How do super-Earths compare in mass and size with Earth?

Created from Britannica articles using AI. AI can make mistakes, so verify using Britannica articles.

Extrasolar planet Artist's conception of the extrasolar planet HD 209458b, some 150 light-years from Earth.

Super-Earths are a category of extrasolar planets that differ from Earth primarily in their increased mass and radius.1

Mass: A super-Earth is defined as a planet with a mass approximately 2 to 10 times that of Earth.1
Size: In terms of radius, some astronomers define these planets as having a size larger than Earth but less than that of Neptune, which is roughly 4 Earth radii.1

While Earth is the largest of the terrestrial planets in our solar system, it does not qualify as a super-Earth. These planets exhibit a wide range of characteristics; the smallest are likely rocky, while those at the higher end of the mass range may be classified as mini-Neptunes or sub-Neptunes. Due to their greater mass, some super-Earths may possess unique geological or atmospheric conditions that could potentially support liquid water, such as high-pressure melting in frozen oceans or the presence of deep oceans on Hycean worlds.1