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  4. Homogeneity in the early chemical evolution of the Sextans dwarf spheroidal galaxy
 
research article

Homogeneity in the early chemical evolution of the Sextans dwarf spheroidal galaxy

Lucchesi, R.
•
Lardo, C.  
•
Primas, F.
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December 2, 2020
Astronomy & Astrophysics

We present the high-resolution spectroscopic analysis of two new extremely metal-poor star (EMPS) candidates in the dwarf spheroidal galaxy Sextans. These targets were preselected from medium-resolution spectra centered around the CaII triplet in the near-infrared and were followed-up at higher resolution with VLT/UVES. We confirm their low metallicities with [Fe/H] = -2.95 and [Fe/H] = -3.01, which place them among the most metal-poor stars known in Sextans. The abundances of 18 elements, including C, Na, the alpha, Fe-peak, and neutron-capture elements, are determined. In particular, we present the first unambiguous detection of Zn in a classical dwarf at extremely low metallicity. Previous indications were made of a large scatter in the abundance ratios of the Sextans stellar population around [Fe/H] similar to -3 when compared to other galaxies, particularly with very low observed [alpha /Fe] ratios. We took the opportunity of reanalyzing the full sample of EMPS in Sextans and find a [alpha /Fe] Milky Way-like plateau and a similar to 0.2 dex dispersion at fixed metallicity.

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Type
research article
DOI
10.1051/0004-6361/202037534
Web of Science ID

WOS:000596874300011

Author(s)
Lucchesi, R.
Lardo, C.  
Primas, F.
Jablonka, P.  
North, P.  
Battaglia, G.
Starkenburg, E.
Hill, V.
Irwin, M.
Francois, P.
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Date Issued

2020-12-02

Publisher

EDP SCIENCES S A

Published in
Astronomy & Astrophysics
Volume

644

Start page

A75

Subjects

Astronomy & Astrophysics

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stars: abundances

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local group

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galaxies: dwarf

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galaxies: formation

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metal-poor stars

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effective temperature scale

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neutron-capture elements

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formation history

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r-process

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high-resolution

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nlte analysis

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s-process

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enrichment

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abundance

Editorial or Peer reviewed

REVIEWED

Written at

EPFL

EPFL units
LASTRO  
Available on Infoscience
June 19, 2021
Use this identifier to reference this record
https://infoscience.epfl.ch/handle/20.500.14299/179363
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