments on spacecraft. However, the mechanism behind these phenomena and their physical properties are still unclear. The optical, spectrocopic and infrared remote imaging system (OSIRIS) onboard the Rosetta spacecraft provided first-hand information on the outbursts from comet 67P/Churyumov-Gerasimenko during its perihelion passage in 2015. The physical properties of the outbursts can be investigated by examining the time series of these high-resolution images. An analysis is made of the wide- and narrow-angle images obtained during the monitoring of the outburst sequences, which occurred between July and September in 2015. A ring-masking technique is used to calculate the excess brightness of the outbursts. The ejected mass and expansion velocity of the outbursts is estimated from differences in images made with the same filter (orange filter). The calculated excess brightness from these outburst plumes ranges from a few per cent to 28 per cent. In some major outbursts, the brightness contribution from the outburst plume can be one or two times higher than that of the typical coma jet activities. The strongest event was the perihelion outburst detected just a few hours before perihelion. The mass ejection rate during a generic outburst could reach a few per cent of the steady-state value of the dust coma. Transient events are detected by studying the brightness slope of the outburst plume with continuous streams of outflowing gas and dust triggered by driving mechanisms, as yet not understood, which remain active for several minutes to less than a few hours.

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