Researchers from the University of Geneva, including Luca Sciarini, Sophie Rosu, Sylvia Ekström, Maxime Marchand, Patrick Eggenberger, and Georges Meynet, have delved into the complex interplay between tidal interactions and chemical mixing in close massive binary star systems. Their work, published in the journal Astronomy & Astrophysics, aims to address uncertainties in stellar models and shed light on the impact of internal transport mechanisms on these celestial bodies.
The study focuses on close massive binaries, where previous theoretical models suggested that tides systematically enhance chemical mixing. However, observational data has not shown a clear trend between orbital period and nitrogen enrichment, challenging these predictions. The researchers sought to understand the interplay between tidal interactions, angular momentum transport (AMT), and chemical mixing by computing grids of binary models with various AMT treatments. They also compared these models to single stars with identical initial conditions to isolate the effects of tidal interactions.
The findings reveal that tides can either enhance or suppress chemical mixing relative to single-star models, with the outcome being highly sensitive to the AMT assumptions. The researchers identified a key difference between magnetic and hydrodynamic models. In close systems subject to tides, magnetic models predict that the mixing efficiency is primarily determined by the orbital configuration. In contrast, hydrodynamic models also depend on the assumed initial velocity. This sensitivity in hydrodynamic models can lead to non-monotonic period-enrichment trends or even period-enrichment correlations.
The practical implications for the energy sector, particularly in astrophysics and stellar modeling, are significant. Understanding the internal transport mechanisms in stars is crucial for predicting their evolution and behavior, which in turn impacts our understanding of stellar nucleosynthesis and the life cycles of stars. This knowledge can help refine models used in various astrophysical applications, including the study of supernovae, gamma-ray bursts, and the synthesis of heavy elements. While the direct impact on energy production technologies may not be immediate, the foundational research provides a deeper understanding of stellar processes that could influence future developments in astrophysics and related fields.
Source: Astronomy & Astrophysics
This article is based on research available at arXiv.