KELT-9b: the planet where a new season arrives every 9 hours

While we can enjoy winter, spring, summer, or autumn for a few months, on planet KELT-9b a new season starts about every nine hours. And that new season is winter or summer because the planet has no more seasons.

Scientists from the American space agency NASA took a closer look at the star KELT-9 and its planet KELT-9b three years after its discovery, using the TESS satellite. This led to some surprising insights.

For example, the planet is 1.8 times larger than Jupiter, the largest planet in our solar system. And the planet KELT-9b is so close to its parent star – which, by the way, is twice as big and twice as warm as the Sun – that it only takes 36 hours to complete a circle around the star.

So the planet goes through four seasons in one and a half days: two summers and two winters. Each season lasts about 9 hours.

Not only does the planet rotate around the parent star in record time, the parent star itself also rotates around its own axis at lightning speed, no less than 38 times faster than the Sun.

This results in an enormous temperature difference, with temperatures rising as the planet moves over the poles (of the parent star). A movement across the equator results in lower temperatures and a winter season.