g2Delphini
| catalogues and names | g2Del, 12 Del, HR 7948, HD 197964, SAO 106476, FK5: 1541, WDS 20467+1607A |
| constellation | Delphinus |
data from The Bright Star Catalogue, 5th Revised Ed. (Preliminary Version) (Hoffleit+, 1991)
position, motion, parallax:
| position (J2000) | RA: 20h 46min 39,5sec | DEC: +16° 7' 27'' |
| position (J1900) | RA: 20h 42min 1,1sec | DEC: +15° 45' 50'' |
| proper motion (J2000) | RA: -0,032 arcsec/a | DEC: -0,197 arcsec/a |
| radial velocity | -7 km/s note: suspected variable radial velocity |
|
| rotational velocity | 0 km/s (uncertain) (variable) | |
| trigonometric parallax | 0,026 arcsec | |
| note (category: dynamical parallaxes): | 0.033". |
magnitude
| visual magnitude | 4,27 (V on UBV Johnson system) |
spectral / color information
| spectral class | K1IV |
| B-V-magnitude | 1,04 |
| U-B-magnitude | 0,97 |
| R-I-magnitude | 0,48 |
double/multiple star system information
| separation | 9,8 arcsec |
| mag difference (of double or brightest multiple) | 1 |
| note (category: double and multiple data): | See HR 7947. |
miscellaneous information
| note (category: group membership): | Wolf 630 group. |
data from SKY2000 - Master Star Catalog (Myers+ 1997)
position, motion, parallax:
| position (J2000) | RA: 20h 46min 39,499sec | DEC: +16° 7' 27,43'' | ±0,06 arcsec | source: 15 |
| proper motion (J2000) | RA: -0,0022 arcsec/a | DEC: -0,197 arcsec/a | source: 25 | |
| radial velocity | -7 km/s | source: 25 | ||
| trigonometric parallax | 0,026 | ±0,003 arcsec | source: 25 | |
| galactic coord. (B1950) | longitude: 61,5° | latitude: -16,58° | ||
| GCI unit vector (J2000) | X: 0,638618 | Y: -0,717662 | Z: 0,277722 | |
magnitude:
| visual | 4,27 (observed) | source: 25 |
| photovisual | 4,5 | source: 2 |
spectral information:
| spectral class | G5 | source: 96 | |
| Morgan-Keenan | K1IV | source: 25 | |
| B-magnitude | 5,31 ±0,05 | B-V-magnitude | 1,04 |
| U-magnitude | 6,28 ±0,05 | U-B-magnitude | 0,97 |
double/multiple star system information:
| separation between brightest and second brightest component | 9,6 arcsec |
| magnitude difference between brightest and second brightest component | 0,87 |
| position angle | 267 ° |
| component | magnitude | spectral class | catalogue(s)/name(s) |
| A | 4,27 | G5 | g2Delphini, 12 Del, HR 7948, HD 197964, SAO 106476 |
| B | 5,14 | F8 | g1Delphini, 12 Del, HR 7947, HD 197963, SAO 106475 |
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 | |
| 15 | FK5, FK5 Extension and FK5 Supplement |
| Fricke, W., H. Schwan and T. Lederle, "Fifth Fundamental Catalogue (FK5), Part I. The Basic Fundamental Stars," Veroff. Astronomisches Recheninstitut, No. 32, Heidelberg, Germany, 1988, and Fricke, W., H. Schwan, and T.E. Corbin, "Fifth Fundamental Catalogue (FK5), Part II. The FK5 Extension," Veröff. Astronomisches Recheninstitut, No. 33, Heidelberg, Germany, 1991 | |
| 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 | |
| 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 44min 20,236sec | DEC: +15° 56' 34,82'' | ±0,006 arcsec |
| position (J2000) | RA: 20h 46min 39,49sec | DEC: +16° 7' 27,39'' | |
| proper motion J1950 (FK4) | RA: -0,0024 arcsec/a | DEC: -0,195 arcsec/a | ±0,001 arcsec/a in RA ±0,001 arcsec/a in DEC |
| proper motion J2000 (FK5) | RA: -0,0023 arcsec/a | DEC: -0,198 arcsec/a | |
| source of proper motion data | Determined by source catalog | ||
magnitude:
| visual | 4,5 (accuracy: 2 decimals) |
| source of visual magnitude data | Taken from the "Henry Draper Catalogue". |
spectral information:
| spectral class | G5 |
| source of spectral data | Taken from the Henry Draper Catalogue or no spectrum in source catalog. |
catalogues
| source catalogue | FK4, catalogue number: 1541 |
| Durchmusterung | BD+15 4255A |
| Boss General Catalogue | 28966 |
| Henry Draper Catalogue | 197964 |
data from The Washington Visual Double Star Catalog, 1996.0 (Worley+, 1996)
position and proper motion:
| position (J2000) | RA: 20h 46,7min | DEC: +16° 7' |
| proper motion (J2000) | RA: -0,032 arcsec/a | DEC: -0,197 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 |
| - | 1823 | often | 274° | 11,9'' | 4,27 | 5,14 | K1IV F7V | STF2727 |
| 1988 | 267° | 9,6'' |
discoverer information:
| discoverer code | discoverer | reference |
| STF2727 | Struve, F.G.W. | - |
notes:
| note | Gamma Del. A premature orbit has been computed. |