Description
One of the stars in the binary system V664 Cassiopeia gave some of its gas to its companion. Before long, though, it’ll take some of it back. And that’ll set up a cycle in which the system periodically flares to many times its normal brightness.
Originally, the system consisted of two stars that probably were a little less massive than the Sun. One of the stars was a bit heavier than the other, though, so it aged more quickly. As it neared the end of its “normal” lifetime, it puffed up to giant proportions.
The star got so big, in fact, that its outer layers engulfed its companion. The companion most likely swept up some of that hot gas for its own, increasing its own mass to roughly that of the Sun. But it scattered most of the gas, forming a glowing bubble around the system. As V664 Cas moves through space, some of the material in the bubble gets left behind, forming a long streamer.
Today, the system consists of the heavier star’s hot, dead core — a white dwarf — and the companion,
