A recently discovered exoplanet is defying long-held theories about planet formation, as a tiny red dwarf star appears to be hosting a giant gas planet — something scientists didn’t think was possible.
The unusual pair, located 238 light-years from Earth, consists of TOI-6894, a red dwarf star with just 20% the mass of our Sun, and its planetary companion TOI-6894b, a gas giant roughly the size of Saturn but with only half its mass.
Red dwarfs are the most common type of star in the galaxy, but very rarely do they host large gas giants. According to statistical studies, only about 1.5% of red dwarfs have such planets. That makes TOI-6894 a rare find — even more so because it’s 60% less massive than the previous record-holder for the smallest star known to host a gas giant.
The discovery, made using data from NASA’s Transiting Exoplanet Survey Satellite (TESS), was led by Edward Bryant of the University of Warwick. “I originally searched through TESS observations of more than 91,000 low-mass red dwarf stars looking for giant planets,” Bryant explained in a statement.
Finding TOI-6894b wasn’t easy. Since giant planets around red dwarfs are extremely uncommon, the signal was hard to pick out from the massive dataset TESS collects. In fact, the “TOI” in the planet’s name stands for “TESS Object of Interest.”
What puzzles scientists most is how such a small star could form — or retain — such a large planet. “We don’t really understand how a star with so little mass can form such a massive planet,” said Vincent Van Eylen, co-author of the study and a researcher at University College London’s Mullard Space Science Laboratory.
In essence, TOI-6894 is like a parent with a child far taller than expected — a cosmic mismatch that challenges current models of star and planet formation. For now, scientists are left with more questions than answers, as they seek to understand just how such an unlikely pairing came to be.
