Bizarre super-puffy exoplanet hosts rare 'thermometer molecule'

[Judi Lynn]

By Robert Lea published 43 minutes ago

The molecule chromium hydride is usually found in stars but was discovered in the atmosphere of the hot Jupiter WASP-31b, which is one of the lightest exoplanets ever seen.



An illustration of an orange jupiter-like planet with a bright yellow-white star in the distance
An illustration shows a hot Jupiter exoplanet orbiting close to its parent star. (Image credit: NASA, ESA, and J. Olmsted (STScI))


Astronomers have discovered a rare temperature-sensitive molecule that is usually associated with stars in the atmosphere of an exoplanet for the first time.

The "thermometer molecule" chromium hydride is abundant in a narrow range of temperatures between 1,700 degrees Fahrenheit to 3,140 degrees Fahrenheit (926 to 1,730 degrees Celsius). It was discovered in the atmosphere of the "hot Jupiter" exoplanet WASP-17b, which orbits an F-type star located around 1,250 light-years from Earth.

The discovery of such a metal hydride — a metal bonded to hydrogen to form a new compound — in the atmosphere of an alien planet could allow scientists to gauge the temperatures of worlds outside the solar system in a new way.

"Chromium hydride molecules are very temperature sensitive," research lead author Laura Flagg, a research associate at Cornell University in New York, said in a statement. "At hotter temperatures, you see just chromium alone. And at lower temperatures, it turns into other things. So there’s only a specific temperature range where chromium hydride is seen in large abundances."

More:
https://www.space.com/hot-jupiter-exoplanet-thermometer-molecule