We’ve been spending some time talking about dwarf planets, featuring Eris and Pluto, so I thought I’d spare a moment for a truly interesting (but often overlooked) member of the dwarf category; Haumea.  Remember, Sedna is a planetoid, and we have five known dwarf planets in the solar system:  Eris, Ceres, Pluto, Makemake, and Haumea.  Orcus, Quaoar, and 2007 OR(10) are dwarf planet candidates, by the way, sure to eventually be admitted to the club.

NASA/A. Feild - Artist's impression of Haumea and her two tiny moons

136108 Haumea was discovered in 2004 by a CalTech team headed by Mike Brown at the Palomar Observatory.  Haumea is the matron goddess of the island of Hawaii.  Boasting two tiny moons (Hi’iaka and Namaka) and an amazing ellipsoid shape, Haumea will certainly capture your attention.  Add a rotation period of about 3.9 hours and an orbital inclination of 28 degrees, and you see why Haumea gets talked about.

Thought to have formed in a collisional event in the scattered disc, Haumea is giving scientists plenty of food for thought.  For one thing, her collisional group has diffused to the point where scientist say the event must have occurred early in the formation of the solar system, say at least a billion years ago.  The problem is that the surface of Haumea and her family “group” is too bright for that length of time to have elapsed.  It appears as if the group was resurfaced within the last 100 million years.  That’s quite a puzzle, one for which no plausible explanation has been found.

Excellent grouping using NASA images, found on English WikiPedia by Lexicon

Haumea’s ellipsoid shape is a product of her blazing rotational speed -vs- her size.  She is in equilibrium in this shape.  With an average diameter of 1,400 km, she is the third or fourth largest of the dwarf planets and dwarf planet candidates, coming in behind Pluto, Eris, and maybe Makemake (we don’t know for sure yet).

Haumea’s tiny moons are believed to be fragments of Haumea herself, probably remnants of the collision which formed her.

All in all, and interesting member of our solar system, and well worth a few moments pause for thought.  Besides, she’s sure to show up in a future riddle!