| Observation data EpochJ2000.0 EquinoxJ2000.0 (ICRS) | |
|---|---|
| Constellation | Cygnus |
| Right ascension | 19h 55m 37.78622s[1] |
| Declination | +52° 26′ 20.2116″[1] |
| Apparent magnitude (V) | 4.92[2] (5.05 + 7.61)[3] |
| Characteristics | |
| A | |
| Spectral type | A4 Vn[4] |
| U−Bcolor index | +0.05[2] |
| B−Vcolor index | +0.13[2] |
| B | |
| Spectral type | F4 V[5] |
| Astrometry | |
| Radial velocity (Rv) | −10[6] km/s |
| Proper motion (μ) | RA: −37.62[1]mas/yr Dec.: −31.13[1]mas/yr |
| Parallax (π) | 11.59±0.38 mas[1] |
| Distance | 281 ± 9 ly (86 ± 3 pc) |
| Absolute magnitude (MV) | +0.23[7] |
| Orbit[8] | |
| Primary | Aa |
| Companion | Ab |
| Period (P) | 54.08yr |
| Semi-major axis (a) | 0.141″ |
| Eccentricity (e) | 0.484 |
| Inclination (i) | 112.0° |
| Details | |
| ψ Cyg Aa | |
| Luminosity | 62[9] L☉ |
| Temperature | 7,971[9] K |
| Rotational velocity (v sin i) | 207[4] km/s |
| ψ Cyg B | |
| Rotational velocity (v sin i) | 120[10] km/s |
| Other designations | |
| ψ Cyg,24 Cygni,BD+52° 2572,HD 189037,HIP 98055,HR 7619,SAO 32114,WDS 19556+5226.[11] | |
| Database references | |
| SIMBAD | data |
ψ Cygni, Latinised asPsi Cygni, is atriple star[3] system in the constellation calledCygnus. With a combinedapparent visual magnitude of 4.92,[2] it is visible to the naked eye. As of 2002, the inner pair, components Aa and Ab, had anangular separation of 0.10 arc seconds along aposition angle of 77.6°.[12] Their combined visual magnitude is 5.05.[3] Relative to this pair, the third member of the system, magnitude 7.61[3] component B, had an angular separation of 2.87 arc seconds along a position angle of 175.6° as of 2010.[13] Based upon an annualparallax shift of 11.59 mas,[1] Psi Cygni is located around 281 light years from theSun.
The brighter member of the system, presumably component Aa, displays thespectrum of anA-type main sequence star with astellar classification of A4 Vn,[4] where the 'n' notation indicates "nebulous"absorption lines due to rapid rotation. It appears to be a spinning with aprojected rotational velocity of 207.[4] The component is radiating 62 times thesolar luminosity from itsouter atmosphere at aneffective temperature of 7,971 K.[9]