We want to perform isotope analyses of near-Earth asteroid 25143 Itokawa silicate grains using the NanoSIMS 50L secondary ion mass spectrometer at Arizona State University (ASU). The analyses include measurement of water and hydrogen isotopes.
We were provided 5 multi-mineralic particles in November 2017. We measured and published the hydrogen isotope compositions of two orthopyoxene particles (Jin and Bose 2019a, Science Advances). The H isotope compositions and water content of Itokawa material is similar to that of earth’s within measurement uncertainties, and out study revealed how ‘wet’ Itokawa is. We estimated that impacts of Itokawa-like S-Type bodies could provide up to ½ of Earth’s oceans. We have also measured four Itokawa olivine particles and are currently preparing a manuscript for publication to Proceedings of the National Academy of Sciences. In addition, a comparison to L/LL 4-6 petrologic type ordinary chondrites from Antarctica was also made to the Itokawa olivines and pyroxenes and is a subject of a third paper to Earth and Planetary Science Letters.
In this proposal, (1) we propose to study Itokawa clinopyroxenes that have not been measured, along with other nominally anhydrous minerals. (2) We also aim to study one loose Itokawa grain. The purpose of the studying one loose grain is to prepare samples without water and epoxy and understand the effects of small amounts of epoxy during sample preparation.
The questions in this proposal can only be answered by studying samples from Itokawa and can provide valuable insight about S-type ‘rubble-pile’ asteroids with similar reflectance spectra.