Impact of stellar rotation on type II supernova progenitor masses from pre-explosion imaging

Abstract

The initial masses of red supergiant (RSG) type II supernova (SN II) progenitors are commonly inferred from pre-explosion imaging by converting the progenitor luminosity into an initial mass estimate using non-rotating stellar evolution models. However, stellar rotation affects the evolution and may influence these estimates. We investigate how the observed distribution of rotational velocities in massive stars influences the progenitor initial masses of SNe II inferred from pre-SN imaging. We compare initial mass estimates obtained from non-rotating models with those derived from rotating models, where the initial rotational velocities of the stellar models are sampled from the observed distribution. We analyse the inferred progenitor initial masses by (i) comparing the results for each SN individually, (ii) examining the overall probability density function, (iii) constructing the cumulative distribution function, and (iv) determining the upper initial-mass boundary. In all cases, the distributions obtained from rotating models are slightly shifted towards lower masses, although the differences remain smaller than the typical uncertainties. When using the observed distribution of initial rotational velocities for massive stars, we infer an upper initial-mass limit for SN II progenitors of 20.4$^{+2.3}_{-1.9} M_{\odot}$. Taken together, these analyses demonstrate that stellar rotation has only a modest impact on progenitor mass estimates from pre-SN imaging within the current observational and model uncertainties when the observed distribution of initial rotational velocities is taken into account. Therefore, adopting this distribution leads to small differences compared to non-rotating models.

Figures (13)

• Figure 1: HR diagrams for a subsample of stellar models. The left panel shows only non-rotating models. Coloured lines correspond to models with initial masses of 10, 15, 20, and 25 $M_{\odot}$, while the remaining models are shown as faint grey lines. The right panel presents evolutionary tracks for stars with initial masses of 10, 15, 20, and 25 $M_{\odot}$ and different initial rotational velocities as indicated in the panel label. We note that the model with an initial mass of 25 $M_{\odot}$ and an initial rotational velocity of 400 km s$^{-1}$ lies outside the parameter space of the current study (see Table \ref{['table:max_initial_mass']}).
• Figure 2: Stellar luminosities at core carbon depletion for a range of initial masses and surface velocities. Only a subset of models is shown for visualisation purposes.
• Figure 3: Probability density of rotational velocities. Projected rotational velocities of young Galactic O-type stars from holgado+22 with masses below 32 $M_{\odot}$ are shown as a histogram. The deconvolved distribution, obtained using the method of lucy74, is overplotted as a thick line.
• Figure 4: Initial-mass distribution of the progenitor of SN 2025pht using the DBR models. The solid vertical line corresponds to the median of the distribution, while dashed vertical lines are the 16th and 84th percentiles.
• Figure 5: Median of the initial-mass distribution of SN II progenitors in the sample, derived from non-rotating (green dots) and DBR models (orange triangles). Error bars correspond to the 16th and 84th percentiles.