[3] The galaxy has a nucleus with a bar structure that is surrounded by a distinct ring of dust that contains recently formed, hot blue stars.

[5] In 1976, the Canadian astronomer Sidney Van den Bergh categorized this galaxy as "anemic" because of the low rate at which stars are being formed.

The distribution of hydrogen has also been deeply perturbed toward the SE spiral arm and is less extended than the optical disk of the galaxy.

[8] Some filaments of gas that have been stripped away are falling back to the galaxy, making NGC 4921 possibly the first observational evidence of this fallback.

[10][11] The light curve proved similar to supernova SN 1987a in the Large Magellanic Cloud,[12] and it displayed "unusual photometric behavior".