Mira, also known as Omicron Ceti, is estimated tp be 200-400 light years away in the constellation Cetus. A binary star system, it consists of a cool, pulsating giant, the famous star Mira A, and a low-mass companion, Mira B, which is accreting matter that has been shed by its larger partner.

In Star Trek, Omicron Ceti III, the site of a colony established in 2264. The Enterprise's was sent there to catalog its destruction under the bombardment of deadly berthold rays, which were only discovered after the colonists left Earth. However, they discover that Elias Sandoval and the other colonists are not dead after all. The Omicron pod plant discovered on planet Omicron Ceti III by botanist Leila Kalomi served as a repository for the Omicron spore, and squirts them out of its flower at anyone uninfected who comes too close. When the inhabitants of Omicron colony tried to infect the crew of the USS Enterprise with the spores, an infected Doctor Leonard H. McCoy had numerous pod plants beamed up to the ship, where the spores quickly spread through the ventilation system. (TOS: "This Side of Paradise")

Another planet in the Mira system, Dytallix B, was visited by the USS Enterprise-D in 2364. Prior to the 2360s, Dytallix B had was mined for the Federation by the Dytallix Mining Company. The mines were located in the temperate zones between the day and night hemispheres. By 2364 the mines were long abandoned and were used a secret meeting place by Starfleet Captains Walker Keel, Rixx, Tryla Scott, and Jean-Luc Picard to discuss the infiltration of Starfleet Command by neural parasites. (TNG: "Conspiracy") (TNG: "Conspiracy")

In astronomy, Mira A lies on the so-called asymptotic giant branch of the Hertzsprung-Russell diagram. It is pulsating variable whose brightness ranges from 2.0 to 10.1 and spectral type from M6e to M9e III over a period of 331.96 days as its surface rises and falls. Visible to the naked eye at its brightest, Mira can be seen only with optical aid for most of its cycle. It is the prototype and brightest long-period variable or Mira star, and was give its name (meaning “wonderful”) by David Fabricius, who was the first to record its brightness fluctuations in 1596. This very luminous and hugely distended star has a diameter of about 650 million km (over 400 million miles) so that it could comfortably swallow the orbit of Mars. Hubble Space Telescope observations have shown that, like some other stars of its type (including R Leonis and W Hydrae), it is conspicuously egg-shaped. Mira’s great size and instability result in a stellar wind that will eventually blow away the star's outer envelope, forming a planetary nebula and leaving behind a white dwarf.

Mira B, also known as VZ Ceti, is separated from Mira A by an average distance of about 100 AU and the two stars complete an orbit around each other in roughly 500 years. Although astronomers used to think that Mira B was a white dwarf, recent evidence suggests that it is a main sequence star with about half the mass of the Sun. The erratic variability of Mira B are probabaly connected with its capture of matter from Mira's stellar wind, making Mira B what is known as a symbiotic star. Mira B accretes as much as one percent of the matter lost by its primary.

In January 2007, a group of astronomers using the the Keck Observatory in Hawaii and the Gemini South telescope in Chile reported the discovery of a protoplanetary disk around Mira B raising the unexpected possibility that planets may form from material shed by dying stars. Though planet formation is perhaps unlikely as long as the disk is in active accretion, it may proceed rapidly once Mira A passes through its giant phase and becomes a white dwarf. Furthermore, if planets do form they will have a palnetiful source of the raw materials necessary for life, including carbon.

The disk around Mira B currently contains less than a Jupiter's worth of material. However, this is likely to increase to between three and five Jupiters' worth of matter before the accretion process ends – roughly the mass needed to form a planetary system like our own. In addition to the light from the ordinary star, any planets that form will be bathed in the pale glow of the white dwarf, which would appear about as bright as a crescent Moon.