X Cygni
catalogues and names
catalogues and names | X Cyg, HR 7932, HD 197572, SAO 70423, BD +35 4234 |
data from The Bright Star Catalogue, 5th Revised Ed. (Preliminary Version) (Hoffleit+, 1991)
position, motion, parallax:
position (J2000) | RA: 20h 43min 24.2sec | DEC: +35° 35' 16'' | ||
position (2000.72) | RA: 20h 43min 26sec | DEC: +35° 35' 25'' | ||
position (B1900) | RA: 20h 39min 29.2sec | DEC: +35° 13' 38'' | ||
proper motion (J2000) | RA: -0.01 arcsec/a | DEC: -0.003 arcsec/a | ||
radial velocity | 10 km/s note: spectroscopic binaries |
|||
rotational velocity | 22 km/s (uncertain) (variable) | |||
trigonometric parallax | -0.008 arcsec | |||
galactic coordinates | longitude: 76.87° | latitude: -4.26° |
magnitude
visual magnitude | 6.47 (V on UBV Johnson system) |
spectral / color information
spectral class | F7Ib-G8Ib |
B-V-magnitude | 1.23 |
U-B-magnitude | 0.99 |
R-I-magnitude | |
IR-note | object is infrared source (NASA merged infrared catalogue, Schmitz et al., 1978) |
variability information
variable star identification | X Cyg |
note (category: variability): | CDelta 5.85 - 6.91, 16.386332d. Period changes. |
data from SKY2000 - Master Star Catalog (Myers+ 1997)
position, motion, parallax:
position (J2000) | RA: 20h 43min 24.202sec | DEC: +35° 35' 15.91'' | ±0.43 arcsec | source: 16 |
position (2000.72) | RA: 20h 43min 26sec | DEC: +35° 35' 25'' | JD: 2451806.24 | |
proper motion (J2000) | RA: -0.0003 arcsec/a | DEC: -0.002 arcsec/a | source: 25 | |
radial velocity | 10 km/s | source: 25 | ||
galactic coord. (B1950) | longitude: 76.88° | latitude: -4.26° |
magnitude:
visual | 5.9 (observed) | source: 31 |
photographic | 7.8 | source: 16 |
spectral information:
spectral class | G0 | source: 96 | |
Morgan-Keenan | F7Ib-G8Ib | source: 25 | |
B-magnitude | 7.7 ±0.05 | B-V-magnitude | 1.23 |
U-magnitude | 8.69 ±0.05 | U-B-magnitude | 0.99 |
variability information:
variability type | 111 |
var. amplitude | 1.06 |
var. period | 16.39 |
var. epoch | 2443830 17. November 1978, 12:00:00 UT |
next max light | 2451811.93 24. September 2000, 10:19:12 UT |
double/multiple star system information:
separation between brightest and second brightest component | 0 arcsec |
position angle | 145 ° |
sources:
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 | |
31 | CRM' (non-GCVS variable data) |
Warren, W.H. Jr., Northern Hemisphere Catalog of Red Magnitudes, 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: 20h 41min 26.598sec | DEC: +35° 24' 23.94'' | ±0.037 arcsec |
position (2000.72) | RA: 20h 43min 26sec | DEC: +35° 35' 26'' | JD: 2451806.24 |
position (J2000) | RA: 20h 43min 24.166sec | DEC: +35° 35' 16.02'' | |
proper motion B1950 (FK4) | RA: -0.001 arcsec/a | DEC: -0.001 arcsec/a | ±0.007 arcsec/a in RA ±0.006 arcsec/a in DEC |
proper motion J2000 (FK5) | RA: -0.0008 arcsec/a | DEC: -0.003 arcsec/a | |
source of proper motion data | Determined by source catalog |
magnitude:
visual | 5.7 (accuracy: 1 decimal) |
source of visual magnitude data | Source cited in source catalog introduction. |
spectral information:
spectral class | G0p |
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 |
catalogues
source catalogue | GC, catalogue number: 28886 |
Durchmusterung | BD+35 4234 |
Boss General Catalogue | 28886 |
Henry Draper Catalogue | 197572 |
data from Combined General Catalogue of Variable Stars (Vol. I-III) (Kholopov+ 1998)
position:
position (equinox 1950.0) | RA: 20h 41min 26.6sec | DEC: +35° 24' 24'' |
variability informations:
variability type | DCEP | pulsating variable star |
magnitute at max. brightness | 5.85 | |
magnitute at min. brightness | 6.91 | |
photometric system | visual, photovisual or Johnson's V | |
epoch for maximum light [JD] | 2443830.387 17. November 1978, 21:17:17 UT |
|
period [d] | 16.386332 | |
next maximum light [JD] | 2451810.530684 23. September 2000, 00:44:11 UT |
|
rising time | 35 % of period |
spectral information
spectral class | F7Ib-G8Ib |
references
to a study | Vol. I GCVS (see Kholopov et al. 1985-1988) |
to a chart/photograph | Vol. I GCVS (see Kholopov et al. 1985-1988) |
miscanellous
ID in the GCVS catalogue | 31/7 |
constellation | Cygnus |
notes on existence | The star is equivalent to '0310008 Y'. |
There are notes in published catalog. |
variability type description
variability type | description |
DCEP | These are the classical cepheids, or Delta Cep-type variables. Comparatively young objects that have left the main sequence and evolved into the instability strip of the Hertzsprung-Russell (H-R) diagram, they obey the well-known Cepheid period-luminosity relation and belong to the young disk population. DCEP stars are present in open clusters. They display a certain relation between the shapes of their light curves and their periods. |