Rudolph the red-dusted Strömgren sphere

The entire universe in blog form
Dec. 23 2011 10:48 AM

Rudolph the red-dusted Strömgren sphere

For some reason, a lot of gorgeous pictures are being released after I post my Top 24 Deep Space Pictures of 2011 gallery. Figures. Since I already had a few images from NASA's WISE observatory in the gallery anyway I guess can't complain too much, especially when they release one as pretty as this!

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!  

Advertisement

[Click to infraredenate.]

This is Barnard 3, a dusty, gassy region of the galaxy about a thousand light years away where young stars are lighting up their neighborhood. WISE observes the skies in the far infrared, well past what our eye can detect, so this false-color picture mostly picks out the dust warmed by nearby stars. What you see as green and yellow-green is actually from long, complex molecules similar to soot, called polycyclic aromatic hydrocarbons or PAHs. Red shows cooler material.

So what's going on here? Right in the center of the red splotch is a star which is brighter and hotter than our Sun, and is flooding the surrounding material with ultraviolet light and a fast wind of subatomic particles (like the Sun's solar wind, but a whole lot stronger and with a much, much farther reach). This has carved out a gigantic cavity in that stuff, creating a bubble about 25 light years in diameter -- that's huge: 250,000,000,000,000 kilometers across, more than 10,000 times the size of our solar system!

The UV from the star is making the gas glow, but that's not visible in this infrared picture; in optical light (the kind we see with) this object is a mess (see here, for example), with gas emitting light, reflecting light, and dust absorbing it. When gas is lit up this way around a star, it's called a Strömgren sphere, after the astronomer Bengt Strömgren who did the first theoretical work on them.

All in all, it's lovely, isn't it? The folks at NASA and WISE are getting into the spirit of the season, billing this picture of Barnard 3 as a wreath, but I think they missed a good bet: it looks a lot more like a reindeer of fable to me. It even has antlers! Well, kinda.

And perhaps a bigger picture should be drawn here; as we near the end of the year, we approach the beginning of a new one. What better way to get into that spirit than to see a place in space where young, vigorous stars are announcing their presence? Hopefully, 2012 will be filled with energy, warmth, color, and as always more amazing science.

And since I mentioned it earlier, take a look back at the deep space pictures I chose as my favorites in 2011, including no fewer than three from WISE! That gallery is below.

Image Credit: NASA/JPL-Caltech/WISE Team