Explode or Not?

Aquila, the eagle, spreads its wings across the evening sky. It’s well up in the east as the sky gets dark. Its brightest star, Altair, is at the bottom right point of the wide-spread Summer Triangle. Altair represents the eagle’s breast, with the wings above and below.

A pair of stars at one of the wingtips faces an uncertain future. Early studies said the two stars will ram together and explode as a supernova -- in 700 million years. But more recent work says they won’t.

Henize 2-428 consists of two white dwarfs -- the dead cores of once-normal stars. They probably started out as fairly massive stars. As the main star aged, it dumped most of its gas onto its companion. As that star aged, it began dumping gas as well, forming a cloud around both stars. The gas was kicked out into space, forming a colorful nebula around the pair.

Today, the stars are so close that they orbit each other once every four hours. As they orbit, they radiate gravitational waves, causing them to spiral even closer -- and eventually merge.

The early work said the combined mass of the two stars would exceed the weight limit for white dwarfs. As a result, they’d blast themselves to bits as a supernova.

But the more recent work said the stars are less massive than originally thought. If that’s true, then their merger will be much less spectacular. Henize 2-428 will survive -- as a heavy stellar “corpse” floating through the galaxy unnoticed.
 

Script by Damond Benningfield