Diffraction modelling of a 2023 March 5 stellar occultation by subkilometer-sized asteroid (98943) 2001 CC21

TL;DR

This paper introduces a new diffraction-based modeling technique to analyze a stellar occultation by asteroid 98943 2001 CC21, revealing its elongated shape and aiding flyby mission planning.

Contribution

We developed DOUSHITE, a novel data reduction method for diffraction-affected light curves, enabling shape constraints from single-chord occultation data.

Findings

Asteroid 98943 2001 CC21 has a highly elongated shape with an axis ratio of 0.37±0.09.

The diffraction modeling improves shape determination accuracy from limited occultation data.

Results assist in optimizing Hayabusa2's flyby trajectory and imaging.

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 March 5, 2023. To accurately determine the asteroid's shape from diffraction-affected light curves, 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 $b/a = 0.37\pm0.09$. This shape can be crucial for planning Hayabusa2's high-speed flyby to optimise the limited imaging opportunities.