Speaking of Mars… I got a note from amateur astronomer Bill Longo recently. On March 19, he went out in the early evening to try to get a picture of a satellite that happened to be passing near Mars in the sky. He took the image below. The satellite isn’t in this shot, but he did get more than he bargained for: he saw Mars, the galaxy M95, and the new supernova!
[Click to supernovenate.]
That’s a happy coincidence. He didn’t even know the supernova had gone off until the next morning. He checked the images from the night before, et voila. The picture itself is amazing; Mars was about 400,000 × brighter than the supernova when he took this shot! The two "wings" coming from it are due to internal reflections in Bill’s optics. But you can clearly see both the galaxy and the supernova in the image.
I’ve already posted some gorgeous shots of the supernova and the galaxy (see Related Posts below) but I think this may be my favorite. It’s not often you see a planet, a galaxy, and a supernova all in one shot… and without the photographer even knowing it at the time!
This is very exciting: the star that blew up to form Supernova 2012aw may have been seen in an older Hubble image!
First, here’s a lovely shot of the galaxy and supernova:
[Click to galactinate.]
This is not from Hubble! It’s from Adam Block, a frequent contributor of stunning pictures to this blog, who took it using the 0.8 meter (32") Schulman Telescope at Mt. Lemmon on March 20. The supernova is the bright bluish star sitting on a spiral arm to the right and just below the core of the galaxy.
M95 is a relatively nearby barred spiral galaxy just about 37 million light years away, so we can see a lot of detail in it. In fact, it’s close enough that with big telescopes, individual stars can be seen in it. Once the supernova was spotted and its location determined, astronomers found a picture of M95 taken with Hubble a few years ago, long before the supernova event, and combed through it. Sure enough, they found a star sitting right where the supernova went off! It’s almost certainly the progenitor of SN2012aw.
Interestingly, given the color and brightness of the the star in the Hubble image, it was not terribly massive, maybe 8 times the mass of the Sun. That’s at the lower limit for how much mass an exploding star of this type can have. It’s probable the star had more mass when it was younger, and shed a lot of it during its short, furious life. I poked around online and found another example like this; SN2003gd was a supernova in the nearby galaxy M74, which is also close enough that a progenitor star was found in older images. Interestingly, it too had about 8 times the Sun’s mass, and had other characteristics similar to this new supernova.
Being able to find the star that blew up in older images is terribly exciting! It’s not that common to find them — they have to be in nearby galaxies, or else they’re too faint to see. And they really help constrain the physics of the explosion. We have a pretty good grasp of the basics on how high-mass stars explode, but the devil’s in the details. The mass of the star right before it blows up, how bright it is, what color it is, what kind of environment it’s sitting in — all these things help astronomers understand better how and why stars like this explode. In fact, Supernova 1987A sparked a revolution of sorts in supernova astrophysics because it was found to be a blue supergiant when it went off — before that, it was thought only red supergiants could explode.
So SN2012aw joins the short — but growing — list of supernovae that have a star identified as the culprit. The more we find, the merrier astronomers will be.
Image credit: Adam Block/Mount Lemmon SkyCenter/University of Arizona. Tip o’ the Chandrasekhar limit to DeepSkyVideos on Twitter.
- Supernova 2012aw: the pictures!
- Breaking: possible supernova in nearby spiral M95
- Supernova update: it’s peaking now! (about a supernova in galaxy M101 in 2011)
- Supernovae popping off like firecrackers in Carina
Last night, I wrote about a possible new supernova in the galaxy M95, a nearby spiral. It has since been confirmed, and is called SN 2012aw. Given that M95 is about 37 or so million light years away — close on a galactic scale — that means this exploding star will be easy to see even with smaller telescopes. I asked folks if they could send me images, and send them they have!
Here’s one from Greek amateur astronomer Anthony Ayiomamitis, using a 30.5 cm (roughly 12") telescope — and it’s hot off the ‘scope; as I write this he took this image just a couple of hours ago:
How about that? The supernova is marked. Not only that, it’s sitting right on a spiral arm, and as soon as I saw that I knew it was a Type II: when a massive star explodes at the end of its life. Those kinds of stars are born in spiral arms and don’t live long enough to wander out of them — that can take many tens of millions of years, and these massive, hot stars live only a few million years at most. And sure enough, spectra taken have revealed the presence of hydrogen in the explosion, which only happens in these kinds of exploding stars*.
