Tau Hydrae

Starbox short
name=τ¹ Hydrae
epoch=J2000.0
constell=Hydra
ra=9^h 29^m 8.9^s
dec=-2° 46' 8"
spectral=F6V
appmag_v=+4.59
dist_ly=56
dist_pc=17.18
names=Ukdah, 31 Hydrae HR 3759,
HD 81997, SAO 136895,
HIP 46509, CCDM J09291-0246A

The Bayer designation Tau Hydrae (τ Hya / τ Hydrae) is shared by two star systems, τ¹ Hydrae and τ² Hydrae, in the constellation Hydra. The two stars are separated by 1.74° on the sky. Tau Hydrae also has the traditional name Ukdah, from the Arabic عقدة "uqdah" meaning "the Knot".

τ¹ Hydrae

Tau-1 Hydrae, also called Ukdah Prima ("First [Star] of the Knot"), is a binary star lying 56 light years from Earth. Tau-1 Hydrae is a spectral type F6 main sequence star which has an apparent magnitude of +4.59.

τ² Hydrae

Starbox short
name=τ² Hydrae
epoch=J2000.0
constell=Hydra
ra=9^h 31^m 58.9^s
dec=-1° 11' 6"
spectral=A3V
appmag_v=+4.54
dist_ly=460
dist_pc=141.10
names=Ukdah, 32 Hydrae, HR 3787,
HD 82446, SAO 136932,
HIP 46776

Tau-2 Hydrae, also called Ukdah Secunda ("Second [Star] of the Knot"), is a spectral type A3 main sequence star which has an apparent magnitude of +4.54. It is about 460 light years from Earth.

References

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External links

* [http://www.alcyone.de/SIT/bsc/ Yale Bright Star Catalog; click on Hydra]