101. Fine-grained region with low thermal inertia in craters on Ryugu
- Author
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Sakatani, N., Tanaka, S., Okada, T., Senshu, H., Arai, T., Demura, H., Suko, K., Shimaki, Y., Sekiguchi, Tomohiko, Takita, J., Fuhuhara, T., Tagucchi, M., Müller, T., Hagermann, A., Biele, Jens, Grott, Matthias, Hamm, Maximilian, Delbo, M, Sugita, Seiji, Honda, R., Morota, T., Yamada, M., Kameda, S., Tatsumi, E., Yokota, Y., Kouyama, Toru, Suzuki, H., Honda, C., Ogawa, Kazunori, Hayakawa, M., Yoshioka, K., Matsuoka, A., Cho, Yuichiro, Sawada, H., and Miuara, A.
- Subjects
Planetenphysik ,Hayabusa2 Ryugu ,Nutzerzentrum für Weltraumexperimente (MUSC) - Abstract
Introduction: The Hayabusa2 spacecraft is surveying asteroid Ryugu from June 2018. Global observation by thermal infrared imager TIR revealed low thermal inertia around 200-300J m-2 K-1 s-0.5 [1]. The expected grain size from this thermal inertia was several centimeters [2]. However, the surface of Ryugu is globally filled with larger boulders [3]. These observational results indicate highly porous nature of the surface boulders with low thermal inertia, unexpectedly different from the carbonaceous meteorites we have. Local observations by MARA radiometer onboard MASCOT lander supported it [4, 5]. In addition to the global observation, close-up imaging by TIR during descending operations, including MINERVA and MASCOT releases, touch-down operations and their rehearsals, were conducted. The high resolution TIR images revealed local temperature anomaly related to the boulders [6] and craters, which showed local variation in thermophysical properties.In this study, we show survey of thermally-unusual craters on Ryugu using these close-up images. The unique feature were found as hot spot around the center of some small craters.
- Published
- 2019