Pluto’s atmosphere imaged by New Horizons on July 15, 2015 after it passed behind the dwarf planet and saw it silhouetted in front of the Sun.
From a May 12, 2020 NASA article:
When the New Horizons spacecraft passed by Pluto in 2015, one of the many fascinating features its images revealed was that this small, frigid world in the distant solar system has a hazy atmosphere. Now, new data helps explain how Pluto’s haze is formed from the faint light of the Sun 3.7 billion miles away as it moves through an unusual orbit.
Remote observations of Pluto by NASA’s telescope on an airplane, the Stratospheric Observatory for Infrared Astronomy, or SOFIA, show that the thin haze enshrouding Pluto is made of very small particles that remain in the atmosphere for prolonged periods of time rather than immediately falling to the surface. SOFIA’s data clarify that these haze particles are actively being replenished – a discovery that is revising predictions on the fate of Pluto’s atmosphere as it moves into even colder areas of space on its 248-Earth-year orbit around the Sun. The results are published in the scientific journal Icarus.
Created as surface ice vaporizes under the distant ...