APOD 3.1
This spectacular picture was taken at dawn. It is a nova. A cataclysmic variable involves gas falling from large stars onto accretion disk surrounding a massive but compact white dwarf star. An explosive cataclysmic event  could be a dwarf nova and can can occur when the accretion disk reaches a certain temperature from the clumps of gas around it. These dwarf novas will not destroy either star, and may occur irregularly on time scales from a few days. This picture by the way is not real and is a portrait of what it would look like. This picture does look spectacular.