R-band image of SN 1998S in NGC 3877 obtained on 1998 March 16.1 ut at t he Jacobus Kapteyn Telescope (JKT), La Palma (north is up and east is to the left).[1]
SN 1998S was a type IIn supernova that was detected in NGC 3877 in March 1998. At the time of discovery, SN 1998S was the brightest type IIn event observed,[2] although later outshone by SN 2010jl.[3]
It was discovered on 1998 March 2.68 UT in NGC 3877 by Z. Wan at a broadband (unfiltered) 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 (CSM) in the vicinity of the supernova. The high luminosity of SN1998S is due to the interaction of fast material (ejecta) with previously-expelled slowly-expanding material (CSM), which can more effectively convert kinetic energy of ejecta into radiation energy.[4]
^Ofek, E. O.; Zoglauer, A.; Boggs, S. E.; Barriere, N. M.; Reynolds, S. P.; Fryer, C. L.; Harrison, F. A.; Cenko, S. B.; Kulkarni, S. R.; Gal-Yam, A.; Arcavi, I.; Bellm, E.; Bloom, J. S.; Christensen, F.; Craig, W. W. (2014-01-06). "SN 2010jl: Optical to hard X-ray observations reveal an explosion embedded in a ten solar mass cocoon". The Astrophysical Journal. 781 (1): 42. arXiv:1307.2247. Bibcode:2014ApJ...781...42O. doi:10.1088/0004-637X/781/1/42. ISSN0004-637X.
