Exoplanets or extrasolar planets, in layman’s terms, refer to those planets that exist outside of our solar system.These extrasolar planets were discovered for the first time in 1917. However, the first confirmation of the same occurred much later.As of December 1, 2021, there are around 4,878 exoplanets in our planetary systems. In addition, there are more than 3,604 planetary systems that exist and among these 807 of them have more than one planet. There are multiple ways through which exoplanets are detected. Doppler spectroscopy and transit photometry are among the most commonly used methods. Unlike all other planets, these exoplanets do not revolve around the Sun. They, in fact, revolve around different stars. Among these exoplanets, those which float freely are named rogue planets. From the Kepler space telescope, it has been discovered that these planets outnumbered the stars in the galaxy. The overall formation of these exoplanets is not completely different from other planets.If you are interested to know more about space, do check out our articles on Mercury planet and Eros planetoid.Facts About ExoplanetsThe first extrasolar planet named Gamma Cepheir Ab was detected in 1998. However, it was confirmed much later. Exoplanets were discovered in 1917 for the very first time but wasn’t announced until 1992. Among these planets are those that float freely in the galaxy. These free-floating exoplanets are known as rogue planets.Until 2013, the color of these exoplanets was not known despite scientists having studied extrasolar planets for decades. In 2013, it was discovered that the color of one of the extrasolar planets with the name HD 189733b was dark blue. It was through the Kepler mission that it was discovered that there are more than 4,000 exoplanets in the galaxy. Interestingly, there is more than one galaxy so there is a large number of exoplanets.Based on the study, it has been found out 20% of stars have a planet like ours that is orbiting around them. However, the atmosphere on these exoplanets is still unknown to all of us. Some of these extrasolar planets are Earth-sized planets.There is not just one solar system that exists but rather are many solar systems in the galaxy. Every solar system contains different types of exoplanets. The surface temperatures on these exoplanets are different. Not all exoplanets have yet been discovered. However, 4,000 of them are known exoplanets. There are many more planets that are yet to be discovered.The largest of all the extrasolar planets that have been detected so far is orbiting around a star named HD 100546 or Muscae. The closest planet outside the solar system is found in the Centaurus constellation and is hence known as Proxima Centauri B.Some of the extrasolar planets are also known as the rocky planet as their structure is similar to Venus with a rocky core. The first exoplanet discovered in 1992 was named M51-ULS-1b. Not one of these exoplanets has habitable zones.Discovered ExoplanetsPlanets orbiting around a star and not around the Sun are generally considered as planets outside the solar system. Using various supercomputers and space telescopes, several extrasolar planets have been discovered. Today, the number of discovered outer planets or extrasolar planets is 4,569 as per NASA.The first exoplanet was discovered in 1992 by astronomers Dale Frail and Aleksander Wolszczan. They announced that two exoplanets were discovered on January 9. Later, various types of exoplanets were discovered. These exoplanets were found to be orbiting around the pulsar PSR 1257+12.Kepler-186f is one of the rocky planets discovered that may have a habitable zone. As far as the size of this planet is concerned, it is similar to that of the planet Earth. The temperature on this planet is not too hot or too cold and the distance between the host star and the planet is perfect for water to exist. However, the technology has yet to be developed to get a closer picture of these exoplanets.51 Pegasi b is another exoplanet that orbits around a star and not around the Sun. In comparison with the earlier exoplanet mentioned, this one is quite big in size. It is a giant planet similar to that of the planet Jupiter. Around every four days, this exoplanet revolves around the star of the planet Jupiter.In addition, the Kepler-444 system is one of the oldest planetary systems and has its five terrestrial planets. This group of planets shows that the solar system has existed nearly for its entire existence. It has a bright, star-like structure and does not orbit around the Sun.55 Cancri e is one the hottest planets orbiting around the star. Interestingly, this exoplanet revolves around the star every 18 hours. The distance of this exoplanet to its star is less than the distance between Mercury and the Sun. The structure of this