Editing Delta Scorpii (section)

==Properties==
δ Scorpii was once used as a spectroscopic standard for the B0 IV classification, but is now considered too unusual and variable.<ref name="miro" />

The primary, δ Scorpii A, is a B class subgiant surrounded by a disc of material spun off by the rapidly rotating star. The secondary, δ Scorpii B, orbits every 10.5 years in a highly elongated elliptical orbit; it appears to be a normal B class [[main sequence]] star. There have been reports that Delta Scorpii A is itself a very close spectroscopic binary, but this does not appear to be the case.<ref name="miro" />

δ Scorpii is a [[proper motion]] member of the Upper Scorpius subgroup of the [[Scorpius–Centaurus association|Scorpius–Centaurus]] [[Stellar kinematics#OB associations|OB association]], the nearest such co-moving association of massive stars to the [[Sun]].<ref name="aaa216_1_44" /><ref name="Pecaut"/> The Upper Scorpius subgroup contains thousands of young stars with mean age 11 million years at average distance of 470 light years (145 parsecs).<ref name="Pecaut" />