A super-Neptune is a

planet A planet is a large, rounded astronomical body that is neither a star nor its remnant. The best available theory of planet formation is the nebular hypothesis, which posits that an interstellar cloud collapses out of a nebula to create a you ...

that is more massive than the planet Neptune. These planets are generally described as being around 5–7 times as large as Earth with estimated masses of 20–80 ; beyond this they are generally referred to as

gas giants A gas giant is a giant planet composed mainly of hydrogen and helium. Gas giants are also called failed stars because they contain the same basic elements as a star. Jupiter and Saturn are the gas giants of the Solar System. The term "gas giant" ...

. A planet falling within this mass range may also be referred to as a sub-Saturn. There have been relatively few discoveries of planets of this kind. The mass gap between Neptune-like and

Jupiter Jupiter is the fifth planet from the Sun and the largest in the Solar System. It is a gas giant with a mass more than two and a half times that of all the other planets in the Solar System combined, but slightly less than one-thousandth t ...

-like planets is thought to exist because of "runaway accretion" occurring for

protoplanet A protoplanet is a large planetary embryo that originated within a protoplanetary disc and has undergone internal melting to produce a differentiated interior. Protoplanets are thought to form out of kilometer-sized planetesimals that gravitation ...

s of more than —once this mass threshold is crossed, they accumulate much additional mass (due to

gravity In physics, gravity () is a fundamental interaction which causes mutual attraction between all things with mass or energy. Gravity is, by far, the weakest of the four fundamental interactions, approximately 1038 times weaker than the stro ...

increasing with mass and the presence of material in an accretion disk) and grow into planets the size of Jupiter or even larger. Known examples include Kepler-101b,

HAT-P-11b HAT-P-11b (or Kepler-3b) is an extrasolar planet orbiting the star HAT-P-11. It was discovered by the HATNet Project team in 2009 using the transit method, and submitted for publication on 2 January 2009. This planet is located approximately ...

, and

K2-33b K2-33b (also known by its EPIC designation ''EPIC 205117205.01'') is a very young super-Neptune exoplanet, orbiting the pre-main-sequence star K2-33. It was discovered by NASA's ''Kepler'' spacecraft on its "Second Light" mission. It is located ...

References

Types of planet * {{extrasolar-planet-stub

See also

References