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

被引：39

作者：

Martin, Nicolas F. ^{[1
,2
]}

Venn, Kim A. ^{[3
]}

Aguado, David S. ^{[4
,5
,6
]}

Starkenburg, Else ^{[7
]}

Gonzalez Hernandez, Jonay I. ^{[5
,8
]}

Ibata, Rodrigo A. ^{[1
]}

Bonifacio, Piercarlo ^{[9
]}

Caffau, Elisabetta ^{[9
]}

Sestito, Federico ^{[3
]}

Arentsen, Anke ^{[1
]}

Allende Prieto, Carlos ^{[5
,8
]}

Carlberg, Raymond G. ^{[10
]}

Fabbro, Sebastien ^{[3
,11
]}

Fouesneau, Morgan ^{[2
]}

Hill, Vanessa ^{[12
]}

Jablonka, Pascale ^{[9
,13
]}

Kordopatis, Georges ^{[12
]}

Lardo, Carmela ^{[14
]}

Malhan, Khyati ^{[15
]}

Mashonkina, Lyudmila I. ^{[16
]}

McConnachie, Alan W. ^{[11
]}

Navarro, Julio F. ^{[3
]}

Sanchez-Janssen, Ruben ^{[17
]}

Thomas, Guillaume F. ^{[5
,8
]}

Yuan, Zhen ^{[1
]}

Mucciarelli, Alessio ^{[14
,18
]}

机构：

[1] Univ Strasbourg, CNRS, Observ Astron Strasbourg, UMR 7550, Strasbourg, France

[2] Max Planck Inst Astron, Heidelberg, Germany

[3] Univ Victoria, Dept Phys & Astron, Victoria, BC, Canada

[4] Univ Cambridge, Inst Astron, Cambridge, England

[5] Inst Astrofis Canarias, San Cristobal la Laguna, Tenerife, Spain

[6] Univ Firenze, Dipartimento Fis & Astron, Sesto Fiorentino, Italy

[7] Univ Groningen, Kapteyn Astron Inst, Groningen, Netherlands

[8] Univ La Laguna, Dept Astrofis, San Cristobal la Laguna, Tenerife, Spain

[9] Univ PSL, CNRS, GEPI, Observ Paris, Meudon, France

[10] Univ Toronto, Dept Astron & Astrophys, Toronto, ON, Canada

[11] NRC Herzberg Astron & Astrophys, Victoria, BC, Canada

[12] Univ Cote Azur, CNRS, Observ Cote Azur, Lab Lagrange, Nice, France

[13] Ecole Polytech Fed Lausanne, Astrophys Lab, Versoix, Switzerland

[14] Univ Bologna, Alma Mater Studiorum, Dipartimento Fis & Astron Augusto Righi, Bologna, Italy

[15] Stockholm Univ, Dept Phys, Oskar Klein Ctr, Stockholm, Sweden

[16] Russian Acad Sci, Inst Astron, Moscow, Russia

[17] Royal Observ, UK Astron Technol Ctr, Edinburgh, Midlothian, Scotland

[18] INAF Osservatorio Astrofis & Sci Spazio Bologna, Bologna, Italy

来源：

NATURE | 2022年 / 601卷 / 7891期

基金：

欧洲研究理事会; 加拿大自然科学与工程研究理事会; 荷兰研究理事会;

关键词：

LTE LINE FORMATION; LATE-TYPE STARS; MILKY-WAY HALO; PRISTINE SURVEY; EVOLUTION; DATABASE; GALAXY; FE; 1D;

D O I：

10.1038/s41586-021-04162-2

中图分类号：

O [数理科学和化学]; P [天文学、地球科学]; Q [生物科学]; N [自然科学总论];

学科分类号：

07 ; 0710 ; 09 ;

摘要：

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 Universe(1). 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]greater than or similar to- 2.7). This metallicity floor appears universal(5,6), 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 day(7). Here we report observations of a stellar stream, C-19, whose metallicity is less than 0.05% of the solar metallicity ([Fe/H]= - 3.38 +/- 0.06 (statistical) +/- 0.20 (systematic)). 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.

引用

页码：45 / +

页数：16

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