Astronomy:20 Cygni
| Observation data Equinox J2000.0]] (ICRS) | |
|---|---|
| Constellation | Cygnus |
| Right ascension | 19h 50m 37.72371s[1] |
| Declination | +52° 59′ 16.7901″[1] |
| Apparent magnitude (V) | 5.030[2] |
| Characteristics | |
| Spectral type | K3 III CN2[3] |
| B−V color index | 1.280[2] |
| Astrometry | |
| Radial velocity (Rv) | −22.04±0.15[4] km/s |
| Proper motion (μ) | RA: −10.29[1] mas/yr Dec.: −69.68[1] mas/yr |
| Parallax (π) | 16.11 ± 0.14[1] mas |
| Distance | 202 ± 2 ly (62.1 ± 0.5 pc) |
| Details | |
| Mass | 1.28[2] M☉ |
| Radius | 13[5] R☉ |
| Luminosity | 57.5[2] L☉ |
| Surface gravity (log g) | 2.2[5] cgs |
| Temperature | 4,337±67[2] K |
| Metallicity [Fe/H] | +0.14[5] dex |
| Rotational velocity (v sin i) | 4.6[5] km/s |
| Other designations | |
| Database references | |
| SIMBAD | data |
20 Cygni is a single,[7] orange-hued star in the northern constellation of Cygnus. It is a faint star but is visible to the naked eye with an apparent visual magnitude of 5.03.[2] The distance to 20 Cygni can be estimated from its annual parallax shift of 16 mas,[1] which yields a range of 202 light years. It is moving closer to the Earth with a heliocentric radial velocity of −22 km/s.[4]
This is an aging red giant star with a stellar classification of K3 III CN2,[3] a star that has used up its core hydrogen and is expanding. The suffix notation indicates there are unusually strong lines of cyanogen in the spectrum. 20 Cyg is listed as one of the least variable stars in the Hipparcos catalogue, changing its brightness by no more than 0.01 magnitude.[8] It has 1.28[2] times the mass of the Sun and has expanded to 13[5] times the Sun's radius. The star is radiating 57.5 times the Sun's luminosity from its enlarged photosphere at an effective temperature of 4,337 K.[2]
References
- ↑ 1.0 1.1 1.2 1.3 1.4 1.5 van Leeuwen, F. (November 2007), "Validation of the new Hipparcos reduction", Astronomy and Astrophysics 474 (2): 653–664, doi:10.1051/0004-6361:20078357, Bibcode: 2007A&A...474..653V.
- ↑ 2.0 2.1 2.2 2.3 2.4 2.5 2.6 2.7 Luck, R. Earle (2015), "Abundances in the Local Region. I. G and K Giants", Astronomical Journal 150 (3): 88, doi:10.1088/0004-6256/150/3/88, Bibcode: 2015AJ....150...88L.
- ↑ 3.0 3.1 Keenan, Philip C.; McNeil, Raymond C. (1989), "The Perkins catalog of revised MK types for the cooler stars", Astrophysical Journal Supplement Series 71: 245, doi:10.1086/191373, Bibcode: 1989ApJS...71..245K
- ↑ 4.0 4.1 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.
- ↑ 5.0 5.1 5.2 5.3 5.4 Massarotti, Alessandro et al. (January 2008), "Rotational and Radial Velocities for a Sample of 761 Hipparcos Giants and the Role of Binarity", The Astronomical Journal 135 (1): 209–231, doi:10.1088/0004-6256/135/1/209, Bibcode: 2008AJ....135..209M.
- ↑ "20 Cyg". SIMBAD. Centre de données astronomiques de Strasbourg. http://simbad.u-strasbg.fr/simbad/sim-basic?Ident=20+Cyg.
- ↑ Eggleton, P. P.; Tokovinin, A. A. (September 2008), "A catalogue of multiplicity among bright stellar systems", Monthly Notices of the Royal Astronomical Society 389 (2): 869–879, doi:10.1111/j.1365-2966.2008.13596.x, Bibcode: 2008MNRAS.389..869E.
- ↑ Adelman, S. J. (2001), "Research Note Hipparcos photometry: The least variable stars", Astronomy and Astrophysics 367: 297–298, doi:10.1051/0004-6361:20000567, Bibcode: 2001A&A...367..297A.
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