KU Hydrae
Star in the constellation Hydra
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KU Hydrae is a binary star in the constellation Hydra. The primary star is an Alpha2 Canum Venaticorum variable with its apparent magnitude varying from 0.05 magnitudes over a period of 33.97 days.[7]
| Observation data Epoch J2000 Equinox J2000 | |
|---|---|
| Constellation | Hydra[2] |
| Right ascension | 09h 22m 50.856s[3] |
| Declination | −09° 50′ 19.66″[3] |
| Apparent magnitude (V) | 6.51 to 6.53[4] |
| Characteristics | |
| Spectral type | Ap EuCrSr[5] |
| U−B color index | +0.11[6] |
| B−V color index | +0.22[6] |
| Variable type | α2 CVn[7] |
| Astrometry | |
| Radial velocity (Rv) | +19.6±5.0 km/s |
| Proper motion (μ) | RA: −27.94±0.61[3] mas/yr Dec.: −13.01±0.36[3] mas/yr |
| Parallax (π) | 6.92±0.61 mas[3] |
| Distance | 470 ± 40 ly (140 ± 10 pc) |
| Orbit[8] | |
| Name | KU Hya B |
| Period (P) | 52.98(37) yr |
| Semi-major axis (a) | 0.169(1)″ |
| Eccentricity (e) | 0.074(8) |
| Inclination (i) | 68.5(6)° |
| Longitude of the node (Ω) | 202.4(4)° |
| Periastron epoch (T) | 2020.20(45) |
| Argument of periastron (ω) (secondary) | 58.7(3.3)° |
| Details[7] | |
| KU Hya A | |
| Mass | 2.07 M☉ |
| KU Hya B | |
| Mass | 2.05 M☉ |
| Other designations | |
| BD−09° 2816, HD 81009, HIP 45999, HR 3724, SAO 136799, A 1342[5] | |
| Database references | |
| SIMBAD | data |
This star was discovered to be a visual binary star by Robert Grant Aitken in 1906 and was given the double star designation A 1342.[9] Additional measurements of the position angle and angular separation showed a rapid orbital motion.[10]
