Gliese 806

Gliese 806 is a star in the northern constellation of Cygnus, located about a degree to the southeast of the bright star Deneb. It is invisible to the naked eye with an apparent visual magnitude of +10.79. The star is located at a distance of 39.3 light years from the Sun based on stellar parallax. It is drifting closer with a radial velocity of −24.6 km/s, and is predicted to come to within in ~198,600 years. The star is suspected to host a substellar companion yet unconfirmed.
The stellar classification of Gliese 806 is dM1.5, 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 billion years old and is spinning with a projected rotational velocity of 0.46 km/s. 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.
Candidate companion.
In 1989, Marcy and Benitz detected a periodicity of 416 days in radial velocity variation, inferring the possible presence of a companion with mass of about . This candidate object has not yet been confirmed.