Astronomers have used the James Webb Space Telescope (JWST) to discover that a distant "hot Jupiter" planet has two staggeringly long tails composed of helium that currently defy explanation. The observations represent the first study of gases leaking from a planet beyond the solar system during one of its complete orbits, and help paint the most complete picture of atmospheric escape thus far.
The extrasolar planet, or exoplanet, in question is WASP-121b, also known as "Tylos," located around 858 light-years away. WASP-121b is an example of an "ultrahot Jupiter," a massive gas giant planet found so close to its parent star that it can complete an orbit in a matter of hours. As WASP-121b whips around its star once every 30 hours, intense radiation from its stellar parent heats its atmosphere to around 4,200 degrees Fahrenheit (2,300 degrees Celsius).
