SN 1998S
SN 1998S was a type IIn supernova that was observed in NGC 3877 in March 1998. SN 1998S was the brightest type IIn event observed
It was discovered on 1998 March 2.68 UT in NGC 3877 by Z. Wan at a broadband optical magnitude of +15.2.
Its spectrum showed prominent H and He emission lines with narrow peaks and broad wings, superimposed on a blue continuum. These narrow lines indicate the presence of a dense circumstellar medium in the vicinity of the supernova. The high luminosity of SN1998S is due to the interaction of fast material with previously-expelled slowly-expanding material, which can more effectively convert kinetic energy of ejecta into radiation energy.
