(via Chandra :: Photo Album :: NGC 1929 :: August 30, 2012)
NGC 1929 (star forming region) in N44 (nebular cloud): A Surprisingly Bright Superbubble
Hey all, before I bid you good night (though I wasn’t exactly on this evening, but hey, I had a queue going…for a bit…in the afternoon mostly but you know what I mean…anyway…) I want you to slow your tumblr-scroll for a second and take a look see here. That amazing picture above? That’s an in-depth analysis of an amazing nebular cavity in the Large Magellanic Cloud, one of our Milky Way’s satellite galaxies. What’s going on here is a classic story of a stellar nursery in a dust cloud. When the particles start to create gravitational collection points, they rapidly accrete matter. As the compressed matter pulls in more gas and dust from the surrounding cloud, it also heats up. Continue this process long enough and you start to form a proto-star, then, once the core gets hot enough, and the hydrogen gets friendly enough, you start getting fusion reactions. Suddenly there’s a whole lot of energy at the center that can push back against the force of gravity pulling everything in. A star is born and reaches hydrostatic equilibrium. But the first new stars in an interstellar cloud are often quite massive, burning very hot, which means they throw off a lot of radiation. As this moves out (along with the particles blown out by the nuclear reactions, mostly neutrinos) it creates a stellar wind, which runs right up against the very gas and dust that gave rise to the stars in the first place. This starts to put pressure on the gas cloud, creating new dense points, eventually creating ideal conditions for another generation of stars. These young stars, however, are rather James Dean-ish. They live fast and die young. (And, if you think supernovae are pretty, they also leave a good looking corpse…unless you consider the neutron star to be the corpse, which would also be good looking. I think they’re cool anyway. Oops, digression.)
"So", you say, somewhat bewilderedly, or not, "what’s all that got to do with a weird four-color mosaic of space bubbles?"
I’m glad you asked. Each color is from a different wavelength source. Let’s go through them, and see what they tell us about what’s going on in NGC 1929.
X-ray imaging from the Chandra X-Ray Observatory (a space telescope because x-rays have a hard time getting through our atmosphere…thankfully) shows - in blue - the insanely hot gas (so hot it lights up in x-ray, now that’s energetic!) around the young stars and the where the shockwaves of the supernovae have run into the nebular material.
Infrared imaging from the Spitzer Space Telescope shows - in red - the dust and cooler gas that is glowing from the ultraviolet radiation coming off the stars. UV is not as energetic as x-rays (remember, a longer wavelength = lower energy) and so the light down in the infrared shows those parts of the cloud that aren’t getting superheated.
Optical light from the 2.2m Max-Planck-ESO telescope in Chile shows - in yellow - more of the glowing gas at a lower temperature than the superheated gas, and also gives us our nice background star field.
So, now you see how we learn so much about something so far away by combining the various types of data we can collect at each wavelength on the electromagnetic spectrum.
Buenos noches! Tschuss! Etc.