This Week Hal Does Just Enif

Jul 11, 2016

Enif already
Credit Till Credner - AlltheSky.com

Hal discusses the big, bright, strange supergiant star Enif in the constellation Pegasus.

Enif of a good thing is visible in southern Colorado skies right now. And by Enif, I mean a remarkable star in the constellation Pegasus. Enif is the brightest star in that winged horse. It’s a fairly bright point of light, in otherwise fairly dim area of the sky, but what makes it special is what’s happening 670 ly away from Earth.

Enif is a very strange star. Astronomers have a highly technical name for this type of star – a supergiant! Enif is a fairly cool star, at only around 7500°F. Our own much smaller Sun is about 3000° hotter. But Enif is much, much larger than our sun. It’s at least 150 times the size of our Sun, and puts out 6700 times more light than our Sun does.

Enif has also been playing games with astronomers for many years. There are reports over the last couple of centuries that it has suddenly brightened dramatically for a very short period of time. In 1972, an observer noted it got five times brighter than normal, but for only 10 minutes, before returning to its previous brightness. Clearly something weird is going on out there. One theory holds that every now and then, Enif throws off a solar flare that would dwarf the entire output of our own Sun for a few minutes. A pretty scary neighborhood.

In addition, Enif appears to be family-oriented. There is pretty good evidence that is part of a trio of three supergiant stars. These three enormous stars all have roughly the same luminosity and distance from the Earth. It appears that over the last 15 million years they’ve slowly drifted and are now about 100 light years apart. That makes family reunions pretty difficult. You might even say, Enif is enough.

If you’d like to take a closer look at Enif, or any of the other wonderful and amazing things in the sky, please visit CSASTRO.org for a link to information on our monthly meetings and our free public star parties! 

This is Hal Bidlack for the Colorado Springs Astronomical Society, telling you to keep looking up, Southern Colorado!