Barnard 3 (Perseus)

November 29, 2014
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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.Complex molecules similar to soot, called polycyclic aromatic hydrocarbons or PAHs. .

So what’s going on here? Near the center is a F2 white-yellow star ( HD 278942) 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.In optical light (this object is a mess , 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.

An infrared image of the area can be seen here:http://wise.ssl.berkeley.edu/gallery_Barnard3.html

Credit: (Phil Plait, Discover Magazine, December 2011)