Mizar

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 (B1900)	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
galactic coordinates	longitude: 113.11°	latitude: 61.58°

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
IR-note	object is infrared source (NASA merged infrared catalogue, Schmitz et al., 1978)

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 arcsec		±0.005 arcsec	source: 25
galactic coord. (B1950)	longitude: 113.11°	latitude: 61.58°

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:

source of data: 19

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 (B1950)	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 B1950 (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	often	153°	14.5''	2.27	3.95	A1VpSrSi	STF1744
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 (B1900)

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.

other name(s)

Mizar Aa, Zeta UMa

data from Combined General Catalogue of Variable Stars (suspected variables) (Kholopov+ 1998)

position:

position (equinox 1950.0)

RA: 13h 21min 54.9sec

DEC: +55° 11' 9''

variability informations:

variability type	-
magnitute at max. brightness	2.27
magnitute at min. brightness
photometric system	visual, photovisual or Johnson's V

spectral information

spectral class

references

to a study

172467D (designation: *)

miscanellous

There are notes in the published catalog (Kukarkin et al.(1982)).

catalogues and names	Mizar, z UMa, NSV 06224, 79 UMa, HR 5054, HD 116656, SAO 28737, BD +55 1598 A, FK5: 497, WDS 13239+5456A
other names	Mirzar, Mizat
constellation	Ursa Major