S/2015 (136472) 1

S/2015 (136472) 1
Makemake and its moon S/2015 (136472) 1, the fainter object pointed at by the arrow
Discovery
Discovered by
Discovery date27 April 2015
Designations
MK 2 (unofficial nickname)
Orbital characteristics
22250±780 km
Eccentricity≈0
18.023±0.017 days
Inclination83.7° wrt Earth line of sight
63°–87° wrt ecliptic (prograde)
Satellite ofMakemake
Physical characteristics
~175 km (4% albedo; best fit)
175–250 km (2–4% albedo)
87.5 km
Albedo0.04 (best fit)
0.02–0.04
25.0
7.89±0.04

S/2015 (136472) 1, unofficially nicknamed MK 2 by the discovery team, is the only known moon of Makemake, a dwarf planet located in the Kuiper belt. It is a dark object about 175 km (110 mi) in diameter, orbiting 22,250 km (13,800 mi) away from Makemake with an orbital period of 18 days. Observations leading to its discovery occurred in April 2015, using the Hubble Space Telescope's Wide Field Camera 3, and its discovery was announced on 26 April 2016.