zeta Cygni

data from The Bright Star Catalogue, 5th Revised Ed. (Preliminary Version) (Hoffleit+, 1991)

position, motion, parallax:

position (J2000)	RA: 21h 12min 56.2sec	DEC: +30° 13' 37''
position (B1900)	RA: 21h 8min 40.7sec	DEC: +29° 49' 0''
proper motion (J2000)	RA: 0.001 arcsec/a	DEC: -0.056 arcsec/a
radial velocity	17 km/s note: spectroscopic binaries
rotational velocity	<17 km/s (uncertain) (variable)
trigonometric parallax	0.027 arcsec
galactic coordinates	longitude: 76.75°	latitude: -12.45°

magnitude

visual magnitude

3.2
(V on UBV Johnson system)

spectral / color information

spectral class	G8+III-IIIaBa0.6
B-V-magnitude	0.99
U-B-magnitude	0.76
R-I-magnitude
IR-note	object is infrared source (NASA merged infrared catalogue, Schmitz et al., 1978)

double/multiple star system information

number of components of multiple star system	4
separation	91.2 arcsec
mag difference (of double or brightest multiple)	7.9
component ID	AC
note	Worley (1978) update of the IDS

note (category: double and multiple data):

White dwarf companion.

data from SKY2000 - Master Star Catalog (Myers+ 1997)

position, motion, parallax:

magnitude:

visual	3.2 (observed)	source: 25
photovisual	3.4	source: 2

spectral information:

double/multiple star system information:

source of data: 19

separation between brightest and second brightest component	66.9 arcsec
magnitude difference between brightest and second brightest component	8.4
position angle	204 °

sources:

2	HD and HDE Catalogs
Cannon, A.J., and E.C. Pickering, Harvard Annals, Vols 91-99, 1918-24, Cambridge, Massachusetts: Harvard University; Cannon, A.J., Harvard Annals, Vol. 100, 1925-36, Cambridge, Massachusetts: Harvard University; and Cannon, A.J., and M. Walton Mayall, Harvard Annals, Vol. 112, 1949, Cambridge, Massachusetts: Harvard University
15	FK5, FK5 Extension and FK5 Supplement
Fricke, W., H. Schwan and T. Lederle, "Fifth Fundamental Catalogue (FK5), Part I. The Basic Fundamental Stars," Veroff. Astronomisches Recheninstitut, No. 32, Heidelberg, Germany, 1988, and Fricke, W., H. Schwan, and T.E. Corbin, "Fifth Fundamental Catalogue (FK5), Part II. The FK5 Extension," Veröff. Astronomisches Recheninstitut, No. 33, Heidelberg, Germany, 1991
19	WDS Catalog
Worley, C.E., and G.G. Douglass, Washington Catalog of Visual Double Stars 1996.0, United States Naval Observatory, 1996
25	Bright Star Catalogue, 5th edition
Hoffleit, D. and Warren, W.H. Jr., The Bright Star Catalogue, 5th Revised Edition, Version 2, 1994
96	SAO or HD/HDE Catalog
Reference from Value 1 or Reference from Value 2

data from Smithsonian Astrophysical Observatory Star Catalog (SAO Staff 1966; USNO, ADC 1990)

position and proper motion:

position (B1950)	RA: 21h 10min 48.357sec	DEC: +30° 1' 15.51''	±0.003 arcsec
position (J2000)	RA: 21h 12min 56.182sec	DEC: +30° 13' 37.07''
proper motion B1950 (FK4)	RA: -0.0001 arcsec/a	DEC: -0.052 arcsec/a	±0.001 arcsec/a in RA ±0.001 arcsec/a in DEC
proper motion J2000 (FK5)	RA: 0 arcsec/a	DEC: -0.056 arcsec/a
source of proper motion data	Determined by source catalog

magnitude:

visual	3.4 (accuracy: 2 decimals)
source of visual magnitude data	Taken from the "Henry Draper Catalogue".

spectral information:

spectral class	K0
source of spectral data	Taken from the Henry Draper Catalogue or no spectrum in source catalog.

catalogues

data from The Washington Visual Double Star Catalog, 1996.0 (Worley+, 1996)

position and proper motion:

position (J2000)	RA: 21h 12.9min	DEC: +30° 14'
proper motion (J2000)	RA: 0.001 arcsec/a	DEC: -0.056 arcsec/a

double/multiple star system information:

discoverer information:

discoverer code	discoverer	reference
BUP 227	-	-

notes:

note	Zeta Cyg. A is a spectroscopic binary. The Bright Star Catalogue lists the spectral type as G8III-IIIaBa0.6.

catalogues and names	z Cyg, 64 Cyg, HR 8115, HD 202109, SAO 71070, BD +29 4348, FK5: 797, WDS 21129+3014A
constellation	Cygnus