TOI-2109b is one of the most extreme exoplanets we have found. With 1.35 times Jupiter’s size and 5 times Jupiter’s mass, it is a massive gas giant! Even closer than any orbit we’ve found, it completes one rotation of its star in just 16 hours. Temperatures naturally exceed those of even some stars, reaching 3,227 degrees Celsius at such a near proximity to the star.
If we’re lucky, we’ll be able to observe how the planet approaches the star in a year or two. Although it won’t hit the star in our lifetime, this planet might vanish in 10 million years.
Such planets are an enigma to astronomy given our present knowledge of planet formation. Since gravity, radiation, and powerful solar winds would prohibit the gas from developing that close to the star, a gas giant cannot form there. However, we have found a large number of these planets with orbits under 10 days. Therefore, astronomers think that these exoplanets formed fairly far from the star and subsequently moved closer to it for some reason. Astronomers aim to examine enough gaseous exoplanets to track the many stages in their evolution since there isn’t one like it in our own Solar System.
About 855 light-years away, TOI-2109b revolves around a yellow star that is 1.4 times the mass and 1.7 times the size of the Sun. They are only separated by 2.4 million kilometers, or 1.6% of the distance between the Earth and the Sun.
With one side continually facing the star, the planet is tidally locked to the star. The night side’s brightness, however, is below the threshold at which our organs can detect it, thus it is still unclear what occurs there.
Are the temperatures too low, or does the planet’s light side somehow lose heat to the dark side? Some of the unusual physical and chemical processes occurring in the atmospheres of these exoplanets are only now becoming clear to us. processes for which our own solar system has no equivalents.
Source: The Astronomical Journal
