Gliese 686 (GJ 686 / HIP 86287 / LHS 452) [6] is a star in the constellation of Hercules, with an apparent magnitude +9.577. [3] Although it is close to the Solar System – at 26.6 light-years – it is not the closest known star in its constellation, since Gliese 661 is 20.9 light years away. [7] The closest system to this star is the bright μ Herculis, at 4.5 light years. They are followed by GJ 1230 and Gliese 673, at 7.2 and 7.6 light years respectively. [8]
Gliese 686 is one of the many red dwarfs in the Solar System neighborhood with a spectral type of M1V, [3] [6] and has an effective temperature of about 3600 K. [3] Its brightness in the visible spectrum is equal to 0.82% of that of the Sun, [9] while its total luminosity is equivalent to 2.7% that of the Sun, [10] since a significant amount of the radiation emitted by these stars is infrared invisible light. Considering only this last parameter, Gliese 686 is considerably brighter than other known red dwarfs; thus, it is 6.5 times more luminous than Ross 154 and 15 times more than Proxima Centauri, the closest star to the Solar System.
Gliese 686 has a radius approximately equal to half the solar radius. Its projected rotation speed is 2.5 km / s, its rotation period being equal to or less than 10.3 days. [11] It has a metallic content lower than that of the Sun; various studies estimate its index metallicity between -0.25 and -0.44. [11] [12] It has an approximate mass between 45% and 49% of the solar mass [13] and is a star with characteristics comparable to that of Lacaille 9352.
Gliese 686 has one known super-Earth planet detected by radial velocity. [3] It is orbiting close to the host star with a separation of 0.091 AU (13.6 Gm) and an orbital period of 15.5 days. Since the inclination of its orbit is unknown, only a lower bound on its mass can be determined: it has at least 6.6 times the mass of the planet Earth.
Companion (in order from star) | Mass | Semimajor axis (AU) | Orbital period (days) | Eccentricity | Inclination | Radius |
---|---|---|---|---|---|---|
b | ≥6.624±0.432 M🜨 | 0.091±0.001 | 15.530±0.0011 | 0.050±0.030 | — | — |
Ross 248, also called HH Andromedae or Gliese 905, is a small star approximately 10.30 light-years from Earth in the northern constellation of Andromeda. Despite its proximity it is too dim to be seen with the naked eye. It was first catalogued by Frank Elmore Ross in 1926 with his second list of proper-motion stars; on which count it ranks 261st in the SIMBAD database. It was too dim to be included in the Hipparcos survey. In about 40,000 years, Voyager 2 will pass 1.7 light-years from the star.
HR 7703 is a binary star system in the constellation of Sagittarius. The brighter component has an apparent visual magnitude of 5.31, which means it is visible from suburban skies at night. The two stars are separated by an angle of 7.10″, which corresponds to an estimated semimajor axis of 56.30 AU for their orbit.
Gliese 1 is a red dwarf in the constellation Sculptor, which is found in the southern celestial hemisphere. It is one of the closest stars to the Sun, at a distance of 14.2 light years. Because of its proximity to the Earth it is a frequent object of study and much is known about its physical properties and composition. However, with an apparent magnitude of about 8.6 it is too faint to be seen with the naked eye.
Gliese 674(GJ 674) is a small red dwarf star with an exoplanetary companion in the southern constellation of Ara. It is too faint to be visible to the naked eye, having an apparent visual magnitude of 9.38 and an absolute magnitude of 11.09. The system is located at a distance of 14.8 light-years from the Sun based on parallax measurements, but is drifting closer with a radial velocity of −2.9 km/s. It is a candidate member of the 200 million year old Castor stream of co-moving stars.
Gliese 849, or GJ 849, is a small, solitary star in the equatorial constellation of Aquarius. It has a reddish hue and is invisible to the naked eye with an apparent visual magnitude of 10.41. The distance to this star is 28.8 light-years based on parallax, but it is drifting closer to the Sun with a radial velocity of −15.3 km/s. It has a pair of confirmed gas giant companions.
Gliese 412 is a pair of stars that share a common proper motion through space and are thought to form a binary star system. The pair have an angular separation of 31.4″ at a position angle of 126.1°. They are located 15.8 light-years distant from the Sun in the constellation Ursa Major. Both components are relatively dim red dwarf stars.
