SN 1988Z

Unlike a typical type II supernova, no P Cygni profiles or absorption lines were observed.

Decline in the Hydrogen-alpha line strength was unusually slow and lacked an explanation in terms of radioactive decay.

The host galaxy shows a redshift of z equal to 0.022, making this the most distant radio supernova detected at that time.

In the late evolutionary stages of the star, it underwent a high rate of mass loss on the order of 10−4 M☉·yr−1, which created a dense circumstellar cocoon.

[10] Most studies now favor a model of a very massive progenitor that ejected up to 10 M☉ at a rate of around 10−3 M☉·yr−1 for a period of about 10,000 years prior to the explosion.