The first carbon-enhanced metal-poor star found in the Sculptor dwarf spheroidal

Abstract

The origin of carbon-enhanced metal-poor (CEMP) stars and their possible connection with the chemical elements produced by the first stellar generation is still highly debated. In contrast to the Galactic halo, not many CEMP stars have been found in the dwarf spheroidal galaxies around the Milky Way. Here we present detailed abundances from ESO VLT/UVES high-resolution spectroscopy for ET0097, the first CEMP star found in the Sculptor dwarf spheroidal. This star has $\text{[Fe/H]}=-2.03\pm 0.10$, $\text{[C/Fe]}=0.51\pm 0.10$ and $\text{[N/Fe]}=1.18\pm 0.20$. The traditional definition of CEMP stars is $\text{[C/Fe]}\ge 0.70$, but taking into account that this luminous red giant branch star has undergone mixing, it was intrinsically less nitrogen enhanced and more carbon-rich when it was formed, and so it falls under the definition of CEMP stars, as proposed by Aoki et al. (2007) to account for this effect. By making corrections for this mixing, we conclude that the star had $\text{[C/Fe]}\approx 0.8$ during its earlier evolutionary stages. Apart from the enhanced C and N abundances, ET0097 shows no peculiarities in other elements lighter than Zn, and no enhancement of the heavier neutron-capture elements (Ba, La, Ce, Nd, Sm, Eu, Dy), making this a CEMP-no star. However, the star does show signs of the weak $r$-process, with an overabundance of the lighter neutron-capture elements (Sr, Y, Zr). To explain the abundance pattern observed in ET0097, we explore the possibility that this star was enriched by primordial stars. In addition to the detailed abundances for ET0097, we present estimates and upper limits for C abundances in 85 other stars in Sculptor derived from CN molecular lines, including 11 stars with $\text{[Fe/H]}\le -2$. Combining these limits with observations from the literature, the fraction of CEMP-no stars in Sculptor seems to be significantly lower than in the Galactic halo.

arXiv comment28 pages, 6 tables, 10 figures, accepted in Astronomy & Astrophysics

References in corpus (70)

• Maps of Dust IR Emission for Use in Estimation of Reddening and CMBR Foregrounds
• A grid of MARCS model atmospheres for late-type stars I. Methods and general properties
• Star Formation Histories, Abundances and Kinematics of Dwarf Galaxies in the Local Group
• First stars V - Abundance patterns from C to Zn and supernova yields in the early Galaxy
• Automated data reduction workflows for astronomy
• Nucleosynthesis and Evolution of Massive Metal-Free Stars
• Galactic Evolution of Sr, Y, Zr: A Multiplicity of Nucleosynthetic Processes
• The effective temperature scale of FGK stars. II. Teff : color : [Fe/H] calibrations
• The Extremely Metal-Poor, Neutron-Capture-Rich Star CS 22892-052: A Comprehensive Abundance Analysis
• Carbon Enhanced Metal-Poor Stars. I. Chemical Compositions of 26 Stars
• VLT/UVES Abundances in Four Nearby Dwarf Spheroidal Galaxies: I. Nucleosynthesis and Abundance Ratios
• The Hamburg/ESO R-process Enhanced Star survey (HERES) II. Spectroscopic analysis of the survey sample
• The Stellar Abundances for Galactic Archeology (SAGA) Database - Compilation of the Characteristics of Known Extremely Metal-Poor Stars
• First stars VI - Abundances of C, N, O, Li, and mixing in extremely metal-poor giants. Galactic evolution of the light elements
• First-generation black-hole-forming supernovae and the metal abundance pattern of a very iron-poor star
• The early star generations: the dominant effect of rotation on the CNO yields
• A single low-energy, iron-poor supernova as the source of metals in the star SMSS J 031300.36-670839.3
• Spectroscopic Studies of Extremly Metal-Poor Stars with Subaru/HDS:II.The r-process Elements, Including Thorium
• The Most Metal-Poor Stars. II. Chemical Abundances of 190 Metal-Poor Stars Including 10 New Stars With [Fe/H] < -3.5
• First Stars VIII -- Enrichment of the neutron-capture elements in the early Galaxy
• The kinematic status and mass content of the Sculptor dwarf spheroidal galaxy
• The Binary Frequency Among Carbon-Enhanced, s-Process Rich, Metal-Poor Stars
• Carbon-Enhanced Metal-Poor Star Frequencies in the Galaxy: Corrections for the Effect of Evolutionary Status on Carbon Abundances
• Supernova Nucleosynthesis in Population III 13 -- 50 $M_{\odot }$ Stars and Abundance Patterns of Extremely Metal-Poor Stars
• The first chemical enrichment in the universe and the formation of hyper metal-poor stars
• Extremely Metal-Poor Stars. VIII. High-Resolution, High-Signal-To-Noise Analysis of Five Stars with [Fe/H] < -3.5
• The Most Metal-Poor Stars. IV. The Two Populations With [Fe/H] < -3.0
• A strong case for fast stellar rotation at very low metallicities
• Production of Light Element Primary Process nuclei in neutrino-driven winds
• Non-standard s process in low metallicity massive rotating stars
• Spectroscopic Studies of Very Metal-Poor Stars with the Subaru High Dispersion Spectrograph. III. Light Neutron-Capture Elements
• 'Sