Mu Hydrae

μ Hydrae
Observation data
Epoch J2000.0      Equinox J2000.0 (ICRS)
Constellation Hydra
Right ascension 10h 26m 05.42630s[1]
Declination −14° 19′ 56.2675″[1]
Apparent magnitude (V) 3.83[2]
Characteristics
Spectral type K4 III[3]
U−B color index +1.83[2]
B−V color index +1.47[2]
Variable type Suspected[4]
Astrometry
Radial velocity (Rv)+40.81±0.36[5] km/s
Proper motion (μ) RA: −129.17[1] mas/yr
Dec.: −79.76[1] mas/yr
Parallax (π)13.93 ± 0.18 mas[1]
Distance234 ± 3 ly
(71.8 ± 0.9 pc)
Absolute magnitude (MV)−0.45[6]
Details[5]
Radius45 R☉
Luminosity332[6] L☉
Surface gravity (log g)1.5 cgs
Temperature3,999±8 K
Metallicity [Fe/H]−0.12 dex
Rotational velocity (v sin i)6.0 km/s
Other designations
μ Hya, 42 Hydrae, BD−16° 3052, FK5 389, HD 90432, HIP 51069, HR 4094, SAO 155980.[7]
Database references
SIMBADdata

μ Hydrae, Latinised as Mu Hydrae, is a solitary,[8] orange-hued star in the equatorial constellation of Hydra. It is visible to the naked eye with an apparent visual magnitude of 3.83.[2] Positioned just 1.8° to the south-southwest is the planetary nebula NGC 3242.[9] Mu Hydrae has an annual parallax shift of 13.93 mas,[1] which yields a distance estimate of 234 light years.

This is an evolved K-type giant star with a stellar classification of K4 III,[3] having used up its core hydrogen and has expanded to around 45 times the radius of the Sun.[5] It is a suspected variable star, with a brightness that varies about 0.03 in magnitude.[4] The relatively cool outer atmosphere has an effective temperature of 3999 K.[5]

  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 c d Cite error: The named reference Mermilliod1986 was invoked but never defined (see the help page).
  3. ^ a b Cite error: The named reference Houk1988 was invoked but never defined (see the help page).
  4. ^ a b Cite error: The named reference gcvs2009 was invoked but never defined (see the help page).
  5. ^ a b c d Cite error: The named reference Massarotti2008 was invoked but never defined (see the help page).
  6. ^ a b Cite error: The named reference Anderson2012 was invoked but never defined (see the help page).
  7. ^ Cite error: The named reference SIMBAD was invoked but never defined (see the help page).
  8. ^ Cite error: The named reference Eggleton2008 was invoked but never defined (see the help page).
  9. ^ Cite error: The named reference OMeara2007 was invoked but never defined (see the help page).