| appmag_v = +4.89[3]
| constell = Apus
}}{{Starbox character
| class = A2MA7-F2[4] or A2(m) CrEu[5]
| b-v = +0.25[6]
| u-b = +0.11[6]
| variable =
}}{{Starbox astrometry
| radial_v = −9.4[3]
| prop_mo_ra = −19.854 ± 0.227[9]
| prop_mo_dec = −65.413 ± 0.222[9]
| parallax = 23.1651
| p_error = 0.1430
| parallax_footnote = [1]
| absmag_v = +1.76[12]
}}{{Starbox detail
| mass = 1.77[13]
| radius = 2.13[13]
| metal_fe =
| gravity =
| age_myr = {{nowrap|250 ± 200}}[13]
| luminosity = 15.5[13]
| temperature = {{nowrap|7,860 ± 20}}[13]
| rotational_velocity = {{nowrap|17.2 ± 0.3}}[18]
}}{{Starbox catalog
| names = CD−80 706, FK5 3129, HD 123998, HIP 69896, HR 5303, SAO 258693.[19]
}}{{Starbox reference
|Simbad=eta+Aps
}}{{Starbox end}}Eta Apodis, Latinized from η Apodis, is a star in the southern circumpolar constellation Apus. Based upon parallax measurements from the Hipparcos mission, it is approximately {{Convert|141|ly|pc|abbr=off|lk=on}} from Earth. With an apparent visual magnitude of +4.9,[3] it can be viewed with the naked eye from the southern hemisphere.
Properties
This star has about 1.77 times the mass of the Sun and 2.13 times the Sun's radius. It is radiating 15.5 times the luminosity of the Sun from its outer atmosphere at an effective temperature of 7,860 K.[13] Eta Apodis is a young star with an age of about 250 million years.[13]
The stellar classification of Eta Apodis shows this to be an Am star, which means the spectrum shows chemically peculiarities. In particular, it is an A2-type star showing an excess of the elements chromium and europium. The spectrum displays magnetically-induced features indicating an estimated surface field strength of roughly 360 G.[5] Based upon observations with the Spitzer Space Telescope, this system is emitting an excess of 24 μm infrared radiation. This may be caused by a debris disk of dust orbiting at a distance of more than 31 astronomical units from the star.[13]
Naming
In Chinese caused by adaptation of the European southern hemisphere constellations into the Chinese system, {{lang|zh|異雀}} ({{lang|zh-Latn|Yì Què}}), meaning Exotic Bird, refers to an asterism consisting of η Apodis, ζ Apodis, ι Apodis, β Apodis, γ Apodis, δ1 Apodis, α Apodis and ε Apodis. Consequently, η Apodis itself is known as {{lang|zh|異雀七}} ({{lang|zh-Latn|Yì Què qī}}, {{lang-en|the Seventh Star of Exotic Bird}}.)[2]
References
1. ^1 2 {{cite DR2}}
2. ^{{zh icon}} AEEA (Activities of Exhibition and Education in Astronomy) 天文教育資訊網 2006 年 7 月 29 日
3. ^1 {{citation | title=XHIP: An extended hipparcos compilation | last1=Anderson | first1=E. | last2=Francis | first2=Ch. | journal=Astronomy Letters | volume=38 | issue=5 | pages=331 | year=2012 | bibcode=2012AstL...38..331A | doi=10.1134/S1063773712050015 | arxiv=1108.4971 | postscript=. }}
4. ^1 2 3 {{citation | display-authors=1 | title=Sixth Catalogue of Fundamental Stars (FK6). Part I. Basic fundamental stars with direct solutions | last1=Wielen | first1=R. | last2=Schwan | first2=H. | last3=Dettbarn | first3=C. | last4=Lenhardt | first4=H. | last5=Jahreiß | first5=H. | last6=Jährling | first6=R. | publisher=Astronomisches Rechen-Institut Heidelberg | issue=35 | date=1999 | bibcode=1999VeARI..35....1W }}
5. ^1 {{citation | title=Michigan catalogue of two-dimensional spectral types for the HD stars | volume=1 | last1=Houk | first1=Nancy | publication-place=Ann Arbor, Michigan | publisher=Dept. of Astronomy, University of Michigan | date=1979 | bibcode=1978mcts.book.....H }}
6. ^1 2 {{citation | display-authors=1 | last1=Johnson | first1=H. L. | last2=Iriarte | first2=B. | last3=Mitchell | first3=R. I. | last4=Wisniewskj | first4=W. Z. | title=UBVRIJKL photometry of the bright stars | journal=Communications of the Lunar and Planetary Laboratory | volume=4 | issue=99 | date=1966 | bibcode=1966CoLPL...4...99J }}
7. ^1 2 {{citation | last1=Bychkov | first1=V. D. | last2=Bychkova | first2=L. V. | last3=Madej | first3=J. | title=Catalogue of averaged stellar effective magnetic fields. I. Chemically peculiar A and B type stars | journal=Astronomy and Astrophysics | volume=407 | pages=631–642 |date=August 2003 | doi=10.1051/0004-6361:20030741 | bibcode=2003A&A...407..631B |arxiv = astro-ph/0307356 }}
8. ^1 2 3 4 5 6 7 8 {{citation | display-authors=1 | last1=Plavchan | first1=Peter | last2=Werner | first2=M. W. | last3=Chen | first3=C. H. | last4=Stapelfeldt | first4=K. R. | last5=Su | first5=K. Y. L. | last6=Stauffer | first6=J. R. | last7=Song | first7=I. | title=New Debris Disks Around Young, Low-Mass Stars Discovered with the Spitzer Space Telescope | journal=The Astrophysical Journal | volume=698 | issue=2 | pages=1068–1094 |date=June 2009 | doi=10.1088/0004-637X/698/2/1068 | bibcode=2009ApJ...698.1068P |arxiv = 0904.0819 }}
9. ^1 {{citation | display-authors=1 | last1=Díaz | first1=C. G. | last2=González | first2=J. F. | last3=Levato | first3=H. | last4=Grosso | first4=M. | title=Accurate stellar rotational velocities using the Fourier transform of the cross correlation maximum | journal=Astronomy & Astrophysics | volume=531 | page=A143 |date=July 2011 | doi=10.1051/0004-6361/201016386 | bibcode=2011A&A...531A.143D |arxiv = 1012.4858 }}
10. ^1 {{citation | title=eta Aps -- Star | work=SIMBAD | publisher=Centre de Données astronomiques de Strasbourg | url=http://simbad.u-strasbg.fr/simbad/sim-id?Ident=HD+123998| accessdate=2012-07-08 | postscript=. }}