HD 1605 and Its Two Known Planets

HD 1605 is a star located 290 light-years from Earth. It is a K1 IV star, and its spectral class places it among the cooler, more orange stars than the Sun. The star's reported mass estimate is 1.31 solar masses, which is larger than the Sun's, and its reported radius estimate is 3.8 solar radii, also larger than the Sun's. Its reported temperature is 4760 K, which is cooler than the Sun's, and its age is 4.59 billion years. Two planets are known to orbit this host: HD 1605 b and HD 1605 c.

Both planets were discovered in 2015 using 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. HD 1605 b has a minimum mass of 297 Earth masses and an orbital period of 577 days, the shortest year among the listed planets by reported estimates. Its minimum mass is larger than Earth's and is the smallest minimum mass among the listed planets. HD 1605 c has a minimum mass of 1150 Earth masses and an orbital period of 2150 days, the longest year among the listed planets by reported estimates. Its minimum mass is larger than Earth's, the largest minimum mass among the listed planets, and roughly 3.62 times Jupiter's mass.