page_title: Super-Earth
section_title: First
hierarchical_section_title: Super-Earth / Discoveries / First
caption_attribution_description: English: Size of Kepler Planet Candidates
context_page_description: A super-Earth is an extrasolar planet with a mass higher than Earth's, but substantially below those of the Solar System's ice giants, Uranus and Neptune, which are 14.5 and 17 times Earth's, respectively. The term "super-Earth" refers only to the mass of the planet, and so does not imply anything about the surface conditions or habitability. The alternative term "gas dwarfs" may be more accurate for those at the higher end of the mass scale, although "mini-Neptunes" is a more common term.
context_section_description: The first super-Earths were discovered by Aleksander Wolszczan and Dale Frail around the pulsar PSR B1257+12 in 1992. 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-Earth around a main-sequence star was discovered by a team under Eugenio Rivera in 2005. It orbits Gliese 876 and received the designation Gliese 876 d (two Jupiter-sized gas giants had previously been discovered in that system). It has an estimated mass of 7.5 Earth masses and a very short orbital period of about 2 days. Due to the proximity of Gliese 876 d to its host star (a red dwarf), it may have a surface temperature of 430–650 kelvins and be too hot to support liquid water.
caption: Sizes of Kepler Planet Candidates – based on 2,740 candidates orbiting 2,036 stars as of November 4, 2013 (NASA)
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