We determine the oxygen density in the central zone of nine type IIP supernovae (SN~IIP) at the nebular stage using oxygen doublet [O I] 6300, 6364 \AA. Combined with two available estimates these data indicate that oxygen densities on day 300 are distributed in rather narrow range (2.3±1)×109 cm−3. The result does not depend on the distance, extinction, or model assumptions. We demonstrate that the found density distribution suggests that the explosion energy of SN~IIP increases with the stellar mass.
@article{arxiv.1403.7360,
title = {Does energy of type IIP supernovae depends on stellar mass?},
author = {N. N. Chugai and V. P. Utrobin},
journal= {arXiv preprint arXiv:1403.7360},
year = {2015}
}