Cataclysmic-variable period bounce ($\zeta =1/3$)

The reversal from decreasing to increasing orbital period during continuing donor mass loss. The Roche-lobe-filling period-density relation gives $d\log P/d\log M_d=(3\zeta -1)/2$, where $\zeta$ is the effective stellar radius response exponent along the mass-losing sequence. A crossing from $\zeta >1/3$ to $\zeta <1/3$ gives a local cataclysmic-variable period minimum.