Hiiaka (moon)
Namaka is the faint spot near the bottom of the photo, directly below Haumea (center), in this Keck telescope image.
|
|
| Discovery | |
|---|---|
| Discovered by |
Michael E. Brown, Chad Trujillo, David Rabinowitz, et al. |
| Discovery date | 30 June 2005 |
| Designations | |
| MPC designation | Haumea II Namaka |
| Pronunciation | /nɑːˈmɑːkə/ nah-MAH-kə |
|
(136108) 2003 EL61 II, S/2005 (2003 EL61) 2 |
|
| Orbital characteristics | |
| Epoch JD 2454615.0 | |
| 25657±91 km | |
| Eccentricity | 0.249±0.015 (in 2009; variable) |
| 18.2783±0.0076 d | |
| 178.5°±1.7° | |
| Inclination |
113.013°±0.075° 13.41°±0.08° relative to Hiʻiaka (in 2008; variable) |
| 205.016°±0.228° | |
| 178.9°±2.3° | |
| Satellite of | Haumea |
| Physical characteristics | |
|
Mean radius
|
~85 km (if albedo is same as primary's 0.7±0.1) |
| Mass | 1.79 ± 1.48×1018kg (0.05% the mass of Haumea) |
|
Mean density
|
(assumed to be near 1 g/cm3) |
| Albedo | 0.8±0.2 |
| Temperature | 32±3 K |
| 21.9 (4.6 difference from primary's 17.3) | |
|
Hiʻiaka is above Haumea (center) in this Keck telescope image.
|
|
| Discovery | |
|---|---|
| Discovered by |
Michael E. Brown, Chad Trujillo, David Rabinowitz, et al. |
| Discovery date | 26 January 2005 |
| Designations | |
| MPC designation | Haumea I Hiʻiaka |
| Pronunciation | /ˌhiːʔiˈɑːkə/ |
|
(136108) 2003 EL61 I, S/2005 (2003 EL61) 1 |
|
| Orbital characteristics | |
| 49880±198 km | |
| Eccentricity | 0.0513±0.0078 |
| 49.12±0.03 d | |
| Inclination | 126.356±0.064° |
| Satellite of | Haumea |
| Physical characteristics | |
|
Mean radius
|
~160 km |
| Mass | (1.79±0.11)×1019 kg (0.45% of Haumea) |
|
Mean density
|
~1 g/cm3 |
| Temperature | 32±3 K |
| 20.3 (3.0 difference from primary's 17.3) | |
The outer Solar System dwarf planet Haumea has two known moons, Hiʻiaka and Namaka, named after Hawaiian goddesses. These small moons were discovered in 2005, from observations of Haumea made at the large telescopes of the W. M. Keck Observatory in Hawaii.
Haumea's moons are unusual in a number of ways. They are thought to be part of its extended collisional family, which formed billions of years ago from icy debris after a large impact disrupted Haumea's ice mantle. Hiʻiaka, the larger, outermost moon, has large amounts of pure water ice on its surface, which is rare among Kuiper belt objects. Namaka, about one tenth the mass, has an orbit with surprising dynamics: it is unusually eccentric and appears to be greatly influenced by the larger satellite.
Two small satellites were discovered around Haumea (which was at that time still designated 2003 EL61) through observations using the W.M. Keck Observatory by a Caltech team in 2005. The outer and larger of the two satellites was discovered January 26, 2005, and formally designated S/2005 (2003 EL61) 1, though nicknamed "Rudolph" by the Caltech team. The smaller, inner satellite of Haumea was discovered on June 30, 2005, formally termed S/2005 (2003 EL61) 2, and nicknamed "Blitzen". On September 7, 2006, both satellites were numbered and admitted into the official minor planet catalogue as (136108) 2003 EL61 I and II, respectively.
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