[Paper Review] Light Curves of Core-Collapse Supernovae with Substantial Mass Loss using the New Open-Source SuperNova Explosion Code (SNEC)

Viktoriya Morozova, Anthony L. Piro+6 more|arXiv (Cornell University)|May 25, 2015

Gamma-ray bursts and supernovae5 references3 citations

TL;DR

This paper introduces SNEC, an open-source 1D Lagrangian hydrodynamics and equilibrium-diffusion radiation transport code for modeling core-collapse supernova light curves. It demonstrates that progenitors of $15 hinspace M_ ext{Sun}$ with substantial mass loss produce light curves with plateau durations of 20–100 days only if $\gtrsim 1.5-2\thinspace M_\text{Sun}$ of hydrogen-rich material remains, suggesting mass loss in low-mass progenitors occurs in an 'all-or-nothing' fashion, implicating binary interactions in shaping Type Ib/c supernovae.

ABSTRACT

We present the SuperNova Explosion Code (SNEC), an open-source Lagrangian code for the hydrodynamics and equilibrium-diffusion radiation transport in the expanding envelopes of supernovae. Given a model of a progenitor star, an explosion energy, and an amount and distribution of radioactive nickel, SNEC generates the bolometric light curve, as well as the light curves in different broad bands assuming black body emission. As a first application of SNEC, we consider the explosions of a grid of 15 Msun (at zero-age main sequence) stars whose hydrogen envelopes are stripped to different extents and at different points in their evolution. The resulting light curves exhibit plateaus with durations of ~20-100 days if >~1.5-2 Msun of hydrogen-rich material is left and no plateau if less hydrogen-rich material is left. If these shorter plateau lengths are not seen for Type IIP supernovae in nature, it suggests that, at least for zero-age main sequence masses

Motivation & Objective

• To develop an open-source, accessible tool for simulating supernova light curves with realistic physics, enabling reproducible and systematic modeling.
• To investigate how varying degrees and timing of hydrogen envelope mass loss in $15\thinspace M_\text{Sun}$ progenitors affect the resulting light curve morphology.
• To test whether gradual mass loss can explain the observed diversity in Type IIL supernovae, particularly their early-time luminosity and plateau behavior.
• To explore the physical origin of double-peaked light curves in Type IIb supernovae and their connection to progenitor radius and residual hydrogen mass.
• To assess the limitations of simple mass-loss models in reproducing observed SNe IIL and IIP light curves, suggesting alternative mechanisms such as extended or structured circumstellar material.

Proposed method

• SNEC employs Lagrangian hydrodynamics to simulate the explosion and expansion of supernova ejecta from a given progenitor model.
• It uses equilibrium-diffusion radiation transport to compute the time-dependent energy deposition and escape of radiation from the ejecta.
• The code includes energy deposition from $^{56}\mathrm{Ni}$ decay, ionization structure, and opacity tables (including OPAL and low-temperature data) for accurate radiative transfer.
• Light curves are computed in bolometric and broad photometric bands assuming blackbody emission from the photosphere.
• A grid of $15\thinspace M_\text{Sun}$ progenitors with varying hydrogen envelope masses and stripping times is simulated to explore the dependence of light curve features on progenitor structure.
• The code is validated against known results (e.g., SN 1999em) and compared with existing models to ensure consistency and reliability.

Experimental results

Research questions

• RQ1 How does the duration of the plateau phase in Type IIP supernova light curves depend on the amount of residual hydrogen in the progenitor's envelope?
• RQ2 Can gradual mass loss in $15\thinspace M_\text{Sun}$ progenitors reproduce the observed light curve morphology of Type IIL supernovae?
• RQ3 What physical conditions lead to double-peaked light curves in Type IIb supernovae, and how do they relate to progenitor radius and hydrogen mass?
• RQ4 Does the absence of short plateau durations in observed Type IIP supernovae imply that mass loss in low-mass progenitors occurs in a binary-driven 'all-or-nothing' fashion?
• RQ5 To what extent can variations in progenitor structure alone explain the diversity seen in Type IIL supernovae, or is additional physics (e.g., circumstellar interaction) required?

Key findings

• Light curves with plateau durations of $\sim 20-100\,\mathrm{days}$ are produced only when $\gtrsim 1.5-2\,M_\odot$ of hydrogen-rich material remains in the progenitor.
• If no such plateaus are observed in nature for Type IIP supernovae, this implies that for $\lesssim 20\,M_\text{Sun}$ progenitors, hydrogen mass loss likely occurs in a discontinuous, 'all-or-nothing' manner.
• Models with less than $1.5-2\,M_\odot$ of hydrogen show no plateau, consistent with the behavior of Type Ib/c supernovae.
• The most stripped models in the grid exhibit double-peaked light curves, confirming that such features arise naturally from progenitors with small hydrogen masses and radii of $\sim 500\,R_\odot$.
• The observed luminosity of SNe IIL cannot be reproduced by simple mass-loss variations in $15\,M_\text{Sun}$ models, as these models do not produce the required early-time brightness.
• The results suggest that SNe IIL may not be explained by gradual mass loss alone, but could instead involve extended or structured circumstellar material, as hinted by narrow emission lines in some cases.