V.D33 — Cepheid readout calibrator

A Cepheid readout calibrator is a stellar configuration in the instability strip whose boundary holonomy algebra admits a periodic orbit phi(t) = phi(t+P) with period P in the (gamma, D)-sector overlap. The period-luminosity relation follows from both period and luminosity being determined by the sector-coupling ratio kappa(D;1)/kappa(B;1).