New research using NASA’s James Webb Space Telescope examines the maximum sizes of gas giant exoplanets, measuring chemical compositions and formation processes in the HR 8799 system.

Gas giants are massive worlds made mostly of hydrogen and helium. They lack solid surfaces, and in our solar system, Jupiter ...

A distant star system with four super-sized gas giants has revealed a surprise. Thanks to JWST’s powerful vision, astronomers detected sulfur in their atmospheres — a chemical clue that they formed ...

Far beyond our solar system, in the distant Pegasus constellation, lies a star system that is reshaping our understanding of planetary formation. HR 8799, located 129 light-years away, is home to a ...

Detection of hydrogen sulfide in four HR 8799 gas giants provides evidence of solid accretion, clarifying how massive exoplanets form and distinguishing them from brown dwarfs ...

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In late 2008, astronomers announced the discovery of a multi-planet system orbiting the star HR 8799. The three planets were discovered the old-fashioned way: they were directly imaged! [A gallery of ...