Nunki
| catalogues and names | Nunki, s Sgr, 34 Sgr, HR 7121, HD 175191, SAO 187448, FK5: 706, WDS 18553-2618 |
| other names | Sadira |
| constellation | Sagittarius |
data from The Bright Star Catalogue, 5th Revised Ed. (Preliminary Version) (Hoffleit+, 1991)
| note (category: star names): | NUNKI; Sadira. |
position, motion, parallax:
| position (J2000) | RA: 18h 55min 15,9sec | DEC: -26° 17' 48'' |
| position (J1900) | RA: 18h 49min 3,9sec | DEC: -26° 25' 15'' |
| proper motion (J2000) | RA: 0,013 arcsec/a | DEC: -0,054 arcsec/a |
| radial velocity | -11 km/s note: variable radial velocity |
|
| rotational velocity | 201 km/s (uncertain) (variable) | |
magnitude
| visual magnitude | 2,02 (V on UBV Johnson system) |
spectral / color information
| spectral class | B2.5V |
| B-V-magnitude | -0,22 |
| U-B-magnitude | -0,75 |
| R-I-magnitude | -0,21 |
| note (category: spectra): | Lyman alpha and Lyman beta observed from COPERNICUS. |
| note (category: colors): | Color excess E(B-V) = +0.02. |
double/multiple star system information
| separation | 309 arcsec |
| mag difference (of double or brightest multiple) | 7,4 |
| note | Worley (1978) update of the IDS |
| note (category: double and multiple data): | Interferometer measures indicate multiple star. |
miscellaneous information
| note (category: group membership): | Sco-Cen assoc. |
data from SKY2000 - Master Star Catalog (Myers+ 1997)
position, motion, parallax:
| position (J2000) | RA: 18h 55min 15,924sec | DEC: -26° 17' 48,23'' | ±0,06 arcsec | source: 15 |
| proper motion (J2000) | RA: 0,001 arcsec/a | DEC: -0,054 arcsec/a | source: 25 | |
| radial velocity | -11 km/s | source: 25 | ||
| galactic coord. (B1950) | longitude: 9,56° | latitude: -12,43° | ||
| GCI unit vector (J2000) | X: 0,214096 | Y: -0,870572 | Z: -0,44302 | |
magnitude:
| visual | 2,02 (observed) | source: 25 |
| photovisual | 2,1 | source: 2 |
| photographic | 2 | source: 2 |
spectral information:
| spectral class | B3 | source: 96 | |
| Morgan-Keenan | B2.5V | source: 25 | |
| B-magnitude | 1,8 ±0,05 | B-V-magnitude | -0,22 |
| U-magnitude | 1,05 ±0,05 | U-B-magnitude | -0,75 |
double/multiple star system information:
| separation between brightest and second brightest component | 309 arcsec |
| magnitude difference between brightest and second brightest component | 7,5 |
| position angle | 244 ° |
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: 18h 52min 9,927sec | DEC: -26° 21' 38,29'' | ±0,005 arcsec |
| position (J2000) | RA: 18h 55min 15,918sec | DEC: -26° 17' 48,21'' | |
| proper motion J1950 (FK4) | RA: 0,001 arcsec/a | DEC: -0,054 arcsec/a | ±0,001 arcsec/a in RA ±0,001 arcsec/a in DEC |
| proper motion J2000 (FK5) | RA: 0,0009 arcsec/a | DEC: -0,054 arcsec/a | |
| source of proper motion data | Determined by source catalog | ||
magnitude:
| visual | 2,1 (accuracy: 2 decimals) |
| source of visual magnitude data | Taken from the "Henry Draper Catalogue". |
spectral information:
| spectral class | B3 |
| source of spectral data | Taken from the Henry Draper Catalogue or no spectrum in source catalog. |
catalogues
| source catalogue | FK4, catalogue number: 706 |
| Durchmusterung | CD-2613595 |
| Boss General Catalogue | 25941 |
| Henry Draper Catalogue | 175191 |
data from The Washington Visual Double Star Catalog, 1996.0 (Worley+, 1996)
position and proper motion:
| position (J2000) | RA: 18h 55,3min | DEC: -26° 18' |
| proper motion (J2000) | RA: 0,013 arcsec/a | DEC: -0,054 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 |
| - | 1837 | 1 | 244° | 309'' | 2,02 | 9,5 | B2.5V | SMY 4 |
discoverer information:
| discoverer code | discoverer | reference |
| SMY 4 | Smythe, W.H. | - |
notes:
| note | Sigma Sgr. B is CD-26@13591. |