4 UMa: A K-Type Giant and Its Single Known Planet

4 UMa is a K1 III star located 240 light-years away. Its spectral type places it in the cooler K class, and measurements give it an age of 4.6 billion years, a mass of 1.23 solar masses, a radius of 18.1 solar radii, and a temperature of 4420 K. The star's reported mass and radius estimates are both larger than the Sun's, while its reported temperature is cooler than the Sun's. One planet is known to orbit this host.

That planet, 4 UMa b, was discovered in 2006 by the radial velocity method, which detects the wobble a planet's gravity induces in its star's motion; repeated wobbles reveal the planet and its orbital period. The planet's minimum mass is 2510 Earth masses, a lower bound on its true mass, and it completes an orbit every 270 days. Its minimum mass is larger than Earth's and roughly 7.9 times Jupiter's mass.