R Hya
| catalogues and names | R Hya, HR 5080, HD 117287, SAO 181695, WDS 13297-2317 |
data from The Bright Star Catalogue, 5th Revised Ed. (Preliminary Version) (Hoffleit+, 1991)
position, motion, parallax:
| position (J2000) | RA: 13h 29min 42,8sec | DEC: -23° 16' 53'' |
| position (J1900) | RA: 13h 24min 14,8sec | DEC: -22° 45' 52'' |
| proper motion (J2000) | RA: -0,056 arcsec/a | DEC: 0,016 arcsec/a |
| radial velocity | -10 km/s note: variable radial velocity |
|
magnitude
| visual magnitude | 4,97 (V on UBV Johnson system) |
spectral / color information
| spectral class | M7IIIe |
| B-V-magnitude | 1,6 |
| U-B-magnitude | 0,68 |
| R-I-magnitude | 2,42 |
| note (category: spectra): | Technetium star. SiO maser emission. Also classified M6e-M9e. |
variability information
| variable star identification | R Hya |
| note (category: variability): | ADS 8920A, M 3.5 - 10.9v, 388.87d. Period varies; was 500d beginning of 18th century. M8 at minimum. Discovered by Montanari in 1670. |
double/multiple star system information
| separation | 21,2 arcsec |
| mag difference (of double or brightest multiple) | 8,5 |
miscellaneous information
| note (category: group membership): | Hyades group. |
| note (category: polarization): | Polarization possibly due to circumstellar dust scattering. |
data from SKY2000 - Master Star Catalog (Myers+ 1997)
position, motion, parallax:
| position (J2000) | RA: 13h 29min 42,791sec | DEC: -23° 16' 52,71'' | ±0,19 arcsec | source: 16 |
| proper motion (J2000) | RA: -0,0041 arcsec/a | DEC: 0,015 arcsec/a | source: 25 | |
| radial velocity | -10 km/s | source: 25 | ||
| galactic coord. (B1950) | longitude: 314,23° | latitude: 38,75° | ||
| GCI unit vector (J2000) | X: -0,849092 | Y: -0,350461 | Z: -0,395246 | |
magnitude:
| visual | 4,97 (observed) | source: 25 |
| photovisual | 5,9 | source: 16 |
spectral information:
| spectral class | M0 | source: 96 | |
| Morgan-Keenan | M7IIIe | source: 25 | |
| B-magnitude | 6,57 ±0,05 | B-V-magnitude | 1,6 |
| U-magnitude | 7,25 ±0,05 | U-B-magnitude | 0,68 |
variability information:
| variability type | 180 |
| var. amplitude | 7,4 |
| var. period | 388,87 |
| var. epoch | 2443596 28. March 1978, 12:00:00 UT |
| next max light | 2451762,27 5. August 2000, 18:28:48 UT |
double/multiple star system information:
| separation between brightest and second brightest component | 21,2 arcsec |
| magnitude difference between brightest and second brightest component | 8,5 |
sources:
| 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 | |
| 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: 13h 26min 58,482sec | DEC: -23° 1' 24,51'' | ±0,023 arcsec |
| position (J2000) | RA: 13h 29min 42,788sec | DEC: -23° 16' 52,57'' | |
| proper motion J1950 (FK4) | RA: -0,0041 arcsec/a | DEC: 0,011 arcsec/a | ±0,004 arcsec/a in RA ±0,005 arcsec/a in DEC |
| proper motion J2000 (FK5) | RA: -0,004 arcsec/a | DEC: 0,016 arcsec/a | |
| source of proper motion data | Determined by source catalog | ||
magnitude:
| visual | 3,5 (accuracy: 1 decimal) |
| source of visual magnitude data | Source cited in source catalog introduction. |
spectral information:
| spectral class | M7e |
| 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 | GC, catalogue number: 18239 |
| Durchmusterung | BD-22 3601 |
| Boss General Catalogue | 18239 |
| Henry Draper Catalogue | 117287 |
data from The Washington Visual Double Star Catalog, 1996.0 (Worley+, 1996)
position and proper motion:
| position (J2000) | RA: 13h 29,7min | DEC: -23° 17' |
| proper motion (J2000) | RA: -0,055 arcsec/a | DEC: 0,011 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 |
| - | 1891 | 7 | 324° | 21,2'' | - | 12 | M7IIIe | HO 381 |
discoverer information:
| discoverer code | discoverer | reference |
| HO 381 | Hough, G.W. | - |
notes:
| note | A is a Mira-type variable, R Hya. Physical pair. |
data from Combined General Catalogue of Variable Stars (Vol. I-III) (Kholopov+ 1998)
position:
| position (J1950) | RA: 13h 26min 58,5sec | DEC: -23° 1' 25'' |
variability informations:
| variability type | M | pulsating variable star |
| magnitute at max. brightness | 3,5 | |
| magnitute at min. brightness | 10,9 | |
| photometric system | visual, photovisual or Johnson's V | |
| epoch for maximum light [JD] | 2443596 28. March 1978, 12:00:00 UT |
|
| period [d] | 388,87 | |
| next maximum light [JD] | 2451762,27 5. August 2000, 18:28:48 UT |
|
| rising time | 49 % of period |
spectral information
| spectral class | M6e-M9eS(Tc) |
references
| to a study | the main characteristics of the star was determined by the authors themselves |
| to a chart/photograph | Vol. I GCVS (see Kholopov et al. 1985-1988) |
miscanellous
| ID in the GCVS catalogue | 42/1 |
| constellation | Hydra |
| notes on existence | The star is equivalent to '0420002 S'. |
| There are notes in published catalog. | |
variability type description
| variability type | description |
| M | Mira (Omicron) Ceti-type variables. These are long-period variable giants with characteristic late-type emission spectra (Me, Ce, Se) and light amplitudes from 2.5 to 11 mag in V. Their periodicity is well pronounced, and the periods lie in the range between 80 and 1000 days. Infrared amplitudes are usually less than in the visible and may be <2.5 mag. For example, in the K band they usually do not exceed 0.9 mag. If the amplitudes exceed 1 - 1.5 mag , but it is not certain that the true light amplitude exceeds 2.5 mag, the symbol "M" is followed by a colon, or the star is attributed to the semiregular class with a colon following the symbol for that type (SR). |