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 (2000.73) | RA: 21h 14min 50sec | DEC: +38° 2' 55'' | ||
| 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 |
| position (2000.73) | RA: 21h 14min 49sec | DEC: +38° 2' 55'' | JD: 2451810.88 | |
| 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 (2000.73) | RA: 21h 14min 49sec | DEC: +38° 2' 33'' | JD: 2451810.88 |
| 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. |