A Super-Earth is an extrasolar planet, which has a mass greater than Earth. The term super earth refers only to the mass of the planet; it is not concerned about the surface conditions, orbital properties, environment and habitation within the planet. The first super-Earth was discovered by Aleksander Wolszczan and Dale Frail in the region of the pulsar PSR B1257+12 in 1992.
In April 2007; the team of Stephane Udry in Switzerland discovered two new super-Earths in the Gliese 581 planetary system. Both were found on the periphery of the habitable zone around the star where liquid water would be possibly present on the surface. Our Solar System contains no known super-Earth, as Earth is the largest terrestrial planet in the Solar system. All the other planets are either Gas Giants or Ice Giants. In January a new Planet Planet Nine was discovered and was supposedly thought to be a Super-Earth, but later research revealed it to be an Ice Giant like Neptune and Uranus.
Characteristics of Super-Earth
- Super-Earths are generally composed of mainly Hydrogen and Helium.
- Super-Earths with intermediate density generally majorly consist of water or covered with a gracious envelope.
- Super-Earths with a higher density are considered to be rocky or metallic.
- The interiors of a Super-Earth may consist of layers of different compositions.
- Super-Earths are more geologically active, with more and vigorous plate tectonics.
- Research suggests that rocky centers of Super-Earths will hardly develop or evolve into the terrestrial rocky planet.
- The mass in Super-Earth can produce high pressure, which prevents the interiors of the planets does not separate into numerous layers; resulting in the formation of undifferentiated coreless mantles.
- The pressures and temperatures in Super-Earths usually generate magnetic fields in the Super-Earths.
- It is hypothesized that Super-Earths consisting of two times more mass than Earth may have life in them. The thicker atmosphere and strong magnetic fields in such planets protect life on the surface of the planet from harmful and destructive cosmic rays.
- Research shows that Super-Earths become compactly compressed as they gain mass. Gravity increases with higher density. It is estimated that gigantic super-Earths may have three times more gravity as compared to Earth.
- Super-Earths grow at a fast rate, due to their high density of mass and fast growth, such planets undergo orbital migration.
- It is also said that due to their faster growth process of Super-Earths and presence of radioactive isotopes within them, they are exposed to high level of heat.
It is said that astronomers have discovered fifty new exoplanets orbiting around stars in close proximity. Out of which sixteen are considered to be Super-Earths. Researchers are trying to find out whether these Super-Earths will be able to support life in the near future.
In short, we can say that Super-Earths are planets that are about one to ten times larger than Earth with the terrestrial rocky surface. Till date, about sixteen Super-Earths have been discovered and researchers are exploring them for habitability i.e. whether they would be able to support any form of life in them.