IC 1993

At a distance of about 50 million light-years, and redshift of 1057 km/s, it is one of the closest to us of the 200 galaxies in the Fornax Cluster.

Most resemble local collisional ring galaxies in morphology, size, and clumpy star formation.

The clump ages are consistent with the expected lifetimes of ring structures if they are formed by collisions.

They could be outer Lindblad resonance rings, although some have no obvious bars or spirals to drive them.

This similarity in radius suggests that the driving pattern speed has not slowed by more by ~30% during the last ~7 Gyr.