HD 39194 and Its Three Planets

HD 39194 is a K0 V star located 86.1 light-years from Earth. Its spectral type indicates a main-sequence dwarf somewhat cooler than the Sun, and its reported temperature of 5210 K is cooler than the Sun's. The star's reported mass estimate is 0.67 solar masses, smaller than the Sun's, and its age is given as 10 billion years. Three planets are known to orbit this host.

All three planets were discovered in 2021 by the radial velocity method, which measures the wobble a planet's gravity induces in its star's motion; repeated wobbles reveal the planet and its orbital period. Each of the three has a minimum mass larger than Earth's, meaning these values are lower bounds on the planets' true masses rather than exact figures.

HD 39194 b has a minimum mass of 4.62 Earth masses and an orbital period of 5.64 days, the shortest year among the listed planets. HD 39194 c has a minimum mass of 7.49 Earth masses and an orbital period of 14 days, the second-shortest year among the listed planets and the largest minimum mass of the three. HD 39194 d has a minimum mass of 5.16 Earth masses and an orbital period of 33.9 days, the longest year among the listed planets and the second-smallest minimum mass.

The radial velocity detections have established the minimum masses and orbital periods of all three planets.