The role of radioactive nickel in shaping the plateau phase of Type II supernovae

Alexandra Kozyreva*, Ehud Nakar, Roni Waldman

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review


In the present study, we systematically explore the effect of the radioactive 56Ni and its mixing properties in the ejecta on the plateau of Type IIP supernovae (SNe IIP). We evaluate the importance of 56Ni in shaping light curves of SNe IIP by simulating light curves for two red supergiant models using different amounts of 56Ni and with different types of mixing: uniform distribution of 56Ni out to different fractions of the envelope and 'boxcar' distribution of 56Ni. We find, similarly to previous studies, that 56Ni extends duration of the plateau. We find a formula to estimate the extension based on the observed bolometric light curves and show that for most SNe IIP 56Ni extends the plateau by about 20 per cent. Another effect of 56Ni consists in reduction of the plateau decline rate, i.e. 56Ni presented in the ejecta flattens the plateau. Our simulations suggest that for typical SNe IIP it can reduce the decline rate by about 1 mag per 100 d. We find that for the contribution of 56Ni seen in most supernovae (SNe) our simulated bolometric light curves resemble observed ones for various types of 56Ni mixing. We thereby cannot determine the level of 56Ni mixing in these SNe based on the light curve alone. However, for SN 2009ib we find that only a model where 56Ni is mixed significantly throughout most of the hydrogen envelope is consistent with the observed light curve.

Original languageEnglish
Pages (from-to)1211-1223
Number of pages13
JournalMonthly Notices of the Royal Astronomical Society
Issue number1
StatePublished - 11 Feb 2019


FundersFunder number
Gamma Ray Burst – Supernova Connection and Shock Breakout Physics
Science and Technology Facilities CouncilST/M006948/1, ST/K000373/1
University of Leicester
European Research Council279368
Israel Science Foundation
Israeli Centers for Research Excellence
Max-Planck-Institut für Physik Komplexer Systeme


    • Radiative transfer
    • Stars: massive
    • Supernovae: general


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