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 Murzim, b CMa, bet CMa, 2 CMa, HR 2294, HD 44743, SAO 151428, FK5: 243, WDS 06227-1757
other names Mirzam, Mirza
constellation Canis Major

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

note (category: star names): Murzim; Mirzam; Mirza.

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

position, motion, parallax:

position (J2000) RA: 6h 22min 42sec DEC: -17 57' 21''
position (J1900) RA: 6h 18min 17,7sec DEC: -17 54' 22''
proper motion (J2000) RA: -0,006 arcsec/a DEC: 0 arcsec/a
radial velocity 34 km/s
note: spectroscopic binaries
rotational velocity 36 km/s (uncertain) (variable)
trigonometric parallax 0,019 arcsec
note (category: radial and/or rotational velocities): 0.25002246 and 49d.


visual magnitude 1,98
(V on UBV Johnson system)

spectral / color information

spectral class B1II-III
B-V-magnitude -0,23
U-B-magnitude -0,98
R-I-magnitude -0,24
note (category: spectra): Lyman alpha and Lyman beta observed from COPERNICUS.
note (category: colors): Color excess E(B-V) = +0.01.

variability information

variable star identification Bet CMa
note (category: variability): Beta C 1.93 - 2.00V. Prototype star. Multi-periodic: 0.25002246, 0.2513003, 49.17 and 0.23904d, others reported. Beat periods 49.198, 5.442 and 4.900d. Sp. also var. over 0.25d.

double/multiple star system information

separation 185,9 arcsec
mag difference (of double or brightest multiple) 7,8
note Worley (1978) update of the IDS

miscellaneous information

note (category: stellar radii or diameters): Diam. = 0.00050 - 0.00052".

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

position, motion, parallax:

position (J2000) RA: 6h 22min 41,969sec DEC: -17 57' 21,37'' 0,06 arcsec source: 15
proper motion (J2000) RA: -0,0004 arcsec/a DEC: 0 arcsec/a source: 25
radial velocity 34 km/s source: 25
trigonometric parallax 0,019 0,002 arcsec source: 25
galactic coord. (B1950) longitude: 226,06 latitude: -14,27
GCI unit vector (J2000) X: -0,094067 Y: 0,946632 Z: -0,308285


visual 1,93 (observed) source: 30
photovisual 2 source: 2
photographic 1,8 source: 2

spectral information:

spectral class B1 source: 96
Morgan-Keenan B1II-III source: 25
B-magnitude 1,75 0,05 B-V-magnitude -0,23
U-magnitude 0,77 0,05 U-B-magnitude -0,98

variability information:

source of data: 30
variability type 140
var. amplitude 0,07
var. period 0,25
var. epoch 2441296
10. December 1971, 12:00:00 UT
next max light 2451620,5
17. March 2000, 00:00:00 UT

double/multiple star system information:

source of data: 19
separation between brightest and second brightest component 185,9 arcsec
magnitude difference between brightest and second brightest component 7,8
position angle 340


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
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
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 (J1950) RA: 6h 20min 29,789sec DEC: -17 55' 47,23'' 0,005 arcsec
position (J2000) RA: 6h 22min 41,966sec DEC: -17 57' 21,59''
proper motion J1950 (FK4) RA: -0,0009 arcsec/a DEC: -0,004 arcsec/a 0,001 arcsec/a in RA
0,001 arcsec/a in DEC
proper motion J2000 (FK5) RA: -0,0005 arcsec/a DEC: -0,002 arcsec/a
source of proper motion data Determined by source catalog


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

spectral information:

spectral class B1
source of spectral data Taken from the Henry Draper Catalogue or no spectrum in source catalog.


source catalogue FK4, catalogue number: 243
Durchmusterung BD-17 1467
Boss General Catalogue 8223
Henry Draper Catalogue 44743

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

position and proper motion:

position (J2000) RA: 6h 22,7min DEC: -17 57'
proper motion (J2000) RA: -0,006 arcsec/a DEC: 0 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
- 1879 2 339 185'' 1,98 9,8 B1II-III BUP 88
1908 340 185,9''

discoverer information:

discoverer code discoverer reference
BUP 88 - -


note Beta CMa. Prototype of its class of variable. B is BD-17@1466.

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


position (J1950) RA: 6h 20min 29,8sec DEC: -17 55' 47''

variability informations:

variability type BCEP pulsating variable star
magnitute at max. brightness 1,93
magnitute at min. brightness 2
photometric system visual, photovisual or Johnson's V
epoch for maximum light [JD] 2441296,175
10. December 1971, 16:12:00 UT
period [d] 0,25003
next maximum light [JD] 2451620,41376
16. March 2000, 21:55:49 UT

spectral information

spectral class B1II-III


to a study Vol. I GCVS (see Kholopov et al. 1985-1988)
to a chart/photograph no chart is avaible, but the star is contained in the 'Bonner Durchmusterung'


ID in the GCVS catalogue 14/9002
constellation Cancer
notes on existence The star is equivalent to '0149009 iot'.
There are notes in published catalog.

variability type description

variability type description
BCEP Variables of the Beta Cephei type (Beta Cep, Beta CMa), which are pulsating O8-B6 I-V stars with periods of light and radial-velocity variations in the range of 0.1 - 0.6 days and light amplitudes from 0.01 to 0.3 mag in V. The light curves are similar in shape to average radial-velocity curves but lag in phase by a quarter of the period, so that maximum brightness corresponds to
maximum contraction, i.e., to minimum stellar radius. The majority of these stars probably show radial pulsations, but some (V649 Per) display nonradial pulsations; multiperiodicity is characteristic of many of these stars.