A type of supergiant pulsating variable star exhibiting non-radial pulsation; abbr. ACYG. The spectral types are Be–Ae Ia, and the optical amplitude is approximately 0.1 mag. Multiple pulsation frequencies are superimposed, giving rise to light-curves that often appear highly irregular. The periods range from a few days to several weeks.
Subjects: Astronomy and Astrophysics.