Brachium

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

note (category: star names):

Brachium; Cornu; Zuben el Genubi; Zuban al Akrab; Zuben Hakrabi. Sigma Lib is also Gamma Sco, in Lib.

position, motion, parallax:

position (J2000)	RA: 15h 4min 4.2sec	DEC: -25° 16' 55''
position (B1900)	RA: 14h 58min 12.9sec	DEC: -24° 53' 20''
proper motion (J2000)	RA: -0.073 arcsec/a	DEC: -0.043 arcsec/a
radial velocity	-4 km/s
trigonometric parallax	0.064 arcsec
galactic coordinates	longitude: 337.22°	latitude: 28.62°

magnitude

visual magnitude

3.29
(V on UBV Johnson system)

spectral / color information

spectral class	M3-III
B-V-magnitude	1.7
U-B-magnitude	1.94
R-I-magnitude
IR-note	object is infrared source (NASA merged infrared catalogue, Schmitz et al., 1978)

note (category: spectra):

Ultraviolet FeII emission.

variability information

variable star identification

Sig Lib

note (category: variability):

SRb 3.20 - 3.46V, 20d.

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

position, motion, parallax:

position (J2000)	RA: 15h 4min 4.218sec	DEC: -25° 16' 55.12''	±0.06 arcsec	source: 15
proper motion (J2000)	RA: -0.0054 arcsec/a	DEC: -0.043 arcsec/a		source: 25
radial velocity	-4 km/s			source: 25
trigonometric parallax	0.064 arcsec		±0.006 arcsec	source: 25
galactic coord. (B1950)	longitude: 337.23°	latitude: 28.62°

magnitude:

visual	3.2 (observed)	source: 30
photovisual	3.4	source: 2

spectral information:

spectral class	M0		source: 96
Morgan-Keenan	M2.5III		source: 25
B-magnitude	4.99 ±0.05	B-V-magnitude	1.7
U-magnitude	6.93 ±0.05	U-B-magnitude	1.94

variability information:

source of data: 30

variability type	194
var. amplitude	0.26
var. period	20

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
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 (B1950)	RA: 15h 1min 8.247sec	DEC: -25° 5' 12.27''	±0.005 arcsec
position (J2000)	RA: 15h 4min 4.215sec	DEC: -25° 16' 55.14''
proper motion B1950 (FK4)	RA: -0.0054 arcsec/a	DEC: -0.047 arcsec/a	±0.001 arcsec/a in RA ±0.001 arcsec/a in DEC
proper motion J2000 (FK5)	RA: -0.0054 arcsec/a	DEC: -0.043 arcsec/a
source of proper motion data	Determined by source catalog

magnitude:

visual	3.4 (accuracy: 2 decimals)
source of visual magnitude data	Taken from the "Henry Draper Catalogue".

spectral information:

spectral class	M3
source of spectral data	Taken from the Henry Draper Catalogue or no spectrum in source catalog.

catalogues

source catalogue	FK4, catalogue number: 556
Durchmusterung	CD-2411834
Boss General Catalogue	20253
Henry Draper Catalogue	133216

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

position:

position (equinox 1950.0)

RA: 15h 1min 8.2sec

DEC: -25° 5' 12''

variability informations:

variability type	SRB	pulsating variable star
magnitute at max. brightness	3.2
magnitute at min. brightness	3.46
photometric system	visual, photovisual or Johnson's V
period [d]	20

spectral information

spectral class

M3.5IIIa

references

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 'Cordoba Durchmusterung'

miscanellous

ID in the GCVS catalogue	49/9018
constellation	Libra
notes on existence	The star is equivalent to '0500001 R'.

variability type description

variability type

description

SRB

Semiregular variables, which are giants or supergiants of intermediate and late spectral types showing noticeable periodicity in their light changes, accompanied or sometimes interrupted by various irregularities. Periods lie in the range from 20 to >2000 days, while the shapes of the light curves are rather different and variable, and the amplitudes may be from several hundredths to several magnitudes (usually 1-2 mag in V).

SRA
Semiregular late-type (M, C, S or Me, Ce, Se) giants displaying persistent periodicity and usually small (<2.5 mag in V) light amplitudes (Z Aqr). Amplitudes and light-curve shapes generally vary and periods are in the range of 35-1200 days. Many of these stars differ from Miras only by showing smaller light amplitudes;

SRB
Semiregular late-type (M, C, S or Me, Ce, Se) giants with poorly defined periodicity (mean cycles in the range of 20 to 2300 days) or with alternating intervals of periodic and slow irregular changes, and even with light constancy intervals (RR CrB, AF Cyg). Every star of this type may usually be assigned a certain mean period (cycle), which is the value given in the Catalogue. In a number of cases, the simultaneous presence of two or more periods of light variation is observed;

SRC
Semiregular late-type (M, C, S or Me, Ce, Se) supergiants (Mu Cep) with amplitudes of about 1 mag and periods of light variation from 30 days to several thousand days;

SRD
Semiregular variable giants and supergiants of F, G, or K spectral types, sometimes with emission lines in their spectra. Amplitudes of light variation are in the range from 0.1 to 4 mag, and the range of periods is from 30 to 1100 days (SX Her, SV UMa).

catalogues and names	Brachium, s Lib, sig Lib, 20 Lib, HR 5603, HD 133216, SAO 183139, CD -24 11834, FK5: 556
other names	Cornu, Zuben el Genubi, Zuban al Akrab, Zuben Hakrabi
constellation	Libra