The Bad Astronomer writes "Astronomers have found what appears to be a planet so hot it's literally vaporizing, boiling away from the heat of its star. KIC 12557548b was found using the transit method, periodically blocking some light from its star as it orbits around. But the amount of light blocked changes every transit. Given it's less than a million miles from the surface of the star, astronomers interpret this (PDF) as the planet itself turning to vapor, and the expanding cloud of rock-laden gas is what's blocking the starlight. The planet is most likely somewhat bigger than Mercury, but losing 100,000 tons of matter every second it'll only be around another few hundred million years."