Alphekka
| 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. |
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 | |
magnitude
| 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 | |
magnitude:
| 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:
| 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 |
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 | |
| 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 | ||
magnitude:
| 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. |
catalogues
| 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:
| 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 |
references
| 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) |
miscanellous
| 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. EA 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. EB 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. EW 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. |