Alpha Phoenicis (α Phoenicis, abbreviated Alpha Phe or α Phe), formally named Ankaa (distinguish Ancha, with the same pronunciation) is the brightest star in the constellation of Phoenix.

Nomenclature

''Alpha Phoenicis'' is the star's

Bayer designation A Bayer designation is a stellar designation in which a specific star is identified by a Greek or Latin letter followed by the genitive form of its parent constellation's Latin name. The original list of Bayer designations contained 1,564 stars. ...

. It also bore the traditional name Ankaa sometime after 1800, from the Arabic العنقاء ''al-ʽanqāʼ'' "the phoenix" for the name of the constellation. Medieval Arab astronomers formed the constellation of the dhow (where Phoenix is), so another popular name for the star is ''Nair al Zaurak'' from نائر الزورق''nayyir az-zawraq'' "the bright (star) of the skiff". The Latin translation is ''Cymbae,'' from ''lūcida cumbae''. In 2016, the International Astronomical Union organized a Working Group on Star Names (WGSN) to catalog and standardize proper names for stars. The WGSN's first bulletin of July 2016 included a table of the first two batches of names approved by the WGSN; which included ''Ankaa'' for this star. In Chinese caused by adaptation of the European southern hemisphere constellations into the Chinese system, (), meaning '' Firebird'', refers to an asterism consisting of α Phoenicis, ι Phoenicis, σ Phoenicis, ε Phoenicis, κ Phoenicis, μ Phoenicis, λ¹ Phoenicis, β Phoenicis and γ Phoenicis . Consequently, α Phoenicis itself is known as (, en, the Sixth Star of Firebird.)AEEA (Activities of Exhibition and Education in Astronomy) 天文教育資訊網 2006 年 7 月 27 日
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Description

This is a

spectroscopic binary A binary star is a system of two star, stars that are gravity, gravitationally bound to and in orbit around each other. Binary stars in the night sky that are seen as a single object to the naked eye are often resolved using a telescope as separa ...

star system with components that orbit each other every 3848.8 days (10.5 years). The combined

stellar classification In astronomy, stellar classification is the classification of stars based on their stellar spectrum, spectral characteristics. Electromagnetic radiation from the star is analyzed by splitting it with a Prism (optics), prism or diffraction grati ...

of the system is K0.5 IIIb, which matches the spectrum of a normal luminosity giant star. It has an apparent visual magnitude of 2.4, so it is somewhat outshined by its first magnitude neighbors

Achernar Achernar is the brightest star in the constellation of Eridanus, and the ninth-brightest in the night sky. It has the Bayer designation Alpha Eridani, which is Latinized from α Eridani and abbreviated Alpha Eri or α Eri. The name A ...

(α Eridani) and Fomalhaut (α Piscis Australis). Based upon

parallax Parallax is a displacement or difference in the apparent position of an object viewed along two different lines of sight and is measured by the angle or semi-angle of inclination between those two lines. Due to foreshortening, nearby objects ...

measurements, this system is at a distance of about from the Earth. The

interferometry Interferometry is a technique which uses the ''interference'' of superimposed waves to extract information. Interferometry typically uses electromagnetic waves and is an important investigative technique in the fields of astronomy, fiber opt ...

-measured angular diameter of the primary component, after correcting for limb darkening, is , which, at its estimated distance, equates to a physical radius of about 15 times the

radius of the Sun Solar radius is a unit of distance used to express the size of stars in astronomy relative to the Sun. The solar radius is usually defined as the radius to the layer in the Sun's photosphere where the optical depth equals 2/3: :1\,R_ = 6.9 ...

. Ankaa is similar to many of the visible stars of the night sky, being an orange giant of relatively average stellar size. It is currently thought to be in the midst of a short but stable helium burning phase of its

stellar evolution Stellar evolution is the process by which a star changes over the course of time. Depending on the mass of the star, its lifetime can range from a few million years for the most massive to trillions of years for the least massive, which is cons ...

, although it probably will not be long in astronomical terms before it sheds its outer layers as a planetary nebula and ends its life quietly as a white dwarf. Ankaa has a small stellar companion, about which little is known.

References

{{Stars of Phoenix Phoenicis, Alpha K-type giants Phoenix (constellation) Spectroscopic binaries Ankaa 002081 0099 002261 Durchmusterung objects