Fourth dwarf planet named as 'Makemake'
BY DR EMILY BALDWIN
ASTRONOMY NOW

Posted: July 22, 2008

The International Astronomical Union (IAU) has named the object formerly known as 2005 FY9 as ‘Makemake’, after the Polynesian creator of humanity and the god of fertility.

Artist impression of Makemake, a plutoid located in the outer Solar System, beyond the orbit of Neptune. Image: IAU, M. Kornmesser (ESA/Hubble).

Makemake (pronounced mah-keh mah-keh), at two-thirds the size of Pluto and only marginally dimmer with a peak magnitude of 16.5, is one of the largest objects in the known outer Solar System. It is now the fourth object to be welcomed into the dwarf planet family, and is the third member of the plutoid sub-category. Like other plutoids, Makemake is located in a region beyond Neptune – the transneptunian region – that is populated with small Solar System bodies. The tiny world appears red through a telescope, which astronomers believe is indicative of a surface covered by a layer of frozen methane.

The object was discovered in 2005 by a team from the California Institute of Technology led by Mike Brown, and was previously known as 2005 FY9 and identified by the IAU Minor Planet Centre by a number designation of 136472. The discoverer of a Solar System object has the privilege of suggesting a name to the IAU, which then judges its suitability.

"We consider the naming of objects in the Solar System very carefully,” says Mike Brown. “Makemake's surface is covered with large amounts of almost pure methane ice, which is scientifically fascinating, but really not easily relatable to terrestrial mythology.” So Brown used his personal experience of his wife being pregnant during the discoveries of not just Makemake, but also of Eris and 2003 EL61, to name the plutoid after the creator of humanity and the god of fertility according the mythology of the South Pacific Island Rapa Nui, or Easter Island.

Along with its companions Eris and 2003 EL61, Makemake was one of the objects whose discovery first prompted the IAU to reconsider the definition of a planet and to create the new group of dwarf planets. The other three dwarf planets are Ceres, Pluto and Eris, however, Ceres is not a member of the distinctive plutoid group because it is located in the asteroid belt between Mars and Jupiter.