Astronomy:74 Cygni
| Observation data Equinox J2000.0]] (ICRS) | |
|---|---|
| Constellation | Cygnus |
| Right ascension | 21h 36m 56.97051s[1] |
| Declination | +40° 25′ 48.5818″[1] |
| Apparent magnitude (V) | 5.04[2] |
| Characteristics | |
| Evolutionary stage | main sequence[3] |
| Spectral type | A3 Vn[4] |
| B−V color index | 0.198±0.003[2] |
| Astrometry | |
| Radial velocity (Rv) | 5.3±2.9 km/s |
| Proper motion (μ) | RA: +2.270[1] mas/yr Dec.: +18.399[1] mas/yr |
| Parallax (π) | 13.0909 ± 0.2893[1] mas |
| Distance | 249 ± 6 ly (76 ± 2 pc) |
| Absolute magnitude (MV) | 0.95[2] |
| Orbit[5] | |
| 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[6] M☉ |
| Radius | 1.6[7] R☉ |
| Luminosity | 35.64[2] L☉ |
| Surface gravity (log g) | 3.89[6] cgs |
| Temperature | 7,859±267[6] K |
| Rotational velocity (v sin i) | 201[3] km/s |
| Age | 606[6] Myr |
| Other designations | |
| Database references | |
| SIMBAD | data |
74 Cygni is a visual binary[9] 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.[2] The pair orbit each other with a period of 1.57 years and an eccentricity of 0.5.[5] The system is a source of X-ray emission, which is most likely coming from the secondary component.[10]
The primary component is an A-type main-sequence star with a stellar classification of A3 Vn;[4] 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.[3] The high rate of spin is giving the star an oblate shape with an equatorial bulge that is 8% larger than the polar radius.[11] The star has 1.68[6] times the mass of the Sun and is radiating 36[2] times the Sun's luminosity from its photosphere at an effective temperature of about 7,859 K.[6]
References
- ↑ 1.0 1.1 1.2 1.3 1.4 Brown, A. G. A. (August 2018). "Gaia Data Release 2: Summary of the contents and survey properties". Astronomy & Astrophysics 616: A1. doi:10.1051/0004-6361/201833051. Bibcode: 2018A&A...616A...1G. Gaia DR2 record for this source at VizieR.
- ↑ 2.0 2.1 2.2 2.3 2.4 2.5 Anderson, E.; Francis, Ch. (2012), "XHIP: An extended hipparcos compilation", Astronomy Letters 38 (5): 331, doi:10.1134/S1063773712050015, Bibcode: 2012AstL...38..331A.
- ↑ 3.0 3.1 3.2 Zorec, J.; Royer, F. (January 2012), "Rotational velocities of A-type stars. IV. Evolution of rotational velocities", Astronomy & Astrophysics 537: A120, doi:10.1051/0004-6361/201117691, Bibcode: 2012A&A...537A.120Z.
- ↑ 4.0 4.1 Abt, Helmut A.; Morrell, Nidia I. (1995), "The Relation between Rotational Velocities and Spectral Peculiarities among A-Type Stars", Astrophysical Journal Supplement 99: 135, doi:10.1086/192182, Bibcode: 1995ApJS...99..135A.
- ↑ 5.0 5.1 ESA (1997), "The HIPPARCOS and TYCHO catalogues. Astrometric and photometric star catalogues derived from the ESA HIPPARCOS Space Astrometry Mission", Esa Special Publication 1200, ISBN 9290923997, Bibcode: 1997ESASP1200.....E.
- ↑ 6.0 6.1 6.2 6.3 6.4 6.5 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, doi:10.1088/0004-637X/804/2/146, Bibcode: 2015ApJ...804..146D.
- ↑ Pasinetti Fracassini, L. E. et al. (February 2001), "Catalogue of Apparent Diameters and Absolute Radii of Stars (CADARS)", Astronomy and Astrophysics 367: 521–524, doi:10.1051/0004-6361:20000451, Bibcode: 2001A&A...367..521P.
- ↑ "74 Cyg". SIMBAD. Centre de données astronomiques de Strasbourg. http://simbad.u-strasbg.fr/simbad/sim-basic?Ident=74+Cyg.
- ↑ 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, doi:10.1111/j.1365-2966.2008.13596.x, Bibcode: 2008MNRAS.389..869E.
- ↑ Schröder, C.; Schmitt, J. H. M. M. (November 2007), "X-ray emission from A-type stars", Astronomy and Astrophysics 475 (2): 677–684, doi:10.1051/0004-6361:20077429, Bibcode: 2007A&A...475..677S.
- ↑ van Belle, Gerard T. (March 2012), "Interferometric observations of rapidly rotating stars", The Astronomy and Astrophysics Review 20 (1): 51, doi:10.1007/s00159-012-0051-2, Bibcode: 2012A&ARv..20...51V.
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