Diffraction modelling of a 2023 March 5 stellar occultation by subkilometer-sized asteroid (98943) 2001 CC21
Arimatsu, Ko; Hirabayashi, Masatoshi; Akitaya, Hiroshi; Imazawa, Ryo; Yoshikawa, Makoto; Hashimoto, George L.; Yoshida, Fumi; Hayamizu, Tsutomu; Ida, Miyoshi; Abe, Takashi; Aratani, Akari; Fukuda, Hidekazu; Fujita, Yasuhide; Fujiwara, Takao; Horikawa, Toshihiro; Iihoshi, Tamio; Imamura, Kazuyoshi; Kasebe, Hisashi; Kawasaki, Ryosuke; Kishimoto, Hiroshi; Mishima, Kazuhisa; Miyachi, Machiko; Mizutani, Masanori; Nakajima, Maya; Nakatani, Hiroyoshi; Okamura, Kazuhiko; Okanobu, Misaki; Okuda, Masataka; Suzuki, Yuji; Tatsumi, Naoto; Uno, Masafumi; Yamamura, Hidehito; Yasue, Mikoto; Yoshihara, Hideki
Japan, United States
Abstract
We present an analysis of a stellar occultation event caused by a near-Earth asteroid (98943) 2001 CC21, an upcoming flyby target in the Hayabusa2 extended mission, on 2023 March 5. To determine the asteroid's shape from diffraction-affected light curves accurately, we developed a novel data-reduction technique named the Diffracted Occultation's United Simulator for Highly Informative Transient Explorations (DOUSHITE). Using DOUSHITE-generated synthetic models, we derived constraints on (98943) 2001 CC21's shadow shape from the single-chord occultation data. Our results suggest a significant elongation of the shadow with an axis ratio of $b/a = 0.37\pm 0.09$. This shape could be crucial for planning Hayabusa2's high-speed flyby to optimise the limited imaging opportunities.