High eccentricities, A-stars and type Ia supernovae

The long term evolution of hierarchical three-body stellar systems often results in extreme close approaches of the inner bodies,
 which could result in mergers or collisions among stars/planets/compact objects/moons/asteroids/satellites/other? 

I will describe new results regarding the theoretical conditions for extreme approaches, 
observational studies of the multiplicity of A-stars (the progenitors of most present white dwarfs) and possible connection (or lack of connection) to type Ia supernovae