HD 4203 and Its Two Known Planets

HD 4203 is a G5 star situated 265 light-years away. The star is estimated to be 5 billion years old and contains 1.15 solar masses of material, with a radius of 1.33 solar radii and a temperature of 5640 K. Its mass and radius are both larger than the Sun's, while its temperature is cooler. Two planets are known to orbit this host, both discovered by the radial velocity method, which detects the wobble a planet's gravity induces in its star's motion.

HD 4203 b was discovered in 2001. It has a minimum mass of 709 Earth masses - roughly 2.23 times Jupiter's mass - and an orbital period of 432 days, the shortest year among the listed planets.

HD 4203 c was discovered in 2014. Its minimum mass is 690 Earth masses, or roughly 2.17 times Jupiter's mass, and it takes 6700 days to complete one orbit, the longest year among the listed planets. It also has the smallest minimum mass of the pair, while HD 4203 b has the largest. Both minimum masses are lower bounds on the planets' true masses, and both are larger than Earth's.