Nebular Phase Synthetic Spectra of SN1993J
Session 39 -- SN1993J, SN1978K and SN1987A
Display presentation, Thursday, January 13, 9:30-6:45, Salons I/II Room (Crystal Gateway)

## [39.05] Nebular Phase Synthetic Spectra of SN1993J

J.Houck, C.Fransson (Stockholm Observatory)

Using a helium star explosion model from Nomoto et al. (1993), we construct non-LTE synthetic spectra for SN1993J for a number of epochs later than 100 days. In the spectrum calculation, line transfer is treated in the Sobolev approximation and explicitly includes non-local radiative coupling. Nonthermal energy deposition from ${}^{56}{\rm Co}$ decay is treated by solving the Boltzman equation; excitation, ionization and thermal equilibrium are solved self consistently. We compare our synthetic spectra with RGO archive data from recent WHT spectral observations of SN1993J. In particular, we investigate the spectroscopic effects of mixing in the ejecta by comparing synthetic spectra of macroscopically mixed models with the observed spectra.