TOI-1278 and Its Jupiter-Like Planet

TOI-1278 is an M0 V star, a small, cool red dwarf, located 246 light-years away. Its reported mass estimate is 0.54 solar masses and its radius estimate is 0.573 solar radii, both smaller than the Sun's. Its reported temperature is 3800 K, cooler than the Sun's. One planet has been found orbiting this star.

TOI-1278 b was discovered in 2021 by the transit method, in which a planet passing in front of its star from our viewpoint causes a small dip in observed brightness. It is a Jupiter-like planet, a size class that exceeds 4 times Earth's radius. Its reported radius estimate is 12.2 Earth radii, larger than Earth's, and its reported mass estimate is 5880 Earth masses, also larger than Earth's and roughly 18.5 times Jupiter's mass. Its mean density is 17.8 g/cm³, 3.22 times Earth's. The planet completes an orbit in 14.5 days.