EDGE-INFERNO : How chemical enrichment assumptions impact the individual stars of a simulated ultra-faint dwarf galaxy
(2026) In Astronomy and Astrophysics 707.- Abstract
The chemical abundances of stars in galaxies are a fossil record of the star formation and stellar evolution processes that regulate galaxy formation, including the stellar initial mass function, the fraction and timing of type Ia supernovae (SNeIa), and nucleosynthesis inside massive stars. In this paper, we systematically explore uncertainties associated with modeling chemical enrichment in dwarf galaxies. We repeatedly simulate a single EDGE-INFERNO dwarf (M ★ ≈ 105 M ⊙), varying the chemical yields of massive stars, the timing and yields of SNeIa, and the intrinsic stochasticity that arises from sampling individual stars and galaxy formation chaoticity. All simulations are high-resolution (3.6 pc),... (More)
The chemical abundances of stars in galaxies are a fossil record of the star formation and stellar evolution processes that regulate galaxy formation, including the stellar initial mass function, the fraction and timing of type Ia supernovae (SNeIa), and nucleosynthesis inside massive stars. In this paper, we systematically explore uncertainties associated with modeling chemical enrichment in dwarf galaxies. We repeatedly simulate a single EDGE-INFERNO dwarf (M ★ ≈ 105 M ⊙), varying the chemical yields of massive stars, the timing and yields of SNeIa, and the intrinsic stochasticity that arises from sampling individual stars and galaxy formation chaoticity. All simulations are high-resolution (3.6 pc), cosmological zoom-in hydrodynamical simulations that track the stellar evolution of all individual stars with masses of > 0.5 M⊙. We find that SNeIa make significant contributions to the iron content of low-mass, reionization-limited galaxies, with possible variations in mean abundance ratios and [Fe/H] related to minor changes in their evolutionary timescales. In contrast, different massive star yields, accounting (or not) for stellar rotation, result in mean abundance variations comparable to those arising from stochasticity, with the possible exception of extremely rapidly rotating stars. Nonetheless, massive stars significantly affect the shape of abundance trends with [Fe/H], for example, through the existence (or not) of a bimodality in the [X/Fe]–[Fe/H] planes, particularly in [Al/Fe]. Finally, we find that the variance arising from random sampling severely limits the interpretation of single galaxies. Our analysis showcases the power of star-by-star cosmological models to unpick how both systematic uncertainties (e.g., assumptions in low-metallicity chemical enrichment) and statistical uncertainties (e.g., averaging over enough galaxies and stars within a galaxy) affect the interpretation of chemical observables in ultra-faint dwarf galaxies.
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- author
- Andersson, Eric P. LU ; Rey, Martin P. LU ; Yates, Robert M. ; Read, Justin I. ; Agertz, Oscar LU ; Ji, Alexander P. ; Mead, Jennifer ; Brauer, Kaley and Mac Low, Mordecai Mark
- organization
- publishing date
- 2026-03-01
- type
- Contribution to journal
- publication status
- published
- subject
- keywords
- galaxies: abundances, galaxies: dwarf, galaxies: formation
- in
- Astronomy and Astrophysics
- volume
- 707
- article number
- A112
- publisher
- EDP Sciences
- external identifiers
-
- scopus:105031763856
- ISSN
- 0004-6361
- DOI
- 10.1051/0004-6361/202558029
- language
- English
- LU publication?
- yes
- additional info
- Publisher Copyright: © The Authors 2026.
- id
- 5420aa5f-136d-46ab-8aa6-c905dbc0bb05
- date added to LUP
- 2026-04-28 14:43:52
- date last changed
- 2026-04-28 14:44:09
@article{5420aa5f-136d-46ab-8aa6-c905dbc0bb05,
abstract = {{<p>The chemical abundances of stars in galaxies are a fossil record of the star formation and stellar evolution processes that regulate galaxy formation, including the stellar initial mass function, the fraction and timing of type Ia supernovae (SNeIa), and nucleosynthesis inside massive stars. In this paper, we systematically explore uncertainties associated with modeling chemical enrichment in dwarf galaxies. We repeatedly simulate a single EDGE-INFERNO dwarf (M <sub>★</sub> ≈ 10<sup>5</sup> M <sub>⊙</sub>), varying the chemical yields of massive stars, the timing and yields of SNeIa, and the intrinsic stochasticity that arises from sampling individual stars and galaxy formation chaoticity. All simulations are high-resolution (3.6 pc), cosmological zoom-in hydrodynamical simulations that track the stellar evolution of all individual stars with masses of > 0.5 M<sub>⊙</sub>. We find that SNeIa make significant contributions to the iron content of low-mass, reionization-limited galaxies, with possible variations in mean abundance ratios and [Fe/H] related to minor changes in their evolutionary timescales. In contrast, different massive star yields, accounting (or not) for stellar rotation, result in mean abundance variations comparable to those arising from stochasticity, with the possible exception of extremely rapidly rotating stars. Nonetheless, massive stars significantly affect the shape of abundance trends with [Fe/H], for example, through the existence (or not) of a bimodality in the [X/Fe]–[Fe/H] planes, particularly in [Al/Fe]. Finally, we find that the variance arising from random sampling severely limits the interpretation of single galaxies. Our analysis showcases the power of star-by-star cosmological models to unpick how both systematic uncertainties (e.g., assumptions in low-metallicity chemical enrichment) and statistical uncertainties (e.g., averaging over enough galaxies and stars within a galaxy) affect the interpretation of chemical observables in ultra-faint dwarf galaxies.</p>}},
author = {{Andersson, Eric P. and Rey, Martin P. and Yates, Robert M. and Read, Justin I. and Agertz, Oscar and Ji, Alexander P. and Mead, Jennifer and Brauer, Kaley and Mac Low, Mordecai Mark}},
issn = {{0004-6361}},
keywords = {{galaxies: abundances; galaxies: dwarf; galaxies: formation}},
language = {{eng}},
month = {{03}},
publisher = {{EDP Sciences}},
series = {{Astronomy and Astrophysics}},
title = {{EDGE-INFERNO : How chemical enrichment assumptions impact the individual stars of a simulated ultra-faint dwarf galaxy}},
url = {{http://dx.doi.org/10.1051/0004-6361/202558029}},
doi = {{10.1051/0004-6361/202558029}},
volume = {{707}},
year = {{2026}},
}