AC Herculis
| catalogues and names |
| SKY2000 - Master Star Catalog |
| Smithsonian Astrophysical Observatory Star Catalog |
| Combined General Catalogue of Variable Stars (Vol. I-III) |
catalogues and names
| catalogues and names | AC Her, HD 170756, SAO 86134, BD +21 3459 |
data from SKY2000 - Master Star Catalog (Myers+ 1997)
position, motion, parallax:
| position (J2000) | RA: 18h 30min 16.238sec | DEC: +21° 52' 0.51'' | ±0.2 arcsec | source: 52 |
| position (2000.72) | RA: 18h 30min 18sec | DEC: +21° 52' 3'' | JD: 2451809.28 | |
| proper motion (J2000) | RA: -0.0003 arcsec/a | DEC: -0.002 arcsec/a | source: 52 | |
| radial velocity | -31 km/s | source: 26 | ||
| galactic coord. (B1950) | longitude: 50.5° | latitude: 14.24° | ||
magnitude:
| visual | 6.8 (observed) | source: 31 |
| photovisual | 7.8 | source: 2 |
| photographic | 7.8 | source: 16 |
spectral information:
| spectral class | F8 | source: 96 | |
| Morgan-Keenan | F2-K4* | source: 26 | |
| B-magnitude | 7.79 ±0.2 | B-V-magnitude | 0.78 |
| U-magnitude | 8 ±0.2 | U-B-magnitude | 0.21 |
variability information:
| variability type | 131 |
| var. amplitude | 2.1 |
| var. period | 75.01 |
| var. epoch | 2435098 21. December 1954, 12:00:00 UT |
| next max light | 2451825.23 7. October 2000, 17:31:12 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 | |
| 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 | |
| 26 | Bright Star Supplement |
| Hoffleit, D. and Warren, W.H. Jr., A Supplement to the Bright Star Catalogue, 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 | |
| 52 | PPMN-HP subset |
| PPMN Star Catalogue (Reference 16) High-Precision Subset (Code H) | |
| 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 28min 9.034sec | DEC: +21° 49' 53.11'' | ±0.018 arcsec |
| position (2000.72) | RA: 18h 30min 18sec | DEC: +21° 52' 2'' | JD: 2451809.28 |
| position (J2000) | RA: 18h 30min 16.223sec | DEC: +21° 52' 0.52'' | |
| proper motion B1950 (FK4) | RA: -0.0005 arcsec/a | DEC: 0 arcsec/a | ±0.005 arcsec/a in RA ±0.005 arcsec/a in DEC |
| proper motion J2000 (FK5) | RA: -0.0004 arcsec/a | DEC: 0 arcsec/a | |
| source of proper motion data | Determined by source catalog | ||
magnitude:
| visual | 8 (accuracy: 1 decimal) |
| source of visual magnitude data | Taken from AGK1. |
| photographic | 8.2 (accuracy: 2 decimals) |
| source of photographic magnitude data | Determined by source catalog. |
spectral information:
| spectral class | F8 |
| source of spectral data | Taken from the HD with M stars reclassified by Miss Cannon. |
catalogues
| source catalogue | Yale Transactions 25, catalogue number: 6501 |
| Durchmusterung | BD+21 3459 |
| Henry Draper Catalogue | 170756 |
data from Combined General Catalogue of Variable Stars (Vol. I-III) (Kholopov+ 1998)
position:
| position (equinox 1950.0) | RA: 18h 28min 9sec | DEC: +21° 49' 53'' |
variability informations:
| variability type | RVA | pulsating variable star |
| magnitute at max. brightness | 6.85 | |
| magnitute at min. brightness | 9 | |
| photometric system | visual, photovisual or Johnson's V | |
| epoch for maximum light [JD] | 2435097.8 21. December 1954, 07:12:00 UT |
|
| period [d] | 75.01 | |
| next maximum light [JD] | 2451825.03 7. October 2000, 12:43:12 UT |
spectral information
| spectral class | F2pIb-K4e(C0,0) |
references
| to a study | Vol. II GCVS |
| to a chart/photograph | Vol. I GCVS (see Kholopov et al. 1985-1988) |
miscanellous
| ID in the GCVS catalogue | 40/57 |
| constellation | Hercules |
| notes on existence | The star is equivalent to '0400058 AD'. |
| There are notes in published catalog. | |
variability type description
| variability type | description |
| RVA | Variables of the RV Tauri type. These are radially pulsating supergiants having spectral types F-G at maximum light and K-M at minimum. The light curves are characterized by the presence of double waves with alternating primary and secondary minima that can vary in depth so that primary minima may become secondary and vice versa. The complete light amplitude may reach 3-4 mag in V. Periods between two adjacent primary minima (usually called formal periods) lie in the range 30-150 days (these are the periods appearing in the Catalogue). Two subtypes, RVA and RVB, are recognized: RVA RV Tauri variables that do not vary in mean magnitude (AC Her); RVB RV Tauri variables that periodically (with periods from 600 to 1500 days and amplitudes up to 2 mag in V) vary in mean magnitude (DF Cyg, RV Tau). |