Proxima Centauri C is a small, nondescript star located 4.2 light years away in the constellation of Centaurus. For its small size, it holds a very important role in the Earth's story as the closest star to our solar system.
Size
Proxima Centauri is a typical red dwarf. It is small, more than ten thousand times less faint than the sun, and only about one-tenth the mass. On the Hertzsprung-Russell diagram it fits along the main sequence, between the spectral class of K and M. This corresponds to a surface temperature of less than 3500 Kelvin. Proxima Centauri is only visible from southern latitudes, and only when using a telescope.
Considerations
Proxima Centauri is actually part of a triple star system. Alpha Centauri A and B are large, bright stars that are located 4.6 light years from the Earth. They revolve around each other every 80 years or so, at a distance of 2.2 billion miles. This is approximately the distance from the sun to Neptune. Alpha Centauri C, also known as Proxima Centauri, is quite a distance from the primary binary system, some 14 light years closer to the Earth. Many astronomers believe that this cool, reddish star follows a wide orbit around the two brighter ones, while others think it follows a more hyperbolic path and is just passing through the system. If Proxima Centauri is orbiting the binary system, it will take millions of years to complete one orbit.
Features
Proxima Centauri is a red dwarf, which is the least luminous class of star and also the type with the longest lifespan. Proxima Centauri is also a flare star. Due to magnetic activity, it can more than double its luminosity in just a couple of hours and just as quickly return to its original level of brightness. Although flare stars fluctuate with no discernible short-term pattern, the fact that they vary makes them a UV Ceti variable star, and Proxima Centauri's variable star name is V645 Centauri. Flares from a red dwarf are analogous to solar flares coming from the sun.
Theories/Speculation
While Proxima Centauri is the closest star to the Earth right now, things will likely change in the distant future. It circles the Alpha-Beta Centauri star system from 930 billion miles away, and as such, has a huge orbit. As it orbits the binary system, Proxima Centauri will reach its furthest distance from Earth and the binary system, which is also referred to as Rigel Kentaurus, will take the title as the closest star to Earth.
History
Proxima Centauri didn't get its name until the early 20th century, when Robert Inness, the director of a South African observatory noticed that it shared the same proper motion as that of Alpha Centauri, which had been discovered between 1832 and 1833. Inness named the star. In 1917, two years after its original discovery, the Dutch astronomer Joan Voute was able to confirm the distance of Proxima Centauri by measuring its trigonometric parallax. It then took 30 more years for astronomers to determine that Proxima Centauri was a flare star.
Potential
As astronomers explore the vastness of the universe, they begin to wonder if there are other planets out there capable of sustaining life. The Centauri system has become a huge target for scientists because of the proximity of its stars to the Earth. While many researchers believe that Proxima Centauri could not sustain a system of planets because it is a flare star, others feel that the star would be an ideal place for an Earth-like planet. Even if the red dwarf is incapable of harboring a terrestrial planet, the binary system of Alpha Centauri A and B is a viable candidate for study. In fact, of the five criteria that a star must meet to qualify as a promising place for terrestrial life, Centauri A, which is of the same spectral class as the sun, meets all five. Centauri B passes all tests but one; as a K-class star, it may not have enough energy available to sustain life.
Tags: Proxima Centauri, binary system, Alpha Centauri, closest star, distance from, flare star
