Kate Maguire (1,2) Anders Kerkstrand (3) Stephen J. Smartt (2) Claes Fransson (3) Andrea Pastorello (4) Stefano Benetti (4) Stefano Valenti (4) Filomena Bufano (5) Giorgios Leloudas (6)
(1) Department of Physics (Astrophysics), University of Oxford (2)Astrophysics Research Centre, Queen’s University Belfast (3) Department of Astronomy, Stockholm University (4) INAF Osservatorio Astronomico di Padova (5) INAF Osservatorio Astronomico di Catania (6) Dark Cosmology Centre, University of Copenhagen
We present a study of the nebular phase spectra of a sample of Type II-Plateau supernovae with identified progenitors or restrictive limits. The evolution of line fluxes, shapes, and velocities are compared within the sample, and interpreted by the use of a spectral synthesis code. The small diversity within the dataset can be explained by strong mixing occurring during the explosion, and by recognising that most lines have significant contributions from primordial metals in the H envelope, which dominates the total ejecta mass in these type of objects. In particular, when using the [O I] 6300, 6364 Angstrom doublet for estimating the core mass of the star, care has to be taken to account for emission from primordial O in the envelope. Finally, a correlation between the H-alpha line width and the mass of 56Ni is presented, suggesting that higher energy explosions are associated with higher 56Ni production.
Complete preprint ==> http://arxiv.org/abs/1112.0035