Analysis of Hybrid Gas–Dust Outbursts Observed at 67P/Churyumov–Gerasimenko

John W. Noonan (1, 2) , Giovanna Rinaldi (3) , Paul D. Feldman (4) , S. Alan Stern (1) , Joel Wm. Parker (1) , Brian A. Keeney (1) , Dominique Bockelée-Morvan (5) , Ronald J. Vervack Jr. (6) , Andrew J. Steffl (1) , Matthew M. Knight (7, 8) , Rebecca N. Schindhelm (1, 9) , Lori M. Feaga (7) , Jon Pineau (10) , Richard Medina (11) , Harold A. Weaver (6) , Jean-Loup Bertaux (12) , Michael F. A’hearn (7)

1 Department of Space Studies [Boulder]
2 LPL - Lunar and Planetary Laboratory [Tucson]
3 IAPS - Istituto di Astrofisica e Planetologia Spaziali - INAF
4 Department of Physics and Astronomy [Baltimore]
5 LESIA - Laboratoire d'études spatiales et d'instrumentation en astrophysique = Laboratory of Space Studies and Instrumentation in Astrophysics
6 APL - Johns Hopkins University Applied Physics Laboratory [Laurel, MD]
7 Department of Astronomy [College Park]
8 Department of Physics [Annapolis]
9 Ball Aerospace and Technology Corp.
10 Stellar Solutions, inc.
11 SwRI Department of Space Operations [Boulder]
12 PLANETO - LATMOS

Cometary outbursts offer a valuable window into the composition of comet nuclei with their forceful ejection of dust and volatiles in explosive events, revealing the interior components of the comet. Understanding how different types of outbursts influence the dust properties and volatile abundances, to better interpret what signatures can be attributed to primordial composition and what features are the result of processing, is an important task best undertaken with a multi-instrument approach. The European Space Agency Rosetta mission to 67P/Churyumov–Gerasimenko carried a suite of instruments capable of carrying out this task in the near-nucleus coma with unprecedented spatial and spectral resolution. In this work, we discuss two outbursts that occurred 2015 November 7 and were observed by three instruments on board: the Alice ultraviolet spectrograph, the Visual Infrared and Thermal Imaging Spectrometer, and the Optical, Spectroscopic, and Infrared Remote Imaging System. Together, the observations show that mixed gas and dust outbursts can have different spectral signatures representative of their initiating mechanisms, with the first outburst showing indicators of a cliff collapse origin and the second more representative of fresh volatiles being exposed via a deepening fracture. This analysis opens up the possibility of remote spectral classification of cometary outbursts with future work.

Domaines: Planète et Univers [physics]

John W. Noonan, Giovanna Rinaldi, Paul D. Feldman, S. Alan Stern, Joel Wm. Parker, et al.. Analysis of Hybrid Gas–Dust Outbursts Observed at 67P/Churyumov–Gerasimenko. The Astronomical Journal, 2021, 162 (1), pp.4. ⟨10.3847/1538-3881/abf8b4⟩. ⟨insu-03257234⟩