Hubble spots a football-shaped planet leaking heavy metals into space
Astronomers just used NASA’s Hubble Space Telescope to take the temperature of an exoplanet called WASP-121b and discovered that the world is so hot that heavy metals actually leak behind it as it whips about its central star. It’s the first time scientists have seen such a phenomenon.
Since the beginning of the exoplanet era, when astronomers began finding planets outside our solar system, these so-called hot Jupiters have demanded attention. They’re as big or bigger than our planet Jupiter, made of mostly gassy hydrogen and helium, and orbit shockingly close to their stars. These monster planets can take mere hours or days to orbit. And as a result of their clinginess, they can be heated to thousands of degrees.
But WASP-121b is extreme even for its class. The planet has an upper atmosphere some 10 times hotter than any other world yet measured. Astronomers think that intense heat is what’s causing the metals, in addition to lighter materials, to puff up and stream away from the planet.
“Heavy metals have been seen in other hot Jupiters before, but only in the lower atmosphere,” David Sing of the Johns Hopkins University in Baltimore, Maryland, said in a press release. He’s the lead author on the paper published August 1 in the Astronomical Journal. “So you don’t know if they are escaping or not. With WASP-121b, we see magnesium and iron gas so far away from the planet that they’re not gravitationally bound.”