planet is rocky with very hot temperatures and hence is not habitable.CoRoT 7b is another exoplanet discovered by astronauts. It has a rocky structure and is considered Earth-like for a variety of reasons. It could be considered by scientists as a possible planet that is as habitable as the planet Earth.HD 209458 b is also termed Osiris and is another exoplanet that was discovered. It has opened up the narrow exoplanet characterizations. Interestingly, it is one of the first confirmed planets outside the solar system that emits its own light.Kepler- 22 b is another exoplanet that may be habitable. It is a water-world exoplanet and has a habitable zone unlike any other planet in the entire solar system.Facts About The Formation Of ExoplanetsExoplanets are formed up in space when smaller objects merge to form a single object. These exoplanets are similar to other planets in many ways. However, there is a slight difference between planets revolving around the Sun compared to how the Sun and exoplanets interact. These exoplanets are also called extrasolar planets. This is because they revolve around stars instead of the Sun, so their orbital positions are different from those of other planets.Exoplanets have been characterized by scientists into four different types. These types are Neptunian, terrestrial, super-Earth, and gas giants. As per current knowledge, these exoplanets - or rather any planets - are formed around a star from remnants of the supernova explosion. The Neptunian exoplanets are similar to that of Uranus and Jupiter. Their overall structure and size are identical to these planets. As far as terrestrial planets are concerned, they have a rocky structure similar to the Earth, Mercury, Venus, and Mars. Those planets that have valleys, craters, and volcanoes are generally referred to as terrestrial planets.Gas giants, as the name suggests, are giant planets of the solar system. These exoplanets are made up of hydrogen or helium similar to the chemical makeup of Saturn and Jupiter. These planets are generally found near their stars and are much larger in size and shape. These are named failed stars because they are similar to stars when it comes to composition. The term ‘gas giant’ for these exoplanets was coined by James Blish in 1952. He used the term to refer to all large planets.The final category of exoplanets, super-Earth, is a type of massive planet that is large and yet not too heavy in weight. In fact, these planets are lighter than planets such as Neptune which is made of ice. The mass of these exoplanets is, however, higher than that of the planet Earth. The gravity on these planets is much stronger than the gravity on Earth.Instruments Used To Study ExoplanetsAs compared to the parent star, exoplanets are much further away and are difficult to get clear pictures of. However, there are various instruments that help scientists to study exoplanets. The exoplanet might seem faint due to the glaring light of the parent star. It was found out with the help of the Kepler mission that there exist more than 4,000 exoplanets in the solar system.One instrument the scientist uses in called a spectrograph. This instrument helps to identify what the light coming from outer space is made of which further helps to identify the composition of the star or the planet that the light is coming from. This is also referred to as transit spectroscopy by the scientist. With data obtained from a spectrograph, a scientist can try to identify the composition of the exoplanet through the light emitted by the exoplanet.In addition, LBTI or the Large Binocular Telescope Interferometer is, in layman’s terms, an instrument funded by NASA that helps to identify the composition of the star or the planet emitting that light. Aside from this, direct aerial imaging can also help a scientist detect exoplanets and study them in greater detail. With the aid of the Kepler Space Telescope, several thousands of exoplanets have been discovered.Scientists are presently using the James Web Space Telescope (also known as JWST) as well as the Spitzer Space Telescope to identify promising specimens of exoplanets for the next generation to study. These telescopes provide a clear picture of exoplanets in outer space. Scientists use various instruments and methods to identify exoplanets. They use the transmit method, the wobble method, and direct imaging, as well as microlensing to identify exoplanets.Here at Kidadl, we have carefully created lots of interesting family-friendly facts for everyone to enjoy! If you liked our suggestions for 133 exoplanet facts: formation, discoveries, and interesting trivia then why not take a look at atlas planet, or is Neptune a water planet.
Exoplanets or extrasolar planets, in layman’s terms, refer to those planets that exist outside of our solar system.
