The white dwarf population of open clusters and their tidal tails. Tracers of contamination and stellar interactions

Recent studies have identified numerous open clusters (OCs) and tidal tail catalogues, enabling systematic searches for white dwarfs (WDs) associated with clusters and their extended structures. We have compiled a literature-based sample of OC--WD pairs to validate WD membership in cluster cores and tidal tails, investigated the initial--final mass relation (IFMR), identified WDs formed through non-canonical evolution, and interpreted the observed WD populations using a grid of N-body simulations. Gaia We combined DR3 cluster and tidal tail catalogues with ultraviolet-to-infrared photometry to analyse the OC--WD pairs. The WD masses, cooling ages, radii, effective temperatures, and luminosities were estimated using colour--magnitude diagrams and spectral energy distributions. These observations were interpreted in the context of N-body simulations. Gaia We identified 235 OC--WD pairs in 80 clusters, including 99 WDs in tidal tails. More than 28% of the pairs are likely spurious, with contamination substantially higher in the tails ($>48%) than in the cluster cores (>13%), indicating significant field-star contamination in current -based catalogues. The Pleiades tidal tails also show severe contamination by old WDs. Simulations predict that the fraction of core WDs increases with cluster age, reaching ≳10%, whereas the observed fractions remain systematically lower, consistent with the WD deficit problem. Despite the high contamination rate, most tail WDs (≈$83%) are consistent with having been born inside the tidal radius. We additionally identified 63 candidate binary-origin WDs and 47 new IFMR candidates. Gaia White dwarfs provide a powerful probe of contamination in cluster and tidal tail catalogues and place important constraints on cluster detection methods and N-body simulations. Resolving the WD deficit and improving membership validation will require improved observations, membership methods, WD physics, and spectroscopic follow-up to ultimately enable stronger constraints on dynamical cluster evolution and the WD IFMR.