The object was found in the following catalogues:
  1. The Bright Star Catalogue, 5th Revised Ed. (Preliminary Version)

  2. SKY2000 - Master Star Catalog

  3. Smithsonian Astrophysical Observatory Star Catalog

  4. Combined General Catalogue of Variable Stars (Vol. I-III)

catalogues and names Alphekka, a CrB, alf CrB, 5 CrB, HR 5793, HD 139006, SAO 83893, FK5: 578
other names Alphecca, Alphacca, Gemma, The Jewel, Gnosia Stella Coronae, Ashtaroth
constellation Corona Borealis

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

note (category: star names): ALPHEKKA; Alphecca; Alphacca; Gemma; Gnosia; The Jewel; Gnosia Stella Coronae; Ashtaroth.

object is infrared source (NASA merged infrared catalogue, Schmitz et al., 1978)

position, motion, parallax:

position (J2000) RA: 15h 34min 41,3sec DEC: +26 42' 53''
position (J1900) RA: 15h 30min 27,2sec DEC: +27 3' 4''
proper motion (J2000) RA: 0,121 arcsec/a DEC: -0,089 arcsec/a
radial velocity 2 km/s
note: spectroscopic binaries
note: orbital data avaible
rotational velocity 133 km/s (uncertain) (variable)
trigonometric parallax 0,045 arcsec


visual magnitude 2,23
(V on UBV Johnson system)

spectral / color information

spectral class A0V+G5V
B-V-magnitude -0,02
U-B-magnitude -0,02
R-I-magnitude -0,04

variability information

variable star identification Alp CrB
note (category: variability): EA 2.21 - 2.32B, 17.359907d. Possibly also intrinsic var.

double/multiple star system information

note (category: spectroscopic binaries): 17.3599d, K 35.8k/s, V0 +1.5k/s, asini 7.83; EB, i 88.3d.

miscellaneous information

note (category: group membership): Sirius group; UMa stream.

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

position, motion, parallax:

position (J2000) RA: 15h 34min 41,276sec DEC: +26 42' 52,94'' 0,06 arcsec source: 15
proper motion (J2000) RA: 0,0091 arcsec/a DEC: -0,089 arcsec/a source: 25
radial velocity 2 km/s source: 25
trigonometric parallax 0,045 0,004 arcsec source: 25
galactic coord. (B1950) longitude: 41,87 latitude: 53,77
GCI unit vector (J2000) X: -0,529171 Y: -0,719642 Z: 0,449548


visual 2,23 (observed) source: 25
photovisual 2,3 source: 2

spectral information:

spectral class A0 source: 96
Morgan-Keenan A0V+G5V source: 25
B-magnitude 2,21 0,05 B-V-magnitude -0,02
U-magnitude 2,19 0,05 U-B-magnitude -0,02

variability information:

source of data: 30
variability type 10
var. amplitude 0,11
var. period 17,36
var. epoch 2423164
19. April 1922, 12:00:00 UT
next max light 2451634,4
30. March 2000, 21:36:00 UT


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 (J1950) RA: 15h 32min 34,144sec DEC: +26 52' 54,75'' 0,003 arcsec
position (J2000) RA: 15h 34min 41,28sec DEC: +26 42' 52,98''
proper motion J1950 (FK4) RA: 0,009 arcsec/a DEC: -0,091 arcsec/a 0,001 arcsec/a in RA
0,001 arcsec/a in DEC
proper motion J2000 (FK5) RA: 0,0091 arcsec/a DEC: -0,088 arcsec/a
source of proper motion data Determined by source catalog


visual 2,3 (accuracy: 2 decimals)
source of visual magnitude data Taken from the "Henry Draper Catalogue".

spectral information:

spectral class A0
source of spectral data Taken from the Henry Draper Catalogue or no spectrum in source catalog.


source catalogue FK4, catalogue number: 578
Durchmusterung BD+27 2512
Boss General Catalogue 20947
Henry Draper Catalogue 139006

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


position (J1950) RA: 15h 32min 34,1sec DEC: +26 52' 55''

variability informations:

variability type EA/DM close binary eclipsing system
magnitute at max. brightness 2,21
magnitute at min. brightness 2,32
photometric system
epoch for maximum light [JD] 2423163,77
19. April 1922, 06:28:48 UT
period [d] 17,359907
next maximum light [JD] 2451634,01748
30. March 2000, 12:25:10 UT
duration of the eclipse 03 % of period
the duration of the light constancy phase at minimum light is equal to zero

spectral information

spectral class A0V+G5V


to a study Vol. I GCVS (see Kholopov et al. 1985-1988)
to a chart/photograph Vol. I GCVS (see Kholopov et al. 1985-1988)


ID in the GCVS catalogue 27/9001
constellation Corona Borealis
notes on existence The star is equivalent to '0279002 bet'.
There are notes in published catalog.

variability type description

variability type description
EA Eclipsing binary systems. These are binary systems with orbital planes so close to the observer's line of sight (the inclination i of the orbital plane to the plane orthogonal to the line of sight is close to 90 deg) that the components periodically eclipse each other.
Consequently, the observer finds changes of the apparent combined brightness of the system with the period coincident with that of the components' orbital motion.

Algol (Beta Persei)-type eclipsing systems. Binaries with spherical or slightly ellipsoidal components. It is possible to specify, for their light curves, the moments of the beginning and end of the eclipses. Between eclipses the light remains almost constant or varies insignificantly because of reflection effects, slight ellipsoidality of components, or physical variations. Secondary minima may be absent. An extremely wide range of periods is observed, from 0.2 to >= 10000 days. Light amplitudes are also quite different and may reach several magnitudes.

Beta Lyrae-type eclipsing systems. These are eclipsing systems having ellipsoidal components and light curves for which it is impossible to specify the exact times of onset and end of eclipses because of a continuous change of a system's apparent combined brightness between eclipses; secondary minimum is observed in all cases, its depth usually being considerably smaller than that of the primary minimum; periods are mainly longer than 1 day. The components
generally belong to early spectral types (B-A). Light amplitudes are usually <2 mag in V.

W Ursae Majoris-type eclipsing variables. These are eclipsers with periods shorter than 1 days, consisting of ellipsoidal components almost in contact and having light curves for which it is impossible to specify the exact times of onset and end of eclipses. The depths of the primary and secondary minima are almost equal or differ insignificantly. Light amplitudes are usually <0.8 mag in V. The components generally belong to spectral types F-G and later.
DM Detached main-sequence systems. Both components are main-sequence stars and do not fill their inner Roche lobes.