Meaning of Exoplanet

What is an Exoplanet:

An exoplanet is a planet outside the Solar System orbiting another star. They are also called extrasolar planets and are characterized by the fact that they revolve around a star that has enough mass to be spherical and is in a more mature stage, that is, free of the dense gas disk that surrounds new stars.

exoplanetThe word exoplanet derives from the Greek, and is composed by the prefix exos-, which means ‘out’, and plan which refers to ‘something errant’.

The discovery of exoplanets is important, as it helps to expand knowledge about the theories and models of galaxy and star formation.

Our Solar System that revolves around our star, the Sun, is 4.6 billion years old. The discovery of younger or more mature systems with exoplanets revolving around other stars would help determine the nature of the Solar System and the habitability of other planets.

See also:

  • Star.
  • Planet.

exoplanets discovered

They have discovered more than 5,000 exoplanets to date with terrestrial telescopes such as HARPS from ESO, and space telescopes such as Kepler from NASA and COROT from CNES in conjunction with ESA.

Within the discovered exoplanets, 2,950 of them have been confirmed as such by detection tools and 2,504 are awaiting confirmation.

In 2017, the discovery by ESO and NASA of seven Earth-sized planets orbiting the TRAPPIST-1 systema small red star the size of Jupiter, located in the constellation of Aquarius 40 light years from Earth, is important since there are three planets that meet the ideal characteristics for the development of carbon-based life: ideal size and located within the range of habitability.

habitable exoplanets

The astrobiology or exobiologyknown as the study of the possibility of life beyond Earth, has defined the following two main characteristics for the development of carbon-based life:

  1. The planet or exoplanet must have a suitable size: This means that it must be large enough (between 1 to 10 Earth masses) so that it can retain atmosphere but, in turn, not so massive that it does not retain only gases such as hydrogen.
  2. The exoplanet must be in the habitable zone (Goldilocks zone): a strip is limited around the star that would allow the existence of water in a liquid state, that is, exoplanets cannot be very close to their star, since water would be in a gaseous state, but it cannot be very far either of it so that the water is in a solid state or in the form of ice.
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In the coming decades, missions Darwin of ESA and Terrestrial Planet Finder of NASA contemplate exploring exoplanets to investigate the existence of oxygen, carbon dioxide and chlorophyll in them.

See also Carbon cycle.