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Title: Sensitivity of carbon and oxygen yields to the triple-alpha resonance in massive stars

Abstract

Motivated by the possible existence of other universes, this study considers the evolution of massive stars with different values for the fundamental constants. We focus on variations in the triple alpha resonance energy and study its effects on the resulting abundances of 12C, 16O, and larger nuclei. In our universe, the 0 + energy level of carbon supports a resonant nuclear reaction that dominates carbon synthesis in stellar cores and accounts for the observed cosmic abundances. Here we define ΔER to be the change in this resonant energy level, and show how different values affect the cosmic abundances of the intermediate alpha elements. Using the state of the art computational package MESA, we carry out stellar evolution calculations for massive stars in the range M* = 15 - 40 M , and for a wide range of resonance energies. We also include both solar and low metallicity initial conditions. For negative ΔER, carbon yields are increased relative to standard stellar models, and such universes remain viable as long as the production of carbon nuclei remains energetically favorable, and stars remain stable, down to Δ E R - 300 keV. For positive ΔER, carbon yields decrease, but significant abundances can be produced for resonance energy increments up to Δ E R + 500 keV. Oxygen yields tend to be anti-correlated with those of carbon, and the allowed range in ΔER is somewhat smaller. We also present yields for neon, magnesium, and silicon. Finally, with updated stellar evolution models and a more comprehensive survey of parameter space, these results indicate that the range of viable universes is larger than suggested by earlier studies.

Authors:
 [1];  [2];  [3]
  1. Univ. of Michigan, Ann Arbor, MI (United States). Physics Dept.
  2. Univ. of Michigan, Ann Arbor, MI (United States). Physics Dept. Astronomy Dept.
  3. Univ. of California, Berkeley, CA (United States). Dept. of Physics; Los Alamos National Lab. (LANL), Los Alamos, NM (United States)
Publication Date:
Research Org.:
Los Alamos National Lab. (LANL), Los Alamos, NM (United States)
Sponsoring Org.:
USDOE; National Science Foundation (NSF); Univ. of Michigan (United States); John Templeton Foundation (United States); Heising-Simons Foundation (United States)
OSTI Identifier:
1477672
Report Number(s):
LA-UR-18-27626
Journal ID: ISSN 0927-6505
Grant/Contract Number:  
AC52-06NA25396; PHY-1630782; ID55112; 2017-228
Resource Type:
Accepted Manuscript
Journal Name:
Astroparticle Physics
Additional Journal Information:
Journal Volume: 105; Journal ID: ISSN 0927-6505
Publisher:
Elsevier
Country of Publication:
United States
Language:
English
Subject:
79 ASTRONOMY AND ASTROPHYSICS; Fine-Tuning; Multiverse; Stellar Nucleosynthesis; Triple Alpha

Citation Formats

Huang, Lillian, Adams, Fred C., and Grohs, Evan. Sensitivity of carbon and oxygen yields to the triple-alpha resonance in massive stars. United States: N. p., 2018. Web. https://doi.org/10.1016/j.astropartphys.2018.09.005.
Huang, Lillian, Adams, Fred C., & Grohs, Evan. Sensitivity of carbon and oxygen yields to the triple-alpha resonance in massive stars. United States. https://doi.org/10.1016/j.astropartphys.2018.09.005
Huang, Lillian, Adams, Fred C., and Grohs, Evan. Mon . "Sensitivity of carbon and oxygen yields to the triple-alpha resonance in massive stars". United States. https://doi.org/10.1016/j.astropartphys.2018.09.005. https://www.osti.gov/servlets/purl/1477672.
@article{osti_1477672,
title = {Sensitivity of carbon and oxygen yields to the triple-alpha resonance in massive stars},
author = {Huang, Lillian and Adams, Fred C. and Grohs, Evan},
abstractNote = {Motivated by the possible existence of other universes, this study considers the evolution of massive stars with different values for the fundamental constants. We focus on variations in the triple alpha resonance energy and study its effects on the resulting abundances of 12C, 16O, and larger nuclei. In our universe, the 0+ energy level of carbon supports a resonant nuclear reaction that dominates carbon synthesis in stellar cores and accounts for the observed cosmic abundances. Here we define ΔER to be the change in this resonant energy level, and show how different values affect the cosmic abundances of the intermediate alpha elements. Using the state of the art computational package MESA, we carry out stellar evolution calculations for massive stars in the range M* = 15-40M⊙, and for a wide range of resonance energies. We also include both solar and low metallicity initial conditions. For negative ΔER, carbon yields are increased relative to standard stellar models, and such universes remain viable as long as the production of carbon nuclei remains energetically favorable, and stars remain stable, down to ΔER≈-300 keV. For positive ΔER, carbon yields decrease, but significant abundances can be produced for resonance energy increments up to ΔER≈+500 keV. Oxygen yields tend to be anti-correlated with those of carbon, and the allowed range in ΔER is somewhat smaller. We also present yields for neon, magnesium, and silicon. Finally, with updated stellar evolution models and a more comprehensive survey of parameter space, these results indicate that the range of viable universes is larger than suggested by earlier studies.},
doi = {10.1016/j.astropartphys.2018.09.005},
journal = {Astroparticle Physics},
number = ,
volume = 105,
place = {United States},
year = {2018},
month = {9}
}

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Figures / Tables:

Figure 1 Figure 1: Heavy element abundances a function of time for a massive star with $M$$\star$ = 15 $M$ , metallicity $\mathcal{Z}$ = 10−4, and the triple alpha resonance properties of our universe. The yields are given as mass fractions $X$i. The time variable is a logarithmic measure of the timemore » remaining before the end of the simulation at $t$end when an iron core develops. As time elapses, progressively heavier nuclei are synthesized and their abundances grow, including carbon (blue), oxygen (orange), neon (green), magnesium (red), silicon (purple), sulfur (brown), iron (pink), and all other metals (gray). The abundances of the alpha elements increase, reach a maximum, and subsequently decline back down to an essentially constant value.« less

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