Summary
22 Cygni is a binary star system in the northern constellation of Cygnus. It is visible to the naked eye as a faint, blue-white hued star with an apparent visual magnitude of 4.95.[2] The annual shift of 3.0 mas[1] yields a distance estimate of around 1,070 light years. It is moving closer to the Earth with a heliocentric radial velocity of −15 km/s.[4]
| Observation data Epoch J2000 Equinox J2000 | |
|---|---|
| Constellation | Cygnus |
| Right ascension | 19h 55m 51.75718s[1] |
| Declination | +38° 29′ 12.154″[1] |
| Apparent magnitude (V) | 4.95[2] |
| Characteristics | |
| Spectral type | B5 IV[3] |
| B−V color index | −0.086±0.009[2] |
| Astrometry | |
| Radial velocity (Rv) | −14.8±2.2[4] km/s |
| Proper motion (μ) | RA: +6.559[1] mas/yr Dec.: −0.469[1] mas/yr |
| Parallax (π) | 3.0418 ± 0.2388 mas[1] |
| Distance | 1,070 ± 80 ly (330 ± 30 pc) |
| Absolute magnitude (MV) | −3.18[2] |
| Orbit[5] | |
| Period (P) | 78.2±0.4 d |
| Eccentricity (e) | 0.17±0.13 |
| Periastron epoch (T) | 2443734.5±2.1 JD |
| Argument of periastron (ω) (secondary) | 139±11° |
| Semi-amplitude (K1) (primary) | 20.7±3.1 km/s |
| Details | |
| 22 Cyg A | |
| Mass | 7.9±0.4[6] M☉ |
| Radius | 5.6[7] R☉ |
| Luminosity | 7,305[8] L☉ |
| Surface gravity (log g) | 3.35[9] cgs |
| Temperature | 15,200[8] K |
| Rotational velocity (v sin i) | 30[10] km/s |
| Age | 37.3±4.2[6] Myr |
| Other designations | |
| Database references | |
| SIMBAD | data |
This is a single-lined spectroscopic binary with an orbital period of 78.2 days and an eccentricity of roughly 0.17.[5] The visible component has a stellar classification of B5 IV[3] that matches a B-type subgiant star. It is 37[6] million years old with a projected rotational velocity of 30[10] km/s and has an essentially solar metallicity, within the margin of error.[9] The star has eight[6] times the mass of the Sun and about 5.6[7] times the Sun's radius. It is radiating 7,305[8] times the Sun's luminosity from its photosphere at an effective temperature of 15,200 K.[8]
References edit
- ^ a b c d e f Brown, A. G. A.; et al. (Gaia collaboration) (August 2018). "Gaia Data Release 2: Summary of the contents and survey properties". Astronomy & Astrophysics. 616. A1. arXiv:1804.09365. Bibcode:2018A&A...616A...1G. doi:10.1051/0004-6361/201833051. Gaia DR2 record for this source at VizieR.
- ^ a b c d Anderson, E.; Francis, Ch. (2012), "XHIP: An extended hipparcos compilation", Astronomy Letters, 38 (5): 331, arXiv:1108.4971, Bibcode:2012AstL...38..331A, doi:10.1134/S1063773712050015, S2CID 119257644.
- ^ a b Lesh, Janet Rountree (December 1968), "The Kinematics of the Gould Belt: an Expanding Group?", Astrophysical Journal Supplement, 17: 371, Bibcode:1968ApJS...17..371L, doi:10.1086/190179.
- ^ a b Gontcharov, G. A. (2006), "Pulkovo Compilation of Radial Velocities for 35 495 Hipparcos stars in a common system", Astronomy Letters, 32 (11): 759–771, arXiv:1606.08053, Bibcode:2006AstL...32..759G, doi:10.1134/S1063773706110065, S2CID 119231169.
- ^ a b Abt, Helmut A.; et al. (October 1990), "The Frequency and Formation Mechanism of B2--B5 Main-Sequence Binaries", Astrophysical Journal Supplement, 74: 551, Bibcode:1990ApJS...74..551A, doi:10.1086/191508.
- ^ a b c d Tetzlaff, N.; et al. (January 2011), "A catalogue of young runaway Hipparcos stars within 3 kpc from the Sun", Monthly Notices of the Royal Astronomical Society, 410 (1): 190–200, arXiv:1007.4883, Bibcode:2011MNRAS.410..190T, doi:10.1111/j.1365-2966.2010.17434.x, S2CID 118629873.
- ^ a b Pasinetti Fracassini, L. E.; et al. (February 2001), "Catalogue of Apparent Diameters and Absolute Radii of Stars (CADARS)", Astronomy and Astrophysics, 367 (Third ed.): 521–524, arXiv:astro-ph/0012289, Bibcode:2001A&A...367..521P, doi:10.1051/0004-6361:20000451, S2CID 425754.
- ^ a b c d Hohle, M. M.; et al. (April 2010), "Masses and luminosities of O- and B-type stars and red supergiants", Astronomische Nachrichten, 331 (4): 349, arXiv:1003.2335, Bibcode:2010AN....331..349H, doi:10.1002/asna.200911355, S2CID 111387483.
- ^ a b Adelman, Saul J. (June 1998), "Elemental abundance analyses with DAO spectrograms - XIX. The superficially normal B stars zeta Draconis, epsilon Lyrae, 8 Cygni and 22 Cygni", Monthly Notices of the Royal Astronomical Society, 296 (4): 856–862, Bibcode:1998MNRAS.296..856A, doi:10.1046/j.1365-8711.1998.01426.x.
- ^ a b Abt, Helmut A.; et al. (July 2002), "Rotational Velocities of B Stars", The Astrophysical Journal, 573 (1): 359–365, Bibcode:2002ApJ...573..359A, doi:10.1086/340590
- ^ "22 Cyg". SIMBAD. Centre de données astronomiques de Strasbourg. Retrieved 2019-01-09.