Makemake
Makemake (minor-planet designation 136472 Makemake) is a dwarf planet and the second-largest of what are known as the classical population of Kuiper belt objects, with a diameter approximately that of Saturn's moon Iapetus, or 60% that of Pluto. It has one known satellite. Its extremely low average temperature, about 40 K (−230 °C), means its surface is covered with methane, ethane, and possibly nitrogen ices.
Makemake and its moon, as seen by the Hubble Space Telescope | |
| Discovery | |
|---|---|
| Discovered by | |
| Discovery date | March 31, 2005 |
| Designations | |
| (136472) Makemake | |
| Pronunciation | UK: /ˌmækiˈmæki/, US: /ˌmɑːkiˈmɑːki/ or /ˌmɑːkeɪˈmɑːkeɪ/ ⓘ |
Named after | Makemake |
| 2005 FY9 | |
| Dwarf planet TNO cubewano scattered-near | |
| Adjectives | Makemakean |
| Symbol | (mostly astrological) |
| Orbital characteristics | |
| Epoch May 31, 2020 (JD 2458900.5) | |
| Earliest precovery date | January 29, 1955 |
| Aphelion | 52.756 AU (7.8922 Tm) |
| Perihelion | 38.104 AU (5.7003 Tm) |
| 45.430 AU (6.7962 Tm) | |
| Eccentricity | 0.16126 |
| 306.21 yr (111,845 d) | |
Average orbital speed | 4.419 km/s |
| 165.514° | |
| Inclination | 28.9835° |
| 79.620° | |
| 17 November 2186 | |
| 294.834° | |
| Known satellites | 1 |
| Physical characteristics | |
| Dimensions | (1434+48 −18) × projected (1420+18 −24 km) |
Mean radius |
|
| Flattening | 0.0098 |
| 6.42×106 km2 | |
| Volume | 1.53×109 km3 |
| Mass | ≈ 3.1×1021 kg |
Mean density | ≈ 1.7 g/cm3 (using Ortiz et al. 2012 radius) ≈ 2.1 g/cm3 (using Brown 2013 radius) |
Equatorial surface gravity | < 0.57 m/s2 |
Equatorial escape velocity | < 0.91 km/s |
| 22.8266±0.0001 h | |
| 0.82±0.02 geometric 0.74±0.06 Bond | |
| Temperature | 32–36 K (single-terrain model) 40–44 K (two-terrain model) |
| B−V=0.83, V−R=0.5 | |
| 17.0 (opposition) | |
| −0.12 0.049±0.020 | |
Makemake was discovered on March 31, 2005 by a team led by Michael E. Brown, and announced on July 29, 2005. It was initially known as 2005 FY9 and later given the minor-planet number 136472. In July 2008, it was named after Makemake, a creator god in the Rapa Nui mythology of Easter Island, under the expectation by the International Astronomical Union (IAU) that it would prove to be a dwarf planet.