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 | 1.83±0.29[6] M☉ |
| Radius | 3.68±0.13[6] R☉ |
| Luminosity | 44±2[6] L☉ |
| Surface gravity (log g) | 3.57±0.08[6] cgs |
| Temperature | 7,757±120[6] K |
| Rotational velocity (v sin i) | 201[3] km/s |
| Age | 606[7] 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 1.83 times the mass of the Sun, 3.68 times the Sun's radius, and is radiating 44 times the Sun's luminosity from its photosphere at an effective temperature of about 7,757 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 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 Stassun, Keivan G.; Oelkers, Ryan J.; Paegert, Martin; Torres, Guillermo; Pepper, Joshua; De Lee, Nathan; Collins, Kevin; Latham, David W. et al. (2019-10-01), "The Revised TESS Input Catalog and Candidate Target List", The Astronomical Journal 158 (4): 138, doi:10.3847/1538-3881/ab3467, ISSN 0004-6256, Bibcode: 2019AJ....158..138S. 74 Cygni's database entry at VizieR.
- ↑ 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.
- ↑ "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), doi:10.1007/s00159-012-0051-2, Bibcode: 2012A&ARv..20...51V.
 |  |
