The
spectrum of this star matches a
stellar classification of K3 Ib-IIa,[3] with the
luminosity class notation 'Ib-IIa' indicating that the star lies part way between a higher luminosity
bright giant (IIa) and a lower luminosity
supergiant (Ib). It has an age estimated at 50 million years, having spent much of its life as a
B-type star.[11] Currently, it has expanded to 141 times the Sun's size and is 5,800 times more energetic.[8] Beta Arae is radiating energy from its outer envelope at an
effective temperature of 4,200 K, which causes it to take on the orange hue of a
K-type star.[12] This enlarged star appears to be rotating slowly with a
projected rotational velocity of about 5 km/s.[3] The abundance of elements other than hydrogen and helium, its
metallicity, is more than three times that of the Sun.[3][a]
Rarely, this star is called Vasat-ül-cemre a
Turkisation of
Arabic وسط الجمر (wasaṭ al-jamar), meaning "middle of the embers."[13] The constellation is named in Arabic المجمرة (al-mijmarah), meaning
brazier/incense-burner.[14] In
Chinese, 杵 (Chǔ), meaning Pestle, refers to an asterism of β,
σ and
α Arae.[15] The
Chinese name for β Arae is 杵三 (Chǔ sān, English: the Third Star of Pestle.)[16]
Notes
^The abundance is estimated by taking [Fe/H] to the power of ten: 10[Fe/H] = 10+0.5 = 3.1
^
abWielen, R.; et al. (1999). "Sixth Catalogue of Fundamental Stars (FK6). Part I. Basic fundamental stars with direct solutions". Veröff. Astron. Rechen-Inst. Heidelb. 35 (35). Astronomisches Rechen-Institut Heidelberg: 1.
Bibcode:
1999VeARI..35....1W.
^
abJohnson, H. L.; et al. (1966). "UBVRIJKL photometry of the bright stars". Communications of the Lunar and Planetary Laboratory. 4 (99): 99.
Bibcode:
1966CoLPL...4...99J.