624 Hektor

624 Hektor is the largest object in a special group of asteroids called the Jupiter trojan. These are rocks that share the same path around the Sun as the planet Jupiter. Hektor was found on 10 February 1907 by astronomer August Kopff at the Heidelberg Observatory in southwest Germany. It was named after Hector, a prince from ancient Greek stories.

This asteroid is very big and has a stretched-out shape. If it were made into a perfect ball, it would be about 225 to 250 kilometers wide. In 2006, scientists discovered that Hektor has a small companion, a tiny moon about 12 kilometers across, named Skamandrios. This makes Hektor special, as it is the only one in its group known to have such a companion, and it gives us clues about how these objects formed and moved through space.

Description

Hektor is a dark, reddish asteroid. It is found in Jupiter's leading Lagrangian point, called the Greek camp, named after one side in the legendary Trojan War. Hektor is named after the Trojan hero Hektor and is one of two trojan asteroids that is in the wrong camp, with the other being 617 Patroclus in the Trojan camp.

Contact-binary hypothesis

Hektor is one of the stretched-out objects of its size in the Solar System. It stretches about 403 km at its longest point but is much smaller in other directions, with a total space taking up the same room as a sphere about 250 km wide. Scientists think Hektor might be made of two smaller round pieces stuck together, similar to 216 Kleopatra.

Observations from the Hubble Space Telescope in 1993 didn’t clearly show this shape because the telescope couldn’t see very fine details. However, in 2006, the Keck telescope with special tools showed that Hektor likely has this two-part shape. Further studies also found that Hektor spins around once every about 6.9 hours.

Skamandrios

A small moon named Skamandrios was found orbiting 624 Hektor in 2006. It is about 10 to 15 kilometers wide and takes about 2.9651 days to go around Hektor. Its orbit is tilted and unusual, and its spinning might be very unpredictable.

Hektor was the first known Jupiter trojan with a moon like this, and it is one of only four known trojan asteroids in the L₄ group that have such companions.

Studies

In 2003, scientists used the Hubble telescope to study asteroids, including 624 Hektor. The telescope helped them look closely at these space rocks. Later, they used special equipment at the Keck Observatory to see binary asteroids for the first time.

Two sky surveys, called NEOWISE and AKARI, also took pictures of 624 Hektor. They guessed different sizes for it, from about 147 to 231 kilometers, mostly because they thought it reflected light differently.