Thermal Analysis of 162173 Ryugu and the Moon

Introduction. The surface temperatures of asteroid Ryugu and the Moon have been measured by the TIR instrument onboard the Hayabusa 2 mission of JAXA 1 and the DIVINER of NASA's Lunar Reconnaissance Orbiter 2. The comparison between observed and calculated temperature allows the retrieval of thermophysical properties of an object; this is a link with the primordial solar system, since the physical structure and composition can be retrieved. Furthermore, the thermal inertia causes an asimmetric thermal emission and non gravitational perturbation on orbital parameters (Yarkovsky effect). In the lunar case, an indication for future landing sites may be also possible.Methods. We developed a thermophysical model for the calculation of surface temperature as function of thermal inertia and emissivity 3. The temperatures can be projected on the target shape model with the MATISSE tool 4.Results and future work. Some theoretical lunar temperatures have been checked with the measurements of the DIVINER instrument. In the future we want to study the permanently shadowed areas. The comparison theoretical-observed temperature for Ryugu will allow to properly modelize the rubble-pile asteroids.References.1 Okada, T., et al. (2017), Space Sci. Rev., 2082 Paige, D. A., et al. (2010), Space Sci. Rev., 1503 Rognini, E., et al. (2019), Journal of Geophysical Research: Planets, 1254 Zinzi, A., et al. (2016), Astronomy and Computing, 15