V0637 Herculis

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

position, motion, parallax:

position (J2000)	RA: 16h 49min 14.2sec	DEC: +45° 59' 0''
position (B1900)	RA: 16h 46min 18.5sec	DEC: +46° 9' 27''
proper motion (J2000)	RA: 0.026 arcsec/a	DEC: -0.055 arcsec/a
radial velocity	-1 km/s note: variable radial velocity
rotational velocity	31 km/s (uncertain) (variable)
trigonometric parallax	0.01 arcsec
galactic coordinates	longitude: 71.61°	latitude: 39.96°

note (category: dynamical parallaxes):

0.024".

magnitude

visual magnitude

4.82
(V on UBV Johnson system)

spectral / color information

spectral class	A2VpSrCrEu
B-V-magnitude	0.09
U-B-magnitude	0.04
R-I-magnitude

note (category: spectra):

Oxygen deficient relative to magnesium. Magnetic star, also classified A3VpSrCrEuMn.

variability information

variable star identification

V637 Her

note (category: variability):

ADS 10227A, Alpha CV 4.78 - 4.83V, 3.8567d. K line varies, 3.88d.

double/multiple star system information

number of components of multiple star system	5
separation	1.8 arcsec
mag difference (of double or brightest multiple)	4.6
component ID	AxBC

note (category: double and multiple data):

BC 9.0, 9.1, 56.75y, a = 0.267". AxBC physical.

miscellaneous information

note (category: group membership):

Sirius group. UMa stream.

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

position, motion, parallax:

position (J2000)	RA: 16h 49min 14.215sec	DEC: +45° 58' 59.96''	ą0.35 arcsec	source: 17
proper motion (J2000)	RA: 0.0022 arcsec/a	DEC: -0.052 arcsec/a		source: 25
radial velocity	-1 km/s			source: 25
trigonometric parallax	0.01 arcsec		ą0.001 arcsec	source: 25
galactic coord. (B1950)	longitude: 71.61°	latitude: 39.96°

magnitude:

visual	4.8 (observed)	source: 31
photovisual	4.9	source: 2
photographic	4.9	source: 16

spectral information:

spectral class	A2		source: 96
Morgan-Keenan	A2VpSrCrEu		source: 25
B-magnitude	4.91 ą0.05	B-V-magnitude	0.09
U-magnitude	4.95 ą0.05	U-B-magnitude	0.04

variability information:

source of data: 30

variability type	160
var. amplitude	0.07
var. period	3.86

double/multiple star system information:

source of data: 19

separation between brightest and second brightest component	1.7 arcsec
magnitude difference between brightest and second brightest component	5.5
position angle	18 °

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
16	PPM North and PPM South Catalogs and PPM Supplement
Roser, S., and U. Bastian, "Catalogue of Positions and Proper Motions," A&AS, Vol. 74, p. 449, 1988, and Bastian, U., et al., "Catalogue of Positions and Proper Motions - South," 1993
17	ACRS
Corbin, T.E., and S.E. Urban, Astrographic Catalog Reference Stars, United States Naval Observatory, 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
30	GCVS, 4th edition
Kholopov, P.N., et al., General Catalogue of Variable Stars, fourth edition, Moscow: Nauka Publishing House, 1985-88
31	CRM' (non-GCVS variable data)
Warren, W.H. Jr., Northern Hemisphere Catalog of Red Magnitudes, 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: 16h 47min 46.246sec	DEC: +46° 4' 10.06''	ą0.018 arcsec
position (J2000)	RA: 16h 49min 14.249sec	DEC: +45° 58' 59.82''
proper motion B1950 (FK4)	RA: 0.0019 arcsec/a	DEC: -0.057 arcsec/a	ą0.003 arcsec/a in RA ą0.002 arcsec/a in DEC
proper motion J2000 (FK5)	RA: 0.0025 arcsec/a	DEC: -0.055 arcsec/a
source of proper motion data	Determined by source catalog

magnitude:

visual	4.9 (accuracy: 2 decimals)
source of visual magnitude data	Taken from Harvard or San Luis photometry.

