Physical characteristics of Jupiter's Trojan (1437) Diomedes from a tri-chord stellar occultation in 2020 and dimensionless three-dimensional model

Jupiter Trojans preserve primitive formation characteristics owing to their collisionless, stable orbits. Determination of their shapes and size-frequency distribution helps constrain the collisional evolution of their parent population, which also originated the Kuiper Belt. We started a programme to find precise sizes/shapes for Trojans, combining stellar occultations and the Database of Asteroid Models from Inversion Techniques (DAMIT) three-dimensional shape models. We report results for Diomedes, by fitting its unit dimensionless three-dimensional model to three chords of a stellar occultation observed in 2020, using iterative [Formula: see text] procedures. The pole coordinates, rotation period, volume-equivalent radius and geometric albedo were [Formula: see text] = 153.73°[Formula: see text] 2.5°, [Formula: see text] = 12.69° [Formula: see text] 2.6°, [Formula: see text] = 24.4984 [Formula: see text] 0.0002 h, [Formula: see text] = 59.4 [Formula: see text] 0.3 km and [Formula: see text] = 0.030 [Formula: see text] 0.004, respectively. A precise position was also obtained.This article is part of the theme issue 'Major advances in planetary sciences thanks to stellar occultations'.