The Theoretical Light Curve and Spectral Evolution of Type II Supernovae

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Session 29 -- Novae and Supernovae
Display presentation, Tuesday, 9:30-6:30, Pauley Room

[29.17] The Theoretical Light Curve and Spectral Evolution of Type II Supernovae

Ronald G. Eastman, S. E. Woosley (UCO/Lick Obs., Astronomy Board, UCSC), T. A. Weaver (General Studies Division, LLNL), and Philip A. Pinto (Univ. Arizona)

The light curve of a Type II plateau (II-p) supernova, observationally the most common supernova event, has been qualitatively well understood for some time as a combination of a) shock break-out and a hard uv-transient; b) recombination of the hydrogen envelope; and c) depending on the mass of $^{56}$Ni ejected, an enduring exponential tail powered by radioactivity However, all calculations thus far (excepting SN 1987A) have been based upon a very simple prescription for radiation transport that allows the computation to proceed in what nominally is a stellar evolution code. The matter and radiation are assumed to have a single temperature and the opacity is treated as purely absorptive even in the case of electron scattering. Here we report the results of a detailed radiation transport calculation for the explosion of a model 15 M\sun \ red supergiant, a typical Type II event which may also be of some relevance to the bright supernova 1993J now transpiring in M81. Two sets of calculations are presented: 1) A light curve (given in terms of photometry in various bandpasses) modelled assuming local thermodynamic equilibrium (LTE), but including the effect of 63 ions and over 100 thousand atomic lines and their Doppler shifts. The transport of radiation is followed in 500 frequency bins from 30 microns to 20 Angstroms and the transport of gamma-rays from radioactive decay is also handled in a way that accounts for non-local deposition. 2) Non-LTE calculations of the spectrum in the same energy band for a grid of times during the first year of the supernova. These calculations and those of other mass supernovae will be compared with observations of Type II supernovae, including as available and appropriate, data from SN 1993J.

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