Gamma Hydri

Gamma Hydri
Observation data
Epoch J2000.0      Equinox J2000.0 (ICRS)
Constellation Hydrus
Right ascension 03h 47m 14.34062s[1]
Declination −74° 14′ 20.2686″[1]
Apparent magnitude (V) 3.26[2]
Characteristics
Spectral type M1 III[3]
U−B color index +1.98[4]
B−V color index +1.62[4]
Astrometry
Radial velocity (Rv)+15.8±0.6[5] km/s
Proper motion (μ) RA: +50.85[1] mas/yr
Dec.: +114.74[1] mas/yr
Parallax (π)15.24 ± 0.11 mas[1]
Distance214 ± 2 ly
(65.6 ± 0.5 pc)
Absolute magnitude (MV)−0.83[6]
Details[7]
Mass1.0 M☉
Radius62±1 R☉
Luminosity513 L☉
Surface gravity (log g)0.84 cgs
Temperature3499 K
Metallicity [Fe/H]0.0 dex
Other designations
γ Hyi, CD−74° 276, HD 24512, HIP 17678, HR 1208, SAO 256029[8]
Database references
SIMBADdata

γ Hydri, Latinised as Gamma Hydri, is a solitary,[9] red-hued star in the constellation Hydrus. It has an apparent visual magnitude of 3.26,[2] making it easily visible to the naked eye at night. Based upon an annual parallax shift of 15.24 mas as measured from Earth,[1] the system is located about 214 light-years from the Sun.

This is an evolved red giant star with a stellar classification of M1 III,[3] and is most likely on the asymptotic giant branch of the HR diagram.[10] It is a semiregular variable that pulsates between magnitudes 3.26 and 3.33, although its period is not known precisely.[11] It has about the same mass as the Sun, but has expanded to around 62 times the Sun's radius. The star is radiating 513 times the Sun's luminosity from its enlarged photosphere at an effective temperature of 3,499 K.[7]

  1. ^ a b c d e f Cite error: The named reference vanLeeuwen2007 was invoked but never defined (see the help page).
  2. ^ a b Cite error: The named reference Ducati2002 was invoked but never defined (see the help page).
  3. ^ a b Cite error: The named reference houk1979 was invoked but never defined (see the help page).
  4. ^ a b Cite error: The named reference Johnson1966 was invoked but never defined (see the help page).
  5. ^ Cite error: The named reference deBruijne2012 was invoked but never defined (see the help page).
  6. ^ Cite error: The named reference Cardini2005 was invoked but never defined (see the help page).
  7. ^ a b Cite error: The named reference Cruzalebes2013 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 eggen1992 was invoked but never defined (see the help page).
  11. ^ Cite error: The named reference Tabur2009 was invoked but never defined (see the help page).