Orbital Evolution and Angular Momentum Loss in Cataclysmic Variables and Eclipsing Binary Systems

Cataclysmic variables and eclipsing binary systems offer some of the clearest observational windows into the physics that governs close binary evolution. High-precision, long-baseline photometry has revealed subtle but systematic variations in orbital periods across many of these systems, pointing to underlying mechanisms such as magnetic braking, gravitational radiation, mass transfer, and, in some cases, the gravitational influence of circumbinary companions, including giant planets. The magnetic activity of the secondary (donor) star adds a further layer to this picture, since starspot cycles and activity-driven changes in the donor can modulate mass transfer and drive cyclic period variations. Disentangling these contributions remains a central challenge in binary star research, requiring both careful observational characterization and refined theoretical modeling.The rapid growth of large photometric and spectroscopic sky surveys has transformed how these systems are found and studied. Time-domain surveys and their public archives now make it possible to discover and characterize new cataclysmic variables and eclipsing binaries, identify promising candidate systems, and assemble homogeneous samples for population-level studies of period evolution. Building sample sizes in this way strengthens statistical tests of the mechanisms driving angular momentum loss.This Research Topic invites contributions that advance our understanding of orbital-period modulation and angular momentum loss in cataclysmic variables, eclipsing binaries, and related interacting systems. We welcome studies based on photometric and spectroscopic monitoring, eclipse-timing analysis, period-change modeling, survey-based discovery and candidate searches, investigations of secondary-star magnetic activity, and theoretical or numerical work addressing the evolutionary pathways of these systems. Contributions examining the role of third bodies or circumbinary companions in modulating binary orbits, as well as work connecting observed period variations to broader stellar evolution theory, are especially encouraged.We welcome Original Research, Review, Methods, and Perspective articles that:(1) Present new photometric or spectroscopic observations of cataclysmic variables or eclipsing binaries(2) Use major sky-survey databases to discover, search for, or characterize new target sources and candidate systems(3) Characterize orbital-period variations through eclipse-timing or O–C analysis(4) Model angular momentum loss mechanisms (magnetic braking, gravitational radiation, mass transfer)(5) Probe secondary-star (donor) magnetic activity and its influence on mass transfer and orbital-period variation(6) Investigate circumbinary companions and their dynamical effects on close binaries(7) Review current theoretical frameworks linking period variations to binary star evolution Topic editors: Zhongtao Han, Xiaohui Fang Source: https://www.frontiersin.org/research-topics/85603/orbital-evolution-and-angular-momentum-loss-in-cataclysmic-variables-and-eclipsing-binary-systems