catalogues and names

SKY2000 - Master Star Catalog

Smithsonian Astrophysical Observatory Star Catalog

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

catalogues and names

catalogues and names

XZ Cyg, HD 239124, SAO 31761, BD +56 2257

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

position, motion, parallax:

position (J2000)	RA: 19h 32min 29.346sec	DEC: +56° 23' 17.3''	±0.43 arcsec	source: 16
position (2000.73)	RA: 19h 32min 30sec	DEC: +56° 23' 23''	JD: 2451810.88
proper motion (J2000)	RA: 0.0107 arcsec/a	DEC: -0.026 arcsec/a		source: 16
galactic coord. (B1950)	longitude: 88.22°	latitude: 16.98°

magnitude:

visual	9.26 (observed)	source: 20
photovisual	9.2	source: 2
photographic	10	source: 16

spectral information:

spectral class	A3		source: 96
Morgan-Keenan	A5-F5		source: 30
B-magnitude	9.43 ±0.045	B-V-magnitude	0.17
U-magnitude	9.6 ±0.036	U-B-magnitude	0.17

variability information:

source of data: 30

variability type	121
var. amplitude	1.3
var. period	0.47
var. epoch	2444124 7. September 1979, 12:00:00 UT
next max light	2451811.32 23. September 2000, 19:40:48 UT

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
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
20	Catalogue of Homogeneous Means in the UBV System
Mermilliod, J.C., Catalogue of Homogeneous Means in the UBV System, Institut d'Astronomie, Universite de Lausanne, 1994
30	GCVS, 4th edition
Kholopov, P.N., et al., General Catalogue of Variable Stars, fourth edition, Moscow: Nauka Publishing House, 1985-88
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: 19h 31min 27.372sec	DEC: +56° 16' 47.18''	±0.014 arcsec
position (2000.73)	RA: 19h 32min 29sec	DEC: +56° 23' 24''	JD: 2451810.88
position (J2000)	RA: 19h 32min 29.369sec	DEC: +56° 23' 17.64''
proper motion B1950 (FK4)	RA: 0.0103 arcsec/a	DEC: -0.019 arcsec/a	±0.007 arcsec/a in RA ±0.007 arcsec/a in DEC
proper motion J2000 (FK5)	RA: 0.0109 arcsec/a	DEC: -0.019 arcsec/a
source of proper motion data	Determined by source catalog

magnitude:

visual	9.2 (accuracy: 1 decimal)
source of visual magnitude data	Taken from AGK1.
photographic	10 (accuracy: 2 decimals)
source of photographic magnitude data	Columbia Contributions Numbers 30 and 31 (Schilt and Hill 1937, 1938)

spectral information:

spectral class	A3
source of spectral data	Taken from the HD with M stars reclassified by Miss Cannon.

catalogues

source catalogue	Yale Transactions 27, catalogue number: 10573
Durchmusterung	BD+56 2257
Henry Draper Catalogue	239124

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

position:

position (equinox 1950.0)

RA: 19h 31min 27.4sec

DEC: +56° 16' 47''

variability informations:

variability type	RRAB	pulsating variable star
magnitute at max. brightness	8.9
magnitute at min. brightness	10.16
photometric system	visual, photovisual or Johnson's V
epoch for maximum light [JD]	2444124.44 7. September 1979, 22:33:36 UT
period [d]	0.4667
next maximum light [JD]	2451810.989 23. September 2000, 11:44:10 UT

spectral information

spectral class

A5-F5

references

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)

miscanellous

ID in the GCVS catalogue	31/51
constellation	Cygnus
notes on existence	The star is equivalent to '0310052 YY'.
There are notes in published catalog.

variability type description

variability type

description

RRAB

Variables of the RR Lyrae type, which are radially-pulsating giant A-F stars having amplitudes from 0.2 to 2 mag in V. Cases of variable light-curve shapes as well as variable periods are known. If these changes are periodic, they are called the "Blazhko effect." Traditionally, RR Lyrae stars are sometimes called short-period Cepheids or cluster-type variables. The majority of these stars belong to the spherical component of the Galaxy; they are present, sometimes in large numbers, in some globular clusters, where they are known as pulsating horizontal-branch stars. Like Cepheids, maximum expansion velocities of surface layers for these stars practically coincide with maximum light. RR(B) RR Lyrae variables showing two simultaneously operating pulsation modes, the fundamental tone with the period P0 and the first overtone, P1 (AQ Leo). The ratio P1/P0 is approximately 0.745; RRAB RR Lyrae variables with asymmetric light curves (steep ascending branches), periods from 0.3 to 1.2 days, and amplitudes from 0.5 to 2 mag in V; RRC RR Lyrae variables with nearly symmetric, sometimes sinusoidal, light curves, periods from 0.2 to 0.5 days, and amplitudes not greater than 0.8 mag in V (SX UMa).