Contact Binary Stars: a roadmap to their nature and evolution

Abstract

A complete life cycle for W UMa systems Mass transfer from secondary driven by primary Sign of flow essential to stability criteria  Consistent with observations of distributions of M, T, P, q, dP/dt, (P,q)merger Ongoing THEORY  Understand f distribution  Compute grid of models to compare with populations of various ages •  OBSERVATION:Rubin observatory data Establish parameter distributions vs. location or kinematics  Find the next red nova before it explode