تقرير
Abundances of iron-peak elements in accreted and in situ born Galactic halo stars
| العنوان: | Abundances of iron-peak elements in accreted and in situ born Galactic halo stars |
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| المؤلفون: | Nissen, P. E., Amarsi, A. M., Skúladóttir, Á., Schuster, W. J. |
| سنة النشر: | 2023 |
| المجموعة: | Astrophysics |
| مصطلحات موضوعية: | Astrophysics - Astrophysics of Galaxies, Astrophysics - Solar and Stellar Astrophysics |
| الوصف: | Previous work on the abundances of C, O, Na, Mg, Si, Ca, Ti, Cr, Mn, Fe, Ni, Cu, and Zn in low-alpha (accreted) and high-alpha (in situ born) halo stars is extended to include the abundances of Sc, V, and Co, enabling us to study the nucleosynthesis of all iron-peak elements along with the lighter elements. The Sc, V, and Co abundances were determined from a 1D MARCS model-atmosphere analysis of equivalent widths of atomic lines in high signal-to-noise, high resolution spectra assuming local thermodynamic equilibrium (LTE). In addition, new 3D and/or non-LTE calculations were used to correct the 1D LTE abundances for several elements including consistent 3D non-LTE calculations for Mg. The two populations of accreted and in situ born stars are well separated in diagrams showing [Sc/Fe], [V/Fe], and [Co/Fe] as a function of [Fe/H]. The [X/Mg] versus [Mg/H] trends for high-alpha and low-alpha stars were used to determine the yields of core-collapse and Type Ia supernovae. The largest Type Ia contribution occurs for Cr, Mn, and Fe, whereas Cu is a pure core-collapse element. Sc, Ti, V, Co, Ni, and Zn represent intermediate cases. A comparison with yields calculated for supernova models shows poor agreement for the core-collapse yields. The Ia yields suggest that sub-Chandrasekhar-mass Type Ia supernovae provide a dominant contribution to the chemical evolution of the host galaxies of the low-alpha stars. A substructure in the abundances and kinematics of the low-alpha stars suggests that they arise from at least two different satellite accretion events, Gaia-Sausage-Enceladus and Thamnos. Comment: Accepted for publication in A&A. 12 pages, 4 tables, and 7 figures |
| نوع الوثيقة: | Working Paper |
| URL الوصول: | http://arxiv.org/abs/2312.07768 |
| رقم الأكسشن: | edsarx.2312.07768 |
| قاعدة البيانات: | arXiv |
| الوصف غير متاح. |