Follow this link to skip to the main content

Cataclysmic Cool Fact - Introduction

Cataclysmic Variables

What is so "cataclysmic" about these variables?

Cataclysmic, or explosive, variables actually undergo an explosive reaction. A cataclysmic variable system consists of a white dwarf star and a normal star. The stars are so close together that gas flows from the normal star onto the dwarf where it swirls into a disk. When this disk of gas collapses onto the white dwarf, it releases large amounts of kinetic energy.

Meanwhile, on the surface of the white dwarf, hydrogen is accumulating. Eventually, it undergoes thermonuclear fusion. This is seen as an explosion. Cataclysmic variables are generally divided into three categories, depending on the intensity of this explosion. After the explosion, the white dwarf begins collecting more hydrogen and the process starts again.


A service of the High Energy Astrophysics Science Archive Research Center (HEASARC), Dr. Alan Smale (Director), within the Astrophysics Science Division (ASD) at NASA/GSFC

NASA Logo, National Aeronautics and Space Administration