Recent supernova searches revealed a number of fast-evolving luminous transients . We perform radiation hydrodynamic simulations of light curves of several models of supernova from super–asymptotic giant branch ( super-AGB , SAGB ) stars with low mass envelopes ( M _ { env } \sim 0.05 - 1.25 M _ { \odot } ) . The differences in the light curves found among the models are used to link the observed events to the most appropriate models . In particular , we propose that KSN 2015K is an electron-capture supernova . We assume ” optically ” thick CSM around SAGB and the circumstellar interaction powers the peak luminosity of the light curve with a short rise time . The faint tail might be influenced by the spin-down luminosity of a newborn Crab-like pulsar . Our fits indicate an ejecta mass of 0.02 - 0.05 M _ { \odot } , a circumstellar medium ( CSM ) mass of 0.10 - 0.12 M _ { \odot } , a radius of the CSM photosphere \sim 10 ^ { 14 } cm , a kinetic energy of \sim 3 \times 10 ^ { 50 } erg , a photospheric velocity v _ { ph } \gtrsim 10 , 000 km s ^ { -1 } and a pulsar total spin energy ( 2.5 - 4 ) \times 10 ^ { 49 } erg .