File:2003 EL61.jpg
Hiʻiaka is above Haumea (center) in this Keck telescope image.
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Discovery | |
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Discovered by | Michael E. Brown, Chad Trujillo, David Rabinowitz, et al. |
Discovery date | 2005 January 26 |
Designations | |
Designation | Haumea I Hiʻiaka |
Pronunciation | /ˌhiːʔiːˈɑːkə/,[1] or as in Hawaiian /ˈhiʔiˈjɐkə/ |
(136108) 2003 EL61 I, S/2005 (2003 EL61) 1 | |
Orbital characteristics[2] | |
49 880 ± 198 km | |
Eccentricity | 0.0513 ± 0.0078 |
49.12 ± 0.03 days | |
Inclination | 126.356 ± 0.064° |
Satellite of | Haumea |
Physical characteristics | |
Mean radius | ~155 km |
Mass | 1.79 ± 0.11×1019 kg[2] (0.45% of Haumea) |
Mean density | (unknown; close to 1 if water ice) |
(unknown) | |
(unknown) | |
Albedo | (unknown) |
Temperature | 32 ± 3 K |
3.3 difference from primary's 17.3 | |
Hiʻiaka is the larger, outer moon of the dwarf planet Haumea.
Hiʻiaka was the first satellite discovered around Haumea. It is named after one of the daughters of Haumea, Hiʻiaka, the patron goddess of the Big Island of Hawaii, though at first it had gone by the nickname "Rudolph" by its discovery team. It orbits once every 49.12 ± 0.03 days at a distance of 49,880 ± 198 km, with an eccentricity of 0.0513 ± 0.0078 and an inclination of 126.356 ± 0.064°. Mutual events expected in July 2009 should improve the knowledge of the orbits and masses of the Haumea system[2].
Measured brightness is 5.9 ± 0.5% translating into the diameter about 22% of its primary, or in the range of 350 km, assuming similar albedo. To put this in perspective, this moon would be the fifth largest (cis-neptunian) asteroid after 1 Ceres, 2 Pallas, 4 Vesta, and 10 Hygiea if it were in the asteroid belt, as it can be seen in the list of largest known asteroids.
The mass of Hiʻiaka is estimated to be 1.79 ± 0.11×1019 kg[2] using precise relative astronometry from Hubble Telescope and Keck Telescope and applying 3-body, point-mass model to the Haumea system.
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Moons and rings |
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Dwarf planets (moons) |
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