Japan Geoscience Union Meeting 2018

Presentation information

[EE] Oral

P (Space and Planetary Sciences) » P-PS Planetary Sciences

[P-PS03] Small Bodies in the Solar System: Current Understanding and Future Prospects

Thu. May 24, 2018 10:45 AM - 12:15 PM A02 (Tokyo Bay Makuhari Hall)

convener:Masateru Ishiguro(Department of Physics and Astronomy, Seoul National University), Taishi Nakamoto(Tokyo Institute of Technology), Masahiko Arakawa(神戸大学大学院理学研究科, 共同), Masanao Abe(Institute of Space and Astronautical Science, Japan Aerospace Exploration Agency), Chairperson:Abe Masanao(Institute of Space and Astronautical Science, JAXA)

11:15 AM - 11:30 AM

[PPS03-20] Study of asteroid interior using Hayabusa2 LIDAR

★Invited Papers

*Noriyuki Namiki1, Ryuhei Yamada2, Hiroki Senshu3, Hirotomo Noda1, Koji Matsumoto1, Keiko Yamamoto1 (1.RISE Project, National Astronomical Observatory of Japan, 2.The University of Aizu, Department of Computer Science and Engineering, 3.PERC/Chitech)

Keywords:topography, gravity, asteroid

LIDAR science team of Hayabusa2 has developed Laser altimeter named LIDAR (LIght Detection And Ranging). Hayabusa2 and LIDAR were launched on December 3, 2014, and are heading for asteroid Ryugu. Meanwhile, the science team has been studying surface processes and interior of minor bodies aiming to
- elucidate formation processes of small asteroids and examine models of their collisional evolution
- clarify geologic processes ocurring on the surfce of asteroids such as both horizontal and vertical transport of regolith and bolders to understand a context of return samles.
LIDAR provides range measurements as well as intensities of transmitted and reflected laser pulses. For details of instrument and observation plans, please refer Mizuno et al. (Space Sci. Rev., 2017, 208, pp 33–47) which describes LIDAR specifications and operation plans, Yamada et al. (Space Sci. Rev., 2017, 208, pp 49–64) for albedo observation, and Senshu et al. (Space Sci. Rev., 2017, 208, pp 65–79) that explains asteroid dust detection experiment.

We wish to study interior of Ryugu, however, we do not expect for the asteroid to have differenciated like the moon and Mars. Instead, we could possibly find heterogenity as a tracer of collision and accretion, both horizontal and vertical transfers of regolith and bolders, and an indication of consequent material evolution. Such findings will be an important a priori information to understand results of meteorite analysis. Currently, few meteorite scientists take into account material transport inside of asteroids or vertical movements of rocks within regolith layer. Remote sensing observations and an impactor experiment of Hayabusa2 may change such static view of asteroid surface. After Hayabusa2, Martian Moons eXplorer (MMX) and Phaethon flyby mission (DESTINY+) are scheduled already in Japan. New insights likely obtained by Hayabusa2 and LIDAR will be a critical source of information necessary to elucidate water transfer within the solar system and pre-biotic environmet.