2013/10/31 by Luc Dessart, Stephane Blondin, S. Blondin +4 · 110 citations
Physics and Astronomy · #Astro and Planetary Science #Astronomy #Astrophysical Phenomena and Observations #Astrophysics #Ejecta #Galaxy #Gamma-ray bursts and supernovae #Line (geometry) #Luminosity #Mixing (physics) #Optics #Pair-instability supernova #Physics #Radiative cooling #Radiative transfer #Stars #Supernova #White dwarf #astro-ph.CO #astro-ph.HE #astro-ph.SR
paper · pdf · doi:10.1093/mnras/stu598
published in Monthly Notices of the Royal Astronomical Society 441(1), 532-550 (Oxford University Press) · Accepted to MNRAS
arxiv created 2014/03/25 · openalex publication_date 2014/04/27 · arxiv updated 2015/06/17 · openalex created_date 2025/10/10 · openalex updated_date 2026/08/05
Observations of SN 2011fe at early times reveal an evolution analogous to a fireball model of constant colour. In contrast, our unmixed delayed detonations of Chandrasekhar-mass white dwarfs (DDC series) exhibit a faster brightening concomitant with a shift in colour to the blue. In this paper, we study the origin of these discrepancies. We find that strong chemical mixing largely resolves the photometric mismatch at early times, but it leads to an enhanced line broadening that contrasts, for example, with the markedly narrow Si ii 6355 Å line of SN 2011fe. We also explore an alternative configuration with pulsational-delayed detonations (PDDEL model series). Because of the pulsation, PDDEL models retain more unburnt carbon, have little mass at high velocity, and have a much hotter outer ejecta after the explosion. The pulsation does not influence the inner ejecta, so PDDEL and DDC models exhibit similar radiative properties beyond maximum. However, at early times, PDDEL models show bluer optical colours and a higher luminosity, even for weak mixing. Their early-time radiation is derived primarily from the initial shock-deposited energy in the outer ejecta rather than radioactive-decay heating. Furthermore, PDDEL models show short-lived C ii lines, reminiscent of SN 2013dy. They typically exhibit lines that are weaker, narrower, and of near-constant width, reminiscent of SN 2011fe. In addition to multidimensional effects, varying configurations for such ‘pulsations’ offer a source of spectral diversity amongst Type Ia supernovae (SNe Ia). PDDEL and DDC models also provide one explanation for low- and high-velocity-gradient SNe Ia.