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Alpha Apodis

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α Apodis
Diagram showing star positions and boundaries of the Apus constellation and its surroundings
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) 3.83[2]
Characteristics
Spectral type K3IIICN0.5[3]
U−B color index +1.68[2]
B−V color index +1.43[2]
R−I color index +0.53[4]
Astrometry
Radial velocity (Rv)−1.1[5] km/s
Proper motion (μ) RA: −5.133 mas/yr[1]
Dec.: −16.299 mas/yr[1]
Parallax (π)6.5509±0.1133 mas[1]
Distance498 ± 9 ly
(153 ± 3 pc)
Absolute magnitude (MV)−1.67[6]
Details
Mass4.46±0.22 M☉[7]
2.97+1.97
−1.16[8] M☉
Radius59.51±2.98 R☉[7]
65 ± 5[8][a] R☉
Luminosity1,072±22[8] L☉
Temperature4,090±80[8] K
Metallicity [Fe/H]−0.3[8] dex
Other designations
α Aps, Alpha Apodis, Alpha Aps, CPD−78°893, FK5 542, HD 129078, HIP 72370, HR 5470, SAO 257193[9]
Database references
SIMBADdata

Alpha Apodis is the brightest star in the southern circumpolar constellation of Apus. It had the Greek alpha designation as part of the constellation which Johann Bayer called Apis Indica in his 1603 Uranometria star atlas.[10] This identifier is a Bayer designation that is Latinied from α Apodis, and abbreviated Alpha Aps or α Aps, respectively. The star has an apparent visual magnitude of approximately 3.825,[11] which can be viewed with the naked eye. 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.[12]

This is a giant star with a stellar classification of K3IIICN0.5,[3] indicating that this star has consumed the hydrogen at its core and has evolved away from the main sequence. The CN0.5 notation indicates a mild overabundance of the cyanide (CN) molecule. The star has expanded to an estimated radius of about 65 times the radius of the Sun and is emitting 1,000 times the Sun's luminosity. The photosphere has an effective temperature of 4,090 K,[8] giving the star the characteristic orange hue of a K-type star.[13] Based upon parallax measurements, this star is 498±9 ly from the Earth.[1] It is not known to have a companion.[14]

Naming

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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.)[15]

Notes

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  1. ^ Applying the Stefan–Boltzmann law with a nominal solar effective temperature of 5,772 K:
    .

References

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  1. ^ a b c d e Brown, A. G. A.; et al. (Gaia collaboration) (2021). "Gaia Early Data Release 3: Summary of the contents and survey properties". Astronomy & Astrophysics. 649: A1. arXiv:2012.01533. Bibcode:2021A&A...649A...1G. doi:10.1051/0004-6361/202039657. S2CID 227254300. (Erratum: doi:10.1051/0004-6361/202039657e). Gaia EDR3 record for this source at VizieR.
  2. ^ a b c Johnson, H. L.; et al. (1966). "UBVRIJKL photometry of the bright stars". Communications of the Lunar and Planetary Laboratory. 4 (99): 99. Bibcode:1966CoLPL...4...99J.
  3. ^ a b Keenan, Philip C.; McNeil, Raymond C. (1989), "The Perkins catalog of revised MK types for the cooler stars", The Astrophysical Journal Supplement Series, 71: 245, Bibcode:1989ApJS...71..245K, doi:10.1086/191373, S2CID 123149047.
  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 online 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, vol. 30, University of Toronto: International Astronomical Union, p. 57, Bibcode:1967IAUS...30...57E.
  6. ^ Cardini, D. (January 2005), "Mg II chromospheric radiative loss rates in cool active and quiet stars", Astronomy and Astrophysics, 430 (1): 303–311, arXiv:astro-ph/0409683, Bibcode:2005A&A...430..303C, doi:10.1051/0004-6361:20041440, S2CID 12136256.
  7. ^ a b Kervella, Pierre; Arenou, Frédéric; Mignard, François; Thévenin, Frédéric (2019-03-01). "Stellar and substellar companions of nearby stars from Gaia DR2. Binarity from proper motion anomaly". Astronomy and Astrophysics. 623: A72. arXiv:1811.08902. Bibcode:2019A&A...623A..72K. doi:10.1051/0004-6361/201834371. ISSN 0004-6361.
  8. ^ a b c d e f Charbonnel, C.; Lagarde, N.; Jasniewicz, G.; North, P. L.; Shetrone, M.; Krugler Hollek, J.; Smith, V. V.; Smiljanic, R.; Palacios, A.; Ottoni, G. (2020-01-01). "Lithium in red giant stars: Constraining non-standard mixing with large surveys in the Gaia era". Astronomy and Astrophysics. 633: A34. arXiv:1910.12732. Bibcode:2020A&A...633A..34C. doi:10.1051/0004-6361/201936360. ISSN 0004-6361.
  9. ^ "alf Aps -- Star", SIMBAD, Centre de Données astronomiques de Strasbourg, retrieved 2011-12-23.
  10. ^ Ridpath, Ian, "Apus, the bird of paradise", Ian Ridpath's Star Tales, retrieved 2011-12-25.
  11. ^ Kaler, James B., "Alpha Aps", Stars, University of Illinois, archived from the original on 2008-12-02, retrieved 2011-12-23.
  12. ^ Moore, Patrick (2000), Exploring the night sky with binoculars (4th ed.), Cambridge University Press, p. 113, ISBN 0-521-79390-4.
  13. ^ "The Colour of Stars", Australia Telescope, Outreach and Education, Commonwealth Scientific and Industrial Research Organisation, December 21, 2004, archived from the original on February 22, 2012, retrieved 2012-01-16.
  14. ^ 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.
  15. ^ (in Chinese) AEEA (Activities of Exhibition and Education in Astronomy) 天文教育資訊網 2006 年 7 月 29 日 Archived 2011-05-22 at the Wayback Machine
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