Pluto’s atmosphere was discovered from the Kuiper Airborne Observatory in 1985. It was observed through the occultation of a star with Pluto. If a planet does not have an atmosphere, the star would disappear immediately. But with Pluto, the star dimmed slowly. The atmospheric temperature of Pluto was discovered to be .15 pascals by measuring the rate of dimming of the star. The initial findings were further confirmed by another masking that occurred on 1988. Another revelation was studied on 2002 wherein the atmospheric pressure of Pluto was measured at 0.3 Pascal.
The ices on the surface of Pluto derive nitrogen, methane and carbon monoxide gasses. This make up the very thin envelope that is Pluto’s atmosphere. The pressure of the surface of Pluto ranges from 6.5-24 ubar. It has been speculated that because of Pluto’s elongated orbit that it has an effect on its atmosphere. The atmosphere slowly freezes out and falls to the ground when Pluto moves away from the Sun. The temperature of the solid surface of Pluto increases when Pluto is nearer the Sun. The Ices sublimate into gas because of this. An anti-greenhouse effect occurs where the surface of Pluto is cooled because of this sublimation. By using the Submillimeter Array, scientists discovered that the temperature in Pluto is around 43 K (−230 °C).
On 2006 it was discovered that there was ethane on Pluto’s surface. The ethane was created by the photolysis of frozen methane. The gas is then emitted into the atmosphere.
Because methane exists temperature inversion is common in Pluto’s atmosphere. The atmosphere is 36K warmer than 10km below.