Essential ingredients in core-collapse supernovae

Abstract

Carrying 1044 joules of kinetic energy and a rich mix of newly synthesized atomic nuclei, core-collapse supernovae are the preeminent foundries of the nuclear species which make up our solar system and ourselves. Signaling the inevitable death of a massive star, and the birth of a neutron star or black hole, core-collapse supernovae combine physics over a wide range in spatial scales, from kilometer-sized hydrodynamic motions (eventually growing to gigameter scale) down to femtometer-scale nuclear reactions. We will discuss our emerging understanding of the convectively-unstable, neutrino-driven explosion mechanism, based on increasingly realistic neutrino radiation hydrodynamic simulations that include progressively better nuclear and particle physics. Multi-dimensional models with spectral neutrino transport from several research groups, which slowly develop successful explosions for a range of progenitors, have recently motivated changes in our understanding of the neutrino reheating mechanism. In a similar fashion, improvements in nuclear physics, most notably explorations of weak interactions on nuclei and the nuclear equation of state, continue to refine our understanding of the births of neutron stars and the supernovae that result. Recent progress on both the macroscopic and microscopic effects that affect core-collapse supernovae are discussed.

The production of proton-rich isotopes beyond iron: The γ-process in stars

“…in the outermost regions of the star, where the 3D model is not very well resolved by tracers. Smaller differences of a factor between two and three, but with the opposite trend (abundances are higher in 3D than in 2D), are seen for 94 Mo, 113 In, 115 Sn, 130,132 Ba, 136,138 Ce, 152 Gd, and 156,158 Dy. All these isotopes are mostly produced at temperatures between 2.6×10 9 and 2.8×10 9 K.…”

“…Furthermore, the multi-dimensional nature of the CCSN explosion (e.g., Refs. [154,155,156,157]) makes less constraining the use of 24 Mg or 16 O as a reference. They are only marginally affected by the SN explosion, while the γ process (or at least a good part of it) is an explosive product.…”

Iron-Group Abundances in the Metal-Poor Main-Sequence Turnoff Star Hd 84937

“…While light elements like O and Mg are mostly made in the pre-SN stage, Fe-group elements are mostly made during the explosion, in the deepest part of the ejecta (e.g., Nomoto et al 2013, for a review). Although there has been great progress in multi-dimensional simulations of SN explosions in recent years, the CCSN engine (Hix et al 2014, and references therein) and subsequent propagation of the SN shock through the progenitor structure (Wongwathanarat et al 2015) are uncertain at present. Modern CCSN yield sets are still calculated with one-dimensional codes (e.g., Nomoto et al 2013), and multi-dimensional effects have not been included in the GCE models yet.…”

The Multi-dimensional Character of Core-collapse Supernovae

“…For an overview of the study of the core-collapse supernova mechanism, the reader is referred to recent reviews, for example, [15,16,17]. Here, we wish to focus on the recent progress in three dimensional (3D) self-consistent models and what we can learn about the limitations of more numerous twodimensional (2D) axisymmetric models from this handful of 3D models.…”