Alpha Apodis

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

Location of α Apodis (circled)
Observation data
Epoch J2000.0      Equinox J2000.0 (ICRS)
Constellation Apus
Right ascension 14h 47m 51.71203s[1]
Declination −79° 02′ 41.1032″[1]
Apparent magnitude (V) 3.825[2]
Characteristics
Spectral type K2.5III[2]
U−B color index +1.68[3]
B−V color index +1.43[3]
R−I color index +0.53[4]
Astrometry
Radial velocity (Rv) −1.1[5] km/s
Proper motion (μ) RA: −4.58[1] mas/yr
Dec.: −15.88[1] mas/yr
Parallax (π) 7.30 ± 0.13[1] mas
Distance 447 ± 8 ly
(137 ± 2 pc)
Details
Radius 48[6] R
Luminosity (bolometric) 980[7] L
Temperature 4,256[7] K
Other designations
α Aps, Alpha Apodis, Alpha Aps, FK5 542, HD 129078, HIP 72370, HR 5470, SAO 257193.[2]
Database references
SIMBAD data

Alpha Apodis (Alpha Aps, α Apodis, α Aps) is the brightest star in the southern circumpolar constellation of Apus, with an apparent magnitude of approximately 3.825.[7] It had the Greek alpha designation at part of the constellation Johann Bode called Apis Indica in his 1603 Uranometria star atlas.[8] With a declination of –79°, this is a circumpolar star for much of the southern hemisphere. It can be identified on the night sky by drawing an imaginary line through Alpha Centauri and Alpha Circini then extending it toward the south celestial pole.[9]

This is a giant star with a stellar classification of K2.5III, indicating that this star has consumed the hydrogen at its core and has evolved away from the main sequence. It has expanded to an estimated radius of about 48 times the radius of the Sun and is emitting 980 times the Sun's luminosity. The photosphere has an effective temperature of 4,256 K, giving the star the characteristic orange hue of a K-type star.[10] Based upon parallax measurements, this star is roughly 447 light-years from the Earth.[1] It is not known to have a companion.[11]

Naming[edit]

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 α Apodis, ζ Apodis, ι Apodis, β Apodis, γ Apodis, δ Octantis, δ1 Apodis, η Apodis, and ε Apodis. Consequently, α Apodis itself is known as 異雀八 (Yì Què bā, English: the Eighth Star of Exotic Bird.)[12]

References[edit]

  1. ^ a b c d e f 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 alf Aps -- Star, SIMBAD (Centre de Données astronomiques de Strasbourg), retrieved 2011-12-23. 
  3. ^ a b 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. 
  4. ^ HR 5470, database entry, The Bright Star Catalogue, 5th Revised Ed. (Preliminary Version), D. Hoffleit and W. H. Warren, Jr., CDS ID V/50. Accessed on line October 3, 2008.
  5. ^ Evans, D. S. (June 20–24, 1966), Batten, Alan Henry; Heard, John Frederick, eds., The Revision of the General Catalogue of Radial Velocities, Determination of Radial Velocities and their Applications, Proceedings from IAU Symposium no. 30 (University of Toronto: International Astronomical Union), Bibcode:1967IAUS...30...57E. 
  6. ^ Pasinetti Fracassini, L. E. et al. (February 2001), Catalogue of Apparent Diameters and Absolute Radii of Stars (CADARS) - Third edition - Comments and statistics, Astronomy and Astrophysics 367: 521–524, arXiv:astro-ph/0012289, Bibcode:2001A&A...367..521P, doi:10.1051/0004-6361:20000451. 
  7. ^ a b c Kaler, James B., Alpha Aps, Stars (University of Illinois), retrieved 2011-12-23. 
  8. ^ Ridpath, Ian, Apus, the bird of paradise, Ian Ridpath's Star Tales, retrieved 2011-12-25. 
  9. ^ Moore, Patrick (2000), Exploring the night sky with binoculars (4th ed.), Cambridge University Press, p. 113, ISBN 0-521-79390-4. 
  10. ^ The Colour of Stars, Australia Telescope, Outreach and Education (Commonwealth Scientific and Industrial Research Organisation), December 21, 2004, retrieved 2012-01-16. 
  11. ^ 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. 
  12. ^ (Chinese) AEEA (Activities of Exhibition and Education in Astronomy) 天文教育資訊網 2006 年 7 月 29 日

External links[edit]