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

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 $\ddot{I}{‡}^2$ procedures. The pole coordinates, rotation period, volume-equivalent radius and geometric albedo were: $\hat{I}»$ = 153.73${}^o$ $\pm$ 2.5${}^o$, ${\hat{I}}^2$ = 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.

14 pages, 6 figures, 7 tables