Xenon isotopes in 67P/Churyumov-Gerasimenko show that comets contributed to Earth's atmosphere.
Bernard MartyKathrin AltweggH BalsigerA Bar-NunDavid V BekaertJ-J BerthelierA BielerC BrioisUrsina CalmonteM CombiJohan De KeyserBjörn FietheStephen A FuselierSebastien GascTamas I GombosiKenneth C HansenM HässigA JäckelE KoppA KorthL Le RoyU MallO MousisT OwenHenri RèmeMartin RubinT SémonChia-Yu TzouJ Hunter WaitePeter WurzPublished in: Science (New York, N.Y.) (2018)
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.