Pherkad
| catalogues and names | Pherkad, g UMi, gam UMi, 13 UMi, HR 5735, HD 137422, SAO 8220, FK5: 569 |
| other names | Pherkad Major |
| constellation | Ursa Minor |
data from The Bright Star Catalogue, 5th Revised Ed. (Preliminary Version) (Hoffleit+, 1991)
| note (category: star names): | Pherkad; Pherkad Major. See HR 5563 and 5714. |
position, motion, parallax:
| position (J2000) | RA: 15h 20min 43,7sec | DEC: +71° 50' 2'' |
| position (J1900) | RA: 15h 20min 52,9sec | DEC: +72° 11' 23'' |
| proper motion (J2000) | RA: -0,019 arcsec/a | DEC: 0,02 arcsec/a |
| radial velocity | -4 km/s note: variable radial velocity |
|
| rotational velocity | 171 km/s (uncertain) (variable) | |
| trigonometric parallax | 0,003 arcsec | |
| note (category: radial and/or rotational velocities): | 0.108449d, but not SB. Variable elements. |
magnitude
| visual magnitude | 3,05 (V on UBV Johnson system) |
spectral / color information
| spectral class | A3II-III |
| B-V-magnitude | 0,05 |
| U-B-magnitude | 0,12 |
| R-I-magnitude | 0,06 |
| note (category: spectra): | Shell star, but shell possibly variable. |
variability information
| variable star identification | Gam UMi |
| note (category: variability): | Delta Sct? Amp. 0.03V. Hydrogen and CaII variable. |
data from SKY2000 - Master Star Catalog (Myers+ 1997)
position, motion, parallax:
| position (J2000) | RA: 15h 20min 43,713sec | DEC: +71° 50' 2,49'' | ±0,06 arcsec | source: 15 |
| proper motion (J2000) | RA: -0,004 arcsec/a | DEC: 0,02 arcsec/a | source: 25 | |
| radial velocity | -4 km/s | source: 25 | ||
| trigonometric parallax | 0,003 | - | source: 25 | |
| galactic coord. (B1950) | longitude: 108,46° | latitude: 40,84° | ||
| GCI unit vector (J2000) | X: -0,199642 | Y: -0,239466 | Z: 0,950157 | |
magnitude:
| visual | 3,05 (observed) | source: 25 |
| photovisual | 3,1 | source: 2 |
spectral information:
| spectral class | A2 | source: 96 | |
| Morgan-Keenan | A3II-III | source: 25 | |
| B-magnitude | 3,1 ±0,05 | B-V-magnitude | 0,05 |
| U-magnitude | 3,22 ±0,05 | U-B-magnitude | 0,12 |
variability information:
| variability type | 10 |
| var. amplitude | 0,05 |
| var. period | 0,14 |
| var. epoch | 2439950 3. April 1968, 12:00:00 UT |
| next max light | 2451622,08 18. March 2000, 13:55:12 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 20min 47,347sec | DEC: +72° 0' 42,97'' | ±0,004 arcsec |
| position (J2000) | RA: 15h 20min 43,726sec | DEC: +71° 50' 2,53'' | |
| proper motion J1950 (FK4) | RA: -0,0051 arcsec/a | DEC: 0,019 arcsec/a | ±0,001 arcsec/a in RA ±0,001 arcsec/a in DEC |
| proper motion J2000 (FK5) | RA: -0,0038 arcsec/a | DEC: 0,021 arcsec/a | |
| source of proper motion data | Determined by source catalog | ||
magnitude:
| visual | 3,1 (accuracy: 2 decimals) |
| source of visual magnitude data | Taken from the "Henry Draper Catalogue". |
spectral information:
| spectral class | A2 |
| source of spectral data | Taken from the Henry Draper Catalogue or no spectrum in source catalog. |
catalogues
| source catalogue | FK4, catalogue number: 569 |
| Durchmusterung | BD+72 679 |
| Boss General Catalogue | 20692 |
| Henry Draper Catalogue | 137422 |
data from Combined General Catalogue of Variable Stars (Vol. I-III) (Kholopov+ 1998)
position:
| position (J1950) | RA: 15h 20min 47,3sec | DEC: +72° 0' 43'' |
variability informations:
| variability type | DSCTC | pulsating variable star |
| magnitute at max. brightness | 3,04 | |
| magnitute amplitude | 0,05 | |
| photometric system | visual, photovisual or Johnson's V | |
| epoch for maximum light [JD] | 2439950,367 3. April 1968, 20:48:29 UT |
|
| period [d] | 0,143009 | |
| next maximum light [JD] | 2451622,046535 18. March 2000, 13:07:01 UT |
spectral information
| spectral class | A3II-III |
references
| to a study | Vol. III GCVS |
| to a chart/photograph | no chart is avaible, but the star is contained in the 'Bonner Durchmusterung' |
miscanellous
| ID in the GCVS catalogue | 84/9003 |
| constellation | Ursa Minor |
| notes on existence | The star is equivalent to '0849005 eps'. |
| There are notes in published catalog. | |
variability type description
| variability type | description |
| DSCTC | Variables of the Delta Scuti type. These are pulsating variables of spectral types A0-F5 III-V displaying light amplitudes from 0.003 to 0.9 mag in V (usually several hundredths of a magnitude) and periods from 0.01 to 0.2 days. The shapes of the light curves, periods, and amplitudes usually vary greatly. Radial as well as nonradial pulsations are observed. The variability of some members of this type appears sporadically and sometimes completely ceases, this being a consequence of strong amplitude modulation with the lower value of the amplitude not exceeding 0.001 mag in some cases. The maximum of the surface layer expansion does not lag behind the maximum light for more than 0.1 periods. DSCT stars are representatives of the galactic disk (flat component) and are phenomenologically close to the SX Phe variables. DSCTC Low amplitude group of Delta Sct variables (light amplitude <0.1 mag in V). The majority of this type's representatives are stars of luminosity class V; objects of this subtype generally are representative of the Delta Sct variables in open clusters. |