Xenon isotopes in 67P/Churyumov-Gerasimenko show that comets contributed to Earth's atmosphere
Wurz, P.; Altwegg, K.; Balsiger, H.; Rème, H.; Fuselier, S. A.; Berthelier, J. -J.; Bieler, A.; Calmonte, U.; Fiethe, B.; Gasc, S.; Gombosi, T. I.; Le Roy, L.; Rubin, M.; Tzou, C. -Y.; Mall, U.; Korth, A.; De Keyser, J.; Owen, T.; Sémon, T.; Waite, J. H.; Mousis, O.; Marty, B.; Combi, M.; Hässig, M.; Bar-Nun, A.; Briois, C.; Hansen, K. C.; Jäckel, A.; Kopp, E.; Bekaert, D. V.
Abstract
The origin of cometary matter and the potential contribution of comets to inner-planet atmospheres are long-standing problems. During a series of dedicated low-altitude orbits, the Rosetta Orbiter Spectrometer for Ion and Neutral Analysis (ROSINA) on the Rosetta spacecraft analyzed the isotopes of xenon in the coma of comet 67P/Churyumov-Gerasimenko. The xenon isotopic composition shows deficits in heavy xenon isotopes and matches that of a primordial atmospheric component. The present-day Earth atmosphere contains 22 ± 5% cometary xenon, in addition to chondritic (or solar) xenon.