‘
I blogged a little while back about a new supernova in the spiral galaxy M100. It’s probably hitting its peak brightness right now, and will soon begin to fade away into obscurity. In the meantime, the folks south of the border– way south, in Chile– have weighed in, observing the exploded star with the mammoth 8-meter Very Large Telescope (yes, that’s its real name).
The picture above (click it for a big 800 kb version) shows an M100 "before and after" shot. The image on the left was taken in 2002, and the one on the right was taken just a few days ago. I marked the supernova to make it easier to see. On the left image, you can see the bright star above the supernova; it may look brighter on the left than on the right because the exposure times were different, and the images were processed differently.
There’s an interesting thing to see right away in the image: the supernova is not in a spiral arm, it’s in the gap between two arms. The spiral arms are big, obvious features in the galaxy because clouds of gas and dust get compressed in them. This triggers star formation, which means you get lots of dinky, dim stars, but also a handful of bright ones. These bright ones are really bright, which in turn light up the gas clouds, which in turn make the arms obvious features.
Now, bright, massive stars don’t live long (a million or so years) and then they explode as supernovae, so you expect to see them in the spiral arms, because they don’t live long enough to make their way out. But this one, SN2006X, is not in a spiral arm. What gives?
What gives is that there are two types of supernovae. When a low-mass star like the Sun ends its life, its core gets compressed into a dense ball called a white dwarf. I explain how these can explode in yet another previous entry. Anyway, stars like the Sun can live for billions of years, so they live long enough to move out of their parent spiral arm. So you don’t necessarily expect to see this kind of supernova (called a Type I) in an arm. It might be, if coincidentally the star happened to be drifting through an arm when it blew up, but it doesn’t have to be, like the other kind of supernova does.
So just by looking at this picture, you can guess the star that blew up was an old, low-mass Type I. And you’d be right!
Usually it takes a lot of work to interpret astronomical images, but sometimes you can tell a lot just at a glance.’
February 23rd, 2006 at 10:28 pm
Man, I wish I could go out and observe this!
I have an 8-inch F/5 newtonian with which I used to looked for galaxies and such. However, due to problems with my legs I can’t do anymore observing.
I saw the Nova in Cygnus in 1975(?), but have yet to see a supernova, and with my ’scope I most likely could see this one. Drat and double drat!
February 24th, 2006 at 2:22 am
What we need is a webcam tied to a scope. Is there such a set up?
February 24th, 2006 at 6:49 am
http://www.slooh.com has an online telescope- don’t know if they’ve done any observing of M100 lately, though, as I’m not a member.
February 24th, 2006 at 7:15 am
Just beautiful. Yeah Spitzer.
However, I thought you were going to say it could also be a Type II due to the time difference between the passing of the spiral “wave” and its present location.
February 24th, 2006 at 8:04 am
Before and after, boy are you in trouble! Never wash the reds with the whites.
February 24th, 2006 at 9:06 am
Dangit! Wrong galaxy again! Where is the ‘type-II-supernova-in-the-milky-way-which-happens-every-40-years-or-so
-but-may-actually-be-every-200-years-but-we’re-astronomers-so
-so-we-can’t-be-sure” that we’ve been promised?
SNO is in it’s last few months of running.. if you want to catch the neutrinos from the darned thing, it’s time to get moving, people! I want everyone to go out, right now, and stomp on your nearest collapsing star.
Hrumph.
February 24th, 2006 at 9:59 am
I captured a shot of the supernova last weekend. I took this image with a 12″ Meade LX200 at f/6.3 with a Canon 10D. Autoguided with a piggyback Orion 80ED with a Meade DSI. This was from my light polluted backyard observatory in Renton, WA.
(see here)
http://www.eastsideastro.org/observatory/galaxies/M100-7Stack-proc.jpg
Tom
February 24th, 2006 at 10:16 am
Thanks Phil. Your explanation is, as usual, thoughtful, insightful, and educational. Anyone know how many supernovae we’ve seen in our own galaxy?
February 24th, 2006 at 4:47 pm
In our galaxy? I think that comes to four, plus another one if you count the Large Magellanic Cloud as our galaxy.
We have:
1006, in Puppis
1054, in Taurus (the Crab Nebula supernova)
1572, in Cassiopeia (Tycho’s star)
1604, in Ophiuchus (Kepler’s star)
1987, in the LMC
Slim pickings!
February 24th, 2006 at 8:42 pm
Well, there are ltos more, of course, but those are the ones in modern times. There are many supernova remnants in our Galaxy; seen on radio. I do wonder how many there are though!
February 25th, 2006 at 12:21 am
The newest term I have seen at some astron websies is “Hypernova.” It is a reference to the very largest stars 100+ solar masses. May we presume the Crab Nebula falls into that newly created category?
February 25th, 2006 at 2:03 am
Thanks, Phil, for another good one.
Tom, that was a very good image from a light-polluted backyard.
February 25th, 2006 at 3:35 am
Tom G now thats the kind of telescope I need! Awesome pic. I hope to have a better telescope soon.
March 7th, 2006 at 3:46 am
Love the shots. To my untrained eye even though all the stars appear bigger in the 2002 shot, without seeing anything in the 2002 shot area that can easily be seen as something that would go supernova, I would have just though an object in front of the smaller star had just orbited down in the 2006 shot. Now laugh it’s good for the soul. I truly hope someday instead of peeping though scopes you will be able to drive through the universe on your way to work…if and only if mankind has finally reached a point of doing no harm.