Alya

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

note (category: star names):

Alya; Alga.

position, motion, parallax:

position (J2000)	RA: 18h 56min 13,2sec	DEC: +4° 12' 13''
position (2001,18)	RA: 18h 56min 17sec	DEC: +4° 12' 19''
position (B1900)	RA: 18h 51min 14,9sec	DEC: +4° 4' 24''
proper motion (J2000)	RA: 0,049 arcsec/a	DEC: 0,031 arcsec/a
radial velocity	-46 km/s note: suspected variable radial velocity
rotational velocity	143 km/s (uncertain) (variable)
trigonometric parallax	0,03 arcsec
galactic coordinates	longitude: 37,22°	latitude: 0,85°

note (category: dynamical parallaxes):

0.019".

magnitude

visual magnitude

4,62
(V on UBV Johnson system)

spectral / color information

spectral class	A5V
B-V-magnitude	0,17
U-B-magnitude	0,09

variability information

variable star identification

11557

note (category: variability):

4.59 - 4.72V.

double/multiple star system information

number of components of multiple star system	3
separation	22,2 arcsec
mag difference (of double or brightest multiple)	0,4
component ID	AB

note (category: double and multiple data):

Binary with HR 7142.

miscellaneous information

note (category: group membership):

Hyades group.

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

position, motion, parallax:

position (J2000)	RA: 18h 56min 13,19sec	DEC: +4° 12' 12,91''	ą0,06 arcsec	source: 15
position (2001,18)	RA: 18h 56min 17sec	DEC: +4° 12' 19''	JD: 2451975,78
proper motion (J2000)	RA: 0,0033 arcsec/a	DEC: 0,031 arcsec/a		source: 25
radial velocity	-46 km/s			source: 25
trigonometric parallax	0,03 arcsec		ą0,003 arcsec	source: 25
galactic coord. (B1950)	longitude: 37,22°	latitude: 0,85°

magnitude:

visual	4,61 (observed)	source: 25
photovisual	4,5	source: 2

spectral information:

spectral class	A5		source: 96
Morgan-Keenan	A5V		source: 25
B-magnitude	4,77 ą0,05	B-V-magnitude	0,16
U-magnitude	4,88 ą0,05	U-B-magnitude	0,11

double/multiple star system information:

source of data: 19

separation between brightest and second brightest component	22,3 arcsec
magnitude difference between brightest and second brightest component	0,36
position angle	104 °

component	magnitude	spectral class	catalogue(s)/name(s)
A	4,61	A5	Alya, q¹Serpentis, 63 Ser, HR 7141, HD 175638, SAO 124068
B	4,98	A5	q²Serpentis, 63 Ser, HR 7142, HD 175639, SAO 124070

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: 18h 53min 43,976sec	DEC: +4° 8' 13,25''	ą0,004 arcsec
position (2001,18)	RA: 18h 56min 17sec	DEC: +4° 12' 17''	JD: 2451975,78
position (J2000)	RA: 18h 56min 13,192sec	DEC: +4° 12' 12,92''
proper motion B1950 (FK4)	RA: 0,0031 arcsec/a	DEC: 0,032 arcsec/a	ą0,001 arcsec/a in RA ą0,001 arcsec/a in DEC
proper motion J2000 (FK5)	RA: 0,0033 arcsec/a	DEC: 0,031 arcsec/a
source of proper motion data	Determined by source catalog

magnitude:

visual	4,5 (accuracy: 2 decimals)
source of visual magnitude data	Taken from the "Henry Draper Catalogue".

spectral information:

spectral class	A5
source of spectral data	Taken from the Henry Draper Catalogue or no spectrum in source catalog.

catalogues

source catalogue	FK4, catalogue number: 709
Durchmusterung	BD+04 3916
Boss General Catalogue	25991
Henry Draper Catalogue	175638

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

position and proper motion:

position (J2000)	RA: 18h 56,2min	DEC: +4° 12'
proper motion (J2000)	RA: 0,049 arcsec/a	DEC: 0,031 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	1822	often	104°	21,6''	4,62	4,98	A5V A5Vn	STF2417
	1984		-	22,3''
BC	1927	2	56°	14,1''	4,98	7,9	A5Vn	STF2417
	1954		58°	26''

discoverer information:

discoverer code	discoverer	reference
STF2417	Struve, F.G.W.	-

notes:

note	Theta (1) Ser. B is BD+04@3917, Theta (2) Ser.

data from Combined General Catalogue of Variable Stars (suspected variables) (Kholopov+ 1998)

position:

position (equinox 1950.0)

RA: 18h 53min 44sec

DEC: +4° 8' 13''

variability informations:

magnitute at max. brightness	4,59
magnitute at min. brightness	4,72
photometric system	visual, photovisual or Johnson's V

spectral information

spectral class

references

to a study

290477D (designation: ZI 1555)

miscanellous

There are notes in the published catalog (Kukarkin et al.(1982)).

catalogues and names	Alya, q¹Ser, NSV 11557, 63 Ser, HR 7141, HD 175638, SAO 124068, BD +4 3916, FK5: 709, WDS 18562+0412A
other names	Alga
constellation	Serpens