General · EdgepediaOctober 21, 20263 min read

1143 Odysseus

1143 Odysseus (provisional designation 1930 BH) is a large Jupiter Trojan asteroid in the Greek camp, the group of asteroids librating (oscillating around a stable orbital point) around Jupiter's leading L4 Lagrange point, 60 degrees ahead of the planet in its orbit. It was discovered by Karl Reinmuth at the Heidelberg-Königstuhl State Observatory on 28 January 1930 and named after the Greek hero Odysseus of Homer's Odyssey.¹^•²

Key fact	Detail
Discovery	28 January 1930, by K. Reinmuth at Heidelberg; provisional designation 1930 BH¹
Dynamical class	Jupiter Trojan, Greek camp at the L4 point, 60° ahead of Jupiter²
Rotation	Synodic period 10.1251 ± 0.0049 hours, lightcurve amplitude 0.16 mag³

Discovery and naming

Odysseus was found on 28 January 1930 at Heidelberg by Karl Reinmuth, who had also discovered several earlier Trojans including 911 Agamemnon (1919) and would go on to find 1172 Aeneas and 1208 Troilus later in 1930 and 1931.¹ By the time of its discovery the convention of naming Jupiter's L4 asteroids after Greek characters and L5 asteroids after Trojan characters from the Trojan War was established, and Odysseus, king of Ithaca, fits the Greek camp placement.⁴ The name refers to the hero who, after the war, wandered ten years before reaching home.⁵

Orbit

Odysseus shares Jupiter's orbit in the 1:1 mean-motion resonance, librating around the stable L4 point. A 400-year numerical integration of Trojan orbits places Odysseus among the objects with modest orbital-element drift over that interval, with a libration amplitude in the range tabulated for the L4 swarm.⁶

Physical properties

An occultation on 30 November 2023 was also observed, with an estimated maximum duration of 10.1 seconds and a magnitude drop of 1.6 mag.⁷

Thermal modeling of its infrared data yields a beaming parameter of 0.84 ± 0.07, a quantity that describes how the surface redirects thermal emission and feeds into diameter and albedo solutions.⁸

Rotation and lightcurve

Photometry at the Calvin Observatory in August 2007, based on 340 images taken over 13 to 18 August, gave a synodic rotation period of 10.1251 ± 0.0049 hours with an estimated amplitude of 0.16 mag.³ The same study's unbiased sample of ten Trojans had a median period of 18.9 hours, longer than similarly sized main-belt asteroids, which the authors suggested may indicate a lower average mass density among Trojans.³ Long-term CCD observations from four observatories determined Odysseus's magnitude–phase relation down to phase angles of 0.1–0.2 degrees and found it linear, with no noticeable opposition brightening in the V or R bands.⁹

Surface and clan membership

Multiple near-infrared spectra of Odysseus taken with different instruments show a broad absorption feature at 1.7 μm, a report that motivated its inclusion in a spectroscopic search for water ice on Jovian Trojans, which also observed 911 Agamemnon, 617 Patroclus, and 2797 Teucer.¹⁰

In a cladistic analysis of the Jovian Trojan swarms, Odysseus serves as the type object of the Greater Odysseus superclan, a group of 36 asteroids containing the Epistrophos clan (5 members) and the Odysseus clan (20 members). The superclan shows taxonomic diversity, including X-type and C-type members alongside the D-type type object.¹¹ Mission-design studies of Trojan rendezvous tours identified Odysseus, together with 624 Hektor, as one of the initial targets offering good all-around performance relative to other L4 objects.¹² The NHATS study does not consider it a viable target for human exploration.¹³

References

Topic: Encyclopedia › Places and geography › Extraterrestrial places › Small bodies of the Solar System › Jupiter Trojans and other dynamical groups › Greek-camp Jupiter Trojans › Leaders of the Achaean forces

Initially written Oct 21, 2026 · Edited: Oct 25, 2026

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