February 10 – Discovery of Asteroid 624 Hektor (1907)

Asteroid 624 Hektor was discovered on February 10th 1907 by August Kopff, a German astronomer working out of the Humboldt University of Berlin, who eventually discovered 68 asteroids.

Being numbered 624 would normally put it below the radar, but this one gets a mention because it is the largest of the Jupiter trojans.  It’s a reddish D-type asteroid (as are the majority of Jupiter trojans) and lies at the L4 Lagrangian point (in other words it precedes Jupiter in its orbit).

L4 Jupiter trojans are supposed to be named after characters from the Greek side of the Trojan Wars.  Hektor is therefore misnamed, as he was on the Trojan side (617 Patroclus is also in a similar predicament, being a Greek hero in the Trojan camp at the L5 Lagrangian point).

Hector Reproaches Paris, by Pierre Delorme (1783-1859).
Hector Reproaches Paris, by Pierre Delorme (1783-1859).

Hektor measures 370 km long by 200 km wide, an unusual shape for an asteroid, leading astronomers to conclude that it might be a “binary”, two conventionally shaped asteroids drawn together by their mutual gravitational pull.  Observations indicate this may well be the case, but with an object of that size at such a great distance, it’s hard to be absolutely sure.

Hektor has also been shown to have a moon, about 12 km in diameter, going by the name S/2006 (624) 1.  Around 6,000 Jupiter trojans are known at present (although there are thought to be around a million up there of over 1 km diameter).  At present, Hektor is the only one at L4 thought to be a binary, and the only one known to have a satellite.

Hektor (you can call him Hector if you like, but there is no “C” in the Greek alphabet), as you may know, was the son of King Priam and Queen Hekabe, and the greatest Trojan hero of the wars, making it all the more unusual that he should be named as one of the Greek asteroids.