Dschubba

Dschubba carries the Delta designation of Scorpius and marks the head of the Scorpion, near the constellation's northern claws. It is a blue-white B-type star, its colour index of −0.117 confirming a hot surface. Situated about 491 light-years away, Dschubba shines at apparent magnitude 2.29, while its absolute magnitude of −3.60 reveals a substantial intrinsic luminosity dimmed by that distance. It stands among the row of stars forming the forehead of Scorpius, a short distance from the red giant Antares that dominates the constellation, its hot blue light offering a marked contrast to that ruddy neighbour. The gap of nearly six magnitudes between its apparent and absolute brightness is itself a record of the long distance its light must cross to reach Earth.