1995A&A...293..723C

We obtained extensive photometric and spectroscopic observations of the Linear type II SN 1990K. The photometry suggests that the SN suffered a relatively high extinction (A_B≃2mag) and was therefore very bright at maximum (M⁰_V≤-18.9). However, the luminosity in the exponential tail is very similar to that of other SNII, in particular to SN 1987A, indicating that the explosion produced a similar mass of radioactive material (M(⁵⁶Ni)≃0.1M_☉). The spectral evolution is typical for SNII, very similar for instance to that of the SN 1987A (neglecting the fact that the latter SN showed unusually strong BaII lines). The line flux evolution of SN 1990K compared with that of other SNe and with theoretical models indicates that the envelope mass of SN 1990K was relatively low (∼5M_☉). Also, the envelope density is probably low (i.e. a factor 3 lower than in SN 1987A). Two months after discovery a bump appeared in the blue side of the Hα line which has a strong similarity to the same feature observed in SN 1987A (Bochum event) and in SN 1988A and has been related to the emergence of radioactive material into the outer hydrogen-rich envelope.