The planets that are outside the Solar System are called extrasolars or exoplanets. These planets orbit around a star that is not the Sun. Most of them are known as gas giants, and their constitution is very similar to that of Jupiter. Its orbits are very close to its star, and its orbital cycles are very short.
In 2005, the first images of an extrasolar planet, 2M1207b, were obtained. It is located at a distance of 55 AU from its star, a brown dwarf that is 230 light years away. These images were made through the VLT telescope of the ESO observatory in Chile. It is a planet whose mass is five times greater than Jupiter's, and it takes 2,450 years to complete a round around its star.
Already in the year 2010, NASA detected through the Kepler Probe more than 700 exoplanets in its first month of operation. Its dimensions vary between those of Neptune and the measurements of the Earth.
Almost a year later, in February 2011, the Kepler probe had already discovered more than a thousand candidates for extrasolar planets. Some of them are very similar in size to Earth, and the distance to their star is also similar. This implies that they would be in a habitable zone.
Curiously, there are exoplanets that do not revolve around a star. They are called wandering planets or interstellar planets, and are considered to have been expelled from the system in which they were formed.
|◄ Previous||Next ►|
|Habitable planet||Stars with planets|