26th Largest Asteroid, 624 Hektor [Largest Jupiter Trojan]

624 Hektor is the largest Jupiter Trojan and is the 26th largest asteroid currently known.

Discovery

624 Hektor was discovered on Feb 10, 1907 by August Kopff at Heidelberg.

Naming

Hektor is named after the Trojan hero Hektor.

In Greek mythology, Hectōr or Hektōr, was a Trojan prince and the greatest fighter for Troy in the Trojan War. He acts as leader of the Trojans and their allies in the defense of Troy, killing 31 Greek fighters in all.

Stats

Diameter (mean): 203 km
Aphelion: 5.349 AU
Perihelion: 5.121 AU
Semi-major axis: 5.243 AU
Orbital Period: 12.01 years
Rotation period: 6.924 hrs
Date discovered: 1907.2.10
Class: D
Satellite: 1
Type: Jupiter Trojan
(data from JPL Small-Body Database)

Orbit

Hektor is a D-type asteroid, dark and reddish in colour. It lies in Jupiter's leading Lagrangian point, L4, called the 'Greek' node after one of the two sides in the legendary Trojan War.

Hektor is thus one of two trojan asteroids that is "misplaced" in the wrong camp (the other being 617 Patroclus in the Trojan node).

Formation

Hektor is found to be a truly extraordinary object in that it is larger and far more irregular in shape than other measured Trojans and far more irregular than other belt asteroids of comparable size.

It is proposed that Hektor could be a partially coalesced pair of Trojan asteroids which collided with energy too low to cause complete fragmentation, thus forming a dumbbell-shaped object.

Contact binary plus moonlet

Hektor is one of the most elongated bodies of its size in the Solar System, being 370 × 200 km. It is thought that Hektor might be a contact binary. Hubble Space Telescope observations of Hektor in 1993 did not show an obvious bilobate shape because of a limited angular resolution.

On 17 July 2006, the Keck-10m II telescope and its Laser guide star Adaptive Optics (AO) system indicated a bilobate shape for Hektor.

Additionally, a 15-km moonlet at 1000 km of Hektor was detected. The satellite's provisional designation is S/2006(624)1.

Hektor is, so far, the only known binary trojan asteroid in the L4 point and the first trojan with a satellite companion.