Megrez

data from The Bright Star Catalogue, 5th Revised Ed. (Preliminary Version) (Hoffleit+, 1991)

note (category: star names):

MEGREZ; Kaffa in Becvar.

position, motion, parallax:

position (J2000)	RA: 12h 15min 25.6sec	DEC: +57° 1' 57''
position (B1900)	RA: 12h 10min 28.7sec	DEC: +57° 35' 18''
proper motion (J2000)	RA: 0.104 arcsec/a	DEC: 0.009 arcsec/a
radial velocity	-13 km/s note: variable radial velocity
rotational velocity	177 km/s (uncertain) (variable)
trigonometric parallax	0.061 arcsec
galactic coordinates	longitude: 132.57°	latitude: 59.42°

magnitude

visual magnitude

3.31
(V on UBV Johnson system)

spectral / color information

spectral class	A3V
B-V-magnitude	0.08
U-B-magnitude	0.07
R-I-magnitude

variability information

variable star identification

5513

double/multiple star system information

number of components of multiple star system	3
separation	189.6 arcsec
mag difference (of double or brightest multiple)	6.6
component ID	AB
note	Worley (1978) update of the IDS

miscellaneous information

note (category: group membership):

"Dipper Stars"; Ursa cluster; Sirius group; UMa stream.

data from SKY2000 - Master Star Catalog (Myers+ 1997)

position, motion, parallax:

position (J2000)	RA: 12h 15min 25.56sec	DEC: +57° 1' 57.42''	±0.06 arcsec	source: 15
proper motion (J2000)	RA: 0.0127 arcsec/a	DEC: 0.009 arcsec/a		source: 25
radial velocity	-13 km/s			source: 25
trigonometric parallax	0.061 arcsec		±0.006 arcsec	source: 25
galactic coord. (B1950)	longitude: 132.56°	latitude: 59.42°

magnitude:

visual	3.31 (observed)	source: 25
photovisual	3.4	source: 2
photographic	3.3	source: 16

spectral information:

spectral class	A2		source: 96
Morgan-Keenan	A3V		source: 25
B-magnitude	3.39 ±0.05	B-V-magnitude	0.08
U-magnitude	3.46 ±0.05	U-B-magnitude	0.07

double/multiple star system information:

source of data: 19

separation between brightest and second brightest component	188.5 arcsec
magnitude difference between brightest and second brightest component	6.7
position angle	73 °

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
16	PPM North and PPM South Catalogs and PPM Supplement
Roser, S., and U. Bastian, "Catalogue of Positions and Proper Motions," A&AS, Vol. 74, p. 449, 1988, and Bastian, U., et al., "Catalogue of Positions and Proper Motions - South," 1993
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: 12h 12min 57.584sec	DEC: +57° 18' 36.95''	±0.004 arcsec
position (J2000)	RA: 12h 15min 25.57sec	DEC: +57° 1' 57.35''
proper motion B1950 (FK4)	RA: 0.0126 arcsec/a	DEC: 0.004 arcsec/a	±0.001 arcsec/a in RA ±0.001 arcsec/a in DEC
proper motion J2000 (FK5)	RA: 0.0128 arcsec/a	DEC: 0.009 arcsec/a
source of proper motion data	Determined by source catalog

magnitude:

visual	3.4 (accuracy: 2 decimals)
source of visual magnitude data	Taken from the "Henry Draper Catalogue".

spectral information:

spectral class	A2
source of spectral data	Taken from the Henry Draper Catalogue or no spectrum in source catalog.

catalogues

source catalogue	FK4, catalogue number: 456
Durchmusterung	BD+57 1363
Boss General Catalogue	16736
Henry Draper Catalogue	106591

data from The Washington Visual Double Star Catalog, 1996.0 (Worley+, 1996)

position and proper motion:

position (J2000)	RA: 12h 15.4min	DEC: +57° 2'
proper motion (J2000)	RA: 0.104 arcsec/a	DEC: 0.009 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	1878	5	73°	192.4''	3.31	10	A3V	BLL 29
	1923		-	188.5''
AC	1879	2	124°	188.6''	3.4	11.6	-	BUP 140
	1907		125°	186.4''

discoverer information:

discoverer code	discoverer	reference
BLL 29	Ball, R.S.	-
BUP 140	-	-

notes:

note	Delta UMa.

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

position:

position (equinox 1950.0)

RA: 12h 12min 57.6sec

DEC: +57° 18' 37''

variability informations:

magnitute at max. brightness	3.27
magnitute at min. brightness	3.34
photometric system	visual, photovisual or Johnson's V

spectral information

spectral class

references

to a study

290477D (designation: ZI 919)

miscanellous

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

catalogues and names	Megrez, d UMa, NSV 05513, 69 UMa, HR 4660, HD 106591, SAO 28315, BD +57 1363, FK5: 456, WDS 12154+5702A
other names	Kaffa in Becvar
constellation	Ursa Major