Castor

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

note (category: star names):

CASTOR; Apollo.

position, motion, parallax:

position (J2000)	RA: 7h 34min 36sec	DEC: +31° 53' 18''
position (2000.72)	RA: 7h 34min 39sec	DEC: +31° 53' 12''
position (B1900)	RA: 7h 28min 13sec	DEC: +32° 6' 27''
proper motion (J2000)	RA: -0.171 arcsec/a	DEC: -0.098 arcsec/a
radial velocity	6 km/s note: spectroscopic binaries, single lined spectra note: orbital data avaible
rotational velocity	14 km/s (uncertain) (variable)
trigonometric parallax	0.067 arcsec
galactic coordinates	longitude: 187.44°	latitude: 22.48°

note (category: dynamical parallaxes):

0.052".

magnitude

visual magnitude

1.98
(V on UBV Johnson system)

spectral / color information

spectral class	A1V
B-V-magnitude	0.03
U-B-magnitude	0.01
R-I-magnitude
IR-note	object is infrared source (NASA merged infrared catalogue, Schmitz et al., 1978)

variability information

variable star identification

YY Gem

note (category: variability):

ADS 6175C at 73" from A, EA 8.91 - 9.60V, 0.81428254d = also SB period. Masses each component 0.64 solar. Both components flare stars, M1Ve + M1Ve.

double/multiple star system information

number of components of multiple star system	6
separation	2 arcsec
mag difference (of double or brightest multiple)	0.9
component ID	AB

note (category: double and multiple data):

AB 1.98 A1V, 2.88 A5Vm, 511.30y, a = 7.369 or 420.07y, a = 6.295". C, 8.8v M1Ve at 73" is physical member of sextuple system in which A,B,C are all SB.

note (category: spectroscopic binaries):

ADS 6175A, 9.2128d, K 12.9k/s, V0 +5.2k/s, asini 1.42. ADS 6175C, 0.8143d, K 120k/s, V0 +0.9k/s, asini 1.34. Two spectra.

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

position, motion, parallax:

position (J2000)	RA: 7h 34min 35.864sec	DEC: +31° 53' 17.63''	ą0.06 arcsec	source: 15
position (2000.72)	RA: 7h 34min 39sec	DEC: +31° 53' 12''	JD: 2451809.27
proper motion (J2000)	RA: -0.0135 arcsec/a	DEC: -0.099 arcsec/a		source: 25
radial velocity	6 km/s			source: 25
trigonometric parallax	0.067 arcsec		ą0.007 arcsec	source: 25
galactic coord. (B1950)	longitude: 187.45°	latitude: 22.48°

magnitude:

visual	1.98 (observed)	source: 25
photovisual	2	source: 2
photographic	2	source: 2

spectral information:

Morgan-Keenan	A1V		source: 25
B-magnitude	2.01 ą0.05	B-V-magnitude	0.03
U-magnitude	2.02 ą0.05	U-B-magnitude	0.01

double/multiple star system information:

source of data: 19

separation between brightest and second brightest component	3.3 arcsec
magnitude difference between brightest and second brightest component	0.9
position angle	73 °

component	magnitude	spectral class	catalogue(s)/name(s)
A	1.98	-	Castor, a Geminorum, 66 Gem, HR 2891, HD 60179,
B	2.88	A0	Castor, a Geminorum, 66 Gem, HR 2890, HD 60178, SAO 60198

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

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

position and proper motion:

position (J2000)	RA: 7h 34.6min	DEC: +31° 53'
proper motion (J2000)	RA: -0.172 arcsec/a	DEC: -0.099 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	1819	often	270°	4.5''	2	2.9	A1V A2Vm	STF1110
	1992		73°	3.3''
AC	1835	often	164°	72.5''	2	8.8	-	STF1110
	1990		-	71.2''
AD	1902	2	222°	204.4''	2	-	-	STF1110
BC	1862	16	160°	70.4''	2.9	8.7	-	STF1110
	1957		163°	69.5''

discoverer information:

discoverer code	discoverer	reference
STF1110	Struve, F.G.W.	-

notes:

note	Alpha Gem. Castor. Mt. Wilson spectral types A2,A2,M1. P = 467yr., a = 6.80", motion retrograde. A and B are both spectroscopic binaries, and C is the eclipsing binary YY Gem, P =0.81d, so the object is sextuple. Castor A is also reported to exhibit x-ray and radio emission.

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

position:

position (B1900)

RA: 7h 28.2min

DEC: +32° 6'

magnitudes, spectral classes, orbital elements:

author:	P. Muller	W. Rabe
date of observation:		1957
magnitude of component A:	1.94	1.94
magnitude of component B:	1.94	1.94
spectral class component B:	A1V	A1V
spectral class component B:	A1V	A1V
period [y]:	511.3	420.07
semi-major axis [arcsec]:	7.369	6.295
inclination [deg]:	112.94	115.94
node [deg]:	41.65 (ascending)	40.47 (ascending)
equinox of node:		1900
eccentricity:	0.36	0.33
time of periastron passage:	1950.65	1965.3
dates of ephemeris:	1950-1970	1957-1967
grade:	reliable	reliable
reference:	Bull. Astron. 20, 145; 1956.	Astron. Nachr. 284, 101; 1958.

notes

Castor, a sextuple system. Both A and B are single-lined spectroscopic binaries with P = 9.21 d and 2.93 d, respectively. Star C (mag. 9.1, M1Ve) is the spectroscopic and detached eclipsing binary YY Gem (P = 0.81 d), 70" from the center of AB and in slow retrograde motion (cf. Heintz, Veroff. Sternw. Munchen 5, 93; 1960).

other name(s)

STF 1110, Castor

catalogues and names	Castor, a Gem, 66 Gem, HR 2891, HD 60179, WDS 07346+3153A
constellation	Gemini