| Observation data Epoch J2000 Equinox J2000 | |
|---|---|
| Constellation | Cygnus |
| Right ascension | 21 36 56.97051 |
| Declination | +40° 25′ 48.5818″ |
| Apparent magnitude (V) | 5.04 |
| Characteristics | |
| Evolutionary stage | main sequence |
| Spectral type | A3 Vn |
| B−V color index | 0.198±0.003 |
| Astrometry | |
| Radial velocity (Rv) | 5.3±2.9 km/s |
| Proper motion (μ) | RA: +2.270 mas/yr Dec.: +18.399 mas/yr |
| Parallax (π) | 13.0909 ± 0.2893 mas |
| Distance | 249 ± 6 ly (76 ± 2 pc) |
| Absolute magnitude (MV) | 0.95 |
| Orbit | |
| Period (P) | 574.632±9.4158 d |
| Semi-major axis (a) | 8.56±0.91 mas |
| Eccentricity (e) | 0.5349±0.1066 |
| Inclination (i) | 102.1±4.39° |
| Longitude of the node (Ω) | 18.92° |
| Periastron epoch (T) | 8579.5387±18.6175 |
| Argument of periastron (ω) (secondary) | 306.56±14.01° |
| Details | |
| 74 Cyg A | |
| Mass | 1.68 M☉ |
| Radius | 1.6 R☉ |
| Luminosity | 35.64 L☉ |
| Surface gravity (log g) | 3.89 cgs |
| Temperature | 7,859±267 K |
| Rotational velocity (v sin i) | 201 km/s |
| Age | 606 Myr |
| Other designations | |
| 74 Cyg, BD+39°4612, FK5 811, HD 205835, HIP 106711, HR 8266, SAO 51101, WDS J21369+4025 | |
| Database references | |
| SIMBAD | data |
74 Cygni is a visual binary star system in the northern constellation Cygnus, located around 249 light years distant from the Sun. It is visible to the naked eye as a faint, white-hued star with a combined apparent visual magnitude of 5.04. The pair orbit each other with a period of 1.57 years and an eccentricity of 0.5. The system is a source of X-ray emission, which is most likely coming from the secondary component.
The primary component is an A-type main-sequence star with a stellar classification of A3 Vn; a star that is fusing its core hydrogen. The 'n' suffix indicates "nebulous" absorption lines due to rapid rotation, with the star having a projected rotational velocity of 201 km/s. The high rate of spin is giving the star an oblate shape with an equatorial bulge that is 8% larger than the polar radius. The star has 1.68 times the mass of the Sun and is radiating 36 times the Sun's luminosity from its photosphere at an effective temperature of about 7,859 K.
References
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- ^ 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.
- ^ Zorec, J.; Royer, F. (January 2012), "Rotational velocities of A-type stars. IV. Evolution of rotational velocities", Astronomy & Astrophysics, 537: A120, arXiv:1201.2052, Bibcode:2012A&A...537A.120Z, doi:10.1051/0004-6361/201117691, S2CID 55586789.
- ^ Abt, Helmut A.; Morrell, Nidia I. (1995), "The Relation between Rotational Velocities and Spectral Peculiarities among A-Type Stars", Astrophysical Journal Supplement, 99: 135, Bibcode:1995ApJS...99..135A, doi:10.1086/192182.
- ^ ESA (1997), "The HIPPARCOS and TYCHO catalogues. Astrometric and photometric star catalogues derived from the ESA HIPPARCOS Space Astrometry Mission", Esa Special Publication, 1200, Bibcode:1997ESASP1200.....E, ISBN 9290923997.
- ^ David, Trevor J.; Hillenbrand, Lynne A. (2015), "The Ages of Early-Type Stars: Strömgren Photometric Methods Calibrated, Validated, Tested, and Applied to Hosts and Prospective Hosts of Directly Imaged Exoplanets", The Astrophysical Journal, 804 (2): 146, arXiv:1501.03154, Bibcode:2015ApJ...804..146D, doi:10.1088/0004-637X/804/2/146, S2CID 33401607.
- 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.
- "74 Cyg". SIMBAD. Centre de données astronomiques de Strasbourg. Retrieved 2019-01-20.
- Eggleton, P. P.; Tokovinin, A. A. (2008), "A catalogue of multiplicity among bright stellar systems", Monthly Notices of the Royal Astronomical Society, 389 (2): 869, arXiv:0806.2878, Bibcode:2008MNRAS.389..869E, doi:10.1111/j.1365-2966.2008.13596.x, S2CID 14878976.
- Schröder, C.; Schmitt, J. H. M. M. (November 2007), "X-ray emission from A-type stars", Astronomy and Astrophysics, 475 (2): 677–684, Bibcode:2007A&A...475..677S, doi:10.1051/0004-6361:20077429.
- van Belle, Gerard T. (March 2012), "Interferometric observations of rapidly rotating stars", The Astronomy and Astrophysics Review, 20 (1): 51, arXiv:1204.2572, Bibcode:2012A&ARv..20...51V, doi:10.1007/s00159-012-0051-2, S2CID 119273474.