Theta Gruis

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Theta Gruis
Observation data
Epoch J2000.0      Equinox J2000.0 (ICRS)
Constellation Grus
Right ascension 23h 06m 52.73046s[1]
Declination −43° 31′ 13.2857″[1]
Apparent magnitude (V) 4.28[2] (4.51 + 6.84 + 7.80)[3]
Spectral type kF3VhF5mF5(II-III)[4] + ? + G2V[3]
U−B color index +0.16[2]
B−V color index +0.42[2]
Radial velocity (Rv) +9.6[5] km/s
Proper motion (μ) RA: −47.17[1] mas/yr
Dec.: −13.49[1] mas/yr
Parallax (π) 24.73 ± 0.45[1] mas
Distance 132 ± 2 ly
(40.4 ± 0.7 pc)
θ Gru A
Rotational velocity (v sin i) 64[6] km/s
Other designations
θ Gru, CD−44° 15149, HD 218227, HIP 114131, HR 8787, SAO 231444[7]
Database references

Theta Gruis (θ Gruis) is a triple star[3] system in the southern constellation of Grus. Its combined apparent visual magnitude is 4.28,[2] which is bright enough to be seen with the naked eye. The system contains a magnetic Delta Delphini-like[8] F5 star with a close fainter companion, plus a more distant G2 main sequence star.[3]


  1. ^ a b c d e van Leeuwen, F. (2007), "Validation of the new Hipparcos reduction", Astronomy and Astrophysics, 474 (2): 653–664, Bibcode:2007A&A...474..653V, arXiv:0708.1752Freely accessible, doi:10.1051/0004-6361:20078357. 
  2. ^ a b c d Nicolet, B. (1978), "Photoelectric photometric Catalogue of homogeneous measurements in the UBV System", Astronomy and Astrophysics Supplement Series, 34: 1–49, Bibcode:1978A&AS...34....1N. 
  3. ^ a b c d 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, Bibcode:2008MNRAS.389..869E, arXiv:0806.2878Freely accessible, doi:10.1111/j.1365-2966.2008.13596.x. 
  4. ^ Gray, R. O.; Garrison, R. F. (1989), "The early F-type stars - Refined classification, confrontation with Stromgren photometry, and the effects of rotation", Astrophysical Journal Supplement Series (ISSN 0067-0049), 69: 301, Bibcode:1989ApJS...69..301G, doi:10.1086/191315. 
  5. ^ Wilson, R. E. (1953), General Catalogue of Stellar Radial Velocities, Carnegie Institute of Washington D.C., Bibcode:1953GCRV..C......0W. 
  6. ^ Uesugi, Akira; Fukuda, Ichiro (1970), "Catalogue of rotational velocities of the stars", Contributions from the Institute of Astrophysics and Kwasan Observatory, University of Kyoto, 
  7. ^ "tet Gru -- Double or multiple star", SIMBAD Astronomical Database, Centre de Données astronomiques de Strasbourg, retrieved 2017-06-26. 
  8. ^ Renson, P.; Manfroid, J. (May 2009), "Catalogue of Ap, HgMn and Am stars", Astronomy and Astrophysics, 498 (3): 961–966, Bibcode:2009A&A...498..961R, doi:10.1051/0004-6361/200810788.