Star

Primary of Mataora.

Spectral Class K2.

This star is categorized as a BY Draconis variable, with variable star designation V2133. The variability is attributed to large-scale magnetic activity on the chromosphere (in the form of starspots) combined with a rotational period that moved the active regions into (and out of) the line of sight. This results in low amplitude variability of 12 Ophiuchi's luminosity. The star also appears to display rapid variation in luminosity, possibly due to changes in the starspots. Measurements of the long-term variability show two overlapping cycles of starspot activity (compared to the Sun's single, 11-year cycle.) The periods of these two cycles are 4.0 and 17.4 years.

Its abundance of heavy elements (elements heavier than helium) is nearly identical to that of the Sun. The surface gravity is equal to , which is somewhat higher than the Sun's. The space velocity is 30 km/s relative to the solar system. The high rotation period and active chromosphere are indicative of a relatively young star.
 

Primary of Teutates.

Spectral Class K0.

HR 4458 (289 G. Hydrae) is a binary star system in the constellation Hydra. At a distance of 31 light years, they are the closest stars to the solar system within this constellation. The pair has an angular separation of 16.2″.

Primary of Pwyll.

61 Ursae Majoris (61 UMa) is an orange-yellow G8 main-sequence star in the constellation Ursa Major. This star is somewhat smaller and fainter than the Sun, and can just barely be seen by the unaided eye (based on a magnitude limit of 6). Since 1943, the spectrum of this star has served as one of the stable anchor points by which other stars are classified.

No substellar companions have been observed in orbit around this star, and it appears to lack a dust ring as is found around some comparable stars. It lies near the same line of sight as the sub-giant star HD 101212, although it is presently unclear whether these two stars are gravitationally bound or even in physical proximity.

The space velocity components of this star are [U, V, W] = [+8, -16, -4] km/s. It is orbiting the galaxy at a mean distance of 7.9 kpc (26 kly) from the core with an eccentricity of 0.06.

Primary of Rangi.

HR 4523 (66 G. Centauri) is a binary star system that is located in the northeastern part of the Centaurus constellation, at a distance of about 30.07 ly (9.22 pc) from the Solar System. The larger member of the system is a G-type star that is smaller than the Sun but of similar mass. It has a common proper motion companion that was discovered by W. J. Luyten in 1960. This M-type star appears to be in a wide orbit around the primary at a current separation of about 211 Astronomical Units (A.U.), (or 211 times the separation of the Earth from the Sun). By comparison, Neptune orbits at an average distance of 30 A.U.

The stellar classification for the primary star in this system is G2V the same as the Sun. That of the red dwarf companion is M4V. The primary star has an estimated 86% to 89% the mass of the Sun, 96% of the Sun's radius, and 85% of the Sun's luminosity. It is a slow rotator, with a projected rotational velocity of 0.5 km/s. Age estimates range from 4.5–5.7 Gyr up to 7.1 Gyr or 9.48 Gyr. Compared to the Sun, it only has about 52% of the abundance of elements other than hydrogen and helium; what astronomers term the metallicity of a star.

This star system has a relatively large proper motion. The HR 4523 system is a member of the Epsilon Indi Moving Group, although it is most likely an interloper. (The star is older and has a different composition than the other group members.) It has space velocity components [U, V, W] = [−67, −40, +4] km/s.

The primary star is believed to be orbited by a Neptune-like planet with a mass 16 times that of the Earth. The orbital period of this planet is 122.1 days.

Primary of Cupara.

Kappa1 Ceti (κ1 Cet, κ1 Ceti) is a yellow dwarf star approximately 30 light-years away in the equatorial constellation of Cetus. The star was discovered to have a rapid rotation, roughly once every nine days. Though there are no extrasolar planets confirmed to be orbiting the star, Kappa1 Ceti is considered a good candidate to contain terrestrial planets (like the Earth). The system is a candidate binary star, but has not been confirmed. The star should not be confused with the star Kappa2 Ceti, which is ten times as distant.

Kappa1 Ceti is a yellow dwarf star of the spectral type G5Ve. Since 1943, the spectrum of this star has served as one of the stable anchor points by which other stars are classified. The star has roughly the same mass as the Sun, with 95% of the Sun's radius but only 85 percent of the luminosity. It is unclear whether the star is equal or is more enriched in elements heavier than hydrogen, but it is determined that the star has between 98 and 240 percent of the Sun's abundance of iron. Kappa1 Ceti is much younger than the Sun, and may only be around 800 million years old.

The rapid rotation rate of this star, approximately once every nine days, is indicative of a relatively youthful body several hundred million years in age. Due to starspots, the star varies slightly over the approximately the same period. The variations in period are thought to be caused by differential rotation at various latitudes, similar to what happens on the surface of our Sun. The star spots on Kappa1 Ceti range in latitude from 10° to 75°. The magnetic properties of this star make it "an excellent match for the Sun at a key point in the Earth's past".

According to recent hypotheses, unusually intense stellar flares from a solar twin star could be caused by the interaction of the magnetic field of a giant planet in tight orbit with that star's own magnetic field. Some Sun-like stars of spectral class F8 to G8 have been found to undergo enormous magnetic outbursts to produce so-called superflares (coronal mass ejections) that release between 100 and 10 million times more energy than the largest flares ever observed on the sun, making them brighten briefly by up to 20 times. In 1998, nine Solar twin stars (including Kappa1 Ceti) were observed to have produced superflares, on average, about once per century. None of these stars rotate particularly fast, have close binary companions, or are very young. Previously, such large flares had not been observed in solar-type main sequence stars, although they are common in a group of dim main-sequence, reddish M dwarfs known as flare stars.

Using the radial velocity technique, the search for substellar companions has thus far failed to find a brown dwarf or extrasolar planet in the "hot zone" orbit around Kappa1 Ceti. Given the regular eruption of superflares, however, it is unlikely that Earth-type life could survive for long on any inner terrestrial planet. The distance from the star where an Earth-type planet (with liquid water) would be stable is centered around 0.92 astronomical units from the star (between the orbital distances of Earth and Venus in the Solar system). At this distance, such a planet would have an orbital period of almost 324 days.

Primary of Tiamat.

Beta Comae Berenices (β Comae Berenices, β Com) is a main sequence dwarf star in the northern constellation of Coma Berenices. It is located at a distance of about 29.78 light-years (9.13 parsecs) from Earth.

This star is similar to our own Sun, being only slightly larger and brighter in absolute magnitude. It has a stellar classification of G0 V, compared to G2 V for the Sun. The effective temperature of the outer envelope is 5,936 K, giving it a yellow hue of a G-type star. In terms of age it is younger than the Sun, being about 3 billion years old.

Observations of short term variations in the chromatic activity suggest that the star undergoes differential rotation, with a rotation period of about 11–13 days. Its surface has a measured activity cycle of 16.6 years, compared to 11 years on our Sun. It may also have a secondary activity cycle of 9.6 years. At one time it was thought that this star might have a spectroscopic companion. However, this was ruled out by means of more accurate radial velocity measurements. No planets have yet been detected around it, and there is no evidence of a dusty disk.

Primary of Telyaveli.

Spectral Class: K0V

Delta Eridani (δ Eri, δ Eridani) is a 3.54 magnitude star in the constellation of Eridanus. It is also called Rana. The name Rana means "the frog" in Latin.

This star is relatively near to the Sun, at a measured distance of about 29 light years. It is sometime listed as a RS Canum Venaticorum-type variable star, but this is likely to be an error. (It is currently a suspected variable.) Rana is a sub-giant star that is near the end of its hydrogen-burning cycle and is now consuming helium. This has caused the star to expand and become hotter than a comparable main sequence star. As a sub-giant star it is subject to pulsations in its atmosphere.

Radial velocity surveys of this star have thus far failed to discern any gas giants in orbit.

Primary of Legba.

Spectral Class: F6

Gamma Leporis (γ Lep, γ Leporis) is a star that is located at a distance of about 29 light-years from Earth. It has a common proper motion companion, AK Leporis, which is a variable star of the BY Draconis type. The star is a member of the Ursa Major Moving Group.

This star is larger than the Sun with 1.2 times the radius of the Sun and 1.3 times the Sun's mass. Based upon its stellar characteristics and distance from Earth, Gamma Leporis is considered a high-priority target for NASA's Terrestrial Planet Finder mission.

Primary of Illapa.

The two components are yellow G-type main-sequence stars. The brighter component, Xi Ursae Majoris A, has a mean apparent magnitude of +4.41. It is classified as an RS Canum Venaticorum type variable star and its brightness varies by 0.01 magnitudes. The companion star, Xi Ursae Majoris B has an apparent magnitude of +4.87. The orbital period of the two stars is 59.84 years, and they are currently separated by 1.2 arcseconds, or at least 10 AUs.

Each component of this double star is itself a spectroscopic binary. B's binary companion, denoted Xi Ursae Majoris Bb, is unresolved, but the binary star is known to have an orbital period of 3.98 days. The masses of both A and B's companions (Ab and Bb) (deduced by the sum total mass of the system minus the likely masses of Aa and Ba determined by their class) indicate that they are probably MV stars (red dwarfs), Bb being on the cool end of the M spectrum, not much hotter than a brown dwarf.

It also has the proper name Alula Australis (and erroneously Alula Australe).

Primary of Tonapa.

Chi1 Orionis (χ1 Ori, χ1 Orionis) is a star about 28 light years away. It is in the constellation Orion.

χ1 Ori is a G0V main-sequence star. It has a faint companion with a mass estimated at about 15% of the mass of the Sun, an orbital period of 14.1 years, and an estimated stellar class of M6. The companion orbits an average distance of 6.1 AU from the primary, but has a fairly high orbital eccentricity, ranging from 3.3 AU out to 8.9 AU from the primary. Because of this red dwarf companion, the likelihood of habitable planets in this system is low.

χ1 Ori is a candidate stream star member of the Ursa Major Moving Group, although there is some evidence to the contrary.