High-entropy ejecta plumes in Cassiopeia A from neutrino-driven convection

Abstract

Recent multi-dimensional simulations suggest that high-entropy buoyant plumes help massive stars to explode. Outwardly protruding iron-rich fingers in the galactic supernova remnant Cassiopeia A are uniquely suggestive of this picture. Detecting signatures of specific elements synthesized in the high-entropy nuclear burning regime (i.e., $\alpha$-rich freeze out) would be among the strongest substantiating evidence. Here we report the discovery of such elements, stable Ti and Cr, at a confidence level greater than 5$\sigma$ in the shocked high-velocity iron-rich ejecta of Cassiopeia A. We found the observed Ti/Fe and Cr/Fe mass ratios require $\alpha$-rich freeze out, providing the first observational demonstration for the existence of high-entropy ejecta plumes that boosted the shock wave at explosion. The metal composition of the plumes agrees well with predictions for strongly neutrino-processed proton-rich ejecta. These results support the operation of the convective supernova engine via neutrino heating in the supernova that produced Cassiopeia A.

arXiv comment34 pages, 13 figures

References in corpus (57)

• Neutron Star Structure and the Equation of State
• Theory of Core-Collapse Supernovae
• Galactic chemical evolution: Carbon through Zinc
• On the Nature of Core Collapse Supernova Explosions
• Inside the Supernova: A Powerful Convective Engine
• Updated Atomic Data and Calculations for X-ray Spectroscopy
• Physics of Core-Collapse Supernovae in Three Dimensions: a Sneak Preview
• Two-dimensional hydrodynamic core-collapse supernova simulations with spectral neutrino transport. I. Numerical method and results for a 15 M_sun star
• Grids of stellar models with rotation - III. Models from 0.8 to 120 Msun at a metallicity Z = 0.002
• The Expansion Asymmetry and Age of the Cassiopeia A Supernova Remnant
• Nucleosynthesis and Mixing in Cassiopeia A
• Non-spherical Core Collapse Supernovae I. Neutrino-Driven Convection, Rayleigh-Taylor Instabilities, and the Formation and Propagation of Metal Clumps
• Variations in the Abundance Pattern of Extremely Metal-poor Stars and Nucleosynthesis in Population III Supernovae
• The Overarching Framework of Core-Collapse Supernova Explosions as Revealed by 3D Fornax Simulations
• Asymmetries in core-collapse supernovae from maps of radioactive ${}^{44}$Ti in CassiopeiaA
• Bipolar Supernova Explosions: Nucleosynthesis & Implication on Abundances in Extremely Metal-Poor Stars
• A Million-Second Chandra View of Cassiopeia A
• Three-Dimensional Simulations of Mixing Instabilities in Supernova Explosions
• Chandra Detection of the Forward and Reverse Shocks in Cassiopeia-A
• The Expansion Center and Dynamical Age of the Galactic Supernova Remnant Cassiopeia A
• A Chandra X-ray Survey of Ejecta in the Cassiopeia A Supernova Remnant
• Self-consistent 3D Supernova Models From -7 Minutes to +7 Seconds: a 1-bethe Explosion of a ~19 Solar-mass Progenitor
• Nucleosynthesis in the Innermost Ejecta of Neutrino-Drive Supernova Explosions in Two Dimensions
• The Three-Dimensional Structure of Cassiopeia A
• X-ray spectral imaging and Doppler mapping of Cassiopeia A
• Explosive Nucleosynthesis in Hypernovae
• Production and Distribution of ${}^{44}$Ti and ${}^{56}$Ni in a Three-dimensional Supernova Model Resembling Cassiopeia A
• The distribution of radioactive ${}^{44}$Ti in Cassiopeia A
• The signature of 44Ti in Cassiopeia A revealed by IBIS/ISGRI on INTEGRAL
• Mapping the X-ray Emitting Ejecta in Cassiopeia A with Chandra
• Stellar Yields of Rotating First Stars. II. Pair Instability Supernovae and Comparison with Observations
• Atomic data and spectral modeling constraints from high-resolution X-ray observations of the Perseus cluster with Hitomi
• A Detailed Kinematic Map of Cassiopeia A's Optical Main Shell and Outer High-Velocity Ejecta
• Trends in Ti44 and Ni56 from Core-Collapse Supernovae
• Detection of the 67.9 keV and 78.4 keV lines associated with the radioactive decay of Ti-44 in Cassiopeia A
• Solar abundance ratios of the iron-peak elements in the Perseus Cluster
• Modeling SNR Cassiopeia A from the Supernova Explosion to its Current Age: The role of post-explosion anisotropies of ejecta
• Where was the Iron Synthesized in Cassiopeia A?
• The Bubble-like Interior of the Core-Collapse Supernova Remnant Cassiopeia A
• Revival of the Fittest: Exploding Core-Collapse Supernovae from 12 to 25 M${}_{\odot }$
• One-, Two-, and Three-dimensional Simulations of Oxygen Shell Burning Just Before the Core-Collapse of Massive Stars
• The fully developed remnant of a neutrino-driven supernova: Evolution of ejecta structure and asymmetries in SNR Cassiopeia A
• Exact and approximate expressions of energy generation rates and their impact on the explosion properties of Pair Instability Supernovae
• High Ratio of 44Ti/56Ni in Cas A and Axisymmetric Collapse-Driven Supernova Explosion
• X-ray Measurements of the Particle Acceleration Properties at Inward Shocks in Cassiopeia A
• Dynamics of Fe-Ni Bubbles in Young Supernova Remnants
• The infancy of core-collapse supernova remnants
• An HST Survey of the Highest-Velocity Ejecta in Cassiopeia A
• A Decline in the Nonthermal X-ray Emission from Cassiopeia A
• The Evolution towards Electron-capture Supernovae: the Flame Propagation and the Pre-bounce Electron-neutrino Radiation
• The Shape of Cas A
• A Comparison of X-ray and Optical Emission in Cassiopeia A
• Matter mixing in aspherical core-collapse supernovae: a search for possible conditions for conveying ${}^{56}$Ni into high velocity regions
• nu-Process Nucleosynthesis in Population III Core-Collapse Supernovae
• A Sub-Solar Metallicity Progenitor for Cassiopeia A, the remnant of a Type IIb Supernova
• Multi-Year X-ray Variations of Iron-K and Continuum Emissions in the Young Supernova Remnant Cassiopeia A
• Titanium and Iron in the Cassiopeia A Supernova Remnant

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