red giant/white dwarf

If marauding black holes, undetected meteorites or hostile alien invasions weren’t enough to worry about, astronomers have detected a distant, dying binary star system whose gravitational waltz manages to periodically eject planet-sized blobs of super-hot plasma into their solar system at trajectories of over one-tenth the speed of light.
Although surely it would be catastrophic for any residents of V Hydræ’s exoplanets to have cowered in the knowledge that once every eight years (or equivalent cycle) a deadly blast comes from the heavens in a civilisation ending event for at least the last four hundred years (if they managed to dodge it at all and aren’t the architects of this Death Star or this cosmic defence shield themselves), this stellar canon is too far away to threaten Earth.