Although appearing as a disk, there is evidence for a non-axisymmetric form of gas distribution, with a suggestion of central bar plus large-scale spiral arms. The inner structure contains many dark lanes and stellar condensations in its disk. There are two strong H II regions, one to each side. The overall star formation rate is  y−1. The outer disk shows a history of steady star formation, although the formation rate has declined significantly over the last billion years and the population is now dominated by older stars. Within a radius of the center, star formation has been steady, having not undergone a recent decline.
