From the article: "As the red giant tears apart nearby stars, the dense white giant absorbs the shrapnel, a mixture of hydrogen-rich materials that come its way. The tiny dead star then gradually becomes hotter until it reaches a breaking point when all that energy is released in a huge cosmic explosion — a so-called nova."

That's the worst explanation of a nova I've ever seen. You'd think the author would have at least glanced at the Wikipedia article about novae.