h Aquilae
| catalogues and names | h Aql, eta Aql, 55 Aql, HR 7570, HD 187929, SAO 125159, FK5: 746 |
| constellation | Aquila |
data from The Bright Star Catalogue, 5th Revised Ed. (Preliminary Version) (Hoffleit+, 1991)
position, motion, parallax:
| position (J2000) | RA: 19h 52min 28,4sec | DEC: +1° 0' 20'' |
| position (J1900) | RA: 19h 47min 22,7sec | DEC: +0° 44' 56'' |
| proper motion (J2000) | RA: 0,011 arcsec/a | DEC: -0,007 arcsec/a |
| radial velocity | -15 km/s note: spectroscopic binaries |
|
| rotational velocity | 0 km/s (uncertain) (variable) | |
| trigonometric parallax | 0,01 arcsec | |
magnitude
| visual magnitude | 3,9 (V on UBV Johnson system) |
spectral / color information
| spectral class | F6Ib |
| B-V-magnitude | 0,89 |
| U-B-magnitude | 0,51 |
| R-I-magnitude | 0,47 |
| note (category: spectra): | Also classified F6Ib-G4Ib. UV suggests A0V companion. |
variability information
| variable star identification | Eta Aql |
| note (category: variability): | Discovered by Pigott in 1784. CDelta 3.50 - 4.30V, 7.176641d. Period changes. Variable He 10830 in emission and absorption. |
data from SKY2000 - Master Star Catalog (Myers+ 1997)
position, motion, parallax:
| position (J2000) | RA: 19h 52min 28,374sec | DEC: +1° 0' 20,37'' | ±0,06 arcsec | source: 15 |
| proper motion (J2000) | RA: 0,0007 arcsec/a | DEC: -0,007 arcsec/a | source: 25 | |
| radial velocity | -15 km/s | source: 25 | ||
| trigonometric parallax | 0,01 | ±0,001 arcsec | source: 25 | |
| galactic coord. (B1950) | longitude: 40,94° | latitude: -13,07° | ||
| GCI unit vector (J2000) | X: 0,47122 | Y: -0,881841 | Z: 0,017551 | |
magnitude:
| visual | 3,5 (observed) | source: 31 |
spectral information:
| spectral class | G0 | source: 96 | |
| Morgan-Keenan | F6Ib | source: 25 | |
| B-magnitude | 4,79 ±0,05 | B-V-magnitude | 0,89 |
| U-magnitude | 5,3 ±0,05 | U-B-magnitude | 0,51 |
variability information:
| variability type | 111 |
| var. amplitude | 0,91 |
| var. period | 7,18 |
| var. epoch | 2436085 3. September 1957, 12:00:00 UT |
| next max light | 2451622,52 19. March 2000, 00:28:48 UT |
sources:
| 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 | |
| 31 | CRM' (non-GCVS variable data) |
| Warren, W.H. Jr., Northern Hemisphere Catalog of Red Magnitudes, 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 (J1950) | RA: 19h 49min 55,525sec | DEC: +0° 52' 33,23'' | ±0,005 arcsec |
| position (J2000) | RA: 19h 52min 28,373sec | DEC: +1° 0' 20,25'' | |
| proper motion J1950 (FK4) | RA: 0,0005 arcsec/a | DEC: -0,006 arcsec/a | ±0,001 arcsec/a in RA ±0,001 arcsec/a in DEC |
| proper motion J2000 (FK5) | RA: 0,0007 arcsec/a | DEC: -0,008 arcsec/a | |
| source of proper motion data | Determined by source catalog | ||
magnitude:
| visual | 4 (accuracy: 2 decimals) |
| source of visual magnitude data | Arithmetic mean of maximum and minimum magnitudes of a variable star |
spectral information:
| spectral class | G0p |
| source of spectral data | Taken from the Henry Draper Catalogue or no spectrum in source catalog. |
remarks for duplicity and variability
| Variable star in visual magnitude in source catalog |
catalogues
| source catalogue | FK4, catalogue number: 746 |
| Durchmusterung | BD+00 4337 |
| Boss General Catalogue | 27517 |
| Henry Draper Catalogue | 187929 |
data from Combined General Catalogue of Variable Stars (Vol. I-III) (Kholopov+ 1998)
position:
| position (J1950) | RA: 19h 49min 55,5sec | DEC: +0° 52' 33'' |
variability informations:
| variability type | DCEP | pulsating variable star |
| magnitute at max. brightness | 3,48 | |
| magnitute at min. brightness | 4,39 | |
| photometric system | visual, photovisual or Johnson's V | |
| epoch for maximum light [JD] | 2436084,656 3. September 1957, 03:44:38 UT |
|
| period [d] | 7,176641 | |
| next maximum light [JD] | 2451622,083765 18. March 2000, 14:00:37 UT |
|
| rising time | 32 % of period |
spectral information
| spectral class | F6Ib-G4Ib |
references
| to a study | Vol. I GCVS (see Kholopov et al. 1985-1988) |
| to a chart/photograph | no chart is avaible, but the star is contained in the 'Bonner Durchmusterung' |
miscanellous
| ID in the GCVS catalogue | 5/9007 |
| constellation | Aquarius |
| notes on existence | The star is equivalent to '0059018 sig'. |
| There are notes in published catalog. | |
variability type description
| variability type | description |
| DCEP | These are the classical cepheids, or Delta Cep-type variables. Comparatively young objects that have left the main sequence and evolved into the instability strip of the Hertzsprung-Russell (H-R) diagram, they obey the well-known Cepheid period-luminosity relation and belong to the young disk population. DCEP stars are present in open clusters. They display a certain relation between the shapes of their light curves and their periods. |