Proxima Centauri

Coordinates: 14^h 29^m 42.9487^s, −62° 40′ 46.141″

Proxima Centauri (from Latin, meaning "nearest (star) of Centaurus") is a red dwarf star about 4.24 light-years from the Sun, inside the G-cloud, in the constellation of Centaurus. It was discovered in 1915 by the Scottish astronomer Robert Innes, the Director of the Union Observatory in South Africa, and is the nearest known star to the Sun, although it is too faint to be seen with the naked eye, with an apparent magnitude of 11.05. Its distance to the second- and third-nearest stars, which form the bright binary Alpha Centauri, is 0.237 ± 0.011 ly (15,000 ± 700 AU). Proxima Centauri is very likely part of a triple star system with Alpha Centauri A and B, but its orbital period may be greater than 500,000 years.

Because of Proxima Centauri's proximity to Earth, its angular diameter can be measured directly, from which it can be determined that its diameter is about one-seventh of that of the Sun. Proxima Centauri's mass is about an eighth of the Sun's mass (M_☉), and its average density is about 40 times that of the Sun. Although it has a very low average luminosity, Proxima is a flare star that undergoes random dramatic increases in brightness because of magnetic activity. The star's magnetic field is created by convection throughout the stellar body, and the resulting flare activity generates a total X-ray emission similar to that produced by the Sun. The mixing of the fuel at Proxima Centauri's core through convection and its relatively low energy-production rate mean that it will be a main-sequence star for another four trillion years, or nearly 300 times the current age of the universe.

Proxima Centauri (disambiguation)

Proxima Centauri may refer to:

See also

Proxima Centauri (short story)

"Proxima Centauri" is a science fiction short story by Murray Leinster that first appeared in the March 1935 issue of Astounding Stories. Unusually for the time, the story adhered to the laws of physics as they were known, showing a starship that was limited by the speed of light, and which took several years to travel between the stars. In his comments on the story in Before the Golden Age, Isaac Asimov thought that "Proxima Centauri" must have influenced Robert A. Heinlein's later story "Universe" and stated that it influenced his own Pebble in the Sky.

Plot summary

Earth's first starship, the Adastra, is approaching Proxima Centauri after a seven-year voyage. The voyage was marred by a mutiny among the crew, and the ship is still divided between a small group of officers who control the Adastra and the remainder of the crew, whom the officers refer to disparagingly as Muts, short for mutineers.

A young Mut named Jack Gary has been picking up and studying transmissions from a race native to the Proxima Centauri system. This has earned him the confidence of Captain Bradley, the love of Bradley's daughter Helen, and the hatred of the Adastra's first officer, Commander Alstair, who also has romantic designs upon Helen. Much to Alstair's disgust, Captain Bradley raises Gary to officer status in recognition of his work with the Centaurian transmissions. Shortly after the elderly Bradley's death, Gary discovers that a Centaurian spaceship is approaching the Adastra, and he suspects that their intention is hostile. The Centaurians confirm his suspicions when they fire a radiation beam at the ship. Although the Adastra has not been harmed, Alstair has the ship play dead to fool the Centaurians into thinking they have succeeded in wiping out the crew. The Centaurian ship docks with the Adastra, and a boarding party attacks the crew. The boarding party is defeated, and the Centaurian ship departs.