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) | 6.75 [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 |
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 [7] | |
Companion | 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 [8] | |
KU Hya A | |
Mass | 2.07 M☉ |
KU Hya B | |
Mass | 2.05 M☉ |
Other designations | |
Database references | |
SIMBAD | data |
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. [8]
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]