1 research outputs found
Detection of argon in the coma of comet 67P/Churyumov-Gerasimenko
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