RW Cygni Distance
The Gaia Data Release 2 parallax for RW Cyg is ± 0.0897 mas kpc [ 1] light-years from the Solar System .[ 3] [ 8] OB stars give RW Cygni a distance of kpc [ 5]
Properties
RW Cygni is a luminous red supergiant with a bolometric luminosity more than 100,000 L ☉ [ 9] [ 3] General Catalogue of Variable Stars as M2-4Ia-Iab, covering the range of previously published values. It has been defined as a standard star for the MK spectral classification of M3-M4Ia-Iab.[ 4] effective temperature is directly calculated to be 3,600 K, giving a radius of 980 R ☉ .[ 3] K and a correspondingly lower radius of 680 R ☉ .[ 9] angular diameter ( mas Gaia Data Release 2 parallax give it a larger radius of 1,100 R ☉ ,[ 6] largest known stars . Using the more conservative figure, if it was placed at the center of Solar System , it would be extend past the orbit of Mars and into the asteroid belt .
A light curve for RW Cygni, plotted from Hipparcos [ 10] The initial mass of RW Cygni has been estimated from its position relative to theoretical stellar evolutionary tracks to be around 20 M ☉ .[ 9] × 10−6 M ☉ per year.[ 11]
In 1885, T. H. E. C. Espin discovered that the star is a variable star . It was listed with its variable star designation , RW Cygni, in Annie Jump Cannon's 1907 work Second Catalog of Variable Stars .[ 12] semiregular variable star . It is given the subtype SRc, indicating that it is a cool supergiant.[ 2] ± 80 d [ 13]
References
1 2 3 4 5 6 7 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 .1 2 3 Samus, N. N.; Durlevich, O. V.; et al. (2009). "VizieR Online Data Catalog: General Catalogue of Variable Stars (Samus+ 2007-2013)". VizieR On-line Data Catalog: B/GCVS. Originally Published in: 2009yCat....102025S . 1 . Bibcode :2009yCat....102025S . 1 2 3 4 5 Levesque, Emily M. ; Massey, Philip; Olsen, K. A. G.; Plez, Bertrand; Josselin, Eric; Maeder, Andre; Meynet, Georges (2005). "The Effective Temperature Scale of Galactic Red Supergiants: Cool, but Not As Cool As We Thought". The Astrophysical Journal . 628 (2): 973– 985. arXiv :astro-ph/0504337 Bibcode :2005ApJ...628..973L . doi :10.1086/430901 . S2CID 15109583 .1 2 Keenan, Philip C.; McNeil, Raymond C. (1989). "The Perkins catalog of revised MK types for the cooler stars". Astrophysical Journal Supplement Series . 71 : 245. Bibcode :1989ApJS...71..245K . doi :10.1086/191373 . S2CID 123149047 . 1 2 3 Davies, Ben; Beasor, Emma R. (March 2020). "The 'red supergiant problem': the upper luminosity boundary of Type II supernova progenitors" . MNRAS 493 (1): 468– 476. arXiv :2001.06020 Bibcode :2020MNRAS.493..468D . doi :10.1093/mnras/staa174 S2CID 210714093 . 1 2 Norris, Ryan (2021-03-01). "An Interferometric Imaging Survey of Red Supergiant Stars". The 20.5Th Cambridge Workshop on Cool Stars : 263. Bibcode :2021csss.confE.263N . doi :10.5281/zenodo.4567641 . ↑ Norris, Ryan P. (2019). Seeing Stars Like Never Before: A Long-term Interferometric Imaging Survey of Red Supergiants (PDF) (PhD). Georgia State University . ↑ Famaey, B.; Jorissen, A.; Luri, X.; Mayor, M.; Udry, S.; Dejonghe, H.; Turon, C. (2005). "Local kinematics of K and M giants from CORAVEL/Hipparcos/Tycho-2 data. Revisiting the concept of superclusters". Astronomy and Astrophysics . 405 : 165. arXiv :astro-ph/0409579 Bibcode :2005A& A...430..165F . doi :10.1051/0004-6361:20041272 . S2CID 17804304 . 1 2 3 Josselin, E.; Plez, B. (2007). "Atmospheric dynamics and the mass loss process in red supergiant stars". Astronomy and Astrophysics . 469 (2): 671. arXiv :0705.0266 Bibcode :2007A& A...469..671J . doi :10.1051/0004-6361:20066353 . S2CID 17789027 . ↑ "Hipparcos Tools Interactive Data Access" . Hipparcos . ESA. Retrieved 8 December 2021 .↑ Mauron, N.; Josselin, E. (2011). "The mass-loss rates of red supergiants and the de Jager prescription". Astronomy and Astrophysics . 526 : A156. arXiv :1010.5369 Bibcode :2011A& A...526A.156M . doi :10.1051/0004-6361/201013993 . S2CID 119276502 . ↑ Cannon, Annie J. (1907). "Second catalogue of variable stars" . Annals of Harvard College Observatory . 55 : 1– 94. Bibcode :1907AnHar..55....1C . Retrieved 16 December 2024 . ↑ Kiss, L. L.; Szabó, Gy. M.; Bedding, T. R. (2006). "Variability in red supergiant stars: Pulsations, long secondary periods and convection noise" . Monthly Notices of the Royal Astronomical Society . 372 (4): 1721– 1734. arXiv :astro-ph/0608438 Bibcode :2006MNRAS.372.1721K . doi :10.1111/j.1365-2966.2006.10973.x S2CID 5203133 .
