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  V1521 Cyg  
000-BDP-365 (1 observation)  
Cygnus Sequence
20 32 25.78 +40 57 27.9  (308.10742 +40.95775) Search nearby
B1950.0 20 30 37.69 +40 47 12.5
Galactic coord. 79.845 +0.700
Other names

(Internal only)
1RXS J203226.2+405725 2MASS J20322578+4057279 4U 2030+40
Cyg X-3 X 20305+407  
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Variability type
Spectral type WN4/7+BH
Mag. range
11.4 (1.53) K
Discoverer --
Outburst --
Period 0.1996907 d  (4.79258 h)
Rise/eclipse dur. --
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1 Otero, Sebastian Alberto Microquasar.
2 GCVS Team Cyg X-3. Peculiar infrared X-ray source. V > 23m. Flare radio source. In the K band short and slow flares on the time scale about 2 minutes and 1-2 hours, irregular variations and longperiodic variability are observed [E.E.Becklin, F.J.Hawkins, K.O. Mason, K.Matthews, G.Neugebauer, D.Packman, P.W.Sanford, B.Schupler, A.Stark, C.G.Wynn- Williams, ApJ 192, L 119, 1974.]. These variations are accompanied by periodical oscillations of infrared, X-ray and gamma radiation with the elements: Min = 2440949.8986 + 0.1996830d*E + 1.25d*10**(-10)*E**2 [M. van der Klis, J.M.Bonnet-Bidaud, AsAp 95, L5, 1981.]. Usually the amplitude of these variations A(K) = 0.5m, but sometimes they disappear completely.
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Click reference title/citation to view in new window. Roll over index number to view submission details.
1 Corral-Santana, J. M.; Casares, J.; Muņoz-Darias, T.; et al., 2016,
WATCHDOG: A Comprehensive All-sky Database of Galactic Black Hole X-ray
2 A description of sources detected by INTEGRAL during the first 4 years of
3 Catalogue of Stellar Spectral Classifications (Skiff, 2005) 1996A&A...314..521V
4 T.C.Weekes, J.G.Geary, PASP 94, 708, 1982. 1982PASP...94..708W
5 M.Milgrom, D.Pines, ApJ 220, N1, 272, 1978. 1978ApJ...220..272M
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Catalog Data
Information from selected catalogs obtained by cross-matching to 2 arc seconds using the CDS X-Match Service. These data may not be complete.
2MASS J = 15.31H = 13.19K = 11.92J - K = 3.39
AllWISE W1 = 10.65W2 = 9.96W3 = 8.58W4 = 6.32W1 - W2 = 0.68W3 - W4 = 2.26
SDSS-DR12 u = 23.36g = 25.11r = 24.43i = 23.32z = 19.71u - g = -1.75r - i = 1.12
Please review Digitized Sky Survey Acknowledgment and Copyright.
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Revision History
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4 Otero, Sebastian Alberto 2018-02-27 21:56 UTC Spectral type from 2016ApJS..222...15T. 2MASS position.
3 Otero, Sebastian Alberto 2011-05-24 21:39 UTC Primary record creation. Orbital period from reference. Type from Liu et al. (2006A&A...455.1165L).
2 Admin, VSX 2007-04-04 05:53 UTC Position and spectral type from Brian Skiff's MKTypes.dat [http://vizier.u-strasbg.fr/viz-bin/Cat?III/233B].
1 Admin, VSX 2005-12-17 20:33 UTC Initial database population.