Is there a recognized definition of what size an exoplanet gas planet has to be to be classed as a SuperEarth or SuperJupiter? Is it based on radius or mass? i.e. All gaseous exoplanets > 1 Jupiter Radii are therefore classed a SuperJupiter? I note on Nasa's page of type of Exoplanets they don't mention e.g. Hot/Super-Jupiters so can I assume those terms are unofficial and therefore there is no consensus?

How about SubEarths and SubJupiters?

Can you tell from the Semi-Major Axis as to whether an exoplanet is a Hot-Jupiter/Hot-Earth or does that require more indepth study than just working out the SMA?

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    $\begingroup$ The only planets likely to have signicantly greater radii than Jupiter are super hot gias giants very close to their stars, whose atmospheres swell up and make them "puffy planets". Gas giants with normal temperatures can't get muhch larger than Jupiter since increased mass will increase their gravitational compression and density instead of their radius. $\endgroup$ Jul 28, 2021 at 17:14
  • $\begingroup$ There is less consistency in the usage of sub-neptune which has been used to describe planets with a lower mass than Neptune but a larger radius, and also used for planets with a smaller radius than Neptune but a greater mass. $\endgroup$
    – sno
    Jul 28, 2021 at 17:49

1 Answer 1


Super-Jupiters are planets with large masses, greater than that of Jupiter.

The "Jupiter" dividing line is rather arbitrary. There is no fundamental change in properties at the Jupiter mass.

Super-Earths are planets with a mass greater than Earth up to about 10 times the mass of Earth. Planets with radii between 1.2 and 2 times that of Earth are also called Super-Earths, though these two definitions overlap.

"Mini-Neptunes" is also a term sometimes used.

Hot Jupiters are typically Jupiter sized planets with an orbital period of less than 10 days.

None of these definitions is "official". This just summarises general usage.

  • $\begingroup$ Additionally, super - earth is rather used for planets with (suspected) solid surface, while mini - neptune rather refers to a gaseous ice or gas giant $\endgroup$ Jul 29, 2021 at 14:01

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