74 Cygni is a visual binary[9] star system in the northern constellation Cygnus, located around 249 light years distant from the Sun. It is visible to the naked eye as a faint, white-hued star with a combined apparent visual magnitude of 5.04.[2] The pair orbit each other with a period of 1.57 years and an eccentricity of 0.5.[5] The system is a source of X-ray emission, which is most likely coming from the secondary component.[10]
Observation data Epoch J2000 Equinox J2000 | |
---|---|
Constellation | Cygnus |
Right ascension | 21h 36m 56.97051s[1] |
Declination | +40° 25′ 48.5818″[1] |
Apparent magnitude (V) | 5.04[2] |
Characteristics | |
Evolutionary stage | main sequence[3] |
Spectral type | A3 Vn[4] |
B−V color index | 0.198±0.003[2] |
Astrometry | |
Radial velocity (Rv) | 5.3±2.9 km/s |
Proper motion (μ) | RA: +2.270[1] mas/yr Dec.: +18.399[1] mas/yr |
Parallax (π) | 13.0909 ± 0.2893 mas[1] |
Distance | 249 ± 6 ly (76 ± 2 pc) |
Absolute magnitude (MV) | 0.95[2] |
Orbit[5] | |
Period (P) | 574.632±9.4158 d |
Semi-major axis (a) | 8.56±0.91 mas |
Eccentricity (e) | 0.5349±0.1066 |
Inclination (i) | 102.1±4.39° |
Longitude of the node (Ω) | 18.92° |
Periastron epoch (T) | 8579.5387±18.6175 |
Argument of periastron (ω) (secondary) | 306.56±14.01° |
Details | |
74 Cyg A | |
Mass | 1.68[6] M☉ |
Radius | 1.6[7] R☉ |
Luminosity | 35.64[2] L☉ |
Surface gravity (log g) | 3.89[6] cgs |
Temperature | 7,859±267[6] K |
Rotational velocity (v sin i) | 201[3] km/s |
Age | 606[6] Myr |
Other designations | |
Database references | |
SIMBAD | data |
The primary component is an A-type main-sequence star with a stellar classification of A3 Vn;[4] a star that is fusing its core hydrogen. The 'n' suffix indicates "nebulous" absorption lines due to rapid rotation, with the star having a projected rotational velocity of 201 km/s.[3] The high rate of spin is giving the star an oblate shape with an equatorial bulge that is 8% larger than the polar radius.[11] The star has 1.68[6] times the mass of the Sun and is radiating 36[2] times the Sun's luminosity from its photosphere at an effective temperature of about 7,859 K.[6]