40 Eridani

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.

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.

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.