The orbital period of a cataclysmic variable stands as a crucial parameter for investigating the structure and physics of these binary systems, as well as understanding their evolution. We use photometric Gaia data of dwarf novae (DNe) in the quiescent state, available over various years, to determine new orbital periods and improve or modify previously suggested period values. Two approaches are implemented for selecting high-inclination targets, either eclipsing or with ellipsoidal variations. We determine new orbital periods for 75 DNe and improve ephemerides for 27 more (three of which change significantly), contributing to 9.4% of the known DNe periods between 0.05 and 2.0 days, and doubling those with periods exceeding 0.44 days. Their phase-folded light curves, available on Zenodo, are presented and arranged by their orbital period, illustrating the transition from short-period systems, dominated by radiation from the accretion disk and the hot spot, to longer-period DNe, where the Roche-lobe filling secondary star is the primary visual flux source. This transition, which occurs around the well-known period gap (between ~ 2 and 3 hours), is expected since DNe with larger orbital periods typically harbour more massive donors contributing to the visible flux. However, this transition is not abrupt. Within the same range of periods, we observe systems dominated by ellipsoidal variations, where the companion star is clearly visible, as well as others dominated by the disk and the hot spot. The presence of some DNe with ellipsoidal variations near the lower edge of the period gap is striking, as the companions in these systems are expected to be cool low-mass M-dwarfs not visible in the light curve. This could indicate that we are observing systems where the donor star was originally much more massive and underwent significant nuclear evolution before mass transfer began, as has been suggested previously for QZ Ser.

Cone search capability for table J/A+A/691/A249/sources (List of studied sources)