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 ...

A newly identified planet candidate, HD 137010 b, looks strikingly Earth-like in size and orbit — but it may be colder than Mars due to its dimmer star. If it has a thick enough atmosphere, though, ...

Gas giants are large planets mostly composed of helium and/or hydrogen. Although these planets have dense cores, they don't ...

Astronomers have found thousands of exoplanets around single stars, but few around binary stars—even though both types of stars are equally common. Physicists can now explain the dearth.

General relativity helps explain the lack of planets around tight binary stars by driving orbital resonances that eject or destroy close-in worlds. This process naturally creates a “desert” of ...

Relatedly, astronomers may have just pushed the upper size limit of what counts as a planet.

Key takeawaysIf a gas giant planet is big enough to ignite deuterium fusion, it becomes a brown dwarf instead of a planet.

Astronomers have spotted an unusual 'inside-out' planetary system where a rocky world seems to have formed far beyond the realm typically reserved for gas giants.

If a gas giant planet is big enough to ignite deuterium fusion, it becomes a brown dwarf instead of a planet. But this definition is incomplete and does not tell us how gas giants form or what ...

With this new survey, astronomers have gained a peek inside a stage of exoplanet system formation they have yet to fully ...

What if humanity could no longer live on Earth? Perhaps a catastrophic event forced us to find a new home among the stars.