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M.D. Baird (Grove City College), P. M. Garnavich, E.M. Schlegel, P. M. Challis, R. P. Kirshner (SAO)
SN 1995N is a peculiar type IIn supernova. Spectroscopic and photometric data for this analysis were gathered between May 10, 1995 (two days after discovery) and July 18, 1998. A total of twenty two photometric images and eight spectra were obtained at the FLWO and MMTO. The photometric data show a broad maximum at R=17.0 occurred in late October, 1995, followed by a very slow decline at a rate of 2.39 {\rm millimag-day}-1 for R and 1.37 {\rm millimag-day}-1 for V. The R decay rate corresponds to a half life of 315 days, which is much longer than that of 56Co. The spectra show broad hydrogen (1500 km/s FWHM) and oxygen (10000 km/s FWZI) emission features along with many unresolved emission lines. Some of the more interesting narrow lines identified correspond to high ionization states for iron such as Fe~VII and Fe~X which indicate temperatures as high as 106 degrees K. These high ionization states, the X-ray detection by Lewin et al. (1996, IAUC 6445) and the slow photometric decay suggest that SN~1995N is powered by a shock propagating through a dense circumstellar environment. From the earliest observations the energy output appears dominated by the interaction and not by radioactivity, implying that the progenitor exploded well before the discovery of SN~1995N. The situation may be similar to SN~1987A, where the rise in emission from a circumstellar interaction is only now beginning and is expected to peak some 15 years after the supernova explosion.
The author(s) of this abstract have provided an email address for comments about the abstract: stu951451@gcc.edu