Smaller lunar evectional constituent. This constituent, with v2, u2, and (S2), modulates the amplitude and frequency of M2 for the effects of variation in solar attraction of the Moon. This attraction results in a slight pear-shaped lunar ellipse and a difference in lunar orbital speed between motion toward and away from the Sun. Although (S2) has the same speed as S2, its amplitude is extremely small. Speed = 2T - s + p = 29.455,625,3° per solar hour.