A new primordial noble gas component in the solar system discovered in Ryugu asteroidOPEN ACCESS 

Alexander Verchovsky, Feargus Abernethy, Mahesh Anand, Ian Franchi and 31 more authors

Nature PREPRINT under review, Version 1, posted 05 Dec, 2023


“Ryugu is the C-type asteroid from which material was brought to Earth by the Hayabusa2 mission. A number of individual grains and fine-grained samples analysed so far for noble gases have indicated that solar wind and planetary (P1=Q) noble gases are present in Ryugu samples with concentrations higher than those observed in CIs, suggesting the former to be more primitive compared to the latter. We analysed three fine-grained samples from Ryugu, one of which contained a Xe concentration an order of magnitude higher (4×10-7 cc STP/g) than previously found in samples from Ryugu. Isotopically, this Xe resembles Q, but with a much stronger (by a factor of four) isotopic fractionation relative to solar wind and an 36Ar/132Xe ratio at least an order of magnitude lower than in P1. This new planetary primordial noble gas component (here termed P7) provides clues to constrain how the solar composition was fractionated to form the planetary components.”