Presentation Information
[R5-14]Microscale Thermal Diffusivity Measurement of Oued Chebeika 002
*Takuya Ishizaki1, Kensaku Moriya2, Yuma Enokido1, Ryosuke Sakurai2, Jay Black2, Brandon Mahan2, Tomohiro Usui1 (1. JAXA, 2. The University of Melbourne)
Keywords:
Thermal diffusivity,Oued Chebeika 002,Carbonaceous chondrite
The thermal diffusivity of materials derived from primitive bodies in the Solar System is a fundamental physical property governing the thermal-physical reaction process that occurred during the formation and evolution of their parent bodies, and is therefore an important parameter for understanding their origin and evolution, both physical and chemical. The Hayabusa2 and OSIRIS REx missions explored the primitive bodies C type asteroid Ryugu and B type asteroid Bennu, respectively, and successfully returned samples to Earth. Characterizing the physical properties of samples recovered directly from primitive bodies is of great importance because they have not experienced terrestrial weathering and their provenance is well constrained. Moreover, such measurements have high scientific value because they can be directly compared with data acquired from asteroid surfaces through remote sensing observations.
In contrast, the amount of material available from returned samples is limited, making it valuable to complement their characterization using Ivuna-type carbonaceous (CI) chondrites with mineralogical compositions similar to those of the Ryugu and Bennu samples. However, reported measurements of the thermal diffusivity of CI chondrites remain extremely limited and are restricted to those conducted by our group. Even in our own studies, the analyzed samples are limited to only five particles in total, consisting of three particles from the Ivuna meteorite and two from the Orgueil meteorite (Ishizaki et al., JpGU Proceedings, 2025). Furthermore, the Ivuna and Orgueil meteorites fell 88 and 164 years ago, respectively, and have been reported to have experienced terrestrial weathering compared with the Ryugu samples (Yokoyama et al., 2022). As a result, their thermomechanical properties may have been altered through compositional modification. For this reason, the present study focuses on Oued Chebeika 002, discovered in 2024. Although its fall date is unknown, Oued Chebeika 002 has experienced minimal terrestrial weathering and has been reported to be the most pristine CI chondrite identified to date, exhibiting a bulk chemical composition remarkably like those of the Ryugu and Bennu samples (Broussard et al., 2026). In this presentation, we report the thermal diffusivity of Oued Chebeika 002 and its relationship with local mineral lithologies, as determined using the lock-in thermography periodic heating method (Ishizaki et al., 2023). This enables the analysis of local thermal diffusivity heterogeneity at the submillimeter scale. The obtained thermal diffusivities are also compared to that of more altered meteorite samples, as well as those from returned asteroid samples, allowing us to begin constructing a framework of understanding for this important emerging research field.
In contrast, the amount of material available from returned samples is limited, making it valuable to complement their characterization using Ivuna-type carbonaceous (CI) chondrites with mineralogical compositions similar to those of the Ryugu and Bennu samples. However, reported measurements of the thermal diffusivity of CI chondrites remain extremely limited and are restricted to those conducted by our group. Even in our own studies, the analyzed samples are limited to only five particles in total, consisting of three particles from the Ivuna meteorite and two from the Orgueil meteorite (Ishizaki et al., JpGU Proceedings, 2025). Furthermore, the Ivuna and Orgueil meteorites fell 88 and 164 years ago, respectively, and have been reported to have experienced terrestrial weathering compared with the Ryugu samples (Yokoyama et al., 2022). As a result, their thermomechanical properties may have been altered through compositional modification. For this reason, the present study focuses on Oued Chebeika 002, discovered in 2024. Although its fall date is unknown, Oued Chebeika 002 has experienced minimal terrestrial weathering and has been reported to be the most pristine CI chondrite identified to date, exhibiting a bulk chemical composition remarkably like those of the Ryugu and Bennu samples (Broussard et al., 2026). In this presentation, we report the thermal diffusivity of Oued Chebeika 002 and its relationship with local mineral lithologies, as determined using the lock-in thermography periodic heating method (Ishizaki et al., 2023). This enables the analysis of local thermal diffusivity heterogeneity at the submillimeter scale. The obtained thermal diffusivities are also compared to that of more altered meteorite samples, as well as those from returned asteroid samples, allowing us to begin constructing a framework of understanding for this important emerging research field.