R Cygni is a variable star of the Mira type in the constellation Cygnus, less than 4' from θ Cygni. This is a red giant star on the asymptotic giant branch located around 2,200 light years away. It is an S-type star ranging between spectral types S2.5,9e to S6,9e(Tc).[3]
| Observation data Epoch J2000 Equinox J2000 | |
|---|---|
| Constellation | Cygnus |
| Right ascension | 19h 36m 49.35633s[1] |
| Declination | +50° 11′ 59.7198″[1] |
| Apparent magnitude (V) | 6.1 - 14.4[2] |
| Characteristics | |
| Spectral type | S2.5,9e-S6,9e(Tc)[3] |
| Variable type | Mira[2] |
| Astrometry | |
| Proper motion (μ) | RA: −3.158[1] mas/yr Dec.: −5.755[1] mas/yr |
| Parallax (π) | 1.4835 ± 0.0963 mas[1] |
| Distance | 2,200 ± 100 ly (670 ± 40 pc) |
| Details | |
| Mass | 0.85[4] M☉ |
| Luminosity | 11,700[5] L☉ |
| Surface gravity (log g) | −0.50[4] cgs |
| Temperature | 2,538[4] K |
| Metallicity [Fe/H] | +0.50[4] dex |
| Other designations | |
| Database references | |
| SIMBAD | data |
Stars at this mass range and evolutionary stage are pulsationally unstable, displaying a variation in their light output.[7] R Cygni has a maximum magnitude of 6.1 and a minimum magnitude of 14.4, with a period of 426.45 days.[2] The variation of this star was discovered by English astronomer N. R. Pogson in 1852, and it has a history of recorded brightness measurements stretching back more than a century.[7] R Cygni shows distinct period-doubling, where alternate maxima are of different brightness, hence the real period of pulsation could be considered to be twice that from one maximum to the next.[7]
The Catalog of Components of Double and Multiple Stars lists 10th magnitude BD+49 3065 as a companion to R Cygni, at a separation of 91", and both stars lie at approximately the same distance. The Washington Double Star Catalog additionally lists a 15th magnitude star as a companion at a separation of about 14".[8]
See also
editReferences
edit- ^ a b c d e 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 Samus', N. N; Kazarovets, E. V; Durlevich, O. V; Kireeva, N. N; Pastukhova, E. N (2017). "General catalogue of variable stars: Version GCVS 5.1". Astronomy Reports. 61 (1): 80. Bibcode:2017ARep...61...80S. doi:10.1134/S1063772917010085. S2CID 125853869.
- ^ a b BSJ (4 January 2010). "R Cygni". AAVSO Website. American Association of Variable Star Observers. Retrieved 21 January 2014.
- ^ a b c d Anders, F.; Khalatyan, A.; Queiroz, A. B. A.; Chiappini, C.; Ardevol, J.; Casamiquela, L.; Figueras, F.; Jimenez-Arranz, O.; Jordi, C.; Monguio, M.; Romero-Gomez, M.; Altamirano, D.; Antoja, T.; Assaad, R.; Cantat-Gaudin, T.; Castro-Ginard, A.; Enke, H.; Girardi, L.; Guiglion, G.; Khan, S.; Luri, X.; Miglio, A.; Minchev, I.; Ramos, P.; Santiago, B. X.; Steinmetz, M. (2022). "VizieR Online Data Catalog: StarHorse2, Gaia EDR3 photo-astrometric distances (Anders+, 2022)". Vizier Online Data Catalog. Bibcode:2022yCat.1354....0A.
- ^ Guandalini, R; Francis, Charles (2010). "Infrared photometry and evolution of mass-losing AGB stars. III. Mass loss rates of MS and S stars". Astronomy and Astrophysics. 513: A4. arXiv:1002.2458. Bibcode:2010A&A...513A...4G. doi:10.1051/0004-6361/200911764. S2CID 119193286.
- ^ "R Cyg". SIMBAD. Centre de données astronomiques de Strasbourg. Retrieved 30 August 2018.
- ^ a b c Kiss, L. L.; Szatmáry, K. (August 2002). "Period-doubling events in the light curve of R Cygni: Evidence for chaotic behaviour". Astronomy and Astrophysics. 390 (2): 585–596. arXiv:astro-ph/0205334. Bibcode:2002A&A...390..585K. doi:10.1051/0004-6361:20020744. S2CID 17698877.
- ^ Mason, Brian D; Wycoff, Gary L; Hartkopf, William I; Douglass, Geoffrey G; Worley, Charles E (2001). "The 2001 US Naval Observatory Double Star CD-ROM. I. The Washington Double Star Catalog". The Astronomical Journal. 122 (6): 3466. Bibcode:2001AJ....122.3466M. doi:10.1086/323920.