spectral information:

spectral class	A2p
source of spectral data	Taken from the Henry Draper Catalogue or no spectrum in source catalog.

remarks for duplicity and variability

Double star in Aitken's Double Star Catalogue (Aitken 1932)

catalogues

source catalogue	GC, catalogue number: 22662
Durchmusterung	BD+46 2220
Boss General Catalogue	22662
Henry Draper Catalogue	152107

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

position and proper motion:

position (J2000)	RA: 16h 49.2min	DEC: +45° 59'
proper motion (J2000)	RA: 0.023 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	1878	49	309°	1.8''	4.9	10.4	A1V	BU 627
	1975		18°	1.7''
AD	1881	4	229°	67''	4.9	11.9	A1V	BU 627
	1984		235°	64.9''
AE	1881	3	268°	43.3''	4.9	11.9	A1V	BU 627
	1962		270°	45.1''
BC	1908	32	°	''	9.5	9.6	-	A 1866

discoverer information:

discoverer code	discoverer	reference
BU 627	Burnham, S.W.	-
A 1866	Aitken, R.G.	-

notes:

note	52 Her. A is an Alpha CVn-type variable, V637 Her. BC: P = 57yr, a = 0.27", motion direct.

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

position:

position (B1900)

RA: 16h 46.3min

DEC: +46° 9'

magnitudes, spectral classes, orbital elements:

author:	G.M. Popovic
date of observation:	1962
magnitude of component A:	9.8
magnitude of component B:	9.8
period [y]:	56.75
semi-major axis [arcsec]:	0.267
inclination [deg]:	46.32
node [deg]:	71.14
eccentricity:	0.22
time of periastron passage:	1944
dates of ephemeris:	1966-1975
grade:	reliable
reference:	Bull. Obs. Astron. Beograd 27, 49; 1969.

notes

Star A (mag. 4.9, A3p) = 52 Her, an Alpha CVn type variable. BC are in slow direct motion about A at 1.8" separation. A-BC = BU 627. The magnitudes of B and C are quite uncertain. The physical nature of the faint and more distant components D and E is unknown.

other name(s)

A 1866, 52 Her BC

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

position:

position (equinox 1950.0)

RA: 16h 47min 46.2sec

DEC: +46° 4' 10''

variability informations:

variability type	ACV	rotating variable star
magnitute at max. brightness	4.78
magnitute at min. brightness	4.85
photometric system	visual, photovisual or Johnson's V
period [d]	3.8567

spectral information

spectral class

A3Vp(Sr-Cr-Eu)

references

to a study	Vol. II GCVS
to a chart/photograph	no chart is avaible, but the star is contained in the 'Bonner Durchmusterung'

miscanellous

ID in the GCVS catalogue	40/637
constellation	Hercules
notes on existence	The star is equivalent to '0400638 V0638'.
There are notes in published catalog.

variability type description

variability type

description

ACV

Alpha2 Canum Venaticorum variables. These are main-sequence stars with spectral types B8p-A7p and displaying strong magnetic fields.
Spectra show abnormally strong lines of Si, Sr, Cr, and rare earths whose intensities vary with rotation. They exhibit magnetic field and brightness changes (periods of 0.5-160 days or more). The amplitudes of the brightness changes are usually withine 0.01-0.1 mag in V.

ACVO
Rapidly oscillating Alpha2 CVn variables. These are nonradially pulsating, rotating magnetic variables of Ap spectral type (DO Eri). Pulsation periods are in the range of 6-12 mmag (0.004-0.01 days), while amplitudes of light variation caused by the pulsation are about 0.01 mag in V. The pulsational variations are superposed on those caused by rotation.

catalogues and names	V0637 Her, 52 Her, HR 6254, HD 152107, SAO 46305, BD +46 2220, WDS 16492+4559A
constellation	Hercules