Neon in interior of the asteroid Vesta and comparison with the terrestrial planets

Abstract

We investigate the neon isotopic composition and elemental abundance in eucrites and diogenites and compare them with the inventories from interiors of the terrestrial planets. The framework of this study is the utilization of isotopic data of eucrites and diogenites in order to constrain the trapped components in Vesta. The isotopic ratios 20Ne/22Ne and 21Ne/22Ne in eucrites and diogenites are dominated by the cosmogenic component. We estimate the average abundances of 20Ne trapped in diogenites as, 1.02 × 10-8 cm3STP/g and in eucrites as, 8.02 × 10-9 cm3STP/g, respectively. The concentrations of trapped 20Ne in diogenites and eucrites are lower by an order compared to the chondrites, but similar to the interiors of the planets Earth and Mars. Preferential degassing of neon during accretionary and post-accretionary processes in Vesta and its subsequent loss to space is considered as a viable mechanism for the observed depletion in the eucrites and diogenites.

Keywords

• Neon
• Eucrites
• Diogenites
• Trapped components