Makemake
Makemake is a dwarf planet in the Kuiper belt and, after Pluto, the brightest known. No spacecraft has visited it; everything we know comes from telescopic spectroscopy and a 2011 stellar occultation, which found no global atmosphere. Its surface temperature is estimated near 30–35 K.
Key facts
Science
Physical
- Mass
- 3.10 × 10²¹ kg · 0.0422 Moon masses
- Radius
- 715 km · 11% of Earth's radius
- Density
- 2,025 kg/m³ · 2× water
- Computed from mass and radius
- Surface gravity
- 0.405 m/s² · 4% of Earth's gravity
- Computed from mass and radius
- Escape velocity
- 761 m/s · 7% of Earth's escape velocity
- Computed from mass and radius
Orbital
- Distance from the Sun
- 52.7 AU
- Computed from the position at the selected time
- Semi-major axis
- 45.6 AU
- Computed from the cached state vector
- Eccentricity
- 0.1581
- Computed from the cached state vector
- Inclination
- 39.96 °
- Computed from the cached state vector
- Orbital period
- 307.94 years
- Computed from the cached state vector
- Perihelion
- 38.4 AU
- Computed from the orbital elements
- Aphelion
- 52.8 AU
- Computed from the orbital elements
- Mean orbital velocity
- 4.41 km/s
- Computed from the orbital elements
Rotation
- Rotation period
- 22.76 hours
Composition
- Bulk composition
- Surface dominated by frozen methane (CH₄), with ethane and possibly nitrogen ices, inferred from near-infrared spectroscopy. The bulk rock/ice interior is unconstrained — no spacecraft has visited.
- Surface imagery
- No real surface imagery exists — this object has never been visited; color is approximate, inferred from spectroscopy.
Radiation & temperature
- Insolation
- 0.000481 S⊕ · 1/2,079 of the sunlight Earth receives
- Computed from the distance to the Sun (inverse-square; Earth's sunlight = 1), before any atmosphere.
- Geometric albedo
- 0.81
- V-band geometric albedo (one of the brightest TNOs); Bond albedo not directly measured.
- Equilibrium temperature
- 27 K (-246 °C)
- Computed from albedo + distance from the Sun (airless black body); uses the geometric albedo as an estimate
Discovery & history
- Discovered
- March 31, 2005
- By
- Mike Brown, Chad Trujillo and David Rabinowitz
- Method
- Photographic plates
- Name
- The creator god of the Rapa Nui people of Easter Island.
Makemake was discovered on 31 March 2005 by Mike Brown, Chad Trujillo and David Rabinowitz at Palomar — just after Easter, which earned it the team's codename 'Easterbunny' before it received the provisional designation 2005 FY9. The second-brightest known Kuiper-belt object after Pluto, it was one of the bodies whose discovery pushed the IAU to define 'dwarf planet' in 2006. It was named for Makemake, the creator god and fertility deity of the Rapa Nui people of Easter Island, in keeping with its Easter-time discovery. A 2011 stellar occultation found no global atmosphere, and in 2016 the Hubble Space Telescope revealed a small, dark moon nicknamed MK 2.
Images
Images from open archives · credit shown per image