This image captures a detailed close-up of the molecular cores and "pillars" within Sh2-132, the Lion Nebula, and the embedded Wolf-Rayet star WR 153ab.
According to
Vasquez et al. (1988), this optically bright section of Sh2-132 is an ordinary HII region excited by the massive O-type star BD+55◦2722 and WR 153ab (see annotation), which are located close to the center of the nebula.
The structures surrounding WR 153ab are part of a molecular ring consisting of well-separated cores which are under gravitational collapse due to external pressure from the surrounding ionized gas.
A small-scale sequential star formation is revealed toward the core (the main "pillar") to the left of WR 153ab in this image (22h19m10s, +56°5'). This core harbors a very young star cluster.
Liu et al. (2012) suggests the presence of fragmentation of the molecular ring, the collapse of the cores, and the large-scale sequential star formation indicate that the “radiation-driven implosion” process functions in this region, leading to triggered star formations.
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