Gamma Reticuli

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]

A light curve for Gamma Reticuli, plotted from Hipparcos data[11]
Gamma Reticuli
Diagram showing star positions and boundaries of the Reticulum constellation and its surroundings
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]
Characteristics
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]
Astrometry
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 mas[1]
Distance469 ± 7 ly
(144 ± 2 pc)
Absolute magnitude (MV)−1.31[7]
Details
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
SIMBADdata

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.[12]

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, S2CID 18759600.
  2. Mermilliod, J.-C. (1986), "Compilation of Eggen's UBV data, transformed to UBV (unpublished)", Catalogue of Eggen's UBV Data, SIMBAD, Bibcode:1986EgUBV........0M.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. 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. Houk, Nancy; Cowley, A. P. (1979), Michigan catalogue of two-dimensional spectral types for the HD stars, vol. 1, Ann Arbor, Michigan: Dept. of Astronomy, University of Michigan, Bibcode:1978mcts.book.....H.
  5. 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, S2CID 49573767.
  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, S2CID 59451347, 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, S2CID 119257644.
  8. 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. "gam Ret". SIMBAD. Centre de données astronomiques de Strasbourg. Retrieved 2017-02-13.{{cite web}}: CS1 maint: postscript (link)
  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, S2CID 14878976.
  11. "/ftp/cats/more/HIP/cdroms/cats". Centre de Données astronomiques de Strasbourg. Strasbourg astronomical Data Center. Retrieved 30 December 2022.
  12. Gamma Reticuli (HIP 18744) Archived 2014-04-14 at the Wayback Machine
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