39 Eridani

39 Eridani
Observation data
Epoch J2000.0      Equinox J2000.0
Constellation Eridanus
Right ascension 04h 14m 23.68902s[1]
Declination −10° 15′ 22.6083″[1]
Apparent magnitude (V) 4.87[2] (5.07 + 8.68)[3]
Characteristics
Spectral type K3 III + G2 V[3]
B−V color index 1.156±0.003[2]
Astrometry
Radial velocity (Rv)6.8±0.8[2] km/s
Proper motion (μ) RA: −7.19[1] mas/yr
Dec.: −161.05[1] mas/yr
Parallax (π)13.46 ± 0.60 mas[1]
Distance240 ± 10 ly
(74 ± 3 pc)
Absolute magnitude (MV)0.52[2]
Details
39 Eri A
Mass1.77±0.49[4] M☉
Radius12[5] R☉
Luminosity81.3[6] L☉
Surface gravity (log g)2.42±0.11[4] cgs
Temperature4,641±92[4] K
Metallicity [Fe/H]0.18±0.06[2] dex
Rotational velocity (v sin i)1.6[5] km/s
Age1.12+0.36
−0.27[4] Gyr
39 Eri B
Radius1.15+0.10
−0.06[7] R☉
Luminosity1.369+0.07
−0.06[7] L☉
Temperature5,816+168
−223[7] K
Other designations
39 Eri, BD−10°867, GC 5114, HD 26846, HIP 19777, HR 1318, SAO 149478, WDS J04144-1015[8]
Database references
SIMBADdata

39 Eridani is a wide binary star[3] system in the equatorial constellation of Eridanus. It is visible to the naked eye as a faint, orange-hued star with a combined apparent visual magnitude of 4.87.[2] As of 2015, the components had an angular separation of 6.4″ along a position angle of 143°.[9] The system is moving further from the Sun with a heliocentric radial velocity of +7 km/s.[2]

The magnitude 5.07[3] primary, designated component A, is an aging giant star with a stellar classification of K3 III.[3] This object is more than a billion[4] years old with 1.77[4] times the mass of the Sun. With the hydrogen at its core exhausted, the star has expanded to 12[5] times the Sun's radius. It is a candidate super metal-rich star, showing a significant overabundance of iron compared to the Sun.[10] 39 Eridani A is radiating 81.3[6] times the luminosity of the Sun from its swollen photosphere at an effective temperature of 4,641 K.[4]

The secondary, component B, is a magnitude 8.68[3] G-type main-sequence star with a class of G2 V.[3] It has 1.15[7] times the Sun's radius and shines with 1.37 times the luminosity of the Sun at an effective temperature of 5,816 K.[7]

  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 f g Cite error: The named reference Anderson2012 was invoked but never defined (see the help page).
  3. ^ a b c d e f g Cite error: The named reference Eggleton2008 was invoked but never defined (see the help page).
  4. ^ a b c d e f g Cite error: The named reference feuillet2016 was invoked but never defined (see the help page).
  5. ^ a b c Cite error: The named reference Massarotti2008 was invoked but never defined (see the help page).
  6. ^ a b Cite error: The named reference Luck2015 was invoked but never defined (see the help page).
  7. ^ a b c d e Cite error: The named reference GaiaDR2B 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 WDSC2014 was invoked but never defined (see the help page).
  10. ^ Cite error: The named reference Buzzoni2001 was invoked but never defined (see the help page).