TOI-2589 and Its Single Known Planet

TOI-2589 is a star 653 light-years away with an age of 11 billion years. Its mass is 0.93 solar masses, its radius is 1.07 solar radii, and its temperature is 5580 K; the reported mass is smaller than the Sun's, the reported radius is larger than the Sun's, and the reported temperature is cooler than the Sun's. One planet is known to orbit this host.

That planet, TOI-2589 b, was discovered by transit in 2023. A transit occurs when a planet passes in front of its star from our viewpoint, dimming the observed brightness, and repeated dips help establish orbital periods. TOI-2589 b is classified as Jupiter-like, a size class for planets exceeding 4 times Earth's radius, and its radius is 12.1 Earth radii, larger than Earth's. Its mass is 1110 Earth masses, larger than Earth's and roughly 3.5 times Jupiter's mass. It completes an orbit every 61.6 days. Its mean density is 3.45 g/cm³, 0.627 times Earth's.