Observation data Epoch J2000 Equinox J2000 | |
---|---|
Constellation | Libra |
Right ascension | 15h 13m 28.6671s [1] |
Declination | −25° 18′ 33.6547″ [1] |
Apparent magnitude (V) | 6.45 [2] |
Characteristics | |
Spectral type | G5 V [3] |
B−V color index | +0.70 [2] |
Astrometry | |
Radial velocity (Rv) | +4.7 [4] km/s |
Proper motion (μ) | RA: −400.308±0.130 [1] mas/yr Dec.: −75.160±0.138 [1] mas/yr |
Parallax (π) | 38.1678 ± 0.0747 [1] mas |
Distance | 85.5 ± 0.2 ly (26.20 ± 0.05 pc) |
Details | |
Mass | 1.07+0.03 −0.08 [3] M☉ |
Radius | 1.25±0.04 [3] R☉ |
Surface gravity (log g) | 4.30 [5] cgs |
Temperature | 5585±50 [3] K |
Metallicity [Fe/H] | 0.25±0.02 [3] dex |
Rotational velocity (v sin i) | 2.17 [3] km/s |
Age | 8.4+1.6 −1.4 to 11.1+1.5 −3.7 [3] Gyr |
Other designations | |
Database references | |
SIMBAD | data |
Exoplanet Archive | data |
Extrasolar Planets Encyclopaedia | data |
23 Librae (23 Lib) is a star in the zodiac constellation Libra, making it visible from most of the Earth's surface. With an apparent visual magnitude of 6.45, [2] it requires dark skies and good seeing conditions to see this star with the naked eye. It has a planetary system with two confirmed extrasolar planets. [3]
Based upon parallax measurements, this star is located at a distance of 85 light-years (26 parsecs ) from the Earth. The spectral properties of 23 Librae identify it as stellar class G5 V, with the luminosity class of 'V' indicating that this is a main sequence star that is generating energy through the thermonuclear fusion of hydrogen at its core. This energy is being radiated from the outer envelope at an effective temperature of about 5,585 K, giving it the yellow hue typical of G-type stars. [7] Estimates of the age of 23 Librae range from 8.4 to 11.1 billion years, making it much older than the Sun. [3]
23 Librae is slightly larger than the Sun, with an estimated 107% of the Sun's mass and 125% of the Sun's radius. The abundance of elements other than hydrogen and helium, what astronomers term the star's metallicity, is higher than in the Sun. It appears to be rotating slowly, with the projected rotational velocity of 2.2 km∙s−1 giving a lower bound to the actual azimuthal velocity along the equator. [3]
In November 1999 an exoplanet 23 Librae b was announced orbiting 23 Librae, [8] [9] and in 2009 an additional planet was detected. [3] Examination of the system in the infrared using the Spitzer Space Telescope did not reveal any excess emission, which might otherwise suggest the presence of a circumstellar debris disk of orbiting dust. [10] In the popular franchise Halo the star system is home to the planets Hesiod farther away from the star and Madrigal in the habitable zone.
Companion (in order from star) | Mass | Semimajor axis (AU) | Orbital period (days) | Eccentricity | Inclination | Radius |
---|---|---|---|---|---|---|
b | ≥ 1.59±0.02 MJ | 0.81±0.02 | 258.19±0.07 | 0.233±0.002 | — | — |
c | ≥ 0.82±0.03 MJ | 5.8±0.5 | 5000±400 | 0.12±0.02 | — | — |
Gliese 570 is a quaternary star system approximately 19 light-years away. The primary star is an orange dwarf star. The other secondary stars are themselves a binary system, two red dwarfs that orbit the primary star. A brown dwarf has been confirmed to be orbiting in the system. In 1998, an extrasolar planet was thought to orbit the primary star, but it was discounted in 2000.
HD 169830 is a star in the southern constellation of Sagittarius. It has a yellow-white hue and is dimly visible to the naked eye with an apparent visual magnitude of +5.90. The star is located at a distance of 120 light years from the Sun based on parallax. It is drifting closer with a radial velocity of −17.3 km/s, and is predicted to come as close as 20.7 ly (6.4 pc) in 2.08 million years. HD 169830 is known to be orbited by two large Jupiter-like exoplanets.
HD 93083 is an orange-hued star in the southern constellation of Antlia. It has the proper name Macondo, after the mythical village of the novel One Hundred Years of Solitude. The name was selected by Colombia during the IAU's NameExoWorlds campaign. The star has an apparent visual magnitude of 8.30, which is too faint to be visible to the naked eye. It is located at a distance of 93 light years from the Sun based on parallax. HD 93083 is drifting further away with a radial velocity of +43.65 km/s, having come to within 43 light-years some 484,000 years ago.
HD 6434 is a star in the southern constellation of Phoenix. Yellow dwarfs such as this are not very luminous, so at a distance of 138 light years it is not visible to the unaided eye. However, with binoculars it is readily visible under ideal observing conditions, having an apparent visual magnitude of 7.71. The star is drifting further from the Sun with a radial velocity of +23 km/s.
