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The evolution of novae and Cataclysmic Variables (CVs) is driven by changesin the binary orbital periods. In a direct and critical test for variousevolution models and their physical mechanisms, I measure the sudden changes inthe period ($\Delta P$) across 14 nova eruptions and I measure the steadyperiod change during quiescence ($\dot{P}$) for 20 inter-eruption intervals.The standard theory for $\Delta P$ is dominated by the mechanism of mass loss,and this fails completely for the five novae with negative values, and it failsto permit the $\Delta P$ for U Sco eruptions to change by oneorder-of-magnitude from eruption-to-eruption. The Hibernation Model ofevolution is refuted because all the $\Delta P$ measures are orders ofmagnitude too small to cause any significant drop in accretion luminosity, andindeed, near half of the nova have negative $\Delta P$ as the opposite of therequired mechanism for any hibernation state. As for the Magnetic BrakingModel, this fails by many orders-of-magnitude in its predictions of therequired $\dot{P}$ for 9-out-of-13 novae. The observed $\dot{P}$ valuesscatter, both positively and negatively, over a range of $\pm$10$^{-9}$, whilethe predicted values are from $-$10$^{-13}$ to $-$10$^{-11}$. This huge scatteris not possible with standard theory, and there must be some currently-unknownmechanism to be added in, with this new mechanism 100--10000$\times$ larger ineffect than the current theory allows. In all, these failed predictionsdemonstrate that nova systems must have unknown physical mechanisms for both$\Delta P$ and $\dot{P}$ that dominate over all other effects.

monthly notices of the royal astronomical society

Orbital Period Changes for Fourteen Novae and the Critical Failures of  the Predictions of Standard Theories, the Hibernation Model, and the Magnetic  Braking Model