2 Cygni
2 Cygni is a blue-white hued star in the northern constellation of Cygnus, located a few degrees from Albireo. It is a probable astrometric binary; the visible component can be viewed with the naked eye, having an apparent visual magnitude of 4.976. Based upon an annual parallax shift of 3.6 mas, it is located roughly 910 light years from Earth. It has a peculiar velocity of 23 km/s and may be a runaway star system.
| Observation data Epoch J2000 Equinox J2000 | |
|---|---|
| Constellation | Cygnus |
| Right ascension | 19h 24m 07.57863s |
| Declination | +29° 37′ 16.7934″ |
| Apparent magnitude (V) | 4.976 |
| Characteristics | |
| Spectral type | B3 IV |
| B−V color index | −0.117 |
| Astrometry | |
| Radial velocity (Rv) | −23.60±2.0 km/s |
| Proper motion (μ) | RA: +12.022 mas/yr Dec.: +12.173 mas/yr |
| Parallax (π) | 3.5657 ± 0.1692 mas |
| Distance | 910 ± 40 ly (280 ± 10 pc) |
| Absolute magnitude (MV) | −2.06 |
| Details | |
| Mass | 7.0±0.1 M☉ |
| Radius | 5.6 R☉ |
| Luminosity (bolometric) | 3,354 L☉ |
| Surface gravity (log g) | 3.653±0.035 cgs |
| Temperature | 16,479±219 K |
| Metallicity [Fe/H] | +0.03±0.05 dex |
| Rotational velocity (v sin i) | 137±8 km/s |
| Age | 36.6±0.5 Myr |
| Other designations | |
| Database references | |
| SIMBAD | data |
The stellar classification of the primary is B3 IV, matching a B-type subgiant star. It has seven times the mass of the Sun and about 5.6 times the Sun's radius. The star is 37 million years old with a high rate of spin; it has a projected rotational velocity of 137 km/s. It is radiating 3,354 times the Sun's luminosity from its photosphere at an effective temperature of 16,479 K.