Gliese 521 is a double star in the northern constellation of Canes Venatici. The system is located at a distance of 43.6 light-years from the Sun based on parallax measurements, but is drawing closer with a radial velocity of −65.6 km/s. It is predicted to come as close as 15.70 light-years from the Sun in 176,900 years. This star is too faint to be visible to the naked eye, having an apparent visual magnitude of +10.26 and an absolute magnitude of 10.24.
Gliese 163 is a faint red dwarf star with multiple exoplanetary companions in the southern constellation of Dorado. Other stellar catalog names for it include HIP 19394 and LHS 188. It is too faint to be visible to the naked eye, having an apparent visual magnitude of 11.79 and an absolute magnitude of 10.91. This system is located at a distance of 49.4 light-years from the Sun based on parallax measurements. Judging by its space velocity components, it is most likely a thick disk star.
Gliese 809 is a red dwarf star in the constellation Cepheus, forming the primary component of a multi-star system. A visual magnitude of 8.55 makes it too faint to see with the naked eye. It is part of the Gliese Catalogue of Nearby Stars and is located about 23 light-years (ly) from the Solar System. Gliese 809 has about 70.5% the radius of the Sun and 61.4% of the Sun's mass. It has a metallicity of −0.06, which means that the abundance of elements other than hydrogen and helium is just 87.1% that of the Sun.
Gliese 754 is a dim star in the southern constellation of Telescopium. It has an apparent visual magnitude of 12.25, which requires a telescope to view. The star is located at a distance of 19.3 light-years from the Sun based on parallax, and it is drifting further away with a radial velocity of +7 km/s. It is one of the hundred closest stars to the Solar System. Calculations of its orbit around the Milky Way showed that it is eccentric, and indicate that it might be a thick disk object.
Gliese 251, also known as HIP 33226 or HD 265866, is a star located about 18 light years away from the Solar System. Located in the constellation of Gemini, it is the nearest star in this constellation. It is located near the boundary with Auriga, 49 arcminutes away from the bright star Theta Geminorum; due to its apparent magnitude of +9.89 it cannot be observed with the naked eye. The closest star to Gliese 251 is QY Aurigae, which is located 3.5 light years away.
Gliese 588 is a nearby red dwarf star of spectral type M2.5, located in the constellation Lupus at 19.34 light-years from Earth. It emits a very stable light flux, with no detectable pulsations.
Gliese 408 is a star located 22.0 light-years from the Solar System, located in the constellation of Leo. The stars nearest to Gliese 408 are Gliese 402, at 6.26 light years, and AD Leonis, at 6.26 light years.
Gliese 402 is a star located 22.7 light years from the Solar System. Located in the constellation of Leo, it is also known as Wolf 358 from its entry in Max Wolf's star catalogue. The stars nearest to Gliese 402 are Gliese 393, at 3.43 light years, Gliese 408, at 6.26 light years, and Gliese 382 at 6.66 light years.
Gliese 880 is a red dwarf star in the northern constellation of Pegasus that may host an exoplanetary companion. No stellar companions to Gliese 880 have been discovered as of 2020.
GL Virginis, also known as G 12-30, is a star in the constellation of Virgo. It is a faint red dwarf, like more than 70% of the stars located within 10 parsecs of the Solar System; its magnitude visual magnitude is 13.898, making it impossible to see with the naked eye.
Gliese 877 is a red dwarf located in the southern constellation of Octans, near the boundary with Indus.
Gliese 49 is a star in the northern constellation of Cassiopeia. Visually, it is located 106 arcminutes north of the bright star γ Cassiopeiae. With an apparent visual magnitude of 9.56, it is not observable with the naked eye. It is located, based on the reduction of parallax data of Gaia, 32.1 light-years away from the Solar System. The star is drifting closer to the Sun with a radial velocity of −6 km/s.
Gliese 514, also known as BD+11 2576 or HIP 65859, is a M-type main-sequence star, in the constellation Virgo 24.85 light-years away from the Sun. The proximity of Gliese 514 to the Sun was known exactly since 1988.