At a distance of 850 light-years, an exoplanet races around its star in record time and its fate is already predetermined: TOI-2109b orbits its Sun in just 16 hours and is attracted to it very quickly at the same time. In an astronomically short time, it will finally rise in the star, write Ian Wong of the Massachusetts Institute of Technology in Cambridge and his team in the »Astronomical Journal«. With this very short year, the gas giant beats the previous record holder by another two hours.
TOI-2109b is an ultra-hot gas giant that is five times more massive than Jupiter. Its diameter is also 35 percent larger. At the same time, it is located at a distance from its star 20 times less than Mercury, which, however, heats up the planet extremely strongly. On the daytime side, the temperatures are at least 3000 degrees Celsius, which makes it an ultra-hot Jupiter. So far, only one planet is known to be even hotter with a surface temperature of 4300 Celsius.
The proximity to his star also means that the celestial body is faster than any other known planet, the working group writes. Every year the circulation time is reduced by another second. In about ten million years, the star will have swallowed the gas giants, said Wong and Co.
Because of its high temperature and the brightness of the star, the exoplanet is easy to observe. Above all, its atmosphere could be studied so well. It was discovered using NASA's Transiting Exoplanet Survey Satellite (TESS).
