Mizar
| catalogues and names | Mizar, z UMa, NSV 06224, 79 UMa, HR 5054, HD 116656, SAO 28737, FK5: 497, WDS 13239+5456A |
| other names | Mirzar, Mizat |
| constellation | Ursa Major |
data from The Bright Star Catalogue, 5th Revised Ed. (Preliminary Version) (Hoffleit+, 1991)
| note (category: star names): | MIZAR; Mizat; Mirza. |
position, motion, parallax:
| position (J2000) | RA: 13h 23min 55,5sec | DEC: +54° 55' 31'' |
| position (J1900) | RA: 13h 19min 54sec | DEC: +55° 26' 51'' |
| proper motion (J2000) | RA: 0,122 arcsec/a | DEC: -0,02 arcsec/a |
| radial velocity | -6 km/s note: spectroscopic binaries, double lined spectra note: orbital data avaible |
|
| rotational velocity | 32 km/s (uncertain) (variable) | |
| trigonometric parallax | 0,047 arcsec | |
| note (category: dynamical parallaxes): | 0.046". |
magnitude
| visual magnitude | 2,27 (V on UBV Johnson system) |
spectral / color information
| spectral class | A1VpSrSi |
| B-V-magnitude | 0,02 |
| U-B-magnitude | 0,03 |
| R-I-magnitude | -0,02 |
| note (category: spectra): | Combined spectrum for Aa also classified A1VpSrSi. |
variability information
| variable star identification | 6224 |
double/multiple star system information
| number of components of multiple star system | 4 |
| separation | 0 arcsec |
| mag difference (of double or brightest multiple) | 1,7 |
| component ID | AP |
| note (category: double and multiple data): | Aa = AP 3.0 A2V, 3.0 A2V, sep. 0.0115", 0.056y, a = 0.012". Combined mag., colors AP. Binary with HR 5055. Alcor, HR 5062, at 709", CPM. |
| note (category: spectroscopic binaries): | ADS 8891Aa, 20.5386d, K 68.8k/s, V0 -5.6k/s, msin3i 1.60, asini 16.4. i 60d. vsini both components 32k/s. The first SB to have been discovered, by Pickering in 1889. First resolved by 20-foot interferometer at Mt. Wilson by Pease in 1925, sep. 0.01". |
miscellaneous information
| note (category: group membership): | "Dipper Stars;" Sirius group; UMa moving cluster. |
data from SKY2000 - Master Star Catalog (Myers+ 1997)
position, motion, parallax:
| position (J2000) | RA: 13h 23min 55,539sec | DEC: +54° 55' 31,38'' | ±0,06 arcsec | source: 15 |
| proper motion (J2000) | RA: 0,0141 arcsec/a | DEC: -0,02 arcsec/a | source: 25 | |
| radial velocity | -6 km/s | source: 25 | ||
| trigonometric parallax | 0,047 | ±0,005 arcsec | source: 25 | |
| galactic coord. (B1950) | longitude: 113,11° | latitude: 61,58° | ||
| GCI unit vector (J2000) | X: -0,536542 | Y: -0,205759 | Z: 0,818404 | |
magnitude:
| visual | 2,27 (observed) | source: 25 |
| photovisual | 2,4 | source: 2 |
spectral information:
| spectral class | A2 | source: 96 | |
| Morgan-Keenan | A1VpSrSi | source: 25 | |
| B-magnitude | 2,29 ±0,05 | B-V-magnitude | 0,02 |
| U-magnitude | 2,32 ±0,05 | U-B-magnitude | 0,03 |
double/multiple star system information:
| separation between brightest and second brightest component | 14,5 arcsec |
| magnitude difference between brightest and second brightest component | 1,68 |
| position angle | 153 ° |
| component | magnitude | spectral class | catalogue(s)/name(s) |
| A | 2,27 | A2 | Mizar, z Ursae Majoris, 79 UMa, HR 5054, HD 116656, SAO 28737 |
| B | 3,95 | A2 | z Ursae Majoris, 79 UMa, HR 5055, HD 116657, SAO 28738 |
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: 13h 21min 54,916sec | DEC: +55° 11' 9,46'' | ±0,003 arcsec |
| position (J2000) | RA: 13h 23min 55,55sec | DEC: +54° 55' 31,39'' | |
| proper motion J1950 (FK4) | RA: 0,0139 arcsec/a | DEC: -0,025 arcsec/a | ±0,001 arcsec/a in RA ±0,001 arcsec/a in DEC |
| proper motion J2000 (FK5) | RA: 0,0142 arcsec/a | DEC: -0,02 arcsec/a | |
| source of proper motion data | Determined by source catalog | ||
magnitude:
| visual | 2,4 (accuracy: 2 decimals) |
| source of visual magnitude data | Taken from the "Henry Draper Catalogue". |
spectral information:
| spectral class | A2p |
| source of spectral data | Taken from the Henry Draper Catalogue or no spectrum in source catalog. |
catalogues
| source catalogue | FK4, catalogue number: 497 |
| Durchmusterung | BD+55 1598A |
| Boss General Catalogue | 18133 |
| Henry Draper Catalogue | 116656 |
data from The Washington Visual Double Star Catalog, 1996.0 (Worley+, 1996)
position and proper motion:
| position (J2000) | RA: 13h 23,9min | DEC: +54° 56' |
| proper motion (J2000) | RA: 0,122 arcsec/a | DEC: -0,02 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 |
| - | 1820 | often | 146° | 14,7'' | 2,27 | 3,95 | A1VpSrSi | STF1744 |
| 1993 | 153° | 14,5'' | ||||||
| AC | 1923 | 2 | 70° | 11,8'' | - | - | - | STF1744 |
discoverer information:
| discoverer code | discoverer | reference |
| STF1744 | Struve, F.G.W. | - |
notes:
| note | Zeta UMa. A is a spectroscopic binary (the first discovered), P = 20.54d. B is also a spectroscopic binary, P = 175.6d, spectrum A1m or A1/A2/A7, Proper motion +115 -033. Also, common proper motion with 80 UMa and other members of the Ursa Major stream. |
data from 4th Catalog of Orbits of Visual Binaries (Worley+, 1983)
position:
| position (J1900) | RA: 13h 19,9min | DEC: +55° 27' |
magnitudes, spectral classes, orbital elements:
| author: | H.N. Russell |
| date of observation: | 1927 |
| magnitude of component A: | 3 |
| magnitude of component B: | 3 |
| spectral class component B: | A1Vp |
| spectral class component B: | A1Vp |
| period [y]: | 0,056 |
| semi-major axis [arcsec]: | 0,012 |
| inclination [deg]: | 60 |
| node [deg]: | 102 |
| eccentricity: | 0,53 |
| time of periastron passage: | 1927,445 |
| reference: | Pub. Astron. Soc. Pacific 39, 313; 1927. |
| notes | The orbit of Aa is combined interferometric-spectroscopic (double-lined spectrum), and not graded, as the delicate measures with the old interferometer have not been supplemented of late. A small magnitude difference (which would probably place the ascending node in the second quadrant) is uncertain. P =20.54 d, a = 0.0115". Star B (mag. 3.96, 15") is physical, and is itself a single-lined spectroscopic binary, P = 175.55 d. This quadruple shares proper motion and parallax with 80 UMa (Alcor, Mag. 4.0, 12', A5V) and with other memebers of the Ursa Major stream. |