James E. Owen

A planet the size of Neptune wandered too close to its star. The star begins to pull the planet's outer layers onto itself — gas streams off the planet like water from an overflowing bucket. This process is called Roche-lobe overflow (astronomers use this term for the boundary beyond which a star can tear material away from a planet).

A world where a year lasts just one and a half Earth days, and the star in its sky is hundreds of times larger than our Sun. This is KELT-9 b — a gas giant heated to temperatures at which iron vaporizes. Its atmosphere is not just hot; it is literally boiling away into space, like steam rising from a giant cauldron.