Birth of a comet magnetosphere: A spring of water ions

Hans Nilsson, Gabriella Stenberg Wieser, Etienne Behar, Cyril Simon Wedlund, Herbert Gunell, Masatoshi Yamauchi, Rickard Lundin, Stas Barabash, Martin Wieser, Chris Carr, Emanuele Cupido, James L. Burch, Andrei Fedorov, Jean André Sauvaud, Hannu Koskinen, Esa Kallio, Jean Pierre Lebreton, Anders Eriksson, Niklas Edberg, Raymond GoldsteinPierre Henri, Christoph Koenders, Prachet Mokashi, Zoltan Nemeth, Ingo Richter, Karoly Szego, Martin Volwerk, Claire Vallat, Martin Rubin

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Abstract

The Rosetta mission shall accompany comet 67P/Churyumov-Gerasimenko from a heliocentric distance of >3.6 astronomical units through perihelion passage at 1.25 astronomical units, spanning low and maximum activity levels. Initially, the solar wind permeates the thin comet atmosphere formed from sublimation, until the size and plasma pressure of the ionized atmosphere define its boundaries: A magnetosphere is born. Using the Rosetta Plasma Consortium ion composition analyzer, we trace the evolution from the first detection of water ions to when the atmosphere begins repelling the solar wind (∼3.3 astronomical units), and we report the spatial structure of this early interaction. The near-comet water population comprises accelerated ions (<800 electron volts), produced upstream of Rosetta, and lower energy locally produced ions; we estimate the fluxes of both ion species and energetic neutral atoms.

Original languageEnglish
Article numberaaa0571
JournalScience
Volume347
Issue number6220
DOIs
Publication statusPublished - Jan 23 2015

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ASJC Scopus subject areas

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Nilsson, H., Wieser, G. S., Behar, E., Wedlund, C. S., Gunell, H., Yamauchi, M., Lundin, R., Barabash, S., Wieser, M., Carr, C., Cupido, E., Burch, J. L., Fedorov, A., Sauvaud, J. A., Koskinen, H., Kallio, E., Lebreton, J. P., Eriksson, A., Edberg, N., ... Rubin, M. (2015). Birth of a comet magnetosphere: A spring of water ions. Science, 347(6220), [aaa0571]. https://doi.org/10.1126/science.aaa0571