Sequential analysis of carbonaceous materials in Hayabusa-returned samples for the determination of their origin

Abstract

Preliminary results of the analyses of five carbonaceous materials (particle size of approximately 50 μm) from the Hayabusa spacecraft sample catcher, including their texture, chemistry, and chemical/isotopic compositions, are summarized. The carbonaceous particles underwent sequential analysis using a series of microanalytical instruments located at several research institutes and universities. Collected particles were initially classified into four categories: two categories containing extraterrestrial silicate particles, one category containing metal and quartz particles consistent with contamination from the sample catcher or sample manipulation tools, and a final category containing carbonaceous particles. Analysis of this final category was the main focus of this study. Through examination of the carbonaceous materials, the appropriate analytical processes for sample transportation and handling were optimized to minimize sample damage and terrestrial contamination. Particles were investigated by transmission electron microscopy/scanning transmission electron microscopy, and Ca-carbonate inclusions were found in one particle. In a different particle, a heterogeneous distribution of silicon in a uniform C, N, and O matrix was found. Though further analysis is required for a strict determination of particle origin, the differences in the microstructure and elemental distribution of the carbonaceous particles suggest multiple origins.

A micro-Raman and infrared study of several Hayabusa category 3 (organic) particles

“…Further analyses by TEM/STEM , N-XANES , and H, C, and N isotopic investigation ) revealed the presence of N in the RB-QD04-0047-02 and RA-QD02-0120 particles. A detailed description of the category 3 particles is given in Uesugi et al (2014). Because the particles must be fixed in some manner for the NanoSIMS and ToF-MS analyses planned as parts of a sequential analysis, they were pressed onto gold plates at the PMSCF/JAXA (The Planetary Material Sample Curation Facility of JAXA).…”

“…Besides the silicate particles, several carbon-rich particles classified into category 3 have been found in the sample catcher (e.g., Yada et al 2014;Uesugi et al 2014). The particles are mainly composed of carbon and often contain oxygen, nitrogen, and sulfur ).…”

Adhering grains and surface features on two Itokawa particles

“…The typical contaminants described so far among the Itokawa particles are metallic Al, tin oxide, quartz particles, and probably carbonaceous particles Uesugi et al 2014). Only one of the ten adhering grains we analyzed was possibly contamination, the Crich grain shown on the right of Fig.…”

ToF-SIMS analysis of carbonaceous particles in the sample catcher of the Hayabusa spacecraft

“…Three category 3 particles (RB-QD04-0047-02, RB-QD04-0037-01, and RA-QD02-0180) were allocated for ToF-SIMS analysis. These were the typical particles of the blocky-shaped samples, which were classified as type I (38 of a total of 52 category 3 particles; Uesugi et al 2014). The samples are described in the following paragraphs in their analytical order.…”