The bright orange star that marks the shoulder of Orion gets most of the attention, but the hunter’s blue-white heel is even brighter. And it faces a similar fate: Both stars will blast themselves to bits.

The shoulder is represented by Betelgeuse. The supergiant star has been unpredictable in recent years. It’s grown dramatically fainter and brighter – the result of “puffs” of gas from its surface that are many times the size of the Sun.

The heel is marked by Rigel. The star appears to be more than 850 light-years away, although there’s a good bit of wiggle room. The details of its mass, size, and brightness all depend on that number. But the best estimates say that Rigel is about 20 times more massive than the Sun, dozens of times wider, and tens of thousands of times brighter.

Rigel’s color tells us that its surface is much hotter than the surface of Betelgeuse. Rigel might once have looked like Betelgeuse does today. But changes in its core caused the star to shrink and get hotter.

Sometime in the next couple of million years, the core will die and collapse. Rigel’s outer layers will explode as a supernova. That will seed the space around it with the raw materials for future stars and planets.

Rigel is low in the east-southeast at nightfall. It’s to the right of Orion’s three-star belt, which extends upward from the horizon. Rigel is the seventh-brightest star system in the night sky, so you can’t miss it.

More about Rigel tomorrow.

Script by Damond Benningfield