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The Pristine Inner Galaxy Survey (PIGS): IX. the largest detailed chemical analysis of very metal-poor stars in the Sagittarius dwarf galaxy

The most metal-poor stars provide valuable insights into the early chemical enrichment history of a system, carrying the chemical imprints of the first generations of supernovae. The most metal-poor region of the Sagittarius dwarf galaxy remains inadequately observed and characterised. To date, only...

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Main Authors: Sestito, Federico (Author) , Vitali, Sara (Author) , Jofre, Paula (Author) , Venn, Kim A. (Author) , Aguado, David S. (Author) , Aguilera-Gómez, Claudia (Author) , Ardern-Arentsen, Anke (Author) , Silva, Danielle de Brito (Author) , Carlberg, Raymond (Author) , Eldridge, Camilla J. L. (Author) , Gran, Felipe (Author) , Hill, Vanessa (Author) , Jablonka, Pascale (Author) , Kordopatis, Georges (Author) , Martin, Nicolas F. (Author) , Matsuno, Tadafumi (Author) , Rusterucci, Samuel (Author) , Starkenburg, Else (Author) , Viswanathan, Akshara (Author)
Format: Article (Journal)
Language:English
Published: September 2024
In: Astronomy and astrophysics
Year: 2024, Volume: 689, Pages: 1-14
ISSN:1432-0746
DOI:10.1051/0004-6361/202450553
Online Access:Verlag, kostenfrei, Volltext: https://doi.org/10.1051/0004-6361/202450553
Verlag, kostenfrei, Volltext: https://www.aanda.org/articles/aa/abs/2024/09/aa50553-24/aa50553-24.html
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Author Notes:Federico Sestito, Sara Vitali, Paula Jofre, Kim A. Venn, David S. Aguado, Claudia Aguilera-Gómez, Anke Ardern-Arentsen, Danielle de Brito Silva, Raymond Carlberg, Camilla J. L. Eldridge, Felipe Gran, Vanessa Hill, Pascale Jablonka, Georges Kordopatis, Nicolas F. Martin, Tadafumi Matsuno, Samuel Rusterucci, Else Starkenburg, and Akshara Viswanathan
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Summary:The most metal-poor stars provide valuable insights into the early chemical enrichment history of a system, carrying the chemical imprints of the first generations of supernovae. The most metal-poor region of the Sagittarius dwarf galaxy remains inadequately observed and characterised. To date, only ∼4 stars with [Fe/H] < −2.0 have been chemically analysed with high-resolution spectroscopy. In this study, we present the most extensive chemical abundance analysis of 12 low-metallicity stars with metallicities down to [Fe/H] = −3.26 and located in the main body of Sagittarius. These targets, selected from the Pristine Inner Galaxy Survey, were observed using the MIKE high-resolution spectrograph at the Magellan-Clay telescope, which allowed us to measure up to 17 chemical species. The chemical composition of these stars reflects the imprint of a variety of type II supernovae (SNe II). A combination of low- to intermediate-mass high-energy SNe and hypernovae (∼10 − 70 M⊙) is required to account for the abundance patterns of the lighter elements up to the Fe-peak. The trend of the heavy elements suggests the involvement of compact binary merger events and fast-rotating (up to ∼300 km s−1) intermediate-mass to massive metal-poor stars (∼25 − 120 M⊙) that are the sources of rapid and slow processes, respectively. Additionally, asymptotic giant branch stars contribute to a wide dispersion of [Ba/Mg] and [Ba/Eu]. The absence of an α−knee in our data indicates that type Ia supernovae did not contribute in the very metal-poor region ([Fe/H] ≤ −2.0). However, they might have started to pollute the interstellar medium at [Fe/H] > −2.0, given the relatively low [Co/Fe] in this metallicity region.
Item Description:Online verfügbar: 13. September 2024
Gesehen am 03.06.2025
Physical Description:Online Resource
ISSN:1432-0746
DOI:10.1051/0004-6361/202450553

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