Two stars orbit their common centre of mass, connected by gravity. Watch mass transfer between them, accretion disc formation and track their evolution on a live Hertzsprung-Russell diagram.
Newtonian gravity with Velocity Verlet integration. Mass transfer occurs when one star fills its Roche lobe, streaming matter to its companion.
Adjust star masses and separation distance. Watch the HR diagram track changes as mass transfer alters each star's luminosity and temperature.
About half of all visible stars are actually binary systems. The nearest star system, Alpha Centauri, is a triple-star system.