There are planets whose conditions are so extreme that simply make us thank that on Earth we have the climate that we have. It is the case of TOI-2109b, a recently discovered gaseous exoplanet. The star has five times the mass of Jupiter and 1.35 times its diameter. In other words: it is huge.
But the really impressive thing about TOI-2109b is not its dimensions, but its orbit. It is so small and close to its star (only 2.4 million km) that complete one lap around it (that is, one “year”) in just 16 hours. And very little by little, but inexorably, that orbit is getting smaller and smaller.
A gas giant that can almost be a star
Being so close to your Sun also has an effect on temperature. When it is daytime in TOI-2109b you get to some not very pleasant 5,840º C, a temperature that surprisingly becomes higher than that of the surface of some stars. It is the price of having the closest orbit to the sun that has ever been recorded. Other extremely hot exoplanets they pale next to TOI-2109b.
Not much can be known about the night face of the planet, although astronomers consider two possibilities: either it is extremely cold, or somehow TOI-2109b distributes some heat from its daytime side to there. What is practically certain is that the planet’s small orbit must have it in synchronous rotation, so that the day and night faces should never change. Again, the person responsible for this discovery has been the TESS telescope analyzing the variations of light from a star that occur when a planet orbits ahead.
And as if these conditions weren’t harsh enough, a violent death awaits TOI-2109b. It will not be soon, but as its orbit is reducing as the planet spirals towards the star it will end up impacting it in a few million years. Come on, it is not the best place for future explorers to consider missions.