Detection of argon in the coma of comet 67P/Churyumov-Gerasimenko
By Hans Balsiger, Kathrin Altwegg, Akiva Bar-Nun, Jean-Jacques Berthelier, Andre Bieler, Peter Bochsler, Christelle Briois, Ursina Calmonte, Michael Combi, Johan De Keyser, Peter Eberhardt, Björn Fiethe, Stephen A. Fuselier, Sébastien Gasc, Tamas I. Gombosi, Kenneth C. Hansen, Myrtha Hässig, Annette Jäckel, Ernest Kopp, Axel Korth, Lena Le Roy, Urs Mall, Bernard Marty, Olivier Mousis, Tobias Owen, Henri Rème, Martin Rubin, Thierry Sémon, Chia-Yu Tzou, J. Hunter Waite, Peter Wurz
Science Advances 25 Sep 2015:
Vol. 1, no. 8, e1500377
DOI: 10.1126/sciadv.1500377
“Comets have been considered to be representative of icy planetesimals that may have contributed a significant fraction of the volatile inventory of the terrestrial planets. For example, comets must have brought some water to Earth. However, the magnitude of their contribution is still debated. We report the detection of argon and its relation to the water abundance in the Jupiter family comet 67P/Churyumov-Gerasimenko by in situ measurement of the Rosetta Orbiter Spectrometer for Ion and Neutral Analysis (ROSINA) mass spectrometer aboard the Rosetta spacecraft. Despite the very low intensity of the signal, argon is clearly identified by the exact determination of the mass of the isotope 36Ar and by the 36Ar/38Ar ratio. Because of time variability and spatial heterogeneity of the coma, only a range of the relative abundance of argon to water can be given. Nevertheless, this range confirms that comets of the type 67P/Churyumov-Gerasimenko cannot be the major source of Earth’s major volatiles.”
