Corona Borealis and bright Alphecca

Many astronomers are currently watching the constellation Corona Borealis (CrB) for the long-awaited outburst of the repeating variable star T CrB. When that happens (possibly in the next few weeks), “T Cor Bor” is expected to brighten dramatically, a couple thousand times in a matter of hours.

Look just above Arcturus and slightly to the left. If the sky is dark, you’ll see a set of stars shaped like a cup without a handle. That’s the constellation Corona Borealis, the Northern Crown. Only one of its seven stars is very bright, and it’s called Alphekka, which is Arabic for “bright star in a broken ring.”

In August, keep an eye on this arc of stars, or at least the one just to the left of Alphekka. That’s where astronomers expect a bright nova to appear over the next few months. It’s designated by the letter T, and such letters are the celestial designation for a star that varies in brightness. This star is known to skywatchers as T Coronae Borealis — or “T Cor Bor” for short.

This star is usually too faint to be seen with the naked eye. But every 80 years, it flares up spectacularly, brightening a couple thousand times in just a few hours. At its peak, it will be about as bright as nearby Alphecca. This dramatic increase in brightness has earned it the nickname “The Blazing Star.”

Meanwhile, look far to the left of Arcturus and down until you reach Antares, just west of due south, at the heart of the constellation Scorpius. Antares means “rival of Mars.” It’s a huge red supergiant star about 550 light-years away. The slightly gibbous Moon will pass close to Antares on the evening of August 14 — making the two very close together when viewed from the West Coast.

If you’re a planet-watcher, plan to head outside early on Wednesday, August 14. Look to the east, and you’ll easily spot brilliant Jupiter, the king of the planets — accompanied by a tiny dot just above it. That’s Mars, and the two planets will be less than ½° apart!

All of this was visible on AstroHat, and we’re doing everything we can to bring the moment of AstroHat 2.0’s reincarnation closer.