HD 21693 and Its Two Known Planets

HD 21693 is a G8 V star located 108 light-years away. Its spectral type marks it as a main-sequence dwarf, and it is cooler than the Sun, with a reported temperature of 5430 K. The star's reported radius estimate is smaller than the Sun's, at 0.923 solar radii, and its mass is 0.95 solar masses. Two planets are known to orbit this host.

HD 21693 b and HD 21693 c were both discovered in 2019 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 21693 b has a minimum mass of 8.23 Earth masses, larger than Earth's, and orbits in 22.7 days. HD 21693 c has a minimum mass of 17.4 Earth masses, also larger than Earth's, and orbits in 53.7 days.

Both minimum masses are lower bounds on the planets' true masses. Among the listed planets, HD 21693 b has the shortest year and the smallest minimum mass, while HD 21693 c has the longest year and the largest minimum mass.