In the realm of astrophysics and energy research, a team of scientists from the University of Geneva, Keele University, and the University of Chicago has been delving into the intricate processes that govern the lives and deaths of massive stars. Led by Emily E. Whitehead, this international group has been exploring how the mixing of materials at the boundaries of convective regions within stars, a process known as convective boundary mixing (CBM) or overshooting, influences the evolution and ultimate fate of these celestial bodies.
The researchers used the Modules for Experiments in Stellar Astrophysics (MESA) code to create two sets of stellar models, each with a different strength of CBM. One set used a typical CBM value found in literature, while the other was guided by results from three-dimensional convection simulations. The study, published in the Monthly Notices of the Royal Astronomical Society, focused on low metallicity massive stars, which are particularly relevant to the early universe and the formation of the first stars.
The team found that interactions between the carbon, neon, and oxygen burning shells (C-Ne-O) were common in both sets of models. However, the models with higher CBM exhibited more frequent interactions between the hydrogen-helium (H-He) and helium-carbon (He-C) shells at lower initial masses compared to the lower CBM models. Some models even underwent multiple interaction events during their evolution.
These findings suggest that the strength of CBM can significantly impact the structure and fate of massive stars. The researchers expect that the new CBM values could lead to unusual nucleosynthesis, including more common or enhanced i- and gamma-process nucleosynthesis. This could have implications for the production of heavy elements in the universe. Additionally, the study suggests that the precursors to supernovae (SN) and the pre-SN structure of massive stars could be significantly altered, with many models not exhibiting the commonly expected onion-ring-like structure. This could also affect the explosion probability of these stars.
While this research is primarily focused on astrophysics, it has potential implications for the energy sector, particularly in the field of nuclear fusion. Understanding the processes that govern the burning of elements within stars can provide insights into the conditions necessary for fusion reactions, which are being explored as a potential source of clean, abundant energy. Furthermore, the nucleosynthesis processes that occur within stars are responsible for the production of many of the elements that make up the universe, including those that are crucial for various energy technologies. Therefore, a deeper understanding of these processes can contribute to the development of new energy technologies and the improvement of existing ones.
In conclusion, this research highlights the importance of convective boundary mixing in the evolution and fate of massive stars. The findings have implications for our understanding of nucleosynthesis, supernovae, and the structure of massive stars, all of which can contribute to the development of new energy technologies. As we continue to explore the universe and the processes that govern it, we may uncover new insights that can help us address the energy challenges facing our planet.
This article is based on research available at arXiv.