P Cyg

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

catalogues and names P Cyg, 34 Cyg, HR 7763, HD 193237, SAO 69773
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: 20h 17min 47,2sec DEC: +38 1' 59''
position (J1900) RA: 20h 14min 6sec DEC: +37 43' 19''
proper motion (J2000) RA: -0,005 arcsec/a DEC: -0,004 arcsec/a
radial velocity -9 km/s
note: variable radial velocity
rotational velocity 75 km/s (uncertain) (variable)
trigonometric parallax 0,004 arcsec
note (category: radial and/or rotational velocities): Outermost shell RV varies -180 to -240k/s in period 114d. Mass loss 0.0004? solar masses/y.


visual magnitude 4,81
(V on UBV Johnson system)

spectral / color information

spectral class B2pe
B-V-magnitude 0,42
U-B-magnitude -0,58
R-I-magnitude 0,26

variability information

variable star identification P Cyg
note (category: variability): SD 3 - 6v. Since 18th century, 4.6 - 5.6v. Shell star, Nova 1600.

miscellaneous information

note (category: group membership): Cyg OB1.
note (category: miscellaneous): Possible radio source.

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

position, motion, parallax:

position (J2000) RA: 20h 17min 47,195sec DEC: +38 1' 58,55'' 0,2 arcsec source: 52
proper motion (J2000) RA: -0,0007 arcsec/a DEC: -0,006 arcsec/a source: 25
radial velocity -9 km/s source: 25
trigonometric parallax 0,004 - source: 25
galactic coord. (B1950) longitude: 75,83 latitude: 1,32
GCI unit vector (J2000) X: 0,445529 Y: -0,649544 Z: 0,616114


visual 4,81 (observed) source: 25
photovisual 4,9 source: 2
photographic 4,7 source: 16

spectral information:

spectral class B1 source: 96
Morgan-Keenan B2pe source: 25
B-magnitude 5,23 0,05 B-V-magnitude 0,42
U-magnitude 4,65 0,05 U-B-magnitude -0,58

variability information:

source of data: 30
variability type 350
var. amplitude 3


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
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
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: 20h 15min 56,5sec DEC: +37 52' 35,55'' 0,025 arcsec
position (J2000) RA: 20h 17min 47,17sec DEC: +38 1' 58,87''
proper motion J1950 (FK4) RA: -0,0007 arcsec/a DEC: -0,002 arcsec/a 0,004 arcsec/a in RA
0,003 arcsec/a in DEC
proper motion J2000 (FK5) RA: -0,0004 arcsec/a DEC: -0,004 arcsec/a
source of proper motion data Determined by source catalog


visual 4,9 (accuracy: 2 decimals)
source of visual magnitude data Taken from Harvard or San Luis photometry.

spectral information:

spectral class B1p
source of spectral data Taken from the Henry Draper Catalogue or no spectrum in source catalog.


source catalogue GC, catalogue number: 28218
Durchmusterung BD+37 3871
Boss General Catalogue 28218
Henry Draper Catalogue 193237

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


position (J1950) RA: 20h 15min 56,5sec DEC: +37 52' 36''

variability informations:

variability type SDOR eruptive variable star
magnitute at max. brightness 3
magnitute at min. brightness 6
photometric system visual, photovisual or Johnson's V

spectral information

spectral class B1Iapeq


to a chart/photograph Vol. I GCVS (see Kholopov et al. 1985-1988)


ID in the GCVS catalogue 31/9216
constellation Cygnus
notes on existence The star is equivalent to '0319217 Q'.
There are notes in published catalog.

variability type description

variability type description
SDOR Variables of the S Doradus type. These are eruptive, high-luminosity Bpec-Fpec stars showing irregular (sometimes cyclic) light changes with amplitudes in the range 1-7 mag in V.
They belong to the brightest blue stars of their parent galaxies. As a rule, these stars are connected with diffuse nebulae and surrounded by expanding envelopes (P Cyg, Eta Car).