A supernova… one of the most spectacular and violent explosions in the universe, where a single star blasts out more energy in a few days than our Sun generates in its lifetime. While several dozen of these fleeting exploding stars are discovered every year, few become bright enough to see in a small telescope. But a couple of weeks ago, a supernova exploded in the galaxy Messier 101 in the constellation Ursa Major… the brightest such event in nearly 20 years. Here’s how to see this magnificent stellar explosion.
This new supernova, now called SN 2011fe, was first seen on August 24 by Caltech astronomers. The star was at first a dim magnitude 17.2, visible only in images. But it has since brightened to magnitude 10. That’s about as bright as the nucleus of the galaxy itself and easily within reach of a 4-inch telescope. Since M101 is a galaxy some 22 million light years away, so the star must be amazingly bright to see with a modest instrument.
Unfortunately, M101 is a little hard to see this time of year because the Big Dipper is low on the horizon for most of the night. And I’m sorry to tell you it’s all but impossible to spot M101 from the deep southern hemisphere this time of year.
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Around the Moon in 28 Days takes you on a full tour of the Moon during the month. Use your binoculars and telescope to learn the seas, highlands, craters and mountains of the Moon, and get a close-up look of the solar system in its earliest days. Click here to learn more…
For northern observers, the best place and time to look for the Dipper and M101 is just above the northern horizon after sunset and before sunrise. Try to look when the sky is as dark as possible; M101 has a low surface brightness and is not easy to find when the sky is anything but very dark. The galaxy makes an equilateral triangle with the last two stars in the handle of the Big Dipper, Alkaid and Mizar (see above). The supernova will look like a single faint star southwest of this faint face-on galaxy’s central nucleus.
From the mannter in which the supernova brightened over time, and its spectrum, astronomers can tell this is a Type Ia supernova, one of the two main types of such explosions. In this case, the detonation is caused by material from one star falling onto a neighbouring white dwarf star. When the mass of the white dwarf increased to about 1.4 times the mass of our Sun… ka-boom! We’ve look at Type Ia supernovae before, and you can learn more here.
So while M101 is a little hard to see, try to find this exploding star over the next week or so, especially as the Moon moves past full after September 12. An bright event like this is rare. And you may recall that a supernova was the #1 sight on the “Bucket List for Backyard Stargazers”. So here’s a chance to cross one off your list…