Haumea (dwarf planet)
|
|
| Discovery | |
|---|---|
| Discovered by | Brown et al.; Ortiz et al. (neither official) |
| Discovery date | 2004 December 28 (Brown et al.); 2005 July (Ortiz et al.) |
| Designations | |
| MPC designation | (136108) Haumea |
| Pronunciation | /haʊˈmeɪ.ə/ or /ˌhɑːuːˈmeɪ.ə/ |
|
Named after
|
Haumea |
| 2003 EL61 | |
|
Dwarf planet, plutoid, TNO, 7:12 resonance, (delisted cubewano) Haumea family, and trinary |
|
| Adjectives | Haumean |
| Orbital characteristics | |
| Epoch 2014-12-09 (JD 2457000.5) | |
| Aphelion |
51.483 AU (7.702 Tm) |
| Perihelion |
34.952 AU (5.229 Tm) |
|
43.218 AU (6.465 Tm) |
|
| Eccentricity | 0.19126 |
| 284.12 yr (103774 d) | |
|
Average orbital speed
|
4.531 km/s |
| 209.07° | |
| Inclination | 28.19° |
| 121.79° | |
| 240.20° | |
| Known satellites | 2 |
| Physical characteristics | |
| Dimensions |
1,920 × 1,540 × 990 km ≈ 1,960 × 1,518 × 996 km (Keck) |
|
Mean radius
|
620+34 −29 km ≈ 650 km (Herschel) 690 km 575+125 −50 km (Spitzer) ≈ 718 km (Keck) |
| ≈ 6.8×106 km2 | |
| Volume | 1.5×109 km3 |
| Mass |
(4.006±0.040)×1021 kg 0.00066 Earths |
|
Mean density
|
2.6 g/cm3 2.6–3.3 g/cm3 |
| 0.63 m/s2 | |
| 0.91 km/s | |
|
Sidereal rotation period
|
0.163146±0.000004 d (3.9155±0.0001 h) |
| Albedo |
0.804+0.062 −0.095 0.7±0.1 0.84+0.1 −0.2 0.70–0.75 |
| Temperature | < 50 K |
|
Spectral type
|
(Neutral) B−V = 0.64, V−R = 0.33 B0−V0 = 0.646 |
| 17.3 (opposition) | |
| 0.03±0.43 | |
1,920 × 1,540 × 990 km
2.6 g/cm3
Haumea, minor-planet designation 136108 Haumea, is a dwarf planet located beyond Neptune's orbit. It was discovered in 2004 by a team headed by Mike Brown of Caltech at the Palomar Observatory in the United States and independently in 2005, by a team headed by José Luis Ortiz Moreno at the Sierra Nevada Observatory in Spain, though the latter claim has been contested. On September 17, 2008, it was recognized as a dwarf planet by the International Astronomical Union (IAU) and named after Haumea, the Hawaiian goddess of childbirth.
Haumea's mass is about one-third that of Pluto, and 1/1400 that of Earth. Although its shape has not been directly observed, calculations from its light curve indicate that it is a triaxial ellipsoid, with its major axis twice as long as its minor. Its gravity is thought to be sufficient for it to have relaxed into hydrostatic equilibrium, making it a dwarf planet. Haumea's elongated shape together with its rapid rotation, high density, and high albedo (from a surface of crystalline water ice), are thought to be the consequences of a giant collision, which left Haumea the largest member of a collisional family that includes several large trans-Neptunian objects (TNOs) and Haumea's two known moons, Hiʻiaka and Namaka.
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