Acrux

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

note (category: star names):

ACRUX.

position, motion, parallax:

position (J2000)	RA: 12h 26min 35,9sec	DEC: -63° 5' 57''
position (2001,18)	RA: 12h 26min 40sec	DEC: -63° 6' 21''
position (B1900)	RA: 12h 21min 2sec	DEC: -62° 32' 41''
proper motion (J2000)	RA: -0,036 arcsec/a	DEC: -0,012 arcsec/a
radial velocity	-11 km/s note: spectroscopic binaries note: orbital data avaible
rotational velocity	117 km/s (uncertain) (variable)
dynamical parallax	0,008 arcsec
galactic coordinates	longitude: 300,13°	latitude: -0,36°

magnitude

visual magnitude

1,33
(V on UBV Johnson system)

spectral / color information

spectral class	B0.5IV
B-V-magnitude	-0,24
U-B-magnitude	-1,03

double/multiple star system information

number of components of multiple star system	3
separation	4,4 arcsec
mag difference (of double or brightest multiple)	0,4
component ID	AB
note	Worley (1978) update of the IDS

note (category: double and multiple data):

AB 1.35 B0.5IV, 1.75 B3n or B0.5Vn, q = 0.916". Mag. and colors for blend of HR 4730-31, 0.76V, -0.25(B-V), -1.00(U-B), -0.24(R-I). Masses 14 and 10 solar for hyperbolic orbit with periastron distance 61 AU.

note (category: spectroscopic binaries):

Primary of visual double, 75.769d, K 32.8k/s, V0 +7.5, asini 30.0.

miscellaneous information

note (category: group membership):

HII region. Although there is disagreement in the RV of HR 4730, 4731, they are both members of the Sco-Cen assoc.

note (category: miscellaneous):

Possibly X-ray source 2U1223-62.

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

position, motion, parallax:

position (J2000)	RA: 12h 26min 35,871sec	DEC: -63° 5' 56,58''	ą0,06 arcsec	source: 15
position (2001,18)	RA: 12h 26min 40sec	DEC: -63° 6' 21''	JD: 2451975,79
proper motion (J2000)	RA: -0,0052 arcsec/a	DEC: -0,012 arcsec/a		source: 15
radial velocity	-11 km/s			source: 25
galactic coord. (B1950)	longitude: 300,13°	latitude: -0,36°

magnitude:

visual	1,33 (observed)	source: 25
photovisual	1,6	source: 2
photographic	1,4	source: 2

spectral information:

spectral class	B1		source: 96
Morgan-Keenan	B0.5IV		source: 25
B-magnitude	1,09 ą0,05	B-V-magnitude	-0,24
U-magnitude	0,06 ą0,05	U-B-magnitude	-1,03

double/multiple star system information:

source of data: 19

separation between brightest and second brightest component	4 arcsec
magnitude difference between brightest and second brightest component	0,5
position angle	112 °

component	magnitude	spectral class	catalogue(s)/name(s)
A	1,33	B1	Acrux, a¹Crucis, HR 4730, HD 108248, SAO 251904
B	1,73	-	a²Crucis, HR 4731, HD 108249,

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 (B1950)	RA: 12h 23min 48,064sec	DEC: -62° 49' 19,43''	ą0,01 arcsec
position (2001,18)	RA: 12h 26min 40sec	DEC: -63° 6' 18''	JD: 2451975,79
position (J2000)	RA: 12h 26min 35,948sec	DEC: -63° 5' 56,5''
proper motion B1950 (FK4)	RA: -0,0036 arcsec/a	DEC: -0,017 arcsec/a	ą0,002 arcsec/a in RA ą0,002 arcsec/a in DEC
proper motion J2000 (FK5)	RA: -0,0044 arcsec/a	DEC: -0,012 arcsec/a
source of proper motion data	Determined by source catalog

magnitude:

visual	1,6 (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.

catalogues

source catalogue	FK4, catalogue number: 462
Durchmusterung	CP-62 2745A
Boss General Catalogue	16952
Henry Draper Catalogue	108248 The "SAO Catalog" entry refers to two consecutive HD numbers, the lower of which is given.

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

position and proper motion:

position (J2000)	RA: 12h 26,6min	DEC: -63° 6'
proper motion (J2000)	RA: -0,036 arcsec/a	DEC: -0,012 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	1826	73	121°	5,6''	1,3	1,8	B1V	DUN 252
AB	1994	73	112°	4''	1,3	1,8	B1V	DUN 252
AC	1826	13	202°	90,1''	1,3	4,86	B4IV	DUN 252
AC	1976	13	204°	89,8''	1,3	4,86	B4IV	DUN 252
BC	1859	1	205°	90''	2,3	6	-	DUN 252

discoverer information:

discoverer code	discoverer	reference
DUN 252	Dunlop, J.	-

notes:

note	Alpha (1) Cru. Spectroscopic binary. Common proper motion with HR 4729 and 4731, so that there are at least five components in the system.

catalogues and names	Acrux, a¹Cru, HR 4730, HD 108248, SAO 251904, CP -62 2745 A, FK5: 462, WDS 12266-6306A
constellation	Crux