Apr 7, 2022 - Science

Hubble takes a peek at "ultra-hot" Jupiter-like planets

An artist's depiction of an ultra-hot gas planet, KELT-20b.

An artist's depiction of an ultra-hot gas planet, KELT-20 b. Illustration: NASA, ESA, Leah Hustak

Teams of Hubble Space Telescope astronomers studying massive, extremely hot Jupiter-like exoplanets have found evidence of extreme weather conditions — like raining vaporized rock — and atmospheric chemistry occurring on the worlds, NASA announced Wednesday.

Why it matters: Studying the exotic weather on these uninhabitable gas giants can help researchers better understand Earth's atmosphere and the atmospheres of other potentially inhabitable terrestrial planets.

On WASP-178 b, a gas giant discovered in 2019 around 1,300 light-years away from Earth, Hubble researchers detected the presence of silicon monoxide, suggesting the solid is condensing and raining from clouds in certain parts of the planet.

  • Because WASP-178 b is fairly close and tidally locked to its star, the cloudless day side of the planet that always faces the star is heated to around 3,950 degrees Fahrenheit and is enriched with gases, including vaporized silicon.
  • The night side of the planet remains comparatively cooler but is thrashed by super-hurricane speeds exceeding 2,000 miles per hour. The researchers believe the super-heated gasses cool and condense into raining solids, including silicon monoxide, on the planet's night side.
  • In a paper published in the journal Nature on April 6, the researchers said they believe it was the first time silicon monoxide had been detected in an exoplanet.

On KELT-20 b, another extremely hot gas giant discovered in 2017 about 400 light-years away, researchers discovered a thermal inversion layer in its atmosphere — similar to Earth's stratosphere — caused by ultraviolet light from its parent star heating atmospheric metals to extremely high temperatures.

  • This inversion layer creates KELT-20 b's unique atmosphere, which seems to contain more water and carbon monoxide than other hot Jupiter-like planets, as detailed in a paper published in the Astrophysical Journal Letters in January.

What they're saying: Figuring out how gas giants' massive atmospheres work is key to understanding the smaller atmospheres of terrestrial exoplanets, Josh Lothringer, an assistant professor at Utah Valley University and lead author of the WASP-178 b paper, said in a statement.

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