This is an artist's impression of the dwarf planet Haumea and its two moons Hi'iaka and Namaka. Notice how Haumea's rapid rotation has stretched it into an elliptical (not spherical) shape. Click on image for full size (25 Kb) Images courtesy of NASA, ESA, and A. Feild (STScI).

Haumea is a dwarf planet in our Solar System. Haumea is the fifth object officially classified as a dwarf planet; the previous four are Pluto, Eris, Ceres, and Makemake. The International Astronomical Union announced Haumea's official status as a dwarf planet in September 2008.

Haumea is a large Kuiper Belt Object (KBO) that orbits far from the Sun on the frozen fringes of our Solar System. Because it is so far away, Haumea takes 285 years to orbit the Sun once! On average, Haumea is about 10% further from the Sun than Pluto, though both of these dwarf planets move closer to and further from the Sun as they go around.

Haumea is smaller than both Pluto and Eris. Haumea is not spherical. Haumea rotates so rapidly that it has been stretched into the shape of an ellipsoid (3D ellipse). This strange body measures 1,960 km (1,218 miles) along its longest axis, but only about half that - 996 km (619 miles) - along its shortest.

The "days" are really short on Haumea. This odd object spins around in less than four hours! That is the shortest rotation period of any known Solar System object larger than 100 km. Haumea is also relatively dense, tipping the scales at 2.6 to 3.3 g/cm³. That probably means it is made mostly of rock, which is somewhat odd since most KBOs have quite a bit of ice (which is less dense) in them. Haumea has known moons, both discovered in 2005. They are named Hi'iaka and Namaka.

Astronomers have a theory that links Haumea's rapid rotation, odd shape, and strange composition. They believe Haumea collided with another large object sometime in the distant past. The collision set Haumea spinning, giving it its odd shape. Outer layers of lightweight ice would have been more easily knocked loose by the collision, leaving behind denser rocks. Haumea's moons may also be leftover debris from the collision.

In Hawaiian mythology, Haumea is the goddess of fertility and childbirth. Her children include Hi'iaka and Namaka, as well as the Hawaiian volcano and fire goddess Pele.

There is some controversy concerning who should be credited with the discovery of Haumea. A group led by Mike Brown of the California Institute of Technology noticed Haumea in December 2004 on images taken in May 2004. Another group, led by José Luis Ortiz Moreno at the Sierra Nevada Observatory in Spain, filed a notification of the discovery of Haumea in July 2005. They had spotted the dwarf planet on images taken in March 2003. It isn't yet clear which group will eventually be given official recognition for the discovery.

Haumea was called 2003 EL61 before it received its official, permanent name. It was formerly nicknamed "Santa" by Brown's group due to its discovery near Christmas in 2004.

This is what an artist thinks Haumea looks like. This drawing shows the dwarf planet and its two moons Hi'iaka and Namaka. Notice how Haumea's fast spin has stretched it into an oval (not spherical) shape. Click on image for full size (25 Kb) Images courtesy of NASA, ESA, and A. Feild (STScI).

Haumea is a dwarf planet in our Solar System. Haumea is officially the fifth dwarf planet. The four that came before it are Pluto, Eris, Ceres, and Makemake. Haumea was classified a dwarf planet in September 2008.

Haumea is a large Kuiper Belt Object (KBO). It is an icy world that orbits far from the Sun on the frozen fringes of our Solar System. Because it is so far away, Haumea takes 285 years to orbit the Sun once! Haumea is usually a bit further from the Sun than Pluto.

Haumea is smaller than both Pluto and Eris. Haumea has an odd shape. It is not a sphere. It is spinning so quickly that it has been stretched into the shape of an ellipsoid (a 3D ellipse). Haumea is 1,960 km (1,218 miles) across at its longest. It is only about half that far across - 996 km (619 miles) - along its shortest axis.

The "days" are really short on Haumea. This weird object spins around in less than four hours! Haumea is fairly dense. That means it is probably made mostly of rock. Most other KBOs probably have more ice in them than Haumea. This dwarf planet has known moons, both discovered in 2005. Their names are Hi'iaka and Namaka.

Astronomers think Haumea collided with another large object a long time ago. A collision like that might explain Haumea's strange shape and why it spins so fast. The big collision might have knocked away most of Haumea's lightweight ice, leaving behind heavier rock. Haumea's moons may be leftover stuff from the collision.

In the mythology of Hawaii, Haumea is the goddess of fertility and childbirth. Her children include Hi'iaka and Namaka, as well as the Hawaiian volcano and fire goddess Pele.

There are two different groups that might get credit for discovering Haumea. One group is led by Mike Brown of the California Institute of Technology. The other group's leader is José Luis Ortiz Moreno at the Sierra Nevada Observatory in Spain. Haumea was discovered sometime between March 2003 and July 2005.

Haumea was called 2003 EL61 before it got its official, permanent name. It had been nicknamed "Santa" by Brown's group because they discovered it near Christmas in 2004.

This is what an artist thinks Haumea looks like. This drawing shows the dwarf planet and its two moons Hi'iaka and Namaka. Notice how Haumea's fast spin has stretched it into an oval (not spherical) shape. Click on image for full size (25 Kb) Images courtesy of NASA, ESA, and A. Feild (STScI).

Haumea is a dwarf planet in our Solar System. Haumea is officially the fifth dwarf planet. The four that came before it are Pluto, Eris, Ceres, and Makemake. Haumea officially became a dwarf planet in September 2008.

Haumea is a large Kuiper Belt Object (KBO). It is an icy world that orbits far from the Sun on the edge of our Solar System. Because it is so far away, Haumea takes 285 years to orbit the Sun once! Haumea is usually a bit further from the Sun than Pluto.

Haumea is smaller than both Pluto and Eris. Haumea has an odd shape. It is not a sphere. It is spinning very quickly. That fast spin has stretched it into the shape of an ellipsoid (a 3D ellipse). Haumea is 1,960 km (1,218 miles) across one direction. It is only about half that far across - 996 km (619 miles) - along its shortest axis!

The "days" are really short on Haumea. This weird object spins around in less than four hours! Haumea has known moons. Both were discovered in 2005. Their names are Hi'iaka and Namaka.

Astronomers think Haumea crashed into another large object a long time ago. That might explain Haumea's strange shape and why it spins so fast. Haumea's moons may be leftover stuff from the collision.

In the mythology of Hawaii, Haumea is the goddess of fertility and childbirth. Her children include Hi'iaka and Namaka, as well as the Hawaiian volcano and fire goddess Pele.

There are two groups that might get credit for discovering Haumea. One group is led by Mike Brown of the California Institute of Technology. The other group is led by José Luis Ortiz Moreno at the Sierra Nevada Observatory in Spain. Haumea was discovered sometime between March 2003 and July 2005.

Haumea was called 2003 EL61 before it got its official, permanent name. It had been nicknamed "Santa" by Brown's group because they discovered it near Christmas in 2004.