Convective H-He Interactions in Massive Population III Stellar Evolution Models

Abstract

In Pop III stellar models convection-induced mixing between H- and He-rich burning layers can induce a burst of nuclear energy and thereby substantially alter the subsequent evolution and nucleosynthesis in the first massive stars. We investigate H-He shell and core interactions in 26 stellar evolution simulations with masses $15-140{\mathrm{M}}_{\odot }$, using five sets of mixing assumptions. In 22 cases H-He interactions induce local nuclear energy release in the range $\sim 10^9-10^{13.5}{\mathrm{L}}_{\odot }$. The luminosities on the upper end of this range amount to a substantial fraction of the layer's internal energy over a convective advection timescale, indicating a dynamic stellar response that would violate 1D stellar evolution modelling assumptions. We distinguish four types of H-He interactions depending on the evolutionary phase and convective stability of the He-rich material. H-burning conditions during H-He interactions give ${}^{12}\mathrm{C}{/}^{13}\mathrm{C}$ ratios between $\approx 1.5$ to $\sim 1000$ and [C/N] ratios from $\approx -2.3$ to $\approx 3$ with a correlation that agrees well with observations of CEMP-no stars. We also explore Ca production from hot CNO breakout and find the simulations presented here likely cannot explain the observed Ca abundance in the most Ca-poor CEMP-no star. We describe the evolution leading to H-He interactions, which occur during or shortly after core-contraction phases. Three simulations without a H-He interaction are computed to Fe-core infall and a $140{\mathrm{M}}_{\odot }$ simulation becomes pair-unstable. We also discuss present modelling limitations and the need for 3D hydrodynamic models to fully understand these stellar evolutionary phases.

Accepted for publication in MNRAS

References in corpus (20)

• Pre-Supernova Evolution of Massive Single and Binary Stars
• The Mass Spectrum of the First Stars
• Very low metallicity massive star models: Pre-SN evolution and primary nitrogen production
• Effects of rotation on the evolution of primordial stars
• A strong case for fast stellar rotation at very low metallicities
• The intermediate neutron-capture process and carbon-enhanced metal-poor stars
• The s process in massive stars at low metallicity. Effect of primary N14 from fast rotating stars
• Bright Metal-Poor Stars from the Hamburg/ESO Survey. I. Selection and Follow-up Observations from 329 Fields
• An Elemental Assay of Very, Extremely, and Ultra Metal-Poor Stars
• On Variations Of Pre-Supernova Model Properties
• Super and massive AGB stars - III. Nucleosynthesis in metal-poor and very metal-poor stars - Z=0.001 and 0.0001
• Pop III $\text{i}$-process Nucleosynthesis and the Elemental Abundances of SMSS J0313-6708 and the Most Iron-Poor Stars
• 3D NLTE analysis of the most iron-deficient star, SMSS0313-6708
• Stellar Yields of Rotating First Stars. I. Yields of Weak Supernovae and Abundances of Carbon-enhanced Hyper Metal Poor Stars
• Learning about the intermediate neutron-capture process from lead abundances
• PUSHing core-collapse supernovae to explosions in spherical symmetry IV: Explodability, remnant properties and nucleosynthesis yields of low metallicity stars
• Near-Infrared Spectroscopy of Carbon-Enhanced Metal-Poor Stars. I. A SOAR/OSIRIS Pilot Study
• 3D1D hydro-nucleosynthesis simulations. I. Advective-reactive post-processing method and its application to H ingestion into He-shell flash convection in rapidly accreting white dwarfs
• Pre-supernova mixing in CEMP-no source stars
• Stellar Evolution at Low Metallicity

Cited by in corpus (22)

• Formation of GW190521 from stellar evolution: the impact of the hydrogen-rich envelope, dredge-up and ${}^{12}$C($\alpha$, $\gamma$)${}^{16}$O rate on the pair-instability black hole mass gap
• Is GW190521 the merger of black holes from the first stellar generations?
• Grids of stellar models with rotation: V. Models from 1.7 to 120 Msun at zero metallicity
• Measurement of ${}^{19}$F($p$,$\gamma$)${}^{20}$Ne reaction suggests CNO break-out in first stars
• The intermediate neutron capture process. III. The i-process in AGB stars of different masses and metallicities without overshoot
• Deep underground laboratory measurement of ${}^{13}$C($\alpha$,$n$)${}^{16}$O in the Gamow windows of the $s$- and $i$-processes
• High resolution spectroscopic follow-up of the most metal-poor candidates from SkyMapper DR1.1
• Evolutionary tracks, ejecta, and ionizing photons from intermediate-mass to very massive stars with PARSEC
• The intermediate neutron capture process II.Nuclear uncertainties
• The impact of (n,$\gamma$) reaction rate uncertainties of unstable isotopes on the i-process nucleosynthesis of the elements from Ba to W
• The Status and Future of Direct Nuclear Reaction Measurements for Stellar Burning
• Rapidly rotating Population III stellar models as a source of primary nitrogen
• Realistic 3D hydrodynamics simulations find significant turbulent entrainment in massive stars
• The chemical evolution of the solar neighbourhood for planet-hosting stars
• Comparison between core-collapse supernova nucleosynthesis and meteoric stardust grains: investigating magnesium, aluminium, and chromium
• Explaining the ${}^{12}\text{C}{/}^{13}\text{C}$ ratio in the Galactic halo: the contribution from shell mergers in primordial massive stars
• Isotopic ratios for C, N, Si, Al, and Ti in C-rich presolar grains from massive stars
• The imprint of convection on Type I X-ray bursts: Pauses in photospheric radius expansion lightcurves
• The $i$-processes nucleosynthesis during the formation of He-rich hot-subdwarf stars
• ${}^{19}$F$(p,\gamma )$${}^{20}$Ne reaction rate and the puzzling calcium abundance in metal poor stars
• 3D non-LTE Ca II line formation in metal-poor FGK stars. I. Abundance corrections, radial velocity corrections, and synthetic spectra
• The challenging first direct measurement of the 65 keV resonance strength in the ${}^{17}$O(p,$\gamma$)${}^{18}$F reaction at LUNA