Eta Reticuli

Eta Reticuli (Eta Ret, η Reticuli, η Ret) is a solitary[10] star in the southern constellation of Reticulum. With an apparent visual magnitude of 5.22,[2] it is faintly visible to the naked eye on a dark night. Based upon an annual parallax shift of 8.48 mas,[1] it is located at a distance of roughly 385 light years from the Sun. It may be a member of the high-velocity Zeta Herculis Moving Group of stars that share a common motion through space.[5]

Eta Reticuli
Location of η Reticuli (circled)
Observation data
Epoch J2000.0      Equinox J2000.0 (ICRS)
Constellation Reticulum
Right ascension  04h 21m 53.32714s[1]
Declination −63° 23′ 11.0072″[1]
Apparent magnitude (V) 5.22[2]
Characteristics
Spectral type G7 III[3]
U−B color index +0.62[2]
B−V color index +0.945[2]
Astrometry
Radial velocity (Rv)+45.0±0.8[4] km/s
Proper motion (μ) RA: +85.56[1] mas/yr
Dec.: +174.62[1] mas/yr
Parallax (π)8.48 ± 0.18[1] mas
Distance385 ± 8 ly
(118 ± 3 pc)
Absolute magnitude (MV)+1.28[5]
Details[6]
Mass2.54 M☉
Radius12[7] R☉
Luminosity120 L☉
Surface gravity (log g)2.49 cgs
Temperature4,951±48 K
Metallicity [Fe/H]−0.15±0.03[8] dex
Age1.17 Gyr
Other designations
η Ret, CPD−63 324, FK5 163, HD 28093, HIP 20384, HR 1395, SAO 249009.[9]
Database references
SIMBADdata

This is an evolved G-type giant star with a stellar classification of G7 III.[3] Based upon stellar models, it has an estimated 2.54[6] times the mass of the Sun and 13.24[7] times the Sun's radius. With an age of around 1.17 billion years, it is radiating 120 times the solar luminosity from its outer atmosphere at an effective temperature of 4,948 K.[6]

Eta Reticuli is moving through the Galaxy at a speed of 117.6 km/s relative to the Sun. Its projected Galactic orbit carries it between 11,700 and 31,600 light years from the center of the Galaxy.[11]

References
  1. 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.
  2. Mermilliod, J.-C. (1986), "Compilation of Eggen's UBV data, transformed to UBV (unpublished)", Catalogue of Eggen's UBV Data, Bibcode:1986EgUBV........0M.
  3. Houk, Nancy; Cowley, A. P. (1979), Michigan catalogue of two-dimensional spectral types for the HD stars, 1, Ann Arbor, Michigan: Dept. of Astronomy, University of Michigan, Bibcode:1978mcts.book.....H.
  4. de Bruijne, J. H. J.; Eilers, A.-C. (October 2012), "Radial velocities for the HIPPARCOS-Gaia Hundred-Thousand-Proper-Motion project", Astronomy & Astrophysics, 546: 14, arXiv:1208.3048, Bibcode:2012A&A...546A..61D, doi:10.1051/0004-6361/201219219, A61.
  5. Eggen, O. J. (1958), "Stellar groups. II. The ζ Herculis, ɛ Indi and 61 Cygni groups of high-velocity stars", Monthly Notices of the Royal Astronomical Society, 118 (2): 154, Bibcode:1958MNRAS.118..154E, doi:10.1093/mnras/118.2.154.
  6. Luck, R. Earle (September 2015), "Abundances in the Local Region. I. G and K Giants", The Astronomical Journal, 150 (3): 23, arXiv:1507.01466, Bibcode:2015AJ....150...88L, doi:10.1088/0004-6256/150/3/88, 88.
  7. Pasinetti Fracassini, L. E.; et al. (2001), "Catalogue of Apparent Diameters and Absolute Radii of Stars (CADARS)", Astronomy & Astrophysics (3rd ed.), 367 (2): 521–24, arXiv:astro-ph/0012289, Bibcode:2001A&A...367..521P, doi:10.1051/0004-6361:20000451.
  8. Alves, S.; et al. (April 2015), "Determination of the spectroscopic stellar parameters for 257 field giant stars", Monthly Notices of the Royal Astronomical Society, 448 (3): 2749–2765, arXiv:1503.02556, Bibcode:2015MNRAS.448.2749A, doi:10.1093/mnras/stv189.
  9. "eta Ret". SIMBAD. Centre de données astronomiques de Strasbourg. Retrieved 2017-02-15.
  10. Eggleton, P. P.; Tokovinin, A. A. (September 2008), "A catalogue of multiplicity among bright stellar systems", Monthly Notices of the Royal Astronomical Society, 389 (2): 869–879, arXiv:0806.2878, Bibcode:2008MNRAS.389..869E, doi:10.1111/j.1365-2966.2008.13596.x.
  11. Eta Reticuli (HIP 20384)
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