Zeta Apodis

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Zeta Apodis
Diagram showing star positions and boundaries of the Ara constellation and its surroundings
Cercle rouge 100%.svg

Location of ζ Apodis (circled)
Observation data
Epoch J2000      Equinox J2000
Constellation Apus
Right ascension 17h 21m 59.47633s[1]
Declination −67° 46′ 14.4072″[1]
Apparent magnitude (V) +4.78[2]
Spectral type K2 III[3]
U−B color index +1.27[2]
B−V color index +1.21[2]
Radial velocity (Rv) +12.6[4] km/s
Proper motion (μ) RA: –37.85[1] mas/yr
Dec.: –7.91[1] mas/yr
Parallax (π) 10.97 ± 0.29[1] mas
Distance 297 ± 8 ly
(91 ± 2 pc)
Absolute magnitude (MV) −0.04[5]
Radius 20[6] R
Luminosity 154[5] L
Temperature 4,388[7] K
Other designations
ζ Aps, CP-67 3310, FK5 3374, HD 156277, HIP 84969, HR 6417, SAO 253882.[8]
Database references

Zeta Apodis, Latinized from ζ Apodis, is the Bayer designation for a star in the southern constellation of Apus. It has an apparent visual magnitude of +4.78,[2] which is bright enough to allow it to be seen with the naked eye. The distance to this star is known from parallax measurements to be around 297 light-years (91 parsecs).[1]

The spectrum of Zeta Apodis matches a stellar classification of K2 III,[3] with the luminosity class of III indicating it is an evolved giant star. The measured angular diameter of this star, after correction for limb darkening, is 2.06 ± 0.02 mas.[9] At the estimated distance of Eta Draconis,[1] this yields a physical size of about 11 times the radius of the Sun.[6] The outer atmosphere has an effective temperature of 4,388 K,[7] which gives it the orange-hued glow of a K-type star.[10]


In Chinese caused by adaptation of the European southern hemisphere constellations into the Chinese system, 異雀 (Yì Què), meaning Exotic Bird, refers to an asterism consisting of ζ Apodis, ι Apodis, β Apodis, γ Apodis, δ Octantis, δ1 Apodis, η Apodis, α Apodis and ε Apodis. Consequently, ζ Apodis itself is known as 異雀一 (Yì Què yī, English: the First Star of Exotic Bird.)[11]


  1. ^ a b c d e f g van Leeuwen, F. (November 2007), "Validation of the new Hipparcos reduction", Astronomy and Astrophysics, 474 (2): 653–664, arXiv:0708.1752Freely accessible, Bibcode:2007A&A...474..653V, doi:10.1051/0004-6361:20078357. 
  2. ^ a b c d Johnson, H. L.; et al. (1966), "UBVRIJKL photometry of the bright stars", Communications of the Lunar and Planetary Laboratory, 4 (99), Bibcode:1966CoLPL...4...99J. 
  3. ^ a b Houk, Nancy; Cowley, A. P. (1978), Michigan catalogue of two-dimensional spectral types for the HD stars, 1, Ann Arbor: Dept. of Astronomy, University of Michigan, Bibcode:1975mcts.book.....H. 
  4. ^ Wilson, R. E. (1953), General Catalogue of Stellar Radial Velocities, Carnegie Institute of Washington D.C., Bibcode:1953GCRV..C......0W. 
  5. ^ a b Anderson, E.; Francis, Ch. (2012), "XHIP: An extended hipparcos compilation", Astronomy Letters, 38 (5): 331, arXiv:1108.4971Freely accessible, Bibcode:2012AstL...38..331A, doi:10.1134/S1063773712050015. 
  6. ^ a b Lang, Kenneth R. (2006), Astrophysical formulae, Astronomy and astrophysics library, 1 (3rd ed.), Birkhäuser, ISBN 3-540-29692-1. . The radius (R*) is given by:
  7. ^ a b di Benedetto, G. P. (November 1998), "Towards a fundamental calibration of stellar parameters of A, F, G, K dwarfs and giants", Astronomy and Astrophysics, 339: 858–871, Bibcode:1998A&A...339..858D. 
  8. ^ "zet Aps -- Star", SIMBAD Astronomical Object Database, Centre de Données astronomiques de Strasbourg, retrieved 2012-02-04 
  9. ^ Richichi, A.; Percheron, I.; Khristoforova, M. (February 2005), "CHARM2: An updated Catalog of High Angular Resolution Measurements", Astronomy and Astrophysics, 431: 773–777, Bibcode:2005A&A...431..773R, doi:10.1051/0004-6361:20042039. 
  10. ^ "The Colour of Stars", Australia Telescope, Outreach and Education, Commonwealth Scientific and Industrial Research Organisation, December 21, 2004, retrieved 2012-01-16. 
  11. ^ (in Chinese) AEEA (Activities of Exhibition and Education in Astronomy) 天文教育資訊網 2006 年 7 月 29 日