Observing Nova Scorpii 2007 -so what?

Cool! well, cold - very cold. At least here on Earth it was cold - 15-degrees, to be exact, with winds gusting hard enough to shake the car. I drove down to East Beach in Westport, parked so I had a good southern view out the side window, turned off the lights and rolled down the window. At first glance the only things obvious to me were Jupiter, Antares, and the graceful curves of Scorpius.

Click on picture above to get a larger version. Look carefully for the nova near the bottom.

I waited for my eyes to dark adapt - but I couldn't spot the Nova. I got my 15X45 IS Canon binoculars and looked again. First I found Jupiter, then Antares, then I traced the arc of the Scorpion's back down to second magnitude Epsilon Scorpii - a quick glance to the east of it and there was the nova, obvious as could be, the brightest star at the head of a neat little triangle that wasn't there a month ago! (Well,the two fainter stars the triangle were, but I would not have seen the nova.) However, it took about 10 minutes of dark adaption for this to become an easy target to my naked eye. I would put it right at magnitude 4.0 jjudging by a comparison star a bit west of it that is magnitude 4.2. be sure to click on the picture above to get a larger image that I think does a pretty good job of approximating the naked eye view. And yes, you will have to look carefully for the nova and its comparison stars.

And if at this point you're murmuring a big "so what!" I wouldn't blame you. it's just another dot of light and not a very bright one at that. With my naked eye I could not see the star marked "50" - that means magnitude 5.0 - so I would say the limiting magnitude was about 4.5. Transparency wasn't that bad, but remember the nova is only 11 degrees above the horizon, so we're looking through an awful lot of atmosphere and that makes all the stars near it harder to see. I had a more difficult time picking up the 4.2 comparison star, wich is why I feel the nova was brighter. It certanly was a lot brighter than the 5.0 star.

But again, so what? Why bother to get up and look for something like this?

And I would have trouble answering that question if all I saw was what my eyes revealed. Of course we all see more. Our eyes just bring us a signal. Our brains do the signal processing and they add some wonderful informatin that makes the sighting of a nova a magical moment of recognition. This apparently insignificant dot of light is really an incredible nuclear reaction so much more powerful than any of our bombs that it would be silly to make comparisons.

And thanks to what scientists have painstakingly pieced together over the years, we now have an idea of how and why this nova - this "new" star - suddenly appeared. And so with our brains we can see this incredibly compact white dwarf - an entire star squeezed down to something like the size of the Earth - sucking the life blood out of its companion star until the dwarf itself becomes overloaded and a nuclear reaction occurs. Talk about hot!

But we ain't seen nothing yet! This kind of explosion can happen with some frequency and it really doesn't do much damage to the white dwarf. However, in some cases it's believed the white dwarf will eventually load up with extra gas in a fatal way and go out with the incredible bang of a super nova, virtually destroying itself in the process.

So as I sit comfortably in the car and look out at this little dot of light over the ocean I think of our sun, big enough to hold one million Earths inside it, and I try to imagine it getting shrunk down to about the size of the Earth. (Yes, in doing so it will lose half it's matter - but it's believed that's what will happen in another 5 billion years or so. ) But for the Sun there won't be any nearby companion star to feed off of - or at least there isn't one now. So when it gos to the white dwarf stage iot will blow off a beautiful smoke ring like we see from the Dumbell nebula, or M57, the "ring nebula."

So it's thoughts like these that leave me warm and in awe while alone at the beach on a cold, winter morning.

Oh - and for the record, the image above was taken with the Canon Rebel. It's a 2-second exposure at F4 and I simply balanced the lens on the half-open window of the car, took several shots, and hoped one of them would be steady enough not to look too bad. ;-)

Some Q & A

Here are some questions froma friend which I think are right on target - and my responses which I give with the caveat that I am not an astronomer, but this is my best understanding of things.

On Feb 19, 2007, at 11:56 AM, Bruce wrote:

It really is amazing if not a "spectacular" visual sight to the newbie. I have some questions about the physics of this. In order to have enough gravity to collapse itself so small it has to have incredible mass.

What matter is at the core that does this to a star but doesn't seem to do it to other heavenly bodies? Why doesn't the earth, or the moon just collapse to a basketball size mass?

You need to understand the dynamic equilibrium a star is in during it's normal life . . . there are two fundamental pressures at work - gravity wants to collapse it, but the conversion of hydrogen to helium in its core - nuclear fusion - produces enough outward pressure to balance the inward pressure of gravity.

In the case of the planets and other bodies, there simply isn't enough mass to break down the forces that hold the atoms together. (Good we're relatively small!) Jupiter is a "failed star" in a sense. It has the right ingredients - not rocky, but gaseous - but it needs more of them. If it had enough mass (about 8X more than it has) that would create enough pressure to start the nuclear reactions in its core and you would have a star.

Also, you write that when our sun eventually collapses down to the size of the earth it will lose half its matter in the process but if its losing its matter why doesn't it loose the gravity (I'm assuming its gravity that causes the collapse) causing this collapse?

Ok - the other part of the equation is this - and you;re onthe right track with gravity. Right now the sun is "burning" hydrogen. That is, it's fusing hydrogen into helium. And there's enough hydrogen in the sun for this to go on for another 5 billion years at the current rate. But eventually it gets used up. When it does the star does burn helium, but that too eventually gives out. However, as it burns up one or the other element, it goes through various stages of collapse - that is gravity starts to win out - it also, in these violent stages of collapse - blows off a lot of matter - which is what we see when we look at certain types of nebula called "planetary" because some of them look like planets (Remember - the cllapse is caused by gravity, but as it collapses, pressure builds up - almost like a spring, and then boing! Out comes some more stuff! Or it returnss to equilibrium for a while.)

The bigger a star is the faster it goes through this process - and if a star is really big, you get one giant explosion near the end - just before that explosion there is rnough pressure to create all the other elements in the periodic table - including carbon - then the star blows up - a super nova - and for a brief time we get an energy output - light - equal to that of all the other stars in the galaxy. It's an incredible event - and it is because of such events in the past that you and I are here to write about it. Without a super nova there would be no carbon and without carbon, of course, no life. Bottom line -we are literally made from star stuff.

And if there isn't a star near by to fuel it does it just float through space for eternity as giant pellet of buckshot?

Yes - but there are various things it can and does become in the process - one being a neutron star that continues to give off a lot of energy, just not in visible light. But eventually it is essentially a cinder. However - the elements it has blown off eventually pool together and as gravity begins its work again and new stars are formed - as we see happening today in places such as the Orion nebula.

The idea of white dwarfs being akey to the nova process is relatively new, i think. At least I seem to remember from my early days in this hobby that "nova" and 'super nova" were just different sized versions of what was roughly the same event. Now it seems nova are tied to this white dwarf interaction with another star, and super nova are justa function of how large the star was in the first place. AT least that's my understanding at this point. ;-)