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Observation data Epoch J2000 Equinox J2000 | |
---|---|
Constellation | Crux |
Right ascension | 12h 27m 28.88s |
Declination | −58° 59′ 30.4″ |
Apparent magnitude (V) | 5.38 |
Characteristics | |
Spectral type | M4-5III |
Variable type | semiregular variable |
Astrometry | |
Radial velocity (Rv) | 71.7 ± 0.9 km/s |
Proper motion (μ) | RA: -20.027 ± 0.301[2] mas/yr Dec.: 3.586 ± 0.268 [2] mas/yr |
Parallax (π) | 6.8429 ± 0.1942 mas[2] |
Distance | 480 ± 10 ly (146 ± 4 pc) |
Other designations | |
Database references | |
SIMBAD | data |
BL Crucis is a red giant and a semiregular variable in the constellation of Crux.[3] A 5th magnitude star, it is visible to the naked eye under good observing conditions. Three periods have been detected in its light curve, 30.7, 42.3 and 43.6 days.[1] It is 480 ± 10 light-years distant from Earth.[2]
In 1969, Olin J. Eggen announced that the star, then called HR 4739, is a variable star.[4] It was given its variable star designation, BL Crucis, in 1977.[5]