Gas giants like Jupiter and Saturn are known to have cores at their centers, but seeing those is difficult — unless nature cooperates, that is. University of Warwick astronomers have discovered (via ScienceNews) what they say is the first known exposed gas giant core. TOI-849b is a planet about 730 light-years away that’s close to Neptune’s size (nearly four times Earth’s) but with an Earth-like density that suggests it should have accumulated layers of hydrogen and helium. It didn’t, however — this indicates that something stripped the gas away, assuming it formed properly in the first place.
The team found the planet by using data from NASA’s Transiting Exoplanet Survey Satellite and refining it using telescopes from the Chile-based Next-Generation Transit Survey and La Silla Observatory. This included gauging the mass of the planet by studying the slight changes in light spectrum from the celestial body’s wobble.