BD-210397: A K-Dwarf with Two Long-Period Planets

BD-210397 is a K7 V star 77.4 light-years away, with two planets in orbit. Its age is 6.2 billion years, and it has a mass of 0.679 solar masses, a radius of 0.747 solar radii, and a temperature of 4050 K. The star's reported mass and radius estimates are smaller than the Sun's, and its reported temperature is cooler than the Sun's.

Both planets were discovered in 2023 by radial velocity, the method that detects the wobble a planet's gravity induces in its star's motion. BD-210397 b has a minimum mass of 214 Earth masses and an orbital period of 1890 days, the shortest among the listed planets. BD-210397 c has a mass of 1530 Earth masses and an orbital period of 6240 days, the longest among the listed planets; its reported mass estimate is roughly 4.8 times Jupiter's mass and larger than Earth's. BD-210397 b's minimum mass is larger than Earth's.