Xi Hydrae

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Xi Hydrae
Observation data
Epoch J2000.0      Equinox J2000.0
Constellation Hydra
Right ascension 11h 33m 00.10s
Declination −31° 58′ 28.0″
Apparent magnitude (V) 3.54[1]
Spectral type G7 III[1]
Distance 129.275 ly
(39.635 pc)
Mass 2.89 ± 0.23[2] M
Radius 10.2 ± 0.1[2] R
Luminosity 57.65 ± 2.39[2] L
Temperature 4,984 ± 54[2] K
Metallicity [Fe/H] +0.21[2] dex
Rotational velocity (v sin i) 2.7[2] km/s
Other designations
288 G. Hydrae, HD 100407, HIP 56343, HR 4450, SAO 202558.

Xi Hydrae (ξ Hya, ξ Hydrae) is a fourth-magnitude star in the constellation Hydra. The star is situated 130 light-years from Earth and has a radius about 10 times that of the Sun. It is radiating 58 times as much luminosity as the Sun.[2] The star is now approaching the end of its life, and has expanded its outer envelope to become a red giant star.

The star Xi Hya was particularly interesting in the field of asteroseismology when an international group of astronomers discovered that it behaves like a giant sub-ultra-bass musical instrument.[3]

Xi Hydrae was a latter designation of 19 Crateris.[4]


  1. ^ a b Mallik, Sushma V. (December 1999), "Lithium abundance and mass", Astronomy and Astrophysics, 352: 495–507, Bibcode:1999A&A...352..495M 
  2. ^ a b c d e f g Bruntt, H.; et al. (July 2010), "Accurate fundamental parameters for 23 bright solar-type stars", Monthly Notices of the Royal Astronomical Society, 405 (3): 1907–1923, arXiv:1002.4268free to read, Bibcode:2010MNRAS.405.1907B, doi:10.1111/j.1365-2966.2010.16575.x 
  3. ^ http://www.innovations-report.com/html/reports/physics_astronomy/report-9950.html
  4. ^ Wagman, M. (August 1987). "Flamsteed's Missing Stars". Journal for the History of Astronomy, Vol.18, NO. 3/AUG, P.209, 1987. 18: 216. Bibcode:1987JHA....18..209W. 

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