ba-BOOM!!!!

Oh, it's been a long couple of months...broken computers, new computers, software that won't run on new computers, etc. etc. etc. Once all of that was sorted out, it's time for June Gloom and overcast skies all night. Thankfully, last night stayed clear enough to get two hours of subs of M51. Sure, it seems like I shoot M51 a lot...why again? Because on May 31, the first images were taken of a supernova in M51. here is a link to an article about it, and some info on one interesting fact about it-it's not uncommon for supernovas in other galaxies to be discovered by amateurs, but this one also had its debut via Twitter. I don't know if that means anything or not. Certainly, it doesn't concern the start that exploded-it happened over 25,000,000 years ago; the light just reached us this month.

The upper photo is from May 2, the lower from June 12. Compared to the photos in the article I linked above, the supernova is even brighter-compare it to the star to its left (USNO J1330149+471027, which is in our own galaxy, and is a lot closer.) In the raw data from my camera, the supernova is brighter than the core of the galaxy itself, and may still be getting brighter. That happens not because the explosion itself takes weeks or days-it doesn't-but because as the fireball grows, there is more surface radiating light. At the Keck Observatory, they have measured parts of the fireball expanding at 11,000 miles per second.  The most up-to-date news articles I have found are about a week old, and it was still clearly around 14th magnitude, slightly fainter than the star next to (which is mag 13.85.) The star that blew up was about 20 times the mass of our Sun, making this a Type II Supernova, which is what happens when really big stars run out of fuel and collapse. It has been designated SN 2011dh. Once the fireball diffuses, the remnant will be a planetary nebula, although sadly we will never see it from this distance.

M51 is actually two galaxies; the upper object is another galaxy that is passing near or through the other. The interaction caused gases and dust that had been spread thinly to condense, all along the arms of M51, and there is furious star birth going on there, lighting the dust up with blue light (a lot like what is going on far closer to home in Orion.) When these sort of star nurseries are formed, they tend to create hugely massive stars with very short lives relative to our star. In the "before" picture, notice how that band of gas has many blue knots of dense star formation; based on the supernova's location and size, this star was likely not more than 100 million years old. (I have heard that a candidate star has been identified in an older Hubble picture, but I don't know any details of that yet.) That's a fast and furious life by stellar standards-our Sun will live ten billion years before dying, and it's actually brighter than all but 15% of the stars in our galaxy; most stars probably live even longer.

I was initially worried that the nearly-full moon plus the chihuahua lights in all their glory would kill any chance of seeing this, but there is obviously no problem there; this thing is bright. Plus, since I was not trying to make the galaxy appear as bright as possible, I didn't have to "stretch" the contrast much in post processing, and that makes for a very tidy photo; a handy lesson for me as I keep learning to grab better raw images. While stretching is one way to make dim objects visible, longer exposures are another, and this clearly shows the increase in quality that would result from being able to keep the camera open longer. (This picture is a stack of 30-second exposures; as always, the quality of the clockworks in my drive is still a limiting factor.)

Pretty cool for the first supernova I have ever seen!