Orion’s Shield

StarDate: February 18, 2012

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Orion is one of the most beautiful constellations, and one of the easiest to find. Tonight, for example, it’s well up in the south at nightfall. Look for a tall box of four bright stars, with a slash of three stars across its middle.

But not all of Orion’s stars are quite so easy to find. Off the top right corner of the box, for example, is a curving lineup of six stars. Depending on whose diagrams you look at, it represents either a shield or a dead lion held in the hunter’s outstretched arm.

The stars are all designated with the Greek letter pi, and from north to south they’re numbered 1 to 6.

The brightest star in the shield is at its middle — Pi-3. It looks bright mainly because it’s close by — just 26 light-years away. In fact, a couple of hundred thousand years ago it was only about half as far as that, so it would have looked much brighter in Earth’s night sky. Pi-3 is similar to the Sun. It’s a bit bigger, brighter, and heavier than the Sun, but still a close match for our own star.

The stars that line up to the south of Pi-3 — Pi-4 and -5 — look slightly fainter, but they’re actually far more impressive. Each is well over a thousand light-years away. And each consists of at least two brilliant, massive stars — stars that make Pi-3 look like a flashlight shining next to a spotlight.

So look carefully for the hunter’s curving shield — a set of stars that’s truly “outside the box.”

 

Script by Damond Benningfield, Copyright 2011

 

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