AA Ceti

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

position, motion, parallax:

position (J2000)	RA: 1h 59min 0.4sec	DEC: -22° 55' 7.93''	ą0.21 arcsec	source: 16
position (2000.73)	RA: 1h 59min 2sec	DEC: -22° 54' 55''	JD: 2451810.11
proper motion (J2000)	RA: 0.0029 arcsec/a	DEC: 0.086 arcsec/a		source: 16
galactic coord. (B1950)	longitude: 201.26°	latitude: -74.14°

magnitude:

visual	6.89 (derived)
photovisual	6.8	source: 2

spectral information:

spectral class	F2		source: 96
Morgan-Keenan	A7/8V+G		source: 23

variability information:

source of data: 30

variability type	10
var. amplitude	0.5
var. period	0.54
var. epoch	2441269 13. November 1971, 12:00:00 UT
next max light	2451810.34 22. September 2000, 20:09:36 UT

double/multiple star system information:

source of data: 19

separation between brightest and second brightest component	8.4 arcsec
position angle	304 °

component	magnitude	spectral class	catalogue(s)/name(s)
A	6.89	F2
B	9.7	-

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
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
23	Michigan Catalog of 2-Dimensional Spectral Types, Volume IV
Houk, N. and Smith-Moore, D., Michigan Catalogue of 2-Dimensional Spectral Types for the HD Stars, Vol. 4, (Zones -25 to -12 Degrees), Ann Arbor: The University of Michigan, 1988
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

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

position and proper motion:

position (B1950)	RA: 1h 56min 40.618sec	DEC: -23° 9' 44.85''	ą0.057 arcsec
position (2000.73)	RA: 1h 59min 3sec	DEC: -22° 55' 0''	JD: 2451810.11
position (J2000)	RA: 1h 59min 0.764sec	DEC: -22° 55' 9.35''
proper motion B1950 (FK4)	RA: 0.0072 arcsec/a	DEC: 0.058 arcsec/a	ą0.01 arcsec/a in RA ą0.01 arcsec/a in DEC
proper motion J2000 (FK5)	RA: 0.0074 arcsec/a	DEC: 0.054 arcsec/a
source of proper motion data	Determined by source catalog

magnitude:

visual	7.3 (accuracy: 2 decimals)
source of visual magnitude data	Taken from Harvard or San Luis photometry.

spectral information:

spectral class	F2
source of spectral data	Taken from the Henry Draper Catalogue or no spectrum in source catalog.

remarks for duplicity and variability

Double star in Aitken's Double Star Catalogue (Aitken 1932)

catalogues

source catalogue	GC, catalogue number: 2392
Durchmusterung	CD-23 737A
Boss General Catalogue	2392
Henry Draper Catalogue	12180

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

position and proper motion:

position (J2000)	RA: 1h 59min	DEC: -22° 55'
proper motion (J2000)	RA: 0.048 arcsec/a	DEC: 0.064 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
-	1822	22	304°	8.4''	-	7.5	F2	H 58

discoverer information:

discoverer code	discoverer	reference
H 58	Herschel, W.	-

notes:

note	H II 58. A is a W UMa-type system, AA Cet.

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

position:

position (equinox 1950.0)

RA: 1h 56min 40.6sec

DEC: -23° 9' 45''

variability informations:

variability type	EW/KE	close binary eclipsing system
magnitute at max. brightness	6.2
magnitute at min. brightness	6.7
photometric system	photographic magnitudes
epoch for maximum light [JD]	2441268.689 13. November 1971, 04:32:10 UT
period [d]	0.53616996
next maximum light [JD]	2451810.32658356 22. September 2000, 19:50:17 UT

spectral information

spectral class

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	21/55
constellation	Cetus
notes on existence	The star is equivalent to '0210056 AB'.
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.
KE	Contact systems of early (O-A) spectral type, both components being close in size to their inner critical surfaces.