Structure and Atmosphere
Very little is known about the distant planet but estimates of its density (2g/cm3) suggests that it is perhaps 70% rock and 30% water ice. The bright areas, have been postulated to consist of frozen nitrogen, solid methane and carbon dioxide. Its thin atmosphere is likely a combination of nitrogen, carbon monoxide and methane. Its eccentric orbit though, means that the atmosphere would only exist at perihelion and would freeze as it moves away from the sun.
