Omega Eridani

ω Eridani
Observation data
Epoch J2000.0      Equinox J2000.0 (ICRS)
Constellation Eridanus
Right ascension 04h 52m 53.66995s[1]
Declination −05° 27′ 09.6972″[1]
Apparent magnitude (V) 4.37[2]
Characteristics
Spectral type A9 IVn[3]
U−B color index +0.12[2]
B−V color index +0.26[2]
Astrometry
Radial velocity (Rv)−8.3[4] km/s
Proper motion (μ) RA: −17.86[1] mas/yr
Dec.: +25.57[1] mas/yr
Parallax (π)13.88 ± 0.24 mas[1]
Distance235 ± 4 ly
(72 ± 1 pc)
Absolute magnitude (MV)0.10[5]
Orbit[6]
Period (P)3,057 d
Eccentricity (e)0.46
Periastron epoch (T)2419973.0 JD
Argument of periastron (ω)
(secondary)		227°
Semi-amplitude (K1)
(primary)		18.1 km/s
Details
Radius6.7[7] R☉
Luminosity69[8] L☉
Surface gravity (log g)3.4[5] cgs
Temperature6,878[8] K
Metallicity [Fe/H]0.18[5] dex
Rotational velocity (v sin i)186[9] km/s
Other designations
ω Eri, BD−05° 1068, 61 Eridani, HD 31109, HIP 22701, HR 1560, SAO 131568.[10]
Database references
SIMBADdata

Omega Eridani (ω Eri) is a binary star[9] system in the constellation Eridanus. It is visible to the naked eye with an apparent visual magnitude is 4.37.[2] The distance to this star, as determined by the parallax method, is around 235 light years.

This is a single-lined spectroscopic binary[11] system with an orbital period of 3,057 days (8.4 years) and an eccentricity of 0.46. The primary component is an A-type subgiant star with a stellar classification of A9 IVn,[3] where the 'n' suffix indicates a broad ("nebulous") absorption due to rotation. The projected rotational velocity is 186[9] km/s.[9] This gives the star an oblate shape with an equator that is 13% wider than the polar radius. The angular size of Omega Eridani is 0.87 mas.[12] At an estimated distance of the star, this yields a physical size of around 6.7 times the radius of the Sun.[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 Cite error: The named reference Mermilliod1986 was invoked but never defined (see the help page).
  3. ^ a b Cite error: The named reference Abt1995 was invoked but never defined (see the help page).
  4. ^ Cite error: The named reference DeBruijne2012 was invoked but never defined (see the help page).
  5. ^ a b c Cite error: The named reference Giridhar2013 was invoked but never defined (see the help page).
  6. ^ Cite error: The named reference pourbaix2004 was invoked but never defined (see the help page).
  7. ^ a b Cite error: The named reference lang2006 was invoked but never defined (see the help page).
  8. ^ a b Cite error: The named reference Mcdonald2012 was invoked but never defined (see the help page).
  9. ^ a b c d Cite error: The named reference Royer2007 was invoked but never defined (see the help page).
  10. ^ Cite error: The named reference SIMBAD was invoked but never defined (see the help page).
  11. ^ Cite error: The named reference Abt2004 was invoked but never defined (see the help page).
  12. ^ Cite error: The named reference vanBelle2012 was invoked but never defined (see the help page).