t Cygni
catalogues and names
| catalogues and names | t Cyg, tau Cyg, 65 Cyg, HR 8130, HD 202444, SAO 71121, BD +37 4240, WDS 21148+3803A |
| constellation | Cygnus |
data from The Bright Star Catalogue, 5th Revised Ed. (Preliminary Version) (Hoffleit+, 1991)
position, motion, parallax:
| position (J2000) | RA: 21h 14min 47.5sec | DEC: +38° 2' 44'' | ||
| position (B1900) | RA: 21h 10min 47.9sec | DEC: +37° 37' 6'' | ||
| proper motion (J2000) | RA: 0.16 arcsec/a | DEC: 0.435 arcsec/a | ||
| radial velocity | -21 km/s note: spectroscopic binaries |
|||
| rotational velocity | 89 km/s (uncertain) (variable) | |||
| trigonometric parallax | 0.055 arcsec | |||
| galactic coordinates | longitude: 82.85° | latitude: -7.43° | ||
| note (category: dynamical parallaxes): | 0.046". |
magnitude
| visual magnitude | 3.72 (V on UBV Johnson system) |
spectral / color information
| spectral class | F2IV |
| B-V-magnitude | 0.39 |
| U-B-magnitude | 0.02 |
| R-I-magnitude | |
| IR-note | object is infrared source (NASA merged infrared catalogue, Schmitz et al., 1978) |
| note (category: colors): | Color excess E(B-V) = +0.09. |
variability information
| variable star identification | Tau Cyg |
| note (category: variability): | Delta Sct 3.65 - 3.84V. 2-3 hrs.? Possibly variable period. |
double/multiple star system information
| number of components of multiple star system | 7 |
| separation | 1 arcsec |
| mag difference (of double or brightest multiple) | 2.5 |
| component ID | AB |
| note (category: double and multiple data): | AB 3.82 F0IV, 6.42 G1V, 49.80y, a = 0.85". Components C, 13v at 29" and P, 12v at 72", both optical. Q, 12v at 90", physical. R, 13v at 90", CPM. |
| note (category: spectroscopic binaries): | 0.143d not confirmed. |
data from SKY2000 - Master Star Catalog (Myers+ 1997)
position, motion, parallax:
| position (J2000) | RA: 21h 14min 47.472sec | DEC: +38° 2' 43.93'' | ±1.24 arcsec | source: 29 |
| proper motion (J2000) | RA: 0.0135 arcsec/a | DEC: 0.435 arcsec/a | source: 25 | |
| radial velocity | -21 km/s | source: 25 | ||
| trigonometric parallax | 0.055 arcsec | ±0.005 arcsec | source: 25 | |
| galactic coord. (B1950) | longitude: 82.85° | latitude: -7.43° | ||
magnitude:
| visual | 3.6 (observed) | source: 31 |
| photovisual | 3.8 | source: 2 |
| photographic | 4.1 | source: 2 |
spectral information:
| spectral class | F0 | source: 96 | |
| Morgan-Keenan | F2IV | source: 25 | |
| B-magnitude | 4.11 ±0.05 | B-V-magnitude | 0.39 |
| U-magnitude | 4.13 ±0.05 | U-B-magnitude | 0.02 |
variability information:
| variability type | 150 |
| var. amplitude | 0.1 |
double/multiple star system information:
| magnitude difference between brightest and second brightest component | 2.5 |
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 | |
| 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 | |
| 29 | SAOJ2000 |
| SAO on FK5 at J2000, 1989 | |
| 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: 21h 12min 47.559sec | DEC: +37° 49' 52.28'' | ±0.009 arcsec |
| position (J2000) | RA: 21h 14min 47.472sec | DEC: +38° 2' 43.93'' | |
| proper motion B1950 (FK4) | RA: 0.0134 arcsec/a | DEC: 0.437 arcsec/a | ±0.001 arcsec/a in RA ±0.002 arcsec/a in DEC |
| proper motion J2000 (FK5) | RA: 0.0135 arcsec/a | DEC: 0.435 arcsec/a | |
| source of proper motion data | Determined by source catalog | ||
magnitude:
| visual | 3.8 (accuracy: 2 decimals) |
| source of visual magnitude data | Taken from the "Henry Draper Catalogue". |
spectral information:
| spectral class | F0 |
| source of spectral data | Taken from the HD with M stars reclassified by Miss Cannon. |
catalogues
| source catalogue | FK3, catalogue number: 799 |
| Durchmusterung | BD+37 4240 |
| Boss General Catalogue | 29723 |
| Henry Draper Catalogue | 202444 |
data from The Washington Visual Double Star Catalog, 1996.0 (Worley+, 1996)
position and proper motion:
