AAS Post #4: News and cool pictures

AAS Post #4: News and cool pictures

AAS Post #4: News and cool pictures

Bad Astronomy
The entire universe in blog form
Jan. 9 2006 8:00 PM

AAS Post #4: News and cool pictures

'Finally, some actual news! I was just at a press reception for the 50th anniversary of the National Radio Astronomy Observatory (oh, do I have stories about that! But they'll have to wait), and then meetings with some folks about possible future projects. But that's all done, and before I go to the bar downstairs to conduct the real business of this meeting (and if you think I'm kidding, I'm not-- a lot of deals get made over drinks at bars), I want to relay a couple of the cooler news bits from today.

News Bit The First: The North Stars

Phil Plait Phil Plait

Phil Plait writes Slate’s Bad Astronomy blog and is an astronomer, public speaker, science evangelizer, and author of Death From the Skies!  

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I have two surprises for you perhaps, about Polaris, the North Star. First, it's not the brightest star in the sky. In fact, it's rather faint. People think it's bright because it's important, but that's a misconception.

Second, it's not just one star! It's been known for a long time that it's actually a three-star system, all orbiting each other. The primary star is what most people think of as Polaris, but there are two much fainter stars. One of these dim bulbs is not too hard to see with a small telescope. I've seen it myself with my old 10-inch 'scope. But the other is way too close to the brighter one to be seen. Its existence was inferred by its spectrum-- when the light from the star(s) is broken up into its constituent colors, it can be seen that it looks like two stars blurred into one by their great distance. A bright, massive star and a faint, low-mass star have different spectra, so when they are added together it's pretty obvious there are two stars there.

But today, the folks at Hubble announced they succeeded in splitting the two for the first time. In the image above you can see the fainter companion at the seven o'clock position. It took all of Hubble's ability to split them, but there you have it.

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Even the most famous star (besides the Sun) can hold hidden surprises.

News Bit the Second: Our Galactic Neighbors in Gassy Detail

Hot, thin gas does not emit light like the Sun does. The Sun emits light at all colors, so a spectrum of the Sun looks like a rainbow (duh, that's what a rainbow is. A rarefied gas, such as one in space, however, emits light at discrete colors. A spectrum of such a gas cloud looks like a series of thin colored lines, called an emission line spectrum.

Such a spectrum can tell you a lot about the gas, such as its temperature, density, and composition. You can do this taking images as well, if you use filters to isolate the colors you want.

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A group of astronomers from the National Optical Astronomy Observatory did just that. They pointed their filtered telescope at the Large and Small Magellanic Clouds, two galaxies that are satellite companions of our own. They took a lot of images: 1500 for the LMC and 500 for the SMC, and stitched them together to produce a gorgeous image.

In this image of the LMC you can see glowing gas from which stars are born, smoke ring puffs of gas that show where sunlike stars have died, and violent expanding shells of gas where massive stars have exploded, raging into that good night. There is so much knowledge tucked into this image, and its beauty is not to be denied. When I get back, this is destined to be my desktop background for my computer.

News Bit the Third: I'm tired. That's the news. I will post more Tuesday about the news and views from this amazing meeting.'