Makemake

Makemake
	Low-resolution image of Makemake and its unnamed moon S/2015 (136472) 1 by the Hubble Space Telescope, April 2015
Discovery
Discovered by	Michael E. Brown; Chad Trujillo; David Rabinowitz;
Discovery site	Palomar Observatory
Discovery date	March 31, 2005
Designations
Pronunciation	UK: /ˌmækiˈmæki/, US: /ˌmɑːkiˈmɑːki/ or /ˌmɑːkeɪˈmɑːkeɪ/ ⓘ
Named after	Makemake
Alternative designations	(136472) Makemake; 2005 FY9; "Easterbunny" (nickname); K05331A (codename)
Minor planet category	Dwarf planet; TNO; classical (hot);
Adjectives	Makemakean
Symbol	(mostly astrological)
Orbital characteristics (barycentric)
	Epoch November 21, 2025; (JD 2461000.5)
	Uncertainty parameter 1
Observation arc	70.53 yr (25,760 d)
Earliest precovery date	January 29, 1955
Aphelion	52.796 AU (7.8982 Tm)
Perihelion	38.201 AU (5.7148 Tm)
Semi-major axis	45.499 AU (6.8066 Tm)
Eccentricity	0.1604
Orbital period (sidereal)	306.70 yr (112,022 d)
Mean anomaly	170.497°
Mean motion	0° 0m 11.569s / day
Inclination	29.002°
Longitude of ascending node	79.441°
Time of perihelion	17 November 2186
Argument of perihelion	296.065°
Known satellites	1 (S/2015 (136472) 1)
Physical characteristics
Dimensions	(1434+48; −18) × (1420+18; −24 km)
Mean radius	715±7 km
Flattening	0.0098
Surface area	6.42×106 km2
Volume	1.53×109 km3
Mass	(2.69±0.20)×1021 kg
Mean density	1.76±0.17 g/cm3
Equatorial surface gravity	0.35 m/s2
Equatorial escape velocity	0.71 km/s
Sidereal rotation period	11.4133 h; or 22.8266±0.0001 h;
Axial tilt	46°–78° wrt orbit; 63°–87° wrt ecliptic;
Geometric albedo	0.82±0.02 (geometric); 0.74±0.06 (Bond);
Temperature	30–40 K
Spectral type	B−V = 0.868±0.004; V−R = 0.449±0.003;
Apparent magnitude	17.0 (opposition)
Absolute magnitude (H)	0.049±0.020 (corrected); −0.25 (JPL/MPC);
Angular diameter	38.28±0.22 milli-arcsec

Makemake (minor-planet number 136472) is a dwarf planet orbiting the Sun in the Kuiper belt, a disc of icy bodies beyond the orbit of Neptune. It is the fourth largest dwarf planet and trans-Neptunian object in the Solar System, having a diameter 60% that of Pluto. It was discovered on March 31, 2005, by American astronomers Michael E. Brown, Chad Trujillo, and David Rabinowitz at Palomar Observatory. As one of the largest outer Solar System objects found by this team, the discovery of Makemake contributed to the reclassification of Pluto as a dwarf planet in 2006.

Makemake's surface is similar to that of Pluto: it is highly reflective, covered largely by frozen methane, and stained reddish-brown by tholins. Makemake has one known moon, which has not been named. The orbit of this moon suggests that Makemake's rotation has a high axial tilt, which implies that it experiences extreme seasons. Makemake shows evidence of geochemical activity and cryovolcanism, which has led scientists to suspect that it might harbor a subsurface ocean of liquid water. Gaseous methane has been detected around Makemake, although it is unclear whether it is contained in an atmosphere or comes from temporary outgassing.

No high-resolution images of Makemake's surface exist because it has not been visited up close by a space probe. Makemake is so far from Earth that it appears as a star-like point of light even when viewed through a telescope. Scientists have expressed desire to send a space probe to explore Makemake because of its geological activity and potential subsurface ocean.