From Wikipedia, the free encyclopedia
(Redirected from Omega Eri)
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
SIMBAD data

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 is giving 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]

References

  1. ^ a b c d e van Leeuwen, F. (2007), "Validation of the new Hipparcos reduction", Astronomy and Astrophysics, 474 (2): 653–664, arXiv: 0708.1752, Bibcode: 2007A&A...474..653V, doi: 10.1051/0004-6361:20078357, S2CID  18759600.
  2. ^ a b c d Mermilliod, J.-C. (1986), "Compilation of Eggen's UBV data, transformed to UBV (unpublished)", Catalogue of Eggen's UBV Data, SIMBAD, Bibcode: 1986EgUBV........0M.
  3. ^ a b Abt, Helmut A.; Morrell, Nidia I. (July 1995), "The Relation between Rotational Velocities and Spectral Peculiarities among A-Type Stars", Astrophysical Journal Supplement, 99: 135, Bibcode: 1995ApJS...99..135A, doi: 10.1086/192182.
  4. ^ De Bruijne, J. H. J.; Eilers, A.-C. (2012), "Radial velocities for the HIPPARCOS-Gaia Hundred-Thousand-Proper-Motion project", Astronomy & Astrophysics, 546: A61, arXiv: 1208.3048, Bibcode: 2012A&A...546A..61D, doi: 10.1051/0004-6361/201219219, S2CID  59451347.
  5. ^ a b c Giridhar, S.; et al. (August 2013), "Identification of metal-poor stars using the artificial neural network", Astronomy & Astrophysics, 556: 11, arXiv: 1307.6308, Bibcode: 2013A&A...556A.121G, doi: 10.1051/0004-6361/201219918, S2CID  118316149, A121.
  6. ^ Pourbaix, D.; et al. (2004), "SB9: The ninth catalogue of spectroscopic binary orbits", Astronomy and Astrophysics, 424 (2): 727–732, arXiv: astro-ph/0406573, Bibcode: 2004A&A...424..727P, doi: 10.1051/0004-6361:20041213, S2CID  119387088.
  7. ^ a b Lang, Kenneth R. (2006), Astrophysical formulae, Astronomy and astrophysics library, vol. 1 (3rd ed.), Birkhäuser, ISBN  3-540-29692-1. The radius (R*) is given by:
  8. ^ a b McDonald, I.; et al. (2012), "Fundamental Parameters and Infrared Excesses of Hipparcos Stars", Monthly Notices of the Royal Astronomical Society, 427 (1): 343–57, arXiv: 1208.2037, Bibcode: 2012MNRAS.427..343M, doi: 10.1111/j.1365-2966.2012.21873.x, S2CID  118665352.
  9. ^ a b c d Royer, F.; et al. (February 2007), "Rotational velocities of A-type stars. III. Velocity distributions", Astronomy and Astrophysics, 463 (2): 671–682, arXiv: astro-ph/0610785, Bibcode: 2007A&A...463..671R, doi: 10.1051/0004-6361:20065224, S2CID  18475298.
  10. ^ "* ome Eri -- Spectroscopic binary". SIMBAD. Centre de données astronomiques de Strasbourg. Retrieved 2016-11-03.{{ cite web}}: CS1 maint: postscript ( link)
  11. ^ Abt, Helmut A.; Boonyarak, Chayan (November 2004), "Tidal Effects in Binaries of Various Periods", The Astrophysical Journal, 616 (1): 562–566, Bibcode: 2004ApJ...616..562A, doi: 10.1086/423795.
  12. ^ van Belle, Gerard T., Gerard T. (March 2012), "Interferometric observations of rapidly rotating stars", The Astronomy and Astrophysics Review, 20 (1): 51, arXiv: 1204.2572, Bibcode: 2012A&ARv..20...51V, doi: 10.1007/s00159-012-0051-2, S2CID  119273474.
Retrieved from " https://en.wikipedia.org/?title=Omega_Eridani&oldid=1170225457"