A stellar stream remnant of a globular cluster below the metallicity floor - Archive ouverte HAL
Article Dans Une Revue Nature Année : 2022

A stellar stream remnant of a globular cluster below the metallicity floor

Stellar ejecta gradually enrich the gas out of which subsequent stars form, making the least chemically enriched stellar systems direct fossils of structures formed in the early Universe1. Although a few hundred stars with metal content below 1,000th of the solar iron content are known in the Galaxy2-4, none of them inhabit globular clusters, some of the oldest known stellar structures. These show metal content of at least approximately 0.2% of the solar metallicity ([Fe /H ]≳−2.7 )?. This metallicity floor appears universal5,6, and it has been proposed that protogalaxies that merged into the galaxies we observe today were simply not massive enough to form clusters that survived to the present day7. Here we report observations of a stellar stream, C-19, whose metallicity is less than 0.05% of the solar metallicity ([F e / H ]=−3.38 ±0.06 (s t a t i s t i c a l )±0.20 (s y s t e m a t i c ))?. The low metallicity dispersion and the chemical abundances of the C-19 stars show that this stream is the tidal remnant of the most metal-poor globular cluster ever discovered, and is significantly below the purported metallicity floor: clusters with significantly lower metallicities than observed today existed in the past and contributed their stars to the Milky Way halo.

Nicolas Martin
Observatoire astronomique de Strasbourg
CV
Kim Venn
David Aguado
Else Starkenburg
  • Fonction : Auteur
Jonay González Hernández
  • Fonction : Auteur
Rodrigo A Ibata
Observatoire astronomique de Strasbourg
CV
Piercarlo Bonifacio
  • Fonction : Auteur
Galaxies, Etoiles, Physique, Instrumentation
Elisabetta Caffau
Galaxies, Etoiles, Physique, Instrumentation
Federico Sestito
Anke Arentsen
Observatoire astronomique de Strasbourg
Carlos Allende Prieto
Raymond Carlberg
Sébastien Fabbro
Morgan Fouesneau
  • Fonction : Auteur
Vanessa Hill
Joseph Louis LAGRANGE
Pascale Jablonka
Georges Kordopatis
  • Fonction : Auteur
Joseph Louis LAGRANGE
Carmela Lardo
Khyati Malhan
Lyudmila Mashonkina
Alan Mcconnachie
  • Fonction : Auteur
Julio Navarro
  • Fonction : Auteur
Rubén Sánchez-Janssen
Guillaume Thomas
Zhen Yuan
Observatoire astronomique de Strasbourg
Alessio Mucciarelli

Domaines

Planète et Univers [physics]

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https://hal.science/hal-03524785

Soumis le : jeudi 13 janvier 2022-14:24:00

Dernière modification le : lundi 2 décembre 2024-14:48:11

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hal-03524785 , version 1 (13-01-2022)

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Nicolas Martin, Kim Venn, David Aguado, Else Starkenburg, Jonay González Hernández, et al.. A stellar stream remnant of a globular cluster below the metallicity floor. Nature, 2022, 601 (7891), pp.45-48. ⟨10.1038/s41586-021-04162-2⟩. ⟨hal-03524785⟩

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