Exoplanet Gliese 876 d. Illustration of the red dwarf star Gliese 876 (upper left) and the orbiting planet Gliese 876 d. This planet, at the time of its announced discovery, was the lowest mass planet discovered to that point. It is 6-8 Earth masses and has a radius of only 1.8 times that of the Earth. It is a hot world very close to its star, and is thought to have a thick cloud layer with possible active volcanism visible through breaks in the clouds. Several other planets have also been discovered in this system, with two of them visible at upper left. Gliese 876 d was discovered in 2005. Gliese 876 is 15 light years from Earth in the constellation of Aquarius.