Normalized X-ray luminosity for stars listed in Table 7 are shown as a function of their periods. The stars largely follow an expected rotation-activity trend, except for AB Aur, which is an A-star near the main sequence and is expected to be faint in X-rays. L _x / L _bol for θ ¹ Ori E is for the system; if each stellar component contributes equally, its value should be divided by two.