catalogues and names

The Bright Star Catalogue, 5th Revised Ed. (Preliminary Version)

SKY2000 - Master Star Catalog

Smithsonian Astrophysical Observatory Star Catalog

The Washington Visual Double Star Catalog, 1996.0

Combined General Catalogue of Variable Stars (Vol. I-III)

catalogues and names

catalogues and names	Mekbuda, z Gem, zet Gem, 43 Gem, HR 2650, HD 52973, SAO 79031, BD +20 1687, FK5: 269, WDS 07041+2034A
constellation	Gemini

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

note (category: star names):

Mekbuda.

position, motion, parallax:

position (J2000)	RA: 7h 4min 6.5sec	DEC: +20° 34' 13''
position (2000.72)	RA: 7h 4min 10sec	DEC: +20° 34' 9''
position (B1900)	RA: 6h 58min 10.6sec	DEC: +20° 43' 2''
proper motion (J2000)	RA: -0.009 arcsec/a	DEC: 0 arcsec/a
radial velocity	7 km/s note: spectroscopic binaries
rotational velocity	=<54 km/s (uncertain) (variable)
trigonometric parallax	-0.006 arcsec
galactic coordinates	longitude: 195.75°	latitude: 11.9°

note (category: radial and/or rotational velocities):

Same period.

magnitude

visual magnitude

3.79 (V on UBV Johnson system)

spectral / color information

spectral class	F7-G3Ib
B-V-magnitude	0.79
U-B-magnitude	0.62
R-I-magnitude
IR-note	object is infrared source (NASA merged infrared catalogue, Schmitz et al., 1978)

variability information

variable star identification

Zet Gem

note (category: variability):

ADS 5742A, CDelta 3.62 - 4.18V, 10.15073d. Period decreasing 3.1s/y.

double/multiple star system information

number of components of multiple star system	6
separation	0.1 arcsec
mag difference (of double or brightest multiple)	0
component ID	O

note (category: double and multiple data):

Component A is suspected occultation double, 4.5, 4.5v, sep. 0.1". B, 10.5v at 87". C, +20d1686, 7.55V, +0.62(B-V), +0. +0.07(U-B), G1V at 96" has high proper motion, 0.100", optical, vsini =<54k/s. Other components fainter.

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

position, motion, parallax:

position (J2000)	RA: 7h 4min 6.522sec	DEC: +20° 34' 13''	±0.06 arcsec	source: 15
position (2000.72)	RA: 7h 4min 10sec	DEC: +20° 34' 9''	JD: 2451806.24
proper motion (J2000)	RA: -0.0007 arcsec/a	DEC: -0.001 arcsec/a		source: 25
radial velocity	7 km/s			source: 25
galactic coord. (B1950)	longitude: 195.75°	latitude: 11.9°

magnitude:

visual

3.7 (observed)

source: 31

spectral information:

spectral class	G0P		source: 29
Morgan-Keenan	F7-G3Ib		source: 25
B-magnitude	4.58 ±0.05	B-V-magnitude	0.79
U-magnitude	5.2 ±0.05	U-B-magnitude	0.62

variability information:

source of data: 30

variability type	111
var. amplitude	0.56
var. period	10.15
var. epoch	2443806 24. October 1978, 12:00:00 UT
next max light	2451814.35 26. September 2000, 20:24:00 UT

double/multiple star system information:

source of data: 19

separation between brightest and second brightest component	87 arcsec
magnitude difference between brightest and second brightest component	6.7
position angle	84 °

component	magnitude	spectral class	catalogue(s)/name(s)
A	3.7	G0P	Mekbuda, z Geminorum, 43 Gem, HR 2650, HD 52973, SAO 79031
B	7.58	G5

sources:

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
29	SAOJ2000
SAO on FK5 at J2000, 1989
30	GCVS, 4th edition
Kholopov, P.N., et al., General Catalogue of Variable Stars, fourth edition, Moscow: Nauka Publishing House, 1985-88
31	CRM' (non-GCVS variable data)
Warren, W.H. Jr., Northern Hemisphere Catalog of Red Magnitudes, 1994

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

position and proper motion:

position (B1950)	RA: 7h 1min 8.627sec	DEC: +20° 38' 43.45''	±0.003 arcsec
position (2000.72)	RA: 7h 4min 10sec	DEC: +20° 34' 9''	JD: 2451806.24
position (J2000)	RA: 7h 4min 6.521sec	DEC: +20° 34' 12.99''
proper motion B1950 (FK4)	RA: -0.0006 arcsec/a	DEC: -0.003 arcsec/a	±0.001 arcsec/a in RA ±0.001 arcsec/a in DEC
proper motion J2000 (FK5)	RA: -0.0007 arcsec/a	DEC: 0 arcsec/a
source of proper motion data	Determined by source catalog

magnitude:

visual	3.9 (accuracy: 2 decimals)
source of visual magnitude data	Arithmetic mean of maximum and minimum magnitudes of a variable star

spectral information:

spectral class	G0p
source of spectral data	Taken from the Henry Draper Catalogue or no spectrum in source catalog.

remarks for duplicity and variability

Variable star in visual magnitude in source catalog

catalogues

source catalogue	FK4, catalogue number: 269
Durchmusterung	BD+20 1687
Boss General Catalogue	9313
Henry Draper Catalogue	52973

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

position and proper motion:

position (J2000)	RA: 7h 4.1min	DEC: +20° 34'
proper motion (J2000)	RA: -0.009 arcsec/a	DEC: -0.001 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	1880	10	84°	87''	3.8	10.5	F7-G3Ib	SHJ 77
AC	1821	19	355°	91''	3.8	7.56	-	SHJ 77
	1984		348°	99.8''
Aa	1905	2	83°	80''	-	12	-	SHJ 77
	1984		352°	70.3''
BC	1913	1	310°	133''	10.6	8.7	-	SHJ 77
CR	1907	1	166°	27.2''	7.56	12.9	G0	SHJ 77

discoverer information:

discoverer code	discoverer	reference
SHJ 77	South & Herschel	-

notes:

note	Zeta Gem. A is a Cepheid, and an occultation double.

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

position:

position (equinox 1950.0)

RA: 7h 1min 8.6sec

DEC: +20° 38' 43''

variability informations:

variability type	DCEP	pulsating variable star
magnitute at max. brightness	3.62
magnitute at min. brightness	4.18
photometric system	visual, photovisual or Johnson's V
epoch for maximum light [JD]	2443805.927 24. October 1978, 10:14:53 UT
period [d]	10.15073
next maximum light [JD]	2451814.85297 27. September 2000, 08:28:17 UT
rising time	50 % of period

spectral information

spectral class

F7Ib-G3Ib

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	38/9006
constellation	Gemini
notes on existence	The star is equivalent to '0389007 eta'.
There are notes in published catalog.

variability type description

variability type

description

DCEP

These are the classical cepheids, or Delta Cep-type variables. Comparatively young objects that have left the main sequence and evolved into the instability strip of the Hertzsprung-Russell (H-R) diagram, they obey the well-known Cepheid period-luminosity relation and belong to the young disk population. DCEP stars are present in open clusters. They display a certain relation between the shapes of their light curves and their periods.