| position (J2000) | RA: 21h 14.8min | DEC: +38° 3' |
| proper motion (J2000) | RA: 0.159 arcsec/a | DEC: 0.436 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 |
| AB | 1875 | often | ° | '' | 3.8 | 6.3 | F3IV-V | AGC 13 |
| AC | 1876 | 8 | 260° | 15.7'' | 3.8 | 12.2 | - | AGC 13 |
| 1914 | 228° | 29.4'' | ||||||
| AB-D | 1852 | 11 | 213° | 136.9'' | 3.8 | 10.1 | - | AGC 13 |
| 1924 | 210° | 170'' | ||||||
| Aa | 1912 | 1 | 288° | 71.7'' | 3.8 | 12.4 | - | AGC 13 |
| Ab | 1912 | 30 | 185° | 89.9'' | 3.8 | 11.8 | - | AGC 13 |
| 1969 | 184° | - |
discoverer information:
| discoverer code | discoverer | reference |
| AGC 13 | - | - |
notes:
| note | Tau Cyg. P = 49.8yr., a = 0.85", motion retrograde. A is a Delta Scuti-type variable. The faint component b is physical with AB. |
data from 4th Catalog of Orbits of Visual Binaries (Worley+, 1983)
position:
| position (B1900) | RA: 21h 10.8min | DEC: +37° 37' |
magnitudes, spectral classes, orbital elements:
| author: | G. Van Biesbroeck | W.D. Heintz |
| date of observation: | 1939 | 1969 |
| magnitude of component A: | 3.82 | 3.82 |
| magnitude of component B: | 3.82 | 3.82 |
| spectral class component B: | F2IV | F2IV |
| spectral class component B: | F2IV | F2IV |
| period [y]: | 49.8 | 49.9 |
| semi-major axis [arcsec]: | 0.85 | 0.88 |
| inclination [deg]: | 134.5 | 134.2 |
| node [deg]: | 160.4 (ascending) | 159.7 (ascending) |
| equinox of node: | 1900 | 2000 |
| eccentricity: | 0.24 | 0.25 |
| time of periastron passage: | 1939.7 | 1939.6 |
| dates of ephemeris: | 1940-1950 | |
| grade: | definitive | definitive |
| reference: | Astron. J. 48, 169; 1940. | Astron. J. 75, 848; 1970. |
| notes | Identification of the ascending node is probable although small variations of non-orbital origin superimpose on the RV. A faint star listed as component Q (mag. 12, 90") in IDS is physical; linear formula given by Heintz. |
| other name(s) | AGC 13, Tau Cyg |
data from Combined General Catalogue of Variable Stars (Vol. I-III) (Kholopov+ 1998)
position:
| position (equinox 1950.0) | RA: 21h 12min 47.6sec | DEC: +37° 49' 52'' |
variability informations:
| variability type | DSCT | pulsating variable star |
| magnitute at max. brightness | 3.65 | |
| magnitute at min. brightness | 3.75 | |
| photometric system | visual, photovisual or Johnson's V |
spectral information
| spectral class | F0IV |
references
| to a study | Vol. I GCVS (see Kholopov et al. 1985-1988) |
| to a chart/photograph | no chart is avaible, but the star is contained in the 'Bonner Durchmusterung' |
miscanellous
| ID in the GCVS catalogue | 31/9019 |
| constellation | Cygnus |
| notes on existence | The star is equivalent to '0319020 ups'. |
| There are notes in published catalog. | |
variability type description
| variability type | description |
| DSCT | Variables of the Delta Scuti type. These are pulsating variables of spectral types A0-F5 III-V displaying light amplitudes from 0.003 to 0.9 mag in V (usually several hundredths of a magnitude) and periods from 0.01 to 0.2 days. The shapes of the light curves, periods, and amplitudes usually vary greatly. Radial as well as nonradial pulsations are observed. The variability of some members of this type appears sporadically and sometimes completely ceases, this being a consequence of strong amplitude modulation with the lower value of the amplitude not exceeding 0.001 mag in some cases. The maximum of the surface layer expansion does not lag behind the maximum light for more than 0.1 periods. DSCT stars are representatives of the galactic disk (flat component) and are phenomenologically close to the SX Phe variables. DSCTC Low amplitude group of Delta Sct variables (light amplitude <0.1 mag in V). The majority of this type's representatives are stars of luminosity class V; objects of this subtype generally are representative of the Delta Sct variables in open clusters. |