TOI-1759b is one of the strangest planets astronomers have ever found, and it might tell us why some worlds are habitable and others are not
Astronomers sifting through data from a NASA planet-hunting satellite have hit the jackpot: a common type of planet 131 light-years away called TOI-1759b, with an extremely uncommon story to tell. Thanks to its close proximity to its host star, the planet's atmosphere appears to be evaporating into dead expanse of space—extremely fast, by astronomical standards.
On gassier and less dense planets with weaker gravities, stellar radiation can kick off a process astronomers call “hydrogen escape” that eventually strips away all the gas that makes up most of the atmosphere, leaving behind inert rocky nubs that are just a fraction of the planet’s original size. It seems to be the unique fate of close-orbiting sub-Neptunes to lose their atmospheres and turn into smaller, naked rocks. The whole process might take hundreds of millions, or even billions, of years.