Giant planets known as hot Jupiters appear to be growing in size as they are heated by their stars over billions of years.

Hot Jupiters are a loosely defined class of gas giant exoplanets that orbit stars incredibly closely, reaching temperatures of more than 4000°C. They can be up to twice as large as their cooler counterparts, such as Jupiter in our own solar system. In 2016, research suggested that hot Jupiters orbiting red giants – stars in an expanded latter stage of their life – could be …