Alamak

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

note (category: star names):

ALMAAK; Almach; Alamak; Almak; Almaach.

position, motion, parallax:

position (J2000)	RA: 2h 3min 54sec	DEC: +42° 19' 47''
position (B1900)	RA: 1h 57min 45.4sec	DEC: +41° 51' 0''
proper motion (J2000)	RA: 0.045 arcsec/a	DEC: -0.052 arcsec/a
radial velocity	-12 km/s note: spectroscopic binaries
rotational velocity	<17 km/s (uncertain) (variable)
trigonometric parallax	0.013 arcsec
galactic coordinates	longitude: 136.96°	latitude: -18.56°

magnitude

visual magnitude

2.26
(V on UBV Johnson system)

spectral / color information

spectral class	K3-IIb
B-V-magnitude	1.37
U-B-magnitude	1.58
R-I-magnitude
IR-note	object is infrared source (NASA merged infrared catalogue, Schmitz et al., 1978)

double/multiple star system information

number of components of multiple star system	4
separation	9.6 arcsec
mag difference (of double or brightest multiple)	2.8
component ID	AxBC

note (category: double and multiple data):

CPM with HR 604.

miscellaneous information

note (category: group membership):

Red star Pleiades group.

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

position, motion, parallax:

position (J2000)	RA: 2h 3min 53.963sec	DEC: +42° 19' 46.99''	±0.06 arcsec	source: 15
proper motion (J2000)	RA: 0.004 arcsec/a	DEC: -0.052 arcsec/a		source: 25
radial velocity	-12 km/s			source: 25
trigonometric parallax	0.013 arcsec		±0.001 arcsec	source: 25
galactic coord. (B1950)	longitude: 136.97°	latitude: -18.56°

magnitude:

visual	2.26 (observed)	source: 25
photovisual	2.3	source: 2

spectral information:

spectral class	K0		source: 96
Morgan-Keenan	K3-IIb		source: 25
B-magnitude	3.63 ±0.05	B-V-magnitude	1.37
U-magnitude	5.21 ±0.05	U-B-magnitude	1.58

double/multiple star system information:

source of data: 19

separation between brightest and second brightest component	9.6 arcsec
magnitude difference between brightest and second brightest component	2.58
position angle	63 °

component	magnitude	spectral class	catalogue(s)/name(s)
A	2.26	K0	Alamak, g¹Andromedae, 57 And, HR 603, HD 12533, SAO 37734
B	4.84	A0	g²Andromedae, 57 And, HR 604, HD 12534, SAO 37735

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: 2h 0min 49.177sec	DEC: +42° 5' 27.01''	±0.003 arcsec
position (J2000)	RA: 2h 3min 53.977sec	DEC: +42° 19' 46.96''
proper motion B1950 (FK4)	RA: 0.0041 arcsec/a	DEC: -0.048 arcsec/a	±0.001 arcsec/a in RA ±0.001 arcsec/a in DEC
proper motion J2000 (FK5)	RA: 0.0042 arcsec/a	DEC: -0.052 arcsec/a
source of proper motion data	Determined by source catalog

magnitude:

visual	2.3 (accuracy: 2 decimals)
source of visual magnitude data	Taken from the "Henry Draper Catalogue".

spectral information:

spectral class	K0
source of spectral data	Taken from the Henry Draper Catalogue or no spectrum in source catalog.

catalogues

source catalogue	FK4, catalogue number: 73
Durchmusterung	BD+41 395A
Boss General Catalogue	2477
Henry Draper Catalogue	12533

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

position and proper motion:

position (J2000)	RA: 2h 3.9min	DEC: +42° 20'
proper motion (J2000)	RA: 0.045 arcsec/a	DEC: -0.052 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
A-BC	1830	often	63°	10.3''	2.26	4.84	K3IIb	STF 205
A-BC	1987	often	-	9.6''	2.26	4.84	K3IIb	STF 205
AD	1898	1	245°	27.9''	-	15	K3IIb	BAR 22
BC	1842	often	°	''	5.1	6.3	B8V+A0V	STT 38

discoverer information:

discoverer code	discoverer	reference
STF 205	Struve, F.G.W.	-
BAR 22	Barnard, E.E.	-
STT 38	Struve, O.	-

notes:

note	H III 5, SHJ 26. Gamma And. BC: P = 61yr., a = -.30", motion retrograde. B is a spectroscopic binary.

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

position:

position (B1900)

RA: 1h 57.8min

DEC: +41° 51'

magnitudes, spectral classes, orbital elements:

author:	P. Muller
date of observation:	1955
magnitude of component A:	5.3
magnitude of component B:	5.3
spectral class component B:	B8V
spectral class component B:	B8V
period [y]:	61.1
semi-major axis [arcsec]:	0.296
inclination [deg]:	111.1
node [deg]:	104.15
equinox of node:	1950
eccentricity:	0.93
time of periastron passage:	1952.1
dates of ephemeris:	1950-1970
grade:	good
reference:	J. Observateurs 40, 52; 1957.

notes

A quadruple system. Star A (mag. 2.3, K3II) forms with BC the pair STF 205, separation 10". Star B is a spectroscopic binary, P = 2.67 d (Maestre and Wright, Astrophys. J. 131, 119; 1960).

other name(s)

STT 38 BC

catalogues and names	Alamak, g¹And, 57 And, HR 603, HD 12533, SAO 37734, BD +41 395 A, FK5: 73, WDS 02039+4220A
other names	Almaak, Almach, Almak, Almaach
constellation	Andromeda