Gamma Reticuli

From Wikipedia, the free encyclopedia
Jump to navigation Jump to search

Gamma Reticuli
Diagram showing star positions and boundaries of the Reticulum constellation and its surroundings
Cercle rouge 100%.svg
Location of γ Reticuli (circled)
Observation data
Epoch J2000.0      Equinox J2000.0 (ICRS)
Constellation Reticulum
Right ascension  04h 00m 53.80860s[1]
Declination −62° 09′ 33.4250″[1]
Apparent magnitude (V) 4.5[2]
Evolutionary stage asymptotic giant branch[3]
Spectral type M4 III[4]
U−B color index +1.81[2]
B−V color index +1.66[2]
Variable type SR[5]
Radial velocity (Rv)−7.0±2.7[6] km/s
Proper motion (μ) RA: +3.03[1] mas/yr
Dec.: +34.67[1] mas/yr
Parallax (π)6.95 ± 0.11[1] mas
Distance469 ± 7 ly
(144 ± 2 pc)
Absolute magnitude (MV)−1.31[7]
Mass1.5−2[5] M
Radius115[5] R
Luminosity1,846[8] L
Surface gravity (log g)0.8[5] cgs
Temperature3,599[8] K
Metallicity [Fe/H]0.0[5] dex
Other designations
γ Ret, CD−62° 149, HD 25705, HIP 18744, HR 1264, SAO 248925.[9]
Database references

Gamma Reticuli (Gamma Ret, γ Reticuli, γ Ret) is a solitary[10] star in the southern constellation of Reticulum. With an apparent visual magnitude of 4.5,[2] it can be faintly seen with the naked eye. Based upon an annual parallax shift of 6.95 mas,[1] it is located roughly 469 light years from the Sun. At that distance, the visual magnitude is diminished by an extinction factor of 0.08 due to interstellar dust.[5]

This is an evolved red giant star, currently on the asymptotic giant branch,[3] with a stellar classification of M4 III.[4] It is a semiregular variable with a period of 25 days.[5] Gamma Reticuli has 1.5−2 times the mass of the Sun, 115 times the Sun's radius,[5] and radiates 1,846 times the solar luminosity from its outer atmosphere at an effective temperature of 3,450 K.[8]

Gamma Reticuli is moving through the Galaxy at a speed of 24.8 km/s relative to the Sun. Its projected Galactic orbit carries it between 24,100 and 39,200 light years from the center of the Galaxy.[11]


  1. ^ a b c d e f 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. ^ a b c d Mermilliod, J.-C. (1986), "Compilation of Eggen's UBV data, transformed to UBV (unpublished)", Catalogue of Eggen's UBV Data, SIMBAD, Bibcode:1986EgUBV........0M.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 Eggen, Olin J. (July 1992), "Asymptotic giant branch stars near the sun", Astronomical Journal, 104 (1): 275–313, Bibcode:1992AJ....104..275E, doi:10.1086/116239.
  4. ^ a b 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,
  5. ^ a b c d e f g h Cruzalèbes, P.; et al. (September 2013), "Fundamental parameters of 16 late-type stars derived from their angular diameter measured with VLTI/AMBER", Monthly Notices of the Royal Astronomical Society, 434 (1): 437–450, arXiv:1306.3288, Bibcode:2013MNRAS.434..437C, doi:10.1093/mnras/stt1037.
  6. ^ 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.
  7. ^ Anderson, E.; Francis, Ch. (2012), "XHIP: An extended hipparcos compilation", Astronomy Letters, 38 (5): 331, arXiv:1108.4971, Bibcode:2012AstL...38..331A, doi:10.1134/S1063773712050015.
  8. ^ a b c 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.
  9. ^ "gam Ret". SIMBAD. Centre de données astronomiques de Strasbourg. Retrieved 2017-02-13.
  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. ^ Gamma Reticuli (HIP 18744) Archived 2014-04-14 at the Wayback Machine