Alhena


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. 4th Catalog of Orbits of Visual Binaries


catalogues and names Alhena, g Gem, 24 Gem, HR 2421, HD 47105, SAO 95912, FK5: 251, WDS 06377+1624A
constellation Gemini

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

note (category: star names): ALHENA.

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

position, motion, parallax:

position (J2000) RA: 6h 37min 42,7sec DEC: +16 23' 57''
position (J1900) RA: 6h 31min 56,1sec DEC: +16 29' 5''
proper motion (J2000) RA: 0,042 arcsec/a DEC: -0,042 arcsec/a
radial velocity -13 km/s
note: spectroscopic binaries
rotational velocity 32 km/s (uncertain) (variable)
trigonometric parallax 0,033 arcsec

magnitude

visual magnitude 1,93
(V on UBV Johnson system)

spectral / color information

spectral class A0IV
B-V-magnitude 0
U-B-magnitude 0,04
R-I-magnitude -0,01
note (category: colors): Color excess E(B-V) = +0.03.

double/multiple star system information

number of components of multiple star system 3
separation 143,5 arcsec
mag difference (of double or brightest multiple) 9
component ID AC
note Worley (1978) update of the IDS
note (category: double and multiple data): A* 1.93 A0IV, 12.9y, a = 0.038".
note (category: spectroscopic binaries): 12.4y. Unresolved by speckle interferometry. RV also var. 0.13d.

miscellaneous information

note (category: stellar radii or diameters): Diam. = 0.00132 - 0.00139".

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

position, motion, parallax:

position (J2000) RA: 6h 37min 42,725sec DEC: +16 23' 57,43'' 0,06 arcsec source: 15
proper motion (J2000) RA: 0,0029 arcsec/a DEC: -0,042 arcsec/a source: 25
radial velocity -12 km/s source: 25
trigonometric parallax 0,033 0,003 arcsec source: 25
galactic coord. (B1950) longitude: 196,78 latitude: 4,45
GCI unit vector (J2000) X: -0,157144 Y: 0,946359 Z: 0,28233

magnitude:

visual 1,93 (observed) source: 25
photovisual 1,9 source: 2

spectral information:

spectral class A0 source: 96
Morgan-Keenan A1IV source: 25
B-magnitude 1,93 0,05 B-V-magnitude 0
U-magnitude 1,97 0,05 U-B-magnitude 0,04

double/multiple star system information:

source of data: 19
separation between brightest and second brightest component 135,5 arcsec
magnitude difference between brightest and second brightest component 9,3
position angle 295

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
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
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 34min 49,396sec DEC: +16 26' 37,4'' 0,004 arcsec
position (J2000) RA: 6h 37min 42,727sec DEC: +16 23' 57,4''
proper motion J1950 (FK4) RA: 0,003 arcsec/a DEC: -0,044 arcsec/a 0,001 arcsec/a in RA
0,001 arcsec/a in DEC
proper motion J2000 (FK5) RA: 0,003 arcsec/a DEC: -0,042 arcsec/a
source of proper motion data Determined by source catalog

magnitude:

visual 1,9 (accuracy: 2 decimals)
source of visual magnitude data Taken from the "Henry Draper Catalogue".

spectral information:

spectral class A0
source of spectral data Taken from the Henry Draper Catalogue or no spectrum in source catalog.

catalogues

source catalogue FK4, catalogue number: 251
Durchmusterung BD+16 1223
Boss General Catalogue 8633
Henry Draper Catalogue 47105

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

position and proper motion:

position (J2000) RA: 6h 37,7min DEC: +16 24'
proper motion (J2000) RA: 0,042 arcsec/a DEC: -0,042 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 2 295 133'' 1,93 11,2 A0IV BUP 90
1907 - 135,5''
AC 1880 2 336 141,7'' 1,93 10,9 - BUP 90
1907 335 143,5''

discoverer information:

discoverer code discoverer reference
BUP 90 - -

notes:

note H V 71. Gamma Gem. A is a long-period spectroscopic pair, P = 12.4yr.

data from 4th Catalog of Orbits of Visual Binaries (Worley+, 1983)

position:

position (J1900) RA: 6h 31,9min DEC: +16 29'

magnitudes, spectral classes, orbital elements:

author: W.R. Beardsley
date of observation: 1958
magnitude of component A: 1,93
magnitude of component B: 1,93
spectral class component B: A0IV
spectral class component B: A0IV
period [y]: 12,9
semi-major axis [arcsec]: 0,038
inclination [deg]: 39
node [deg]: 115
eccentricity: 0,8
time of periastron passage: 1941,9
reference: IAU Symposium No. 30, 189; 1967.
notes Elements P, T, e, and the longitude of periastron are from a spectroscopic orbit. Beardsley's data are inconsistent; the values of a, i, and the node given here approximate his ABFG most closely.