Revisiting inelastic Cu+H collisions and the non-LTE Galactic evolution of copper
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arXiv
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| Autori principali: | , , , , , , |
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| Natura: | Preprint |
| Pubblicazione: |
2025
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| _version_ | 1866915265421246464 |
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| author | Caliskan, S. Amarsi, A. M. Racca, M. Koutsouridou, I. Barklem, P. S. Lind, K. Salvadori, S. |
| author_facet | Caliskan, S. Amarsi, A. M. Racca, M. Koutsouridou, I. Barklem, P. S. Lind, K. Salvadori, S. |
| contents | The Galactic evolution of copper remains poorly understood, partly due to the strong departures from local thermodynamic equilibrium (LTE) affecting Cu I lines. A key source of uncertainty in non-LTE modelling is the treatment of inelastic Cu+H collisions. We present new rate coefficients based on a combined asymptotic LCAO and free electron model approach, which show significant differences from previous calculations. Applying these updated rates to non-LTE stellar modelling, we find reduced line-to-line scatter and improved consistency between metal-poor dwarfs and giants. Our non-LTE analysis reveals a strong upturn in the [Cu/Fe] trend towards lower [Fe/H] < -1.7. We show that this may reflect the interplay between external enrichment of Cu-rich material of the Milky Way halo at low metallicities, and metallicity-dependent Cu yields from rapidly rotating massive stars. This highlights the unique diagnostic potential of accurate Cu abundances for understanding both stellar and Galactic evolution. |
| format | Preprint |
| id |
arxiv_https___arxiv_org_abs_2503_22566 |
| institution | arXiv |
| publishDate | 2025 |
| record_format | arxiv |
| spellingShingle | Revisiting inelastic Cu+H collisions and the non-LTE Galactic evolution of copper Caliskan, S. Amarsi, A. M. Racca, M. Koutsouridou, I. Barklem, P. S. Lind, K. Salvadori, S. Solar and Stellar Astrophysics Astrophysics of Galaxies Atomic Physics The Galactic evolution of copper remains poorly understood, partly due to the strong departures from local thermodynamic equilibrium (LTE) affecting Cu I lines. A key source of uncertainty in non-LTE modelling is the treatment of inelastic Cu+H collisions. We present new rate coefficients based on a combined asymptotic LCAO and free electron model approach, which show significant differences from previous calculations. Applying these updated rates to non-LTE stellar modelling, we find reduced line-to-line scatter and improved consistency between metal-poor dwarfs and giants. Our non-LTE analysis reveals a strong upturn in the [Cu/Fe] trend towards lower [Fe/H] < -1.7. We show that this may reflect the interplay between external enrichment of Cu-rich material of the Milky Way halo at low metallicities, and metallicity-dependent Cu yields from rapidly rotating massive stars. This highlights the unique diagnostic potential of accurate Cu abundances for understanding both stellar and Galactic evolution. |
| title | Revisiting inelastic Cu+H collisions and the non-LTE Galactic evolution of copper |
| topic | Solar and Stellar Astrophysics Astrophysics of Galaxies Atomic Physics |
| url | https://arxiv.org/abs/2503.22566 |