b Hydrae
| catalogues and names | b Hya, bet Hya, HR 4552, HD 103192, SAO 202901, WDS 11529-3354 |
| constellation | Hydra |
data from The Bright Star Catalogue, 5th Revised Ed. (Preliminary Version) (Hoffleit+, 1991)
position, motion, parallax:
| position (J2000) | RA: 11h 52min 54,6sec | DEC: -33° 54' 29'' |
| position (J1900) | RA: 11h 47min 51,3sec | DEC: -33° 21' 6'' |
| proper motion (J2000) | RA: -0,05 arcsec/a | DEC: 0,005 arcsec/a |
| radial velocity | -1 km/s | |
| rotational velocity | 72 km/s (uncertain) (variable) | |
| dynamical parallax | 0,01 arcsec | |
magnitude
| visual magnitude | 4,28 (V on UBV Johnson system) |
spectral / color information
| spectral class | B9IIIpSi |
| B-V-magnitude | -0,1 |
| U-B-magnitude | -0,33 |
| R-I-magnitude | -0,08 |
variability information
| variable star identification | Bet Hya |
| note (category: variability): | Alpha CV, amp. 0.04V, 0.04B, 2.344d. |
double/multiple star system information
| separation | 0,8 arcsec |
| mag difference (of double or brightest multiple) | 0,9 |
| note | Worley (1978) update of the IDS |
data from SKY2000 - Master Star Catalog (Myers+ 1997)
position, motion, parallax:
| position (J2000) | RA: 11h 52min 54,532sec | DEC: -33° 54' 29,38'' | ±0,19 arcsec | source: 16 |
| proper motion (J2000) | RA: -0,0046 arcsec/a | DEC: -0,011 arcsec/a | source: 25 | |
| radial velocity | -1 km/s | source: 25 | ||
| galactic coord. (B1950) | longitude: 289,28° | latitude: 27,41° | ||
| GCI unit vector (J2000) | X: -0,829536 | Y: 0,025675 | Z: -0,557863 | |
magnitude:
| visual | 4,28 (observed) | source: 25 |
| photovisual | 3,5 | source: 16 |
| photographic | 4,4 | source: 2 |
spectral information:
| spectral class | B9 | source: 96 | |
| Morgan-Keenan | B9IIIpSi | source: 25 | |
| B-magnitude | 4,18 ±0,05 | B-V-magnitude | -0,1 |
| U-magnitude | 3,85 ±0,05 | U-B-magnitude | -0,33 |
variability information:
| variability type | 160 |
| var. amplitude | 0,04 |
| var. period | 2,34 |
| var. epoch | 2442452 8. February 1975, 12:00:00 UT |
| next max light | 2451622,46 18. March 2000, 23:02:24 UT |
double/multiple star system information:
| separation between brightest and second brightest component | 0,7 arcsec |
| magnitude difference between brightest and second brightest component | 0,8 |
| position angle | 28 ° |
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 | |
| 19 | WDS Catalog |
| Worley, C.E., and G.G. Douglass, Washington Catalog of Visual Double Stars 1996.0, United States Naval Observatory, 1996 | |
| 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: 11h 50min 22,635sec | DEC: -33° 37' 47,13'' | ±0,015 arcsec |
| position (J2000) | RA: 11h 52min 54,56sec | DEC: -33° 54' 28,59'' | |
| proper motion J1950 (FK4) | RA: -0,0042 arcsec/a | DEC: 0,001 arcsec/a | ±0,003 arcsec/a in RA ±0,003 arcsec/a in DEC |
| proper motion J2000 (FK5) | RA: -0,004 arcsec/a | DEC: 0,005 arcsec/a | |
| source of proper motion data | Determined by source catalog | ||
magnitude:
| visual | 4,4 (accuracy: 2 decimals) |
| source of visual magnitude data | Taken from Harvard or San Luis photometry. |
spectral information:
| spectral class | B9 |
| source of spectral data | Taken from the Henry Draper Catalogue or no spectrum in source catalog. |
remarks for duplicity and variability
| Double star in Aitken's Double Star Catalogue (Aitken 1932) |
catalogues
| source catalogue | GC, catalogue number: 16258 |
| Durchmusterung | CD-33 8018 |
| Boss General Catalogue | 16258 |
| Henry Draper Catalogue | 103192 |
data from The Washington Visual Double Star Catalog, 1996.0 (Worley+, 1996)
position and proper motion:
| position (J2000) | RA: 11h 52,9min | DEC: -33° 54' |
| proper motion (J2000) | RA: -0,051 arcsec/a | DEC: 0 arcsec/a |
double/multiple star system information:
| component | year | number of measures | position angle | angular separation | magnitude of 1st component | magnitude of 2nd component | spectral class(es) | discoverer code |
| - | 1834 | 65 | 340° | 2,2'' | 4,8 | 5,6 | B9IIIpSi | HJ 4478 |
| 1991 | 28° | 0,7'' |
discoverer information:
| discoverer code | discoverer | reference |
| HJ 4478 | Herschel, J. | - |
notes:
| note | Beta Hya. A is an Alpha CVn-type variable. |
data from Combined General Catalogue of Variable Stars (Vol. I-III) (Kholopov+ 1998)
position:
| position (J1950) | RA: 11h 50min 22,6sec | DEC: -33° 37' 47'' |
variability informations:
| variability type | ACV | rotating variable star |
| magnitute at max. brightness | 4,27 | |
| magnitute amplitude | 0,04 | |
| photometric system | visual, photovisual or Johnson's V | |
| epoch for maximum light [JD] | 2442451,78 8. February 1975, 06:43:12 UT |
|
| period [d] | 2,344 | |
| next maximum light [JD] | 2451621,508 18. March 2000, 00:11:31 UT |
spectral information
| spectral class | B9IIIp(Si) |
references
| to a study | Vol. II GCVS |
| to a chart/photograph | no chart is avaible, but the star is contained in the 'Cordoba Durchmusterung' |
miscanellous
| ID in the GCVS catalogue | 42/9002 |
| constellation | Hydra |
| notes on existence | The star is equivalent to '0429005 eps'. |
| There are notes in published catalog. | |
variability type description
| variability type | description |
| ACV | Alpha2 Canum Venaticorum variables. These are main-sequence stars with spectral types B8p-A7p and displaying strong magnetic fields. Spectra show abnormally strong lines of Si, Sr, Cr, and rare earths whose intensities vary with rotation. They exhibit magnetic field and brightness changes (periods of 0.5-160 days or more). The amplitudes of the brightness changes are usually withine 0.01-0.1 mag in V. ACVO Rapidly oscillating Alpha2 CVn variables. These are nonradially pulsating, rotating magnetic variables of Ap spectral type (DO Eri). Pulsation periods are in the range of 6-12 mmag (0.004-0.01 days), while amplitudes of light variation caused by the pulsation are about 0.01 mag in V. The pulsational variations are superposed on those caused by rotation. |