[P-PS03] 太陽系小天体：太陽系の形成と進化における最新成果と今後の展望

[PPS03-P05] Occultation Observations and Shape Model of DESTINY's Target Asteroid (3200) Phaethon

*Fumi Yoshida^1,2、Tomoko Arai²、Sean Marshall^3,4 (1.University of Occupational and Environmental Health, Japan、2.Chiba Institute of Technology、3.Arecibo Observatory 、4.University of Central Florida)

キーワード：Asteroids, Flyby mission, (3200) Phaethon

The DESTINY⁺ mission is a flyby mission to the asteroid (3200) Phaethon, the parent body of the Geminids meteor shower. The spacecraft is scheduled for launch in 2024 and the Phaethon flyby in 2028. Due to the orbital configuration between Phaethon and the spacecraft, there's not enough time to observe Phaethon on board prior to the flyby to obtain the necessary information for autonomous flyby imaging. Therefore, the mission's science team is working together to conduct thorough preliminary ground observations to understand the size of the Phaethon, its surface reflectivity, and interesting surface features, in order to optimize imaging during the flyby.

Among the various observations, we have conducted observation campaign for stellar occultation, which provide the most accurate measurements of the size and shape of asteroids. Since 2019, professional and amateur observers have gathered at every opportunity to observe stellar occultation by Phaethon. In Japan, the occultation observations on October 3, 2021 and October 21, 2022 were very successful.

Here we compare the cross sections of the Phaethon obtained from these observations with the shape model of the Phaethon derived from the light curves obtained from previous radar and photometric observations.

The 3D shape model of Phaethon is being refined using the results of occultation observations.
There will be many opportunities for occultation observations before the Phaethon flyby, and we plan to continue our observations. We are looking forward to seeing how close we can get to the actual 3D shape of Phaethon through ground-based observations.