Another image was taken by George Carey which looks very much like Anthony’s (they both have the same sized telescopes, though very different in design). This makes me think we’ll be seeing a lot more images of this soon, including from some big, professional observatories.
I have to point out this sequence taken by Parijat Singh, which he made into an animation. The first half of the sequence was taken on March 15, and the second on March 16. Keep your eyes just above and to the right of the galaxy center… [You may need to refresh this page to see the embedded video.]
Pop! [The various streaks you see in some frames are, I believe, satellites passing through the field of view.]
Images like these are critical; they put an upper limit on how bright the supernova was just before it exploded, which helps scientists figure out the physical processes that go in in the very early hours of a star exploding. That’s hard to catch, so there aren’t many observations of very young supernovae. Clearly though, with more amateur astronomers with better equipment patrolling the skies all the time, we’ll be getting more shots like these.
The current brightness of the supernova is around 13.3, but I expect it’ll get brighter in the coming days. Not bright enough to see naked eye, and you’ll still probably need a 30cm telescope to see it without a digital camera, but that’s still pretty cool. Stay tuned!
Images credits: Anthony Ayiomamitis; George Carey; Parijat Singh.
* UPDATE: I got a note from my friend and supernova expert Alex Filippenko. He points out that just seeing a supernova in a spiral arm doesn’t guarantee that it was a massive star; the other major type of supernova (Type Ia) happens with very old stars, and these can by coincidence happen to be in a spiral arm when they go off. He’s right (of course). He also notes that Type Ib and Ic supernovae are from massive stars; and perhaps I shouldn’t have limited myself to this one being a Type II. The taxonomy of supernovae is a little confusing, and maybe someday that’ll be the topic of a post here!
I just learned that there’s a possible (but nearly certain) supernova on the rise in the relatively nearby spiral galaxy M95. This is exciting, because it should get bright enough to spot in small telescopes! By coincidence, Mars happens to be sitting in the sky very close to the location of M95; that makes it easier to find in that you have an obvious landmark in the sky, but tougher because Mars is so close and so bright it swamps the region with light!
Right now, the supernova is still at roughly 12th magnitude, making it too faint to see without bigger ‘scopes, or smaller ones with digital cameras. However, it was only discovered on March 16, so it’s most likely going to get brighter. The galaxy itself is about magnitude 9 or 10, so the supernova may get that bright.
There are quite a few pictures of the galaxy+supernova on Flickr, but most
are copyrighted aren’t free license so I can’t post them here. However, searching the site for "M95 supernova" yielded a few of them. You can also find a list of links here. I think this one in particular is cool; it has bright lines going across that’s scattered light from nearby Mars!
However, by a funny coincidence (?), the European Southern Observatory chose a Very Large Telescope image of M95 as its Picture of the Week just this morning:
[Click to galactinate.]
I say it’s a coincidence because there’s no mention of the supernova in the caption. Anyway, M95 is a gorgeous barred ring spiral: the bar is the rectangular feature in the middle, and the ring around it of gas and stars is not uncommon in galaxies (like here and here). M95 is about 35-40 million light years away, and is part of a small group of a couple of dozen galaxies called the Leo I group. M96, another spiral in the group, is even prettier!
Back to the supernova, DeepSkyVideos put together a very quick-and-dirty video about it which manages to be very informative and good despite being put up so quickly:
If you have a good telescope and detector, the coordinates of the supernova are online. Astrobob has a good finder chart for it. I’ll note that observations right now are critical; the physics of the explosion are best characterized by how rapidly it brightens. At this point, we don’t even know if it’s a Type I or Type II! So observe it if you can. And if you take good pictures or see any online that are
not copyrighted freely licensed, please let me know!
And as a final note for now: we’re in no danger from this. I normally wouldn’t bother writing that, but a lot of people seem jittery due to 1) the 2012 nonsense, b) the recent (coincidental) solar flares, and γ) the asteroids (DA14 and AG5) I wrote about last week. So to proclude any fear-mongering, I’ll just say this supernova is something like 400 million trillion kilometers away, and probably won’t even get bright enough to see in binoculars. I hope that helps assuage any fears.
Image credit: ESO