The progenitor mass of the Type IIP supernova SN 2004et from late-time spectral modeling

TL;DR

This study uses late-time spectral modeling of SN 2004et to estimate its progenitor star's mass, finding it to be around 15 solar masses, which aligns with direct detection but conflicts with early-time hydrodynamical models.

Contribution

The paper provides a detailed spectral modeling approach to determine the progenitor mass of SN 2004et, reconciling observational data with stellar evolution models.

Findings

Progenitor mass estimated at 15 Msun from spectral lines.

Mid-infrared analysis yields Ni-bubble density and filling factor.

Detection of silicate dust, CO, and SiO emission in spectra.

Abstract

SN 2004et is one of the nearest and best-observed Type IIP supernovae, with a progenitor detection as well as good photometric and spectroscopic observational coverage well into the nebular phase. Based on nucleosynthesis from stellar evolution/explosion models we apply spectral modeling to analyze its 140-700 day evolution from ultraviolet to mid-infrared. We find a M_ZAMS= 15 Msun progenitor star (with an oxygen mass of 0.8 Msun) to satisfactorily reproduce [O I] 6300, 6364 {\AA} and other emission lines of carbon, sodium, magnesium, and silicon, while 12 Msun and 19 Msun models under- and overproduce most of these lines, respectively. This result is in fair agreement with the mass derived from the progenitor detection, but in disagreement with hydrodynamical modeling of the early-time light curve. From modeling of the mid-infrared iron-group emission lines, we determine the density of the "Ni-bubble" to rho(t) = 7E-14*(t/100d)^-3 g cm^-3, corresponding to a filling factor of f = 0.15 in the metal core region (V = 1800 km/s). We also confirm that silicate dust, CO, and SiO emission are all present in the spectra.