Xi Hydrae

Xi Hydrae
Observation data
Epoch J2000.0      Equinox J2000.0 (ICRS)
Constellation Hydra
Right ascension 11h 33m 00.11505s[1]
Declination −31° 51′ 27.4435″[1]
Apparent magnitude (V) 3.54[2]
Characteristics
Spectral type G7 III[2]
Astrometry
Radial velocity (Rv)−4.90±0.30[3] km/s
Proper motion (μ) RA: −209.62[1] mas/yr
Dec.: −40.84[1] mas/yr
Parallax (π)25.16 ± 0.16 mas[1]
Distance129.6 ± 0.8 ly
(39.7 ± 0.3 pc)
Absolute magnitude (MV)+0.54[4]
Details
Mass2.94±0.15[5] M☉
Radius10.2±0.1[6] R☉
Luminosity57.65±2.39[6] L☉
Surface gravity (log g)2.87±0.02[5] cgs
Temperature5,044±40[5] K
Metallicity [Fe/H]+0.16±0.20[5] dex
Rotational velocity (v sin i)2.7[6] km/s
Other designations
ξ Hya, 288 G. Hydrae,[7] CD−31° 9083, HD 100407, HIP 56343, HR 4450, SAO 202558[8]
Database references
SIMBADdata
One possible non-radial oscillation mode of Xi Hydrae

Xi Hydrae, Latinised from ξ Hydrae, is a solitary[9] star in the equatorial constellation of Hydra. It was also given the Flamsteed designation 19 Crateris. This magnitude 3.54[2] 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.[6]

Flamsteed gave Xi Hydrae the designation 19 Crateris. He included a number of stars now within the IAU boundaries of Hydra as part of a Hydra & Crater constellation overlapping parts of both modern constellations.[10]

The star Xi Hydrae is particularly interesting in the field of asteroseismology since it shows solar-like oscillations. Multiple frequency oscillations are found with periods between 2.0 and 5.5 hours.[11]

Xi Hydrae has left the main sequence, having exhausted the supply of hydrogen in its core. Its spectrum is that of a red giant. Modelling its physical properties against theoretical evolutionary tracks shows that it has just reached the foot of the red giant branch for a star with an initial mass around 3 M☉. This puts its age at about 510 myr.[12]

  1. ^ a b c d e Cite error: The named reference vanLeeuwen2007 was invoked but never defined (see the help page).
  2. ^ a b c Cite error: The named reference Mallik1999 was invoked but never defined (see the help page).
  3. ^ Cite error: The named reference deBruijne2012 was invoked but never defined (see the help page).
  4. ^ Cite error: The named reference Anderson2012 was invoked but never defined (see the help page).
  5. ^ a b c d Cite error: The named reference Heiter2015 was invoked but never defined (see the help page).
  6. ^ a b c d Cite error: The named reference Bruntt2010 was invoked but never defined (see the help page).
  7. ^ Cite error: The named reference gould was invoked but never defined (see the help page).
  8. ^ Cite error: The named reference SIMBAD was invoked but never defined (see the help page).
  9. ^ Cite error: The named reference Eggleton2008 was invoked but never defined (see the help page).
  10. ^ Cite error: The named reference Wagman1987 was invoked but never defined (see the help page).
  11. ^ Cite error: The named reference frandsen was invoked but never defined (see the help page).
  12. ^ Cite error: The named reference thevenin was invoked but never defined (see the help page).