Turbulent times: When stars approach

When we look at the night sky, we see stars as tiny points of light eking out a solitary existence at immense distances from Earth. But appearances are deceptive. More than half the stars we know of have a companion, a second nearby star that can have a major impact on their primary companions. The interplay within these so-called binary star systems is particularly intensive when the two stars involved are going through a phase in which they are surrounded by a common envelope consisting of hyd...