W Ursae Majoris

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

position, motion, parallax:

position (J2000)	RA: 9h 43min 45.551sec	DEC: +55° 57' 9.49''	ą0.43 arcsec	source: 16
position (2000.73)	RA: 9h 43min 49sec	DEC: +55° 56' 57''	JD: 2451810.12
proper motion (J2000)	RA: 0.0035 arcsec/a	DEC: -0.021 arcsec/a		source: 16
radial velocity	-53.7 km/s			source: 11
trigonometric parallax	0.015 arcsec		ą0.009 arcsec	source: 6
galactic coord. (B1950)	longitude: 158.92°	latitude: 45.9°

magnitude:

visual	7.75 (observed)	source: 30
photographic	8.4	source: 16

spectral information:

spectral class	G0		source: 96
Morgan-Keenan	F8V		source: 98
B-magnitude	8.56 ą0.02	B-V-magnitude	0.66
U-magnitude	8.64 ą0.07	U-B-magnitude	0.08

variability information:

source of data: 30

variability type	10
var. amplitude	0.73
var. period	0.33
var. epoch	2445766 6. March 1984, 12:00:00 UT
next max light	2451810.28 22. September 2000, 18:43:12 UT

double/multiple star system information:

source of data: 19

separation between brightest and second brightest component	6.7 arcsec
magnitude difference between brightest and second brightest component	4.5
position angle	46 °

sources:

6	General Catalog of Trigonometric Stellar Parallaxes
Stellar Parallaxes, New Haven: Yale University Observatory, 1952; and Supplement, 1963
11	General Catalogue of Stellar Radial Velocities
Wilson, R.E., General Catalogue of Stellar of Stellar Radial Radial Velocities, Washington, DC: Carnegie Institute of Washington, 1953
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
30	GCVS, 4th edition
Kholopov, P.N., et al., General Catalogue of Variable Stars, fourth edition, Moscow: Nauka Publishing House, 1985-88
96	SAO or HD/HDE Catalog
Reference from Value 1 or Reference from Value 2
98	SKYMAP Master Catalog Version 3.7
Reference from Value 97 [original data sources Catalog Version 3.7 are identified in SKYMAP Version 3.7]

data from Smithsonian Astrophysical Observatory Star Catalog (SAO Staff 1966; USNO, ADC 1990)

position and proper motion:

position (B1950)	RA: 9h 40min 15.405sec	DEC: +56° 10' 56.26''	ą0.014 arcsec
position (2000.73)	RA: 9h 43min 48sec	DEC: +55° 56' 58''	JD: 2451810.12
position (J2000)	RA: 9h 43min 45.541sec	DEC: +55° 57' 9.21''
proper motion B1950 (FK4)	RA: 0.003 arcsec/a	DEC: -0.029 arcsec/a	ą0.007 arcsec/a in RA ą0.007 arcsec/a in DEC
proper motion J2000 (FK5)	RA: 0.0031 arcsec/a	DEC: -0.025 arcsec/a
source of proper motion data	Determined by source catalog

magnitude:

visual	7.9 (accuracy: 1 decimal)
source of visual magnitude data	Taken from AGK1.

spectral information:

spectral class	G0
source of spectral data	Taken from the HD with M stars reclassified by Miss Cannon.

remarks for duplicity and variability

Both double and variable, in either visual or photographic magnitudes

catalogues

source catalogue	Yale Transactions 27, catalogue number: 6057
Durchmusterung	BD+56 1400
Henry Draper Catalogue	83950

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

position and proper motion:

position (J2000)	RA: 9h 43.8min	DEC: +55° 57'
proper motion (J2000)	RA: 0.018 arcsec/a	DEC: -0.026 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
-	1920	2	46°	6.7''	7.9	12.35	F8:Vp	ES 1825

discoverer information:

discoverer code	discoverer	reference
ES 1825	Espin, T.E.	-

notes:

note	A is W UMa, prototype of its class. A distant star, BD+55@1351, may have common proper motion and radial velocity.

data from Combined General Catalogue of Variable Stars (Vol. I-III) (Kholopov+ 1998)

position:

position (equinox 1950.0)

RA: 9h 40min 15.4sec

DEC: +56° 10' 56''

variability informations:

variability type	EW/KW	close binary eclipsing system
magnitute at max. brightness	7.75
magnitute at min. brightness	8.48
photometric system	visual, photovisual or Johnson's V
epoch for maximum light [JD]	2445765.7385 6. March 1984, 05:43:26 UT
period [d]	0.33363749
next maximum light [JD]	2451810.24890633 22. September 2000, 17:58:26 UT

spectral information

spectral class

F8Vp+F8Vp

references

to a study	the main characteristics of the star was determined by the authors themselves
to a chart/photograph	Vol. I GCVS (see Kholopov et al. 1985-1988)

miscanellous

ID in the GCVS catalogue	83/6
constellation	Ursa Major
notes on existence	The star is equivalent to '0830007 X'.
There are notes in published catalog.

variability type description

variability type	description
EW	Eclipsing binary systems. These are binary systems with orbital planes so close to the observer's line of sight (the inclination i of the orbital plane to the plane orthogonal to the line of sight is close to 90 deg) that the components periodically eclipse each other. Consequently, the observer finds changes of the apparent combined brightness of the system with the period coincident with that of the components' orbital motion. EA Algol (Beta Persei)-type eclipsing systems. Binaries with spherical or slightly ellipsoidal components. It is possible to specify, for their light curves, the moments of the beginning and end of the eclipses. Between eclipses the light remains almost constant or varies insignificantly because of reflection effects, slight ellipsoidality of components, or physical variations. Secondary minima may be absent. An extremely wide range of periods is observed, from 0.2 to >= 10000 days. Light amplitudes are also quite different and may reach several magnitudes. EB Beta Lyrae-type eclipsing systems. These are eclipsing systems having ellipsoidal components and light curves for which it is impossible to specify the exact times of onset and end of eclipses because of a continuous change of a system's apparent combined brightness between eclipses; secondary minimum is observed in all cases, its depth usually being considerably smaller than that of the primary minimum; periods are mainly longer than 1 day. The components generally belong to early spectral types (B-A). Light amplitudes are usually <2 mag in V. EW W Ursae Majoris-type eclipsing variables. These are eclipsers with periods shorter than 1 days, consisting of ellipsoidal components almost in contact and having light curves for which it is impossible to specify the exact times of onset and end of eclipses. The depths of the primary and secondary minima are almost equal or differ insignificantly. Light amplitudes are usually <0.8 mag in V. The components generally belong to spectral types F-G and later.
KW	Contact systems of the W UMa type, with ellipsoidal components of F0-K spectral type. Primary components are main-sequence stars and secondaries lie below and to the left of the main sequence in the (MV,B-V) diagram.