The big, bright constellation Orion scampers across the southwestern quadrant of the sky on March nights. It’s high in the sky at nightfall, just past due south, and doesn’t fully set until about 2 a.m. Look for its three-star belt. At nightfall, it’s flanked by bright orange Betelgeuse to the upper left, and blue-white Rigel to the lower right.

In mythology, Orion was a hunter. And one of the creatures he hunted stands just below his feet. Lepus, the rabbit, contains a few moderately bright stars. Their proximity to Orion makes them easier to pick out.

The brightest is Arneb. And it really is a bright star — more than 30,000 times brighter than the Sun. In fact, it’s impressive just about any way you look at it. It’s far bigger and heavier than the Sun, and it faces a more impressive fate — it will explode as a supernova.

Arneb is only about 13 million years old, compared to four-and-a-half billion years for the Sun. But because it’s so much more massive, it “burns” through the fuel in its core much more quickly. As a result, it’s already nearing the end of its life. Changes in its core have caused it to puff up — it’s big enough to extend to the orbit of Mercury or beyond if it took the Sun’s place.

Soon, it’ll get even bigger and brighter. Eventually, though, it will stop producing nuclear reactions in its core. The core will collapse, with the outer layers blasting out into space — giving the hunter a bit of a hotfoot.
 

Script by Damond Benningfield

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