Beta Apodis

Beta Apodis

Location of β Apodis (circled)
Observation data Epoch J2000      Equinox J2000
Constellation	Apus
Right ascension	16^h 43^m 04.65651^s[1]
Declination	−77° 31′ 02.7629″[1]
Apparent magnitude (V)	+4.24[2]
Characteristics
Spectral type	K0 III[3]
U−B color index	+0.95[2]
B−V color index	+1.06[2]
Astrometry
Radial velocity (Rv)	−30.3 ± 0.7[4] km/s
Proper motion (μ)	RA: −282.70 ± 0.14[1] mas/yr Dec.: −354.81 ± 0.17[1] mas/yr
Parallax (π)	20.78 ± 0.20[1] mas
Distance	157 ± 2 ly (48.1 ± 0.5 pc)
Details
Mass	1.84[5] M☉
Radius	11[6] R☉
Surface gravity (log g)	3.0[7] cgs
Temperature	4,900[7] K
Metallicity [Fe/H]	–0.02[7] dex
Other designations
CP-77 1221, FK5 3319, HD 149324, HIP 81852, HR 6163, SAO 257424.[8]
Database references
SIMBAD	data

Beta Apodis (β Aps, β Apodis) is the Bayer designation for a star in the southern circumpolar constellation of Apus. It is located approximately 158 light-years (48 parsecs) from Earth,^[1] as determined by parallax measurements. The apparent visual magnitude of this star is +4.24,^[2] which is bright enough to be seen with the naked eye

The spectrum of this star matches the characteristics of a K0 III,^[3] which, according to models of stellar evolution, indicates that it is in the giant star stage, having exhausted the supply of hydrogen at its core. The measured angular diameter of this star is 2.09 ± 0.11 mas.^[9] At the estimated distance of this star, this yields a physical size of about 11 times the radius of the Sun.^[6] The expanded outer atmosphere of Beta Apodis has an effective temperature of about 4,900 K.^[7] This heat is causing it to glow with the characteristic orange hue of a K-type star.^[10]

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 β Apodis, ζ Apodis, ι Apodis, γ Apodis, δ Octantis, δ¹ Apodis, η Apodis, α Apodis and ε Apodis. Consequently, β Apodis itself is known as 異雀三 (Yì Què sān, English: the Third Star of Exotic Bird.)^[11]

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. 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. Eggen, O. J. (1962), "Space-velocity vectors for 3483 stars with proper motion and radial velocity", Royal Observatory Bulletin, 51, Bibcode:1962RGOB...51...79E.
4. Evans, D. S. (June 20–24, 1966), "The Revision of the General Catalogue of Radial Velocities", in Batten, Alan Henry; Heard, John Frederick, Determination of Radial Velocities and their Applications, Proceedings from IAU Symposium no. 30, University of Toronto: International Astronomical Union, Bibcode:1967IAUS...30...57E.
5. Liu, Y. J.; Zhao, G.; Shi, J. R.; Pietrzyński, G.; Gieren, W. (2007). "The abundances of nearby red clump giants". Monthly Notices of the Royal Astronomical Society. 382 (2): 553–66. Bibcode:2007MNRAS.382..553L. doi:10.1111/j.1365-2966.2007.11852.x.
6. 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:

   ${\displaystyle {\begin{aligned}2\cdot R_{*}&={\frac {(48\cdot 2.09\cdot 10^{-3})\ {\text{AU}}}{0.0046491\ {\text{AU}}/R_{\bigodot }}}\\&\approx 22\cdot R_{\bigodot }\end{aligned}}}$

7. Jones, K. L.; et al. (June 1992), "Spectroscopic investigation of cool giants and the authenticity of their reported microwave emission", Monthly Notices of the Royal Astronomical Society, 256 (3): 535–544, Bibcode:1992MNRAS.256..535J, doi:10.1093/mnras/256.3.535.
8. "LTT 6652 -- High proper-motion Star", SIMBAD Astronomical Object Database, Centre de Données astronomiques de Strasbourg, retrieved 2012-06-28
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, archived from the original on 2012-03-10, retrieved 2012-01-16
11. (Chinese) AEEA (Activities of Exhibition and Education in Astronomy) 天文教育資訊網 2006 年 7 月 29 日

External links

• Image Beta Apodis