Eris

Discovered recently in 2005, Eris is a dwarf planet that resides in the Kuiper Belt. Not much is known about the dwarf planet, as only observations from ground-based telescopes have gathered light from the surface. Based on spectroscopic measurements of Eris, the surface is expected to contain methane in small quantities, like the surface on Pluto. It is possible that Eris may gain an atmosphere when the dwarf planet approaches its closest distance to the Sun, though none has been detected as of now. More information is expected to be gathered about Eris in the future.