19h34m 50.9285s[1]
+29° 27′ 46.697″[1]
Characteristics
G8 IIIa + A2 V[4]
B−V color index
0.581[2]
Radial velocity (Rv)
20.09±1.98[1] km/s
Proper motion (μ)
RA: +14.822[1] mas/yr
Dec.: +13.554[1] mas/yr
Parallax (π)
Absolute magnitude (MV)
−0.70[2]
Period (P)
4.56 yr
Semi-major axis (a)
0.030″
Eccentricity (e)
0.82
Inclination (i)
114.6°
29.3°
Periastron epoch (T)
1985.56
Argument of periastron (ω)
(secondary)
45.5°
Details
9 Cyg A
Surface gravity (log g)
Metallicity [Fe/H]
9 Cyg B
9 Cyg A: HD 184759
9 Cyg B: HD 184760
Database references
9 Cygni is a binary star system in the northern constellationofCygnus. 9 Cygni is its Flamsteed designation. The two stars have a combined magnitude of 5.39,[2] so it can be seen with the naked eye under good viewing conditions. Parallax measurements made by Gaia put the star at a distance of around 590 light-years (182 parsecs) away.[1]
The two stars of 9 Cygni are a G-type giant and an A-type star. Both stars are over twice as massive as the Sun.[2] They orbit once every 4.56 years, separated with a semi-major axisof0.030 arcseconds. However, the eccentricity is high, at 0.82.[3] The primary is a red clump giant, a star on the cool end of the horizontal branch fusing helium in its core. The secondary star has begun to evolve off the main sequence; it is sometimes classified as a giant star[2] and sometimes as a main-sequence star.[4]
Other
Other
Other
