40 Eridani (also known as Omicron 2 Eridani, or Keid, from the Arabic word qayd "(egg) shells") is a triple star system less than 16.5 light years away from Earth. It is in constellation Eridanus and was discovered to be a double star in 1783 by William Herschel. In 1851, Otto Wilhem von Struve discovered that one of the stars in the double was itself a double. The Pleiades star cluster A star is any massive gaseous body in outer space, just like the Sun. ... A triple star system consists of three gravitationally bound stars. ... A star system or stellar system is a group of stars (and possibly smaller bodies such as planets or asteroids) that orbit one another (a system with planetary bodies orbiting stars, are referred to as solar systems or planetary systems). ... A light year, abbreviated ly, is the distance light travels in one year: roughly 9. ... Earth, also known as the Earth or Terra, is the third planet outward from the Sun. ... Eridanus is the sixth largest of the 88 modern constellations. ... Double Star is a science fiction novel by Robert A. Heinlein. ... 1783 was a common year starting on Wednesday (see link for calendar). ... Sir Wilhelm Friedrich Herschel (Hanover, November 15, 1738 – August 25, 1822 Slough, then in Buckinghamshire now in Berkshire) was a German-born British astronomer and composer who became famous for discovering the planet Uranus, and made many other astronomical discoveries. ... Events January 23 - The flip of a coin determines whether a new city in Oregon is named after Boston, Massachusetts, or Portland, Maine, with Portland winning. ...

General information

The primary star of 40 Eridani is an orange main sequence dwarf of spectral type K1, observed to be about 4 billion years old. The two companion stars, 40 Eridani B, a 9th magnitude white dwarf (spectral type A VII) and 40 Eridani C an 11th magnitude red dwarf (spectral type M4e V), orbit each other 400 astronomical units from the primary star. Hertzsprung-Russell diagram The main sequence of the Hertzsprung-Russell diagram is the curve where the majority of stars are located in this diagram. ... Hertzsprung-Russell diagram The main sequence of the Hertzsprung-Russell diagram is the curve where the majority of stars are located in this diagram. ... In astronomy, stellar classification is a classification of stars based initially on photospheric temperature and its associated spectral characteristics, and subsequenly refined in terms of other characteristics. ... White dwarf Sirius-B in x-rays A white dwarf is an astronomical object which is produced when a low to medium mass star dies. ... Red Dwarf is a British science fiction comedy, created and originally written by Rob Grant and Doug Naylor. ... The astronomical unit (AU or au or a. ...

40 Eridani in fiction

In the Star Trek fictional universe, 40 Eridani A is the location of the Vulcan home planet. Although this was never stated on any TV show or film, both the authorized Star Trek book Star Trek: Star Charts and Gene Roddenberry (see [1]) give this location. In addition, Commander Tucker's statement in Star Trek: Enterprise that Vulcan is 16 light years from Earth confirms this. The Enterprise boldly going where no man had gone before. ... Vulcans are a humanoid species in the fictional Star Trek universe who reside on the planet Vulcan and are noted for their attempt to live by reason and logic. ... In the fictional Star Trek universe, Vulcan, or Vulcanis, is a reddish Minshara-Class planet orbiting the star 40 Eridani A, 16 light years from Earth. ... The starship Enterprise (NX-01) Star Trek: Enterprise is a science fiction television series set in the Star Trek universe. ...