Chemical Evolution and Abundance Patterns in Metal-Poor Stars

Metal-poor stars serve as time capsules of the early Universe, preserving elemental fingerprints from the first generations of massive stars. Their chemical abundance patterns—spanning iron-peak, α-elements and neutron-capture species—enable reconstruction of core-collapse supernova yields, asymptotic giant branch contributions and rapid versus slow neutron-capture processes. Observed features such as the odd–even effect, carbon enhancement and rare intermediate neutron-capture signatures have driven refinements in nucleosynthesis models, stellar evolution theory and feedback mechanisms in protogalactic environments. Large surveys coupled with high-resolution spectroscopy have delineated the metallicity distribution of the Galactic halo and its dwarf satellites, revealing bursty star formation, efficient metal mixing and accretion of low-mass systems. Collectively, these insights constrain progenitor masses, rotation rates and explosion dynamics of the earliest stars, while anchoring cosmological simulations of galaxy assembly and chemical enrichment over cosmic time.

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Chemical Evolution and Abundance Patterns in Metal-Poor Stars publication trend

The graph below shows the total number of articles in chemical evolution and abundance patterns in metal-poor stars across all publications each year (not limited to Nature Index journals).

Technical terms

[Fe/H]: Logarithmic ratio of iron to hydrogen relative to the Sun, used as a proxy for stellar metallicity.

α-elements: Elements such as O, Mg, Si, Ca and Ti formed predominantly in core-collapse supernovae, indicating early massive-star enrichment.

r-process: Rapid neutron-capture process occurring in high-energy sites (e.g. neutron-star mergers), responsible for synthesising the heaviest nuclei.

s-process: Slow neutron-capture process in asymptotic giant branch stars, producing elements up to bismuth over extended timescales.

CEMP star: Carbon-enhanced metal-poor star with elevated [C/Fe], reflecting unique nucleosynthetic pathways or mass transfer events.

Odd–even effect: Systematic variation in abundances between odd and even atomic numbers, offering clues to the neutron-capture environment and reaction rates.

References

1. Metal Mixing in the r-process Enhanced Ultrafaint Dwarf Galaxy Reticulum II* *This paper includes data gathered with the 6.5 m Magellan Telescopes, located at Las Campanas Observatory, Chile.. The Astronomical Journal (2023).
2. Timing the r-process Enrichment of the Ultra-faint Dwarf Galaxy Reticulum II. The Astrophysical Journal (2023).
3. THE DIVERSE ORIGINS OF NEUTRON-CAPTURE ELEMENTS IN THE METAL-POOR STAR HD 94028: POSSIBLE DETECTION OF PRODUCTS OF i-PROCESS NUCLEOSYNTHESIS* * These data are associated with Program 072.B-0585(A), PI. Silva. Some data presented in this paper were obtained from the Barbara A. Mikulski Archive for Space Telescopes (MAST). The Space Telescope Science Institute is operated by the Association of Universities for Research in Astronomy, Inc., under NASA contract NAS5-26555. These data are associated with Programs GO-7402 and GO-8197. This work is based on data obtained from the European Southern Observatory (ESO) Science Archive Facility. These data are associated with Program 072.B-0585(A). This paper includes data taken at The McDonald Observatory of The University of Texas at Austin.. The Astrophysical Journal (2016).
4. Four-hundred Very Metal-poor Stars Studied with LAMOST and Subaru. II. Elemental Abundances. The Astrophysical Journal (2022).