Phi3 Hydrae

For other stars with this Bayer designation, see φ Hydrae
Phi3 Hydrae
Observation data
Epoch J2000.0      Equinox J2000.0 (ICRS)
Constellation Hydra
Right ascension 10h 38m 34.95281s[1]
Declination −16° 52′ 35.6665″[1]
Apparent magnitude (V) 4.90[2]
Characteristics
Spectral type G8 III[3]
B−V color index 0.912[4]
Astrometry
Radial velocity (Rv)+17.45±0.70[5] km/s
Proper motion (μ) RA: −98.92[1] mas/yr
Dec.: +25.84[1] mas/yr
Parallax (π)15.49 ± 0.57 mas[1]
Distance211 ± 8 ly
(65 ± 2 pc)
Absolute magnitude (MV)+0.89[6]
Orbit[2]
Period (P)1200 d
Eccentricity (e)0.1
Periastron epoch (T)2420760 JD
Argument of periastron (ω)
(secondary)		270°
Semi-amplitude (K1)
(primary)		4.0 km/s
Details
φ3 Hya
Mass2.04[3] M☉
Radius9[4] R☉
Luminosity48[3] L☉
Surface gravity (log g)2.95[6] cgs
Temperature4,952±17[3] K
Metallicity [Fe/H]−0.22±0.12[6] dex
Rotational velocity (v sin i)3.6[4] km/s
Age1.17[3] Gyr
Other designations
φ3 Hya, BD−16°3100, FK5 2850, HD 92214, HIP 52085, HR 4171, SAO 156122[7]
Database references
SIMBADdata

Phi3 Hydrae (φ3 Hya) is a binary star[2] in the equatorial constellation of Hydra. It originally received the Flamsteed designation of 2 Crateris before being placed in the Hydra constellation.[8] Based upon an annual parallax shift of 15.49 mas as seen from Earth, it is located around 211 light years from the Sun. It is visible to the naked eye with an apparent visual magnitude of 4.90.[2] It forms a triangle with the fainter φ1 Hydrae and φ2 Hydrae, between μ Hydrae and ν Hydrae.

This is a single-lined spectroscopic binary star system with an orbital period of about 1,200 days and an eccentricity of 0.1.[2] The primary, component A, is an evolved G-type giant star with a stellar classification of G8 III.[3] It is a red clump star,[9] which means it is generating energy through the fusion of helium at its core. The star has twice[3] the mass of the Sun and has expanded to 9[4] times the Sun's radius. It is 1.17[3] billion years old and is radiating 48[3] times the solar luminosity from its photosphere at an effective temperature of 4,952 K.[3]

  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 d e Cite error: The named reference Pourbaiz2004 was invoked but never defined (see the help page).
  3. ^ a b c d e f g h i j Cite error: The named reference Luck2015 was invoked but never defined (see the help page).
  4. ^ a b c d Cite error: The named reference Massarotti2008 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. ^ a b c Cite error: The named reference McWilliam1990 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 Wagman1987 was invoked but never defined (see the help page).
  9. ^ Cite error: The named reference Laney2012 was invoked but never defined (see the help page).