2023/07/10 by Jonathan Morag, Morag, Jonathan, I. Irani +5 · 3 citations
Physics and Astronomy · #Astrophysical Phenomena and Observations #FOS: Physical sciences #Gamma-ray bursts and supernovae #High Energy Astrophysical Phenomena (astro-ph.HE) #Solar and Stellar Astrophysics (astro-ph.SR) #Stellar, planetary, and galactic studies
paper · pdf · doi:10.48550/arxiv.2307.05598
openalex publication_date 2023/07/10 · openalex created_date 2025/10/10 · openalex updated_date 2026/07/28
Light emission in the first hours and days following core-collapse supernovae (SNe) is dominated by the escape of photons from the expanding shock heated envelope. In a preceding paper, Paper I, we provided a simple analytic description of the time dependent luminosity, L, and color temperature, T\rm col, valid up to H recombination (T≈0.7 eV), for explosions of red supergiants with convective polytropic envelopes without significant circum-stellar medium (CSM). The analytic description was calibrated against "gray" (frequency-independent) photon diffusion numeric calculations. Here we present the results of a large set of 1D multi-group (frequency-dependent) calculations, for a wide range of progenitor parameters (mass, radius, core/envelope mass ratios, metalicity) and explosion energies, using opacity tables that we constructed (and made publicly available), including the contributions of bound-bound and bound-free transitions. We provide an analytic description of the small, ≃10% deviations of the spectrum from blackbody at low frequencies, hν< 3T\rm col, and an improved (over Paper I) description of `line dampening' for hν> 3T\rm col. We show that the effects of deviations from initial polytropic density distribution are small, and so are the effects of `expansion opacity' and deviations from LTE ionization and excitation (within our model assumptions). A recent study of a large set of type II SN observations finds that our model accounts well for the early multi-band data of more than 50% of observed SNe (the others are likely affected by thick CSM), enabling the inference of progenitor properties, explosion velocity, and relative extinction.