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Which gases make up Pluto’s atmosphere?
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Pluto
Pluto as observed by the New Horizons spacecraft, July 13, 2015.
Pluto’s atmosphere is primarily composed of nitrogen, which serves as its main constituent. In addition to nitrogen, the atmosphere contains smaller amounts of several other gases and compounds, including:1
- Methane1
- Carbon monoxide1
- Hydrogen cyanide1
- Acetylene1
- Ethylene1
- Ethane1
Because Pluto’s atmosphere consists of vapors in equilibrium with surface ices, the composition and density of the atmosphere can fluctuate based on temperature changes as the dwarf planet moves along its orbit.1