Gliese 686
Gliese 686 (GJ 686 / HIP 86287 / LHS 452) is a star in the constellation of Hercules, with an apparent magnitude +9.577. 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. 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.
| Observation data Epoch J2000 Equinox J2000 | |
|---|---|
| Constellation | Hercules |
| Right ascension | 17h 37m 53.347s |
| Declination | +18° 35′ 30.16″ |
| Apparent magnitude (V) | 9.577 |
| Characteristics | |
| Spectral type | M1.0V |
| B−V color index | 1.530±0.015 |
| Astrometry | |
| Radial velocity (Rv) | −9.55±0.1 km/s |
| Proper motion (μ) | RA: 926.638 mas/yr Dec.: 984.455 mas/yr |
| Parallax (π) | 122.5546 ± 0.0176 mas |
| Distance | 26.613 ± 0.004 ly (8.160 ± 0.001 pc) |
| Absolute magnitude (MV) | 10.08 |
| Details | |
| Mass | 0.426±0.017 M☉ |
| Radius | 0.427±0.013 R☉ |
| Luminosity | 0.0295±0.0007 L☉ |
| Surface gravity (log g) | 4.87±0.07 cgs |
| Temperature | 3,656±51 K |
| Metallicity [Fe/H] | −0.23±0.16 dex |
| Rotation | 38.732±0.286 d |
| Rotational velocity (v sin i) | 2.49 km/s |
| Other designations | |
| Database references | |
| SIMBAD | data |
| ARICNS | data |
Gliese 686 is one of the many red dwarfs in the Solar System neighborhood with a spectral type of M1V, and has an effective temperature of about 3600 K. Its brightness in the visible spectrum is equal to 0.82% of that of the Sun, while its total luminosity is equivalent to 2.7% that of the Sun, 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. It has a metallic content lower than that of the Sun; various studies estimate its index metallicity between -0.25 and -0.44. It has an approximate mass between 45% and 49% of the solar mass and is a star with characteristics comparable to that of Lacaille 9352.