2004MNRAS.355..627C

We propose a model to account for the bolometric light curve, the quasi-continuum and the CaII emission features of the peculiar type Ia supernova (SN) 2002ic, which exploded in a dense circumstellar envelope. The model suggests that the SN Ia had the maximum possible kinetic energy and that the ejecta expand in an approximately spherically symmetric (possibly clumpy) circumstellar environment. The CaII and the quasi-continuum are emitted by shocked SN ejecta that underwent deformation and fragmentation in the intershock layer. Modelling of the CaII triplet implies that the contribution of the OI 8446-Åline is about 25 per cent of the 8500-Åfeature on day 234, which permits us to recover the flux in the CaII 8579-Åtriplet from the flux of 8500-Åblend reported by Deng et al. We use the CaII doublet and triplet fluxes on day 234 to derive the electron temperature (~ 4400 K) in the CaII line-emitting zone and the ratio of the total area of dense fragments to the area of the shell, S/S₀∼ 10². We argue that CaII bands and the quasi-continuum originate from different zones of the shocked ejecta that reflect the abundance stratification of the supernova.