Supernova in M82
I have been busy and not had as much time to do any astrophotography recently. Fortunately, I had some good luck and timing yesterday.
Wednesday morning, I woke up to news of a supernova in M82. Fortunately, I saw this before I went to work. I was scheduled to work with some students at Tohono O’odham Commuity College in Sells last night and thought I might get a chance to try to catch the supernova from there. The college site is nice and dark so it was worth a shot throwing my equipment in the car. Fortune also smiled with clear skies when I got out there.
I was using my Canon 60D, EF 75-300mm zoom lens and iOptron Skytracker, my usual setup. Although there are people with larger, better setups out there that will no doubt take more spectacular pics, I can at least purse the record for the person who imaged the supernova with the smallest setup!
I took some pics of M82 and the nearby galaxy M81 a few weeks ago before the supernova. Here is one of those pics. I took this one on Christmas Eve and believe I used my 250mm lens so the scale is a little different.
Okay, now here is the one from last night. The two lines point to the new little point of light that is the supernova (I did not crop the pics the same and they were taken with slightly different lenses so the scale is different). Click the images for larger versions.
This supernova is interesting for many reasons. First, M82 is undergoing a rapid burst of star formation due to a recent pass by the nearby galaxy M81 (also seen in the pic). Increased rates of star formation lead to higher rates of supernova. Second, M82 is a relatively nearby galaxy (only 12 million light years away or so) which means we can study it in greater detail than more distant supernova.
Finally, this is a type 1a supernova. Type 1a supernova form when a white dwarf star sucks matter off a nearby companion star. White dwarfs have a maximum mass about 1.4 times the mass of our Sun. If you add more matter than that, you get a huge explosion which destroys the star. This white dwarf suffered that fate leading to the supernova we are now observing.
Since type 1a supernova always happen when the mass hits 1.4 times that of our Sun, they are always about the same brightness. If you know the brightness of an object, you can figure out its distance. Type 1a supernova are very bright and can be seen in distant galaxies and are very important for astronomers to determine the distance to other galaxies. The more we can study nearby ones, the better we understand them and the better we can measure the distances to other galaxies. Therefore, astronomers are training lots of scopes on this supernova right now!
Oh, I got so excited about the pics, I should mention that we saw it visually as well. We were using a 6″ Celestron Nexstar SE and could see a little bright spot in the galaxy right where the supernova is. I am always nervous showing objects like this to people as you sometimes get the disappointed “Is that it?” reaction. The students last night, however, were happy to be able to see it and I didn’t have to deal with that common reaction. So I can tell you it is visible with a 6″ or larger scope…wouldn’t surprise me if people spot it with even smaller scopes.
This supernova looks like it was discovered before peak brightness. It will probably get brighter for another week or two before starting to fade. How much brighter is an open question and hard to predict. We don’t know how long it took after the explosion for us to discover the supernova (several pre-discovery images have already turned up) and there may be intervening dust that dims the supernova. Worst case scenario, it will not get worse for a week or two. Best case scenario, it brightens another couple of magnitudes.
My sympathies to the northerners who have to brave the cold to see it…I was out in just a sweatshirt last night!
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