Alpha Arae
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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 | |
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 Mandarin 杵 chǔ 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]