Doomed Deneb
The Northern Cross stands atop the northwestern horizon during the mid-evening hours this week. It's highlighted by brilliant Deneb at the top of the cross. Deneb is one of the brightest stars in the galaxy -- and one that's destined to shine a whole lot brighter.
Deneb is a supergiant. It's a couple of hundred times bigger than the Sun, and a couple of hundred thousand times brighter. Both of those numbers are caused by the most important number of all: the star's mass. Deneb is about 25 times as massive as the Sun, which means it's burning through the nuclear fuel in its core in a hurry.
Within a couple of million years, it'll reach the point where it can no longer produce energy in its core. It will explode as a supernova, outshining most of the other stars in the galaxy combined.
In less than a second, the core will collapse to form a neutron star, and the layers around the core will fall inward, then rebound, creating a powerful shockwave. The shockwave will rip the star apart, blasting its outer layers into space -- creating a supernova.
Astronomers have found one problem with this scenario, though. As matter from the outer layers falls toward the core, it causes the shockwave to stall. If it remains stalled, the star won't explode. So astronomers are trying to find out what gives the shockwave the extra boost it needs to plow through the star and blast it to cosmic dust. More about that tomorrow.
Script by Damond Benningfield, Copyright 2006
For more skywatching tips, astronomy news, and much more, read StarDate magazine.
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