— Analysis of extraterrestrial material by WDXRF and TG-MS —
Abstract
Spacecraft HAYABUSA2 successfully collected a 5.4 g sample from the surface of asteroid Ryugu that was returned to Earth on Dec. 6, 2020. Analysis of the asteroid Ryugu sample was performed using a ZSX Primus IV wavelength dispersive X-ray spectrometer and a Thermo plus EVO2 TG-DTA8122 thermogravimetric differential thermal analyzer coupled with GC-MS (TG-MS).
A very small (24 mg) Ryugu sample (C0108) was analyzed by XRF in powder form without any pelletization or thin film covering. Analytical results by the fundamental parameter (FP) method for 23 elements including carbon and oxygen were consistent with the values from other analytical methods. Elemental abundance in Ryugu shows close similarity with the abundance determined for the CI chondrite meteorite, whose composition is the most primitive and similar to solar system elemental abundance.
About 1 mg of Ryugu sample grain A0040 was used for the TG-MS measurement. Total H₂O and CO₂ content of the Ryugu sample were 6.8 and 5.5 mass%, respectively. The Ryugu sample contains less H₂O than CI chondrite does. The TG-MS measurement reveals differences in H₂O release behavior at low temperature (< 300°C) between Ryugu and CI chondrite.