3 Cancri is a single star in the zodiac constellation of Cancer, located around 810 light years from the Sun. It is visible to the naked eye as a dim, orange-hued star with an apparent visual magnitude of 5.60. This object is moving further from the Earth with a heliocentric radial velocity of +39.5 km/s, and may be a member of the Hyades group. It is located near the ecliptic and thus is subject to lunar eclipses.
Nu2 Canis Majoris (ν2 Canis Majoris) is a single star in the southern constellation of Canis Major.
HD 154345 is a star in the northern constellation of Hercules. With an apparent visual magnitude of +6.76 it is a challenge to view with the naked eye, but using binoculars it is an easy target. The distance to this star is 59.7 light years based on parallax, but it is drifting closer with a radial velocity of −47 km/s. At least one exoplanet is orbiting this star.
HD 47536 is a single star in the southern constellation of Canis Major. It has an orange hue and is dimly visible to the naked eye with an apparent visual magnitude of +5.25. The star is located at a distance of approximately 401 light years from the Sun based on parallax. It is drifting further away with a radial velocity of 80 km/s.
HD 222582 is a multiple star system in the equatorial constellation of Aquarius. It is invisible to the naked eye with an apparent visual magnitude of 7.7, but can be viewed with binoculars or a small telescope. The system is located at a distance of 138 light years from the Sun based on parallax, and it is drifting further away with a radial velocity of +12 km/s. It is located close enough to the ecliptic that it is subject to lunar occultations.
Gliese 86 is a K-type main-sequence star approximately 35 light-years away in the constellation of Eridanus. It has been confirmed that a white dwarf orbits the primary star. In 1998 the European Southern Observatory announced that an extrasolar planet was orbiting the star.
HD 141937 is a star in the southern zodiac constellation of Libra, positioned a couple of degrees to the north of Lambda Librae. It is a yellow-hued star with an apparent visual magnitude of 7.25, which means it is too faint to be seen with the naked eye. This object is located at a distance of 108.9 light years from the Sun based on parallax, but is drifting closer with a radial velocity of −2.2 km/s. It has an absolute magnitude of 4.71.
HD 24040 is a metal-rich G-type star located approximately 152 light-years away in the constellation of Taurus. In 2006 a long-period planet was discovered.
WASP-8 is a binary star system of 9.9 magnitude. The star system is much younger than Sun at 0.3+0.9
−0 billion years age, and is heavily enriched in heavy elements, having nearly twice the concentration of iron compared to the Sun.
HD 131664 is an 8th magnitude star in the southern constellation of Apus with an orbiting brown dwarf companion. Parallax measurements by the Gaia space observatory provide an estimated distance of 172.5 light years from the Earth. The system is moving further away with a baseline heliocentric radial velocity of +35 km/s.
HD 145377 is a star in the southern constellation Scorpius. It has an apparent visual magnitude of 8.10 and can be viewed with a small telescope. The star is located at a distance of 175 light years from the Sun based on parallax, and it is drifting further away with a radial velocity of +11.6. The absolute magnitude of this star is 4.31, indicating it would be visible to the naked eye if it were at a distance of 10 parsecs.
HD 6718 is a solar twin star in the equatorial constellation of Cetus. It has a yellow hue but is too faint to be viewed with the naked eye, having an apparent visual magnitude of 8.45. The distance to this object, as determined from parallax measurements, is 168 light years. It is drifting away from the Sun with a radial velocity of +35 km/s.
HD 8535 is a star located 181 light years away from the Sun in the southern constellation of Phoenix. It has a yellow hue and can be viewed using binoculars or a small telescope, having a low apparent visual magnitude of 7.70. The star is drifting further away from the Sun with a radial velocity of +2.4 km/s.
HD 215497 is a single star in the southern constellation of Tucana. It has an orange hue with an apparent visual magnitude of 8.96, which is too dim to be viewed with the naked eye. A 2015 survey ruled out the existence of any stellar companions at projected distances from 26 to 300 astronomical units. Based on parallax measurements, it is located at a distance of 132 light years from the Sun. The star is drifting further away with a radial velocity of +49 km/s, having come as close as 45 light-years some 774,000 years ago. The absolute magnitude of this star is 5.77.
41 Comae Berenices is a single, orange-hued star in the northern constellation of Coma Berenices. It is visible to the naked eye, having an apparent visual magnitude of 4.80. Based upon an annual parallax shift of 9.8 mas, it is located around 331 light years away. It is moving closer to the Earth with a heliocentric radial velocity of −17 km/s.
HD 217786 is a binary star system in the equatorial constellation of Pisces. With an apparent visual magnitude of 7.78, it requires binoculars or a small telescope to view. The system is located at a distance of 181 light-years from the Sun based on parallax, and is drifting further away with a radial velocity of +10 km/s. Kinematically, the star system belongs to the thin disk population of the Milky Way.