Haumea

Haumea (<a href="/facts/Minor-planet_designation/le4Ro9Xj">minor-planet designation</a>: 136108 Haumea) is a <a href="/facts/Dwarf_planet/IkQoCdwD">dwarf planet</a> located <a href="/facts/Trans-Neptunian_object/oF5vsbz9">beyond</a> <a href="/facts/Neptune/1eucwHIC">Neptune</a>'s orbit. It was discovered in 2004 by a team headed by <a href="/facts/Michael_E._Brown/Y5Jn22Tl">Mike Brown</a> of <a href="/facts/California_Institute_of_Technology/3FPcp7BL">Caltech</a> at the <a href="/facts/Palomar_Observatory/vRLjmDfr">Palomar Observatory</a>, and formally announced in 2005 by a team headed by <a href="/facts/Jos%25C3%25A9_Luis_Ortiz_Moreno/LgomYt86">José Luis Ortiz Moreno</a> at the <a href="/facts/Sierra_Nevada_Observatory/SKdl7fVc">Sierra Nevada Observatory</a> in <a href="/facts/Spain/bIyrB8EY">Spain</a>, who had discovered it that year in precovery images taken by the team in 2003. From that announcement, it received the provisional designation 2003 EL61.
On 17 September 2008, it was named after <a href="/facts/Haumea_(mythology)/HmQWUEg9">Haumea</a>, the Hawaiian goddess of childbirth and fertility, under the expectation by the <a href="/facts/International_Astronomical_Union/GMFPImXo">International Astronomical Union</a> (IAU) that it would prove to be a dwarf planet. Nominal estimates make it the <a href="/facts/List_of_Solar_System_objects_by_size/Aob1rVgh">third-largest known trans-Neptunian object</a>, after <a href="/facts/Eris_(dwarf_planet)/vuaR65F7">Eris</a> and <a href="/facts/Pluto/egq7MBeR">Pluto</a>, and approximately the size of Uranus's moon <a href="/facts/Titania_(moon)/Ts4j9JLM">Titania</a>. Precovery images of Haumea have been identified back to 22 March 1955.
Haumea's mass is about one-third that of Pluto and 1/1400 that of <a href="/facts/Earth/HLLmDfj0">Earth</a>. Although its shape has not been directly observed, calculations from its <a href="/facts/Light_curve/zN0wdtaR">light curve</a> are consistent with it being a <a href="/facts/Jacobi_ellipsoid/JSaIqJLU">Jacobi ellipsoid</a> (the shape it would be if it were a dwarf planet), with its major <a href="/facts/Axis_of_rotation/PGcg3IY5">axis</a> twice as long as its minor. In October 2017, astronomers announced the discovery of a <a href="/facts/Ring_system/KNCgIIX7">ring system</a> around Haumea, representing the first ring system discovered for a <a href="/facts/Trans-Neptunian_object/oF5vsbz9">trans-Neptunian object</a> and a dwarf planet.
Haumea's gravity was until recently thought to be sufficient for it to have relaxed into <a href="/facts/Hydrostatic_equilibrium/e75gVkh2">hydrostatic equilibrium</a>, though that is now unclear. Haumea's elongated shape together with its rapid <a href="/facts/Rotation/yChkz49x">rotation</a>, rings, and high <a href="/facts/Albedo/TJDRdKEB">albedo</a> (from a surface of crystalline water ice), are thought to be the consequences of a <a href="/facts/Impact_event/fbWu9Q4p">giant collision</a>, which left Haumea the largest member of a <a href="/facts/Collisional_family/jd9fDoXu">collisional family</a> (the <a href="/facts/Haumea_family/Muafyhym">Haumea family</a>) that includes several large <a href="/facts/Trans-Neptunian_object/oF5vsbz9">trans-Neptunian objects</a> and Haumea's two known moons, <a href="/facts/Moons_of_Haumea/HkHkdaFm">Hiʻiaka and Namaka</a>.

Haumea open-in-new

Haumea