Gliese 806

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Gliese 806
Observation data
Epoch J2000        Equinox J2000
Constellation Cygnus
Right ascension 20h 45m 04.09925s [1]
Declination +44° 29 56.6451 [1]
Apparent magnitude  (V)+10.79 [2]
Characteristics
Spectral type dM1.5 [3]
B−V color index 1.491±0.005 [2]
Astrometry
Radial velocity (Rv)−24.99±0.15 [1]  km/s
Proper motion (μ)RA: 434.028  mas/yr [1]
Dec.: 271.022  mas/yr [1]
Parallax (π)82.8903 ± 0.0167  mas [1]
Distance 39.348 ± 0.008  ly
(12.064 ± 0.002  pc)
Details
Mass 0.423±0.010 [3]   M
Radius 0.4144±0.0038 [4]   R
Luminosity 0.0026±0.0003 [3]   L
Surface gravity (log g)4.89±0.07 [3]   cgs
Temperature 3,586±51 [3]   K
Metallicity [Fe/H]−0.28±0.07 [4]   dex
Rotation 34.6–48.1  d [4]
Rotational velocity (v sin i)0.46 [5]  km/s
Age ~3 [6]   Gyr
Other designations
NSV  13280, BD+44 3567, GJ  806, HIP  102401, LTT  16068, TOI-4481, TIC  239332587, TYC  3178-00633-1, 2MASS J20450403+4429562 [7] [8]
Database references
SIMBAD data

Gliese 806 is a star in the northern constellation of Cygnus, located about a degree to the southeast of the bright star Deneb. [9] It is invisible to the naked eye with an apparent visual magnitude of +10.79. [2] The star is located at a distance of 39.3  light years from the Sun based on stellar parallax. [1] It is drifting closer with a radial velocity of −24.6 km/s, and is predicted to come to within 30.1 light-years in ~198,600 years. [10] The star hosts two known planetary companions. [4]

Contents

The stellar classification of Gliese 806 is dM1.5, [3] which indicates this is a small red dwarf star – an M-type main-sequence star that is generating energy through core hydrogen fusion. It is roughly three [6] billion years old and is spinning with a projected rotational velocity of 0.46 km/s. [5] The star has 42% of the mass and radius of the Sun. It is radiating 0.3% of the luminosity of the Sun from its photosphere at an effective temperature of 3,586 K. [3]

Planetary system

In 1989, Marcy and Benitz detected a periodicity of 416 days in radial velocity variation, inferring the possible presence of a companion with a mass of about 0.011 M. [11] However, this candidate object was never confirmed.

More recently, observations by TESS have found a candidate transiting planet with a period of less than a day. [8] In January 2023, this planet was confirmed and a second, non-transiting planet found via radial velocity observations. A third radial velocity signal was also found, but the study was unable to confirm it as having a planetary origin. All known planets are super-Earths, and the inner transiting planet Gliese 806 b is likely to be rocky. [4]

The Gliese 806 planetary system [4]
Companion
(in order from star)
Mass Semimajor axis
(AU)
Orbital period
(days)
Eccentricity Inclination Radius
b1.90±0.17  M🜨 0.01406±0.000300.9263237±0.000000987.7+0.6
−0.5
°
1.331±0.023  R🜨
c≥5.80±0.30  M🜨 0.0523±0.00116.64064±0.00025
(unconfirmed)≥8.50±0.45 M🜨 0.0844±0.001713.60588±0.00065

See also

Related Research Articles

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<span class="mw-page-title-main">HD 219134</span> Star in the constellation Cassiopeia

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<span class="mw-page-title-main">GJ 1151</span> Red dwarf star

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<span class="mw-page-title-main">HD 189567</span> Star in the constellation Pavo

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References

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