An outer ring of baby stars glows brightly in infrared around a core of cooler, older stars. A faint S-bar in the middle identifies NGC 1291 as a barred galaxy.
At 33 million light years away, galaxy NGC 1291 has had 12 billion years for stars to gobble up dust and burn through their fuel. When it was young, stellar bars drove gas towards the center, enhancing star-birthing rates. As the Spitzer Space Telescope press release explains:
Over time, as the star-making fuel runs out, the central regions become quiescent and star-formation activity shifts to the outskirts of a galaxy. There, spiral density waves and resonances induced by the central bar help convert gas to stars. The outer ring, seen here in red, is one such resonance location, where gas has been trapped and ignited into a star-forming frenzy.
In this infrared image, hot dust glowing at 8.0 microns are coloured red, while wavelength 4.5 microns is green and 3.4 microns is in blue.