Observation data Epoch J2000 Equinox J2000 | |
---|---|
Constellation | Cygnus |
Right ascension | 19h 26m 09.12787s [1] |
Declination | +36° 19′ 04.4369″ [1] |
Apparent magnitude (V) | 5.17 [2] |
Characteristics | |
Evolutionary stage | main sequence [3] |
Spectral type | B8p Si (Fe II) [4] |
B−V color index | −0.120±0.001 [2] |
Variable type | α2 CVn [5] |
Astrometry | |
Radial velocity (Rv) | −22 [6] km/s |
Proper motion (μ) |
RA: +3.769
[1]
mas/
yr Dec.: +13.236 [1] mas/ yr |
Parallax (π) | 5.8357 ± 0.1372 mas [1] |
Distance | 560 ± 10
ly (171 ± 4 pc) |
Absolute magnitude (MV) | −1.51 [2] |
Orbit [7] | |
Period (P) | 35.0225±0.0002 d |
Eccentricity (e) | 0.45±0.13 |
Periastron epoch (T) | 2438929.1±1.1 JD |
Argument of periastron (ω) (secondary) | 290±21° |
Semi-amplitude (K1) (primary) | 5.7±0.6 km/s km/s |
Details [3] | |
Mass | 4.08±0.18 M☉ |
Radius | 5.03 [8] R☉ |
Luminosity | 501+130 −103 L☉ |
Temperature | 12,190+399 −387 K |
Rotational velocity (v sin i) | 30±4 [9] km/s |
Age | 145 Myr |
Other designations | |
Database references | |
SIMBAD | data |
4 Cygni is a binary star [7] system in the northern constellation of Cygnus. It is a faintly visible to the naked eye with an apparent visual magnitude of 5.17. [2] The distance to 4 Cygni, as determined from its annual parallax shift of 5.8 mas, [1] is about 560 light years.
This is single-lined spectroscopic binary with an orbital period of 35 days and an eccentricity of 0.45. [7] The visible component is a B-type star with a stellar classification of B8p Si (Fe II), [4] where the suffix notation indicates this is type of chemically peculiar star known as a silicon star. It displays an overabundance of iron in the visual spectrum, while the star appears helium-weak in the ultraviolet. [4]
4 Cygni A is an Alpha2 Canum Venaticorum variable that varies by 0.02 magnitude over a period of 0.68674 days. [5] The average quadratic field strength of the magnetic field is (254.7±57.2)×10−4 T. [11] With an age of 145 million years, it has four [3] times the mass of the Sun and five [8] times the Sun's radius. It radiates around 501 times the Sun's luminosity from its photosphere at an effective temperature of 12,190 K. [3]