"Despite its small size and extreme distance from the Sun, Pluto does have an atmosphere. The atmosphere arises because there are periods when Pluto is closer to the Sun than Neptune, making it the 8th planet from the Sun for roughly 20 years at a time.*
During this plutonian "summer" the ices on Pluto's surface sublimate and form a methane and nitrogen atmosphere. This atmosphere is continually produced and lost again while Pluto is inside Neptune's orbit; during this time the density of Pluto's atmosphere may rival that of Mars.
* On 11 February 1999, Pluto crossed Neptune's orbit and once again became the furthest planet from the Sun and will remain so until the year 2231."
The above info was found on a website after Pluto recently had been kicked out of the World Federation of Nine Planets. It was discovered that Pluto was nothing more than a goofy shaped ice ball with no intention of orbiting the Sun anytime soon. After its downfall, all things Pluto have become hot selling items! T-shirts, bumper stickers, songs, books, artwork and even bad movies are selling like there's no tomorrow.
The schools are in an uproar because textbooks are now obsolete and a new mnemonic device is under construction. On the top of the list is "My Very Exotic Mistress Just Showed Up Nude." This helpful sentence will teach youngsters the eight planets in proper order --- Mercury, Venus, Earth, Mars, Jupiter, Saturn, Uranus, and Neptune.
So long, Pluto, my hot planet, you're on you own! I hope you've had a good summer.