3794 Sthenelos

3794 Sthenelos (provisional designation 1985 TF3) is a medium-sized Jupiter Trojan asteroid, an object locked in the same orbit as Jupiter, located in the Greek camp that travels ahead of the planet. It was discovered by C. Shoemaker at Palomar Observatory on 12 October 1985 and is about 35 kilometers across¹.

Orbit

A later orbit solution gives a semi-major axis of 5.209 AU, eccentricity 0.1471, and inclination 6.06 degrees¹. One orbit takes 4,340 days, or 11.88 years¹.

The orbit is well determined because the observation record is long. The Minor Planet Center's orbit solution rests on 3,057 observations, with precovery observations dating back to 23 September 1949, more than three decades before the official discovery; the asteroid was last officially observed on 21 April 2023¹.

Physical characteristics

The diameter is measured at 34.531 km, with a geometric albedo of 0.112, meaning the surface reflects about 11 percent of the sunlight striking it¹. The Rice and Laughlin study lists the diameter as 34.531 ± 0.364 km². Its lightcurve gives a rotation period of 12.88 hours¹.

Use as an occultation case study

Sthenelos served as a worked example in a 2019 study by Rice and Laughlin published in The Astronomical Journal (volume 158, article 19) on the value of a large-scale stellar occultation (asteroid briefly blocking a star's light) network. Taking the JPL Small-Body Database orbit as the true orbit, the authors simulated successive occultations of the Trojan and measured how well such observations refine its orbital elements, reporting a semi-major axis of 5.204 au with an uncertainty of 1.246 × 10⁻⁷ au and an eccentricity of 0.147². The same study found a median of 7.42 occultations per year for the Trojans it sampled over a two-year simulation².

Context among the Trojans

Jupiter Trojans are trapped at Jupiter's stable L4 and L5 Lagrange points, 60 degrees ahead of and behind the planet³. Objects with similar orbits include 588 Achilles, 617 Patroclus, and 884 Priamus¹.

Because its orbit never brings it near Earth, JPL has not classified Sthenelos as potentially hazardous, and simulations by JPL's Center for Near-Earth Object Studies show no close Earth approaches; it is also not considered a viable target for human exploration under the NHATS study¹.

References

1. Asteroid Sthenelos, Space Reference
2. Rice & Laughlin (2019). The Case for a Large-scale Occultation Network. The Astronomical Journal 158:19.
3. Origin and Evolution of Jupiter's Trojan Asteroids (arXiv:2312.02864)

Topic: Encyclopedia › Places and geography › Extraterrestrial places › Small bodies of the Solar System › Jupiter Trojans and other dynamical groups › Greek-camp Jupiter Trojans › Figures of the Theban cycle

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

© 2026 Biostate AI. Free to use with credit under the Edgepedia Community License. Developers: read Edgepedia by API or MCP. Embed a reference card.