The Big Brother Moon Of Haumea

Haumea has two known moons (Hi'iaka being the largest), which were both formed billions of years ago from icy debris blasted into orbit from Haumea. Yet these moons remained unknown to astronomers until their discovery in 2005!


Fast Summary Facts

  • Discovered: January 26th 2005 by a Caltech team utilizing the Keck Observatory
  • Name: Named after a Hawaiian goddess, the daughter of Haumea!
  • Size: Measuring approx 310 km and is believed to be irregular in shape
  • Moon Ranking: 23rd largest moon
  • Rotation: Believed to rotate in only 9.8 hrs!
  • Time to Orbit Haumea: 5 days
  • Surface material: Water ice

Extra Facts About Hiʻiaka!

  • Hiʻiaka was the first satellite discovered around the outer Solar System’s dwarf planet Haumea which itself was only discovered in 2004.
  • Hiʻiaka is one of two (the other being Namaka which is 1/10th the size of Hi’iaka) and the largest moon of Haumea.
  • If Hiʻiaka were located in the Asteroid Belt it would be the 5th largest object there!
  • Analysis by the Hubble Space Telescope suggests that water ice covers the surface which was unexpected considering its age and constant bombardment by cosmic rays.
  • Hiʻiaka has a very fast rotational rate, much faster than the expected tidally locked synchronous rate. The reason for this is unclear, but may have been the result of a glancing impact.
Haumea With Moons
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