Alpha Arae

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α Arae
Observation data
Epoch J2000.0
Constellation
(pronunciation)
Ara
Right ascension 17h 31m 50.5s
Declination −49° 52' 34"
Apparent magnitude (V) +2.84
Distance 242 ± 17 ly
(74 ± 5 pc)
Spectral type B2Vne
Other designations
HR 6510, HD 158427, CD-49°11511, FK5 651, HIP 85792, SAO 228069, GC 23708, CCDM 17318-4953

Alpha Arae (α Ara / α Arae) is the second brightest star in the constellation Ara. It also has the traditional name Tchou or Choo from the Mandarinchǔ meaning "pestle".

Alpha Arae is a blue-white B-type main sequence dwarf with a mean apparent magnitude of +2.84. It is a variable Be star and its brightness varies from magnitude +2.79 to +3.13. It is approximately 242 light years from Earth.

Some studies have shown that Alpha Arae has a very high rotational speed of 470 kilometers per second at the equator. [1]