TOI-5143 c: A Jupiter-Like World Around a Cool Dwarf

TOI-5143 is a K V star, a main-sequence dwarf cooler and redder than the Sun, located 592 light-years away. Its reported mass is 0.864 solar masses and its radius is 0.852 solar radii, both smaller than the Sun's corresponding values. The star's temperature is 5180 K, cooler than the Sun's, and its age is 7.4 billion years. One planet is known to orbit this host.

That planet is TOI-5143 c, a Jupiter-like world discovered by the transit method in 2025. It completes an orbit in 5.21 days and has a reported radius of 16.3 Earth radii. This radius is larger than Earth's, and it exceeds four times Earth's radius, the threshold for the Jupiter-like size class. Its mass has not been reported, so no mass comparison can be drawn. The transit method detects the small dip in a star's observed brightness as a planet passes in front of it from our viewpoint, and repeated dips help establish the planet's orbital period of 5.21 days.