# Zeta Apodis

"ζ Apodis" redirects here. It is not to be confused with Z Apodis.
Observation data Constellation Epoch J2000      Equinox J2000 Location of ζ Apodis (circled) Apus 17h 21m 59.47633s[1] −67° 46′ 14.4072″[1] +4.78[2] K2 III[3] +1.27[2] +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) Radius 20[5] R☉ Temperature 4,388[6] K CP-67 3310, FK5 3374, HD 156277, HIP 84969, HR 6417, SAO 253882.[7]

Zeta Apodis (ζ Aps, 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.[8] At the estimated distance of Eta Draconis,[1] this yields a physical size of about 11 times the radius of the Sun.[5] The outer atmosphere has an effective temperature of 4,388 K,[6] which gives it the orange-hued glow of a K-type star.[9]

## Naming

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.)[10]

## References

1. van Leeuwen, F. (November 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 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 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:
{\displaystyle {\begin{aligned}2\cdot R_{*}&={\frac {(91\cdot 2.06\cdot 10^{-3})\ {\text{AU}}}{0.0046491\ {\text{AU}}/R_{\bigodot }}}\\&\approx 40\cdot R_{\bigodot }\end{aligned}}}
6. ^ 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.
7. ^ "zet Aps -- Star", SIMBAD Astronomical Object Database, Centre de Données astronomiques de Strasbourg, retrieved 2012-02-04
8. ^ 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.
9. ^ "The Colour of Stars", Australia Telescope, Outreach and Education, Commonwealth Scientific and Industrial Research Organisation, December 21, 2004, retrieved 2012-01-16.
10. ^