Antares B (St Patricks Day Green Star)

March 15, 2019

All right—I’m no trickster, so I’d make a lousy leprechaun. No… there are no green stars. But there are a few that can appear green.
Blue stars that are really close to red stars can appear to us as a greenish blue. One good example is Antares B, the binary companion to the red giant Antares A, the heart of Scorpius.

If you wake up EARLY on St. Patrick’s Day, or any day in the next month or so, you can’t miss bright orange Antares A low in the southern sky. To see Antares B, you’ll need a decent-sized telescope at least 6 inches in diameter. Point it right at Antares, and look for a much dimmer, greenish blue companion. That’s Antares B. Now again, the only reason it appears green is because a giant bright red star is right next door. It’s an optical trick. But as long as you’re outside with a big telescope, there are a couple other nearby objects you’ll want to see.

First, let’s address the VERY bright object to the left of Antares. That’s Jupiter. Of course, any telescope should show you its four largest moons. Larger telescopes will show you the cloud belts.

And now for the pot of gold…

With Antares in your eyepiece, move to slowly to the right, or West until you see what looks like a dim, fuzzy ball of light. That’s Messier 4, an ancient globular cluster over 12 billion years old, and over 7000 light years away.

So if you’re up for some early morning observation, there’s plenty to see in the southern sky.