Timing is everything. One day after I submitted my What’s Up in Durango Skies column for January, the brightest supernova in a generation went off in M82. This one appears bright because M82 is relatively close to the Milky Way. At least close as far as galaxies go – it’s about 12 million light years away, or about 70 trillion miles.
M82 is called the cigar galaxy, because of its elongated shape. It is one of the few galaxies visible with a standard 10x50 pair of binoculars, and is very near the much brighter M81 spiral galaxy. Although both galaxies are in the constellation Ursa Major, they are outside of the Big Dipper asterism.
Through binoculars this pair of galaxies appear as just tiny smudges on the sky. But in a small telescope they make a great target because you can easily see that M81 and M82 are different shapes. I tried unsuccessfully to see the supernova through binoculars – 10X magnification wasn’t quite enough for my eyes to resolve it from the slightly brighter galaxy core. To see the supernova first hand, you only need a little bit more magnification, easily provided by a small telescope. Although the brightness of the supernova is now fading, it will be visible for a few more weeks.
Visually, M82 looks sort of like an edge-on spiral with some random dust lanes, but photographically, there is a very interesting bunch of red filaments of hydrogen gas that look like they are coming out of the core. Until recently this galaxy was classified as an “irregular” galaxy, which simply meant that it didn’t look quite elliptical, or spiral. However, new infrared observations suggest a spiral structure that is just hard to see because of all the dust lanes and hydrogen filaments.
The new supernova, designated 2014J is a type Ia (I discussed this type last September). Type Ia are particularly important for determining distances to galaxies, because according to the most widely accepted theory, they are all exactly the same luminosity. And if you know how much light they give off, you can use their apparent brightness to accurately calculate their distance – the dimmer they appear, the farther away they actually are. Because M82 is so close to the Milky Way, this supernova provides an excellent opportunity to check the consistency of many of the scientific models for determining galaxy distances.
I found the story of the discovery particularly interesting (see the link). A team of undergraduate students at the University of London Observatory was being shown the observatory by Dr. Steve Fossey. M82 was selected as a target of opportunity, I am sure because it is not only bright, but quite photogenic. This is a good example of how important discoveries can be made when you least expect them.
In 2005, I was with a couple of Fort Lewis College students and chose M82 as the first target to be imaged when we tried out our new camera. Too bad we didn’t get any supernovae back then.
email@example.com. Charles Hakes is an assistant professor in the physics and engineering department at Fort Lewis College and is director of the Fort Lewis Observatory.