5 Astraea is a large asteroid from the asteroid belt. Its surface is highly reflective (bright) and its composition is probably a mixture ofnickel–iron with silicates of magnesium and iron. It was the 5th asteroid discovered (December 8, 1845) by K. L. Hencke and named for Astræa, a goddess of justice named after the stars. It was his first of two asteroid discoveries. The second was 6 Hebe.