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Shaula (Lambda Scorpii)

Shaula and Scorpius
The second brightest star in the constellation Scorpius; its Arabic name means "the stinger." Along with Lesath and several other stars in southern Scorpius, it belongs to the huge, relatively nearby Scorpius OB1 Association.

Shaula is a subgiant B star with a temperature around 25,000 K and a total luminosity that is about 35,000 that of the Sun. It is, however, a close double made of roughly similar hot stars with an orbital period of 5.9 days. There may also be a third, more distant companion, possibly a white dwarf given that Shaula is an unusually strong source of low-energy X-rays.

Shaula has either stopped hydrogen fusion in its core or is close to doing so. With a mass of around 11 solar masses, it may eventually explode or more likely turn into a heavy white dwarf, possibly one with a neon-oxygen core. Like Mirzam, it is a Beta Cephei star, fluctuating by less than a tenth of a magnitude with two simultaneous periods of 0.21 and 0.11 days.

visual magnitude 1.62
absolute magnitude -5.05
spectral type B1IV
distance 703 light-years (214 pc)
position R.A. 17h 33m 36.5s,
Dec. -37 06' 14"
other designations 35 Sco, GC 23769,
HD 158926, HIP 85927,
HR 6527, SAO 208954

Related entry

   • brightest stars

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