Due to the proximity of Gliese 876 d to its host star (a red dwarf), it may have a surface temperature of 430–650 kelvin and be too hot to support liquid water. It has an estimated mass of 7.5 Earth masses and a very short orbital period of about 2 days. It orbits Gliese 876 and received the designation Gliese 876 d (two Jupiter-sized gas giants had previously been discovered in that system). The first super-Earth around a main-sequence star was discovered by a team under Eugenio Rivera in 2005. The two outer planets ( Poltergeist and Phobetor) of the system have masses approximately four times Earth-too small to be gas giants. The first super-Earths were discovered by Aleksander Wolszczan and Dale Frail around the pulsar PSR B1257+12 in 1992. Sizes of Kepler Planet Candidates – based on 2,740 candidates orbiting 2,036 stars as of Novem( NASA) Planets above 10 Earth masses are termed massive solid planets, mega-Earths, or gas giant planets, depending on whether they are mostly rock and ice or mostly gas. Some authors further suggest that the term Super-Earth might be limited to rocky planets without a significant atmosphere, or planets that have not just atmospheres but also solid surfaces or oceans with a sharp boundary between liquid and atmosphere, which the four giant planets in the Solar System do not have. This definition was made by the Kepler space telescope personnel. The term "super-Earth" is also used by astronomers to refer to planets bigger than Earth-like planets (from 0.8 to 1.2 Earth-radius), but smaller than mini-Neptunes (from 2 to 4 Earth-radii). While sources generally agree on an upper bound of 10 Earth masses (~69% of the mass of Uranus, which is the Solar System's giant planet with the least mass), the lower bound varies from 1 or 1.9 to 5, with various other definitions appearing in the popular media.
In general, super-Earths are defined by their masses, and the term does not imply temperatures, compositions, orbital properties, habitability, or environments.
Artist's impression of the super-Earth exoplanet LHS 1140b.