Gliese 686

Gliese 686 (GJ 686 / HIP 86287 / LHS 452)[4] is a star in the constellation of Hercules, with an apparent magnitude +9.577.[2] Although it is close to the Solar System - at 26.5 light years - it is not the closest known star in its constellation, since Gliese 661 is 20.9 light years away.[5] 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.[6]

Gliese 686
Observation data
Epoch J2000      Equinox J2000
Constellation Hercules
Right ascension  17h 37m 53.34674s[1]
Declination +18° 35′ 30.1607″[1]
Apparent magnitude (V) 9.577[2]
Characteristics
Spectral type M1[2]
Astrometry
Radial velocity (Rv)−9.55 ± 0.1[3] km/s
Proper motion (μ) RA: 926.741[1] mas/yr
Dec.: 984.697[1] mas/yr
Parallax (π)122.5609 ± 0.0346[1] mas
Distance26.612 ± 0.008 ly
(8.159 ± 0.002 pc)
Details[2]
Mass0.42 ± 0.05 M☉
Radius0.42 ± 0.05 R☉
Luminosity0.028 ± 0.006 L☉
Surface gravity (log g)4.83 ± 0.04 cgs
Temperature3663 ± 68 K
Metallicity [Fe/H]−0.30 ± 0.09 dex
Rotational velocity (v sin i)1.01 ± 0.80 km/s
Other designations
BD+18 3421, HIP 86287, G 170-55, LHS 452[4]
Database references
SIMBADdata
ARICNSdata

Gliese 686 is one of the many red dwarfs in the Solar System neighborhood with a spectral type of M1V,[2][4] and has an effective temperature of about 3600 K.[2] Its brightness in the visible spectrum is equal to 0.82% of that of the Sun,[7] while its total luminosity is equivalent to 2.7% that of the Sun,[8] 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.[9] It has a metallic content lower than that of the Sun; various studies estimate its index metallicity between -0.25 and -0.44.[9][10] It has an approximate mass between 45% and 49% of the solar mass [11] and is a star with characteristics comparable to that of Lacaille 9352.

Planetary system

Gliese 686 has one known super-Earth planet detected by radial velocity.[2]

The Gliese 686 planetary system
Companion
(in order from star)		 Mass Semimajor axis
(AU)		 Orbital period
(days)		 Eccentricity Inclination Radius
b 7.1±0.9 M⊕ 0.091±0.004 15.53209+0.00166−0.00167 — — —

References
  1. Brown, A. G. A.; et al. (Gaia collaboration) (August 2018). "Gaia Data Release 2: Summary of the contents and survey properties". Astronomy & Astrophysics. 616. A1. arXiv:1804.09365. Bibcode:2018A&A...616A...1G. doi:10.1051/0004-6361/201833051.
  2. Affer, L.; Damasso, M.; Micela, G.; Poretti, E.; Scandariato, G.; Maldonado, J.; Lanza, A. F.; Covino, E.; Rubio, A. Garrido (31 January 2019). "HADES RV program with HARPS-N at TNG. IX. A super-Earth around the M dwarf Gl686". Astronomy & Astrophysics. 622: A193. arXiv:1901.05338. doi:10.1051/0004-6361/201834868. ISSN 0004-6361.
  3. Nidever, David L.; Marcy, Geoffrey W.; Butler, R. Paul; Fischer, Debra A.; Vogt, Steven S.; McGahee, C. E.; O'Donoghue, A. A.; Knox, E. R. (2002). "Radial Velocities for 889 Late-Type Stars". The Astrophysical Journal Supplement Series. 141 (2): 503–522. arXiv:astro-ph/0112477. Bibcode:2002ApJS..141..503N. doi:10.1086/340570.
  4. "LHS 452". SIMBAD. Centre de données astronomiques de Strasbourg. Retrieved 2019-09-02.
  5. "Closest stars". closeststars.com. Retrieved 2019-03-31.
  6. "Stars within 15 light-years of Bonner Durchmusterung +18°3421 (The Internet Stellar Database)". stellar-database.com. Retrieved 2019-03-31.
  7. "Bonner Durchmusterung +18°3421 (The Internet Stellar Database)". stellar-database.com. Retrieved 2019-03-31.
  8. Morales, J. C.; Ribas, I.; Jordi, C. (2008). "The effect of activity on stellar temperatures and radii". Astronomy and Astrophysics. 478 (2). arXiv:0711.3523. pp. 507-512.
  9. Houdebine, E. R. (2010). "Observation and modelling of main-sequence star chromospheres - XIV. Rotation of dM1 stars". Monthly Notices of the Royal Astronomical Society. 407 (3). pp. 1657–1673.
  10. Jenkins, J. S.; Ramsey, L. W.; Jones, H. R. A.; Pavlenko, Y.; Gallardo, J.; Barnes, J. R.; Pinfield, D. J. (2009). "Rotational Velocities for M Dwarfs". The Astrophysical Journal. 704 (2). pp. 975-988.
  11. Bonfils, X.; Delfosse, X.; Udry, S.; Santos, N. C.; Forveille, T.; Ségransan, D. (2005). "Metallicity of M dwarfs. I. A photometric calibration and the impact on the mass-luminosity relation at the bottom of the main sequence". Astronomy and Astrophysics. 442 (2). pp. 635-642.
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