Physical Characteristics of Jupiter's Trojan (1437) Diomedes from a Tri-chord Stellar Occultation in 2020 and Dimensionless 3D Model

TL;DR

This study combines stellar occultation data and 3D modeling to accurately determine the physical characteristics of Jupiter's Trojan asteroid Diomedes, providing insights into its shape, size, and rotation.

Contribution

It introduces a method integrating stellar occultation observations with dimensionless 3D models to precisely characterize Trojan asteroids.

Findings

Pole coordinates and rotation period determined.

Dimensionless 3D model fitted to occultation chords.

Estimated size and albedo of Diomedes provided.

Abstract

Jupiter Trojans preserve primitive formation characteristics due to their collisionless stable orbits. Determination of their shapes and size-frequency distribution constrains the collisional evolution of their parent population which also originated the Kuiper Belt. We started a program to find precise sizes/shapes for Trojans, combining stellar occultations and DAMIT 3D shape models. We report results for Diomedes, by fitting its dimensionless 3D model to 3 chords of a stellar occultation observed in 2020, using iterative $\chi^{2}$ procedures. The pole coordinates, rotation period, volume-equivalent radius and geometric albedo were: $\lambda$ = 153.73$^{o}$ $\pm$ 2.5$^{o}$, $\beta$ = 12.69$^{o}$ $\pm$ 2.6$^{o}$, $P$ = 24.4984 $\pm$ 0.0002 h, $R_{eq}$ = 59.4 $\pm$ 0.3 km and $p_{V}$ = 0.030 $\pm$ 0.004. A precise position was obtained too.