The object was found in the following catalogues:
  1. The Bright Star Catalogue, 5th Revised Ed. (Preliminary Version)

  2. SKY2000 - Master Star Catalog

  3. Smithsonian Astrophysical Observatory Star Catalog

  4. The Washington Visual Double Star Catalog, 1996.0

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

catalogues and names Mekbuda, z Gem, zet Gem, 43 Gem, HR 2650, HD 52973, SAO 79031, 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.

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

position, motion, parallax:

position (J2000) RA: 7h 4min 6,5sec DEC: +20 34' 13''
position (J1900) 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
note (category: radial and/or rotational velocities): Same period.


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 0,41

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
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
GCI unit vector (J2000) X: -0,25849 Y: 0,899851 Z: 0,351356


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 2451621,5
18. March 2000, 00:00:00 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


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 (J1950) RA: 7h 1min 8,627sec DEC: +20 38' 43,45'' 0,003 arcsec
position (J2000) RA: 7h 4min 6,521sec DEC: +20 34' 12,99''
proper motion J1950 (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


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


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 -


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 (J1950) 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] 2451621,9891
18. March 2000, 11:44:18 UT
rising time 50 % of period

spectral information

spectral class F7Ib-G3Ib


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)


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.