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;^[10] the visible component can be viewed with the naked eye, having an apparent visual magnitude of 4.976.^[2] Based upon an annual parallax shift of 3.6 mas,^[1] it is located roughly 910 light years from Earth. It has a peculiar velocity of 23 km/s and may be a runaway star^[5] system.

2 Cygni

Observation data Epoch J2000      Equinox J2000
Constellation	Cygnus
Right ascension	19h 24m 07.57863s[1]
Declination	+29° 37′ 16.7934″[1]
Apparent magnitude (V)	4.976[2]
Characteristics
Spectral type	B3 IV[3]
B−V color index	−0.117[2]
Astrometry
Radial velocity (Rv)	−23.60±2.0[4] km/s
Proper motion (μ)	RA: +12.022[1] mas/yr Dec.: +12.173[1] mas/yr
Parallax (π)	3.5657±0.1692 mas[1]
Distance	910 ± 40 ly (280 ± 10 pc)
Absolute magnitude (MV)	−2.06[4]
Details
Mass	7.0±0.1[5] M☉
Radius	5.6[6] R☉
Luminosity (bolometric)	3,354[2] L☉
Surface gravity (log g)	3.653±0.035[7] cgs
Temperature	16,479±219[7] K
Metallicity [Fe/H]	+0.03±0.05[8] dex
Rotational velocity (v sin i)	137±8[7] km/s
Age	36.6±0.5[5] Myr
Other designations
BD+29°3584, FK5 3550, GC 26785, HD 182568, HIP 95372, HR 7372, SAO 87159[9]
Database references
SIMBAD	data

The stellar classification of the primary is B3 IV,^[3] matching a B-type subgiant star. It has seven^[5] times the mass of the Sun and about 5.6^[6] times the Sun's radius. The star is 37^[5] million years old with a high rate of spin; it has a projected rotational velocity of 137 km/s.^[7] It is radiating 3,354^[2] times the Sun's luminosity from its photosphere at an effective temperature of 16,479 K.^[7]

In 2024, imaging detected a candidate companion star at an angular separation of 70 mas. It appears to be a main sequence star with an estimated mass of 5.90±0.18 M_☉.^[11]