Does Pluto have an atmosphere?

Yes, Pluto has a thin, extended atmosphere. Its existence was first confirmed in 1988 when Pluto passed in front of a star, an event known as an occultation, which allowed astronomers to observe the dimming of starlight as it passed through the gases.1

The atmosphere is primarily composed of nitrogen, with smaller amounts of methane, carbon monoxide, and hydrogen cyanide. During its 2015 flyby, the New Horizons spacecraft also detected acetylene, ethylene, and ethane.1

Because the atmosphere consists of vapors in equilibrium with surface ices, its density is highly sensitive to temperature changes. It is at its thickest when Pluto is near its perihelion and may become undetectable at aphelion when the planet receives the least sunlight. The atmosphere is quite cold and extended, reaching up to 1,800 km (1,100 miles) above the surface, with haze layers visible up to 200 km (120 miles).1