RCW 120 is a bubble blown by a central star (not visible at these infrared wavelengths) that has exerted enough pressure in the bubble ‘walls’ that material can begin collapsing into the next generation of star. The bright knot in the bottom right of the bubble is one such stellar embryo, which is surrounding by material amounting to 2000 solar masses. The star already has a mass of about 8–10 Suns, and will likely grow larger still. RCW 120 lies about 4300 light-years away.
The image was created from data collected using the PACS and SPIRE instruments on ESA’s Herschel space observatory, covering wavelengths of 100µm (blue), 160µm (green) and 250µm (red).