The closest star to Earth is a triple-star system called Alpha Centauri.The two main stars are Alpha Centauri A and Alpha Centauri B, which form a binary set. The third star is called Proxima Centauri or Alpha Centauri C, and it is about 4.25 light-years from Earth, making it the closest star other than the sun.According to NASA, Alpha Centauri A and B are on average about 23 huge systems (AU) from each other– a little bit more than the distance between the sun and Uranus. The closest the 2 stars ever come to each other is 11 huge systems, according to NASA, and the two stars orbit a typical center of gravity every 80 years.Related: Alpha Centauri stars and world explained: our closest next-door neighbors (infographic)Proxima Centauri, meanwhile, is about one-fifth of a light-year or 13,000 AUs from the two other stars, a range that makes some astronomers question whether it ought to even be thought about part of the same system.Proxima Centauri may be passing through the system and will leave the vicinity in a number of million years, or it may be gravitationally bound to the binary set. If its bound, it has an orbital duration around the other two stars of about 500,000 years.Meet the stars of Alpha CentauriTo the naked eye, the Alpha Centauri A and B shine as one, making them the third brightest “star” in our night sky. It is three times closer to Earth than the next nearby star like our sun, according to NASA.Alpha Centauri B is an orange K1-type star somewhat smaller sized than the sun.
The closest star to Earth is a triple-star system called Alpha Centauri.The two main stars are Alpha Centauri A and Alpha Centauri B, which form a binary set. They are about 4.35 light-years from Earth, according to NASA. The third star is called Proxima Centauri or Alpha Centauri C, and it is about 4.25 light-years from Earth, making it the closest star other than the sun.According to NASA, Alpha Centauri A and B are on average about 23 astronomical units (AU) from each other– a little bit more than the range between the sun and Uranus. (An astronomical system is the average distance in between Earth and the sun, which equates to 92,955,807 miles or 149,597,870 kilometers.) The closest the 2 stars ever come to each other is 11 huge units, according to NASA, and the two stars orbit a common center of mass every 80 years.Related: Alpha Centauri stars and world explained: our nearest next-door neighbors (infographic)Proxima Centauri, on the other hand, has to do with one-fifth of a light-year or 13,000 AUs from the two other stars, a distance that makes some astronomers question whether it ought to even be considered part of the exact same system.Proxima Centauri may be going through the system and will leave the area in a number of million years, or it might be gravitationally bound to the binary set. If its bound, it has an orbital duration around the other 2 stars of about 500,000 years.Meet the stars of Alpha CentauriTo the naked eye, the Alpha Centauri A and B shine as one, making them the 3rd brightest “star” in our night sky. The 2 separate stars can be seen through a little telescope, making the system among the finest binary stars that can be observed. Proxima Centauri is too faint to see unaided, and through a telescope it appears about four sizes of the complete moon far from the other two.Alpha Centauri A, likewise referred to as Rigel Kentaurus, is a yellow star of the exact same type (G2) as the sun, although somewhat bigger, according to NASA. It is 3 times closer to Earth than the next nearby star like our sun, according to NASA.Alpha Centauri B is an orange K1-type star slightly smaller than the sun. Proxima Centauri is a red dwarf about one-eighth the size of the sun, according to NASA.The system remains in the Southern sky and is not noticeable to observers above the latitude of 29 degrees north, according to EarthSky.org– a line that passes near Houston and Orlando, Fla. In the Southern Hemisphere, the Alpha Centauri system is simple to discover due to the fact that the cross-piece of the Southern Cross (from Delta to Beta Crucis) points the way. Its right ascension is 14h 39m 41s and its declination is minus 60 degrees 50 minutes 7 seconds.Are there planets in the Alpha Centauri system?Astronomers announced in August 2016 that they had found an Earth-size world orbiting Proxima Centauri. The planet, called Proxima b, has to do with 1.3 times more massive than Earth, which suggests that the exoplanet is a rocky world, scientists stated. And Proxima bs fairly small distance from Earth makes it a particularly appealing target for scientists.The world is also in the stars habitable zone, that just-right variety of ranges from a star where liquid water can exist on the surface area of a body. Proxima b lies simply 4.7 million miles (7.5 million km) from its host star and completes one orbit every 11.2 Earth-days. Nevertheless, despite Proxima bs size and place, its unclear from todays telescopes just how habitable the planet may be. Astronomers require to run more models and do more comparative research studies to better understand how habitable the world may be.As a start, researchers need to be able to look for signs of an environment. From there, the detectives can theorize whether that atmosphere (if present) allows liquid water to flow on the surface. Even the surface area temperature level of the world, which would likewise affect habitability characteristics, depends on the atmosphere.The planet might also be so near its star that it is tidally locked, suggesting it constantly shows the same face to its host star, just as the moon reveals only one face (the near side) to Earth. This arrangement would make one side of the planet very warm and the other extremely cold unless winds might disperse the heat around the world. If that stark temperature distinction does exist, it would be an extreme obstacle to any life.An artists depiction of the view from the surface of Proxima b, with the 2 stars of Alpha Centauri visible low in the skies. (Image credit: ESO/M. Kornmesser)And Proxima Centauris status as a red dwarf also most likely decreases habitability. Red dwarfs are unsteady stars, especially when they are young– such stars produce a lot of excellent activity and emit charged particles, which can trigger extreme radiation on close-by planets. Some of this radiation can strip particles off the top of a worlds atmosphere and thin it over time, according to 2017 research studies led by the NASA Goddard Space Flight Center in Greenbelt, Maryland.Scientists are continuing to study red dwarf stars to better understand the habitability of worlds like Proxima b. (NASAs Transiting Exoplanet Survey Satellite, or TESS, is an exoplanet-hunter especially skilled at spotting worlds around this category of star.)In November 2017, scientists found Ross 128b, another world in the habitable zone of a red dwarf that is nearly as close to Earth as Proxima Centauri is, but that seems a much quieter star.However, discovering out more about its environment will need a next-generation ground-based telescope. (The James Webb Space Telescope, set to introduce in late 2021, cant gather the necessary observations because the planet does not transit throughout the face of its star.)In 2019, scientists spotted what might be a second planet orbiting Proxima Centauri, although the discovery has not yet been confirmed.This story was upgraded Nov. 5, 2021, and March 20, 2019.
