Fresh off the press of the ESO's Wide Field Imager at the La Silla Observatory in Chile, we see NGC 3603: a cluster of stars found 20,000 light-years from Earth in the constellation of Carina.
This new image gives us the best-look-yet at the central system that shapes this stellar arena. Instead of a single massive hyper-giant driving the changes in the surrounding nebula, this system is comprised of three Wolf-Rayet stars, which are, by nature, highly unstable stars that are nearing the end of their life-spans. As the end approaches, they shed more and more of their stellar envelope into space through vivacious stellar winds, which travel at speeds exceeding 3 million kilometers per hour.
According to the press release, this particular system, dubbed HD 97950, is notable for belonging to a region with the highest concentration of massive stars found anywhere in our galaxy thus far. By proxy, NGC 3603 is incredibly bright, but its brightness is toned down due to the fact that the stars are buried by an even larger concentration of interstellar gas and dust, obscuring the stars from sight. Eventually, they emerge from the darkness, after ultraviolet radiation eats holes, called cavities, into the material.
That's not the only impact ultraviolet radiation has on this material. It also invokes something called ionization, which is the process in which nebulae glow. Said regions are generally very large, spanning several hundreds of light-years across, with NGC 3603 being the largest of them all.. It contains two prominent regions. On the right, which can be found in the Carina-Sagittarius spiral arm of the Milky Way (about 9,000 light-years from Earth), we have NGC 3576. This region is separate from the primary nebula, but it appears close-by in the sky.
The second notable thing (or third, if you want to be pedantic) is the two impressively large, curved pillars of gas and dust. Overall, they span about 100 light-years across Highlighting these regions are additional pillars composed of dense, dark dust, called bok globules.
See a larger image here.