The Planets of GJ 667 C

GJ 667 C is an M1.5 V star 23.6 light-years away with five planets orbiting it. Its spectral type describes a small, cool red dwarf, and its reported temperature of 3350 K is cooler than the Sun's. The star's reported mass is 0.33 solar masses, smaller than the Sun's, and its age carries a reported lower limit of 2 billion years.

Radial velocity observations revealed the planets, which range in minimum mass from 2.7 to 4.6 Earth masses. A minimum mass is a lower bound on a planet's true mass, so each of these values marks how light the world could be rather than a precise figure. Two of the planets, GJ 667 C e and GJ 667 C f, share the same minimum mass of 2.7 Earth masses, while GJ 667 C c reaches 3.8 Earth masses and GJ 667 C g is the heaviest of the group at 4.6 Earth masses. All four are more massive than Earth. GJ 667 C b, discovered in 2012, is the remaining planet and has no reported mass, only an orbital period.

The planets complete their orbits in periods ranging from 7.2 to 256 days. GJ 667 C b has the shortest year among the listed planets at 7.2 days, followed by GJ 667 C c at 28.1 days. GJ 667 C f orbits in 39 days and GJ 667 C e in 62.2 days, with GJ 667 C e holding the second-longest year. GJ 667 C g completes the group with the longest year at 256 days.