c Cygni

The object was found in the following catalogues:
  1. The Bright Star Catalogue, 5th Revised Ed. (Preliminary Version)

  2. SKY2000 - Master Star Catalog

  3. Smithsonian Astrophysical Observatory Star Catalog

  4. The Washington Visual Double Star Catalog, 1996.0

  5. Combined General Catalogue of Variable Stars (Vol. I-III)

catalogues and names c Cyg, khi Cyg, HR 7564, HD 187796, SAO 68943, WDS 19506+3255
constellation Cygnus

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

object is infrared source (NASA merged infrared catalogue, Schmitz et al., 1978)

position, motion, parallax:

position (J2000) RA: 19h 50min 33,9sec DEC: +32 54' 51''
position (J1900) RA: 19h 46min 43,2sec DEC: +32 39' 40''
proper motion (J2000) RA: -0,027 arcsec/a DEC: -0,04 arcsec/a
radial velocity -2 km/s
note: suspected variable radial velocity
trigonometric parallax 0,012 arcsec


visual magnitude 4,23
(V on UBV Johnson system)

spectral / color information

spectral class S6+/1e
B-V-magnitude 1,82
U-B-magnitude 0,96
R-I-magnitude 2,68
note (category: spectra): Probable SiO maser emission. Most intense infrared CO bands observed in any star to 1973. Technetium found in spectrum. Also classified S6,2e-S10,4e.

variability information

variable star identification Chi Cyg
note (category: variability): Discovered by Kirch in 1686. M 3.3 - 14.2v. Period changes: 1686-1842, 405.88d; subsequently 408.05d. Variable CO emission from circumstellar envelope and enhancement of shell at minimum light. Total visual absorption of shell = 2 mag. Variable SiO maser source. Appreciable reddening at ascending light.

double/multiple star system information

separation 158 arcsec
mag difference (of double or brightest multiple) 5,2
note Worley (1978) update of the IDS

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

position, motion, parallax:

position (J2000) RA: 19h 50min 33,902sec DEC: +32 54' 50,7'' 0,2 arcsec source: 52
proper motion (J2000) RA: -0,0023 arcsec/a DEC: -0,041 arcsec/a source: 25
radial velocity -2 km/s source: 25
trigonometric parallax 0,012 0,001 arcsec source: 25
galactic coord. (B1950) longitude: 68,54 latitude: 3,28
GCI unit vector (J2000) X: 0,389466 Y: -0,743675 Z: 0,543381


visual 4,23 (observed) source: 25
photographic 8,2 source: 16

spectral information:

spectral class M0 source: 96
Morgan-Keenan S6+/1e source: 25
B-magnitude 6,05 0,05 B-V-magnitude 1,82
U-magnitude 7,01 0,05 U-B-magnitude 0,96

variability information:

source of data: 30
variability type 180
var. amplitude 10,9
var. period 408,05
var. epoch 2442140
2. April 1974, 12:00:00 UT
next max light 2451933,2
23. January 2001, 16:48:00 UT

double/multiple star system information:

source of data: 19
separation between brightest and second brightest component 158 arcsec
position angle 254


16 PPM North and PPM South Catalogs and PPM Supplement
Roser, S., and U. Bastian, "Catalogue of Positions and Proper Motions," A&AS, Vol. 74, p. 449, 1988, and Bastian, U., et al., "Catalogue of Positions and Proper Motions - South," 1993
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
30 GCVS, 4th edition
Kholopov, P.N., et al., General Catalogue of Variable Stars, fourth edition, Moscow: Nauka Publishing House, 1985-88
52 PPMN-HP subset
PPMN Star Catalogue (Reference 16) High-Precision Subset (Code H)
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 (J1950) RA: 19h 48min 38,484sec DEC: +32 47' 11,79'' 0,031 arcsec
position (J2000) RA: 19h 50min 33,86sec DEC: +32 54' 51,03''
proper motion J1950 (FK4) RA: -0,0024 arcsec/a DEC: -0,038 arcsec/a 0,006 arcsec/a in RA
0,006 arcsec/a in DEC
proper motion J2000 (FK5) RA: -0,0022 arcsec/a DEC: -0,04 arcsec/a
source of proper motion data Determined by source catalog


visual 4,2 (accuracy: 1 decimal)
source of visual magnitude data Source cited in source catalog introduction.

spectral information:

spectral class M7e
source of spectral data Taken from the Henry Draper Catalogue or no spectrum in source catalog.

remarks for duplicity and variability

Variable star in visual magnitude in source catalog


source catalogue GC, catalogue number: 27481
Durchmusterung BD+32 3593
Boss General Catalogue 27481
Henry Draper Catalogue 187796

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

position and proper motion:

position (J2000) RA: 19h 50,6min DEC: +32 55'
proper motion (J2000) RA: -0,028 arcsec/a DEC: -0,046 arcsec/a

double/multiple star system information:

component year number of measures position angle angular separation magnitude of 1st component magnitude of 2nd component spectral class(es) discoverer code
- 1880 3 254 160,2'' - 10,8 S6+/1e BLL 42
1909 - 158''

discoverer information:

discoverer code discoverer reference
BLL 42 Ball, R.S. -


note Chi Cyg. A is a Mira-type variable. Proper motion of B 000 +004

data from Combined General Catalogue of Variable Stars (Vol. I-III) (Kholopov+ 1998)


position (J1950) RA: 19h 48min 38,5sec DEC: +32 47' 12''

variability informations:

variability type M pulsating variable star
magnitute at max. brightness 3,3
magnitute at min. brightness 14,2
photometric system visual, photovisual or Johnson's V
epoch for maximum light [JD] 2442140
2. April 1974, 12:00:00 UT
period [d] 408,05
next maximum light [JD] 2451933,2
23. January 2001, 16:48:00 UT
rising time 41 % of period

spectral information

spectral class S6,2e-S10,4e(MSe)


to a study the main characteristics of the star was determined by the authors themselves
to a chart/photograph Vol. I GCVS (see Kholopov et al. 1985-1988)


ID in the GCVS catalogue 31/9022
constellation Cygnus
notes on existence The star is equivalent to '0319216 P'.
There are notes in published catalog.

variability type description

variability type description
M Mira (Omicron) Ceti-type variables. These are long-period variable giants with characteristic late-type emission spectra (Me, Ce, Se) and light amplitudes from 2.5 to 11 mag in V. Their periodicity is well pronounced, and the periods lie in the range between 80 and 1000 days. Infrared amplitudes are usually less than in the visible and may be <2.5 mag. For example, in the K band they
usually do not exceed 0.9 mag. If the amplitudes exceed 1 - 1.5 mag , but it is not certain that the true light amplitude exceeds 2.5 mag, the symbol "M" is followed by a colon, or the star is attributed to the semiregular class with a colon following the symbol for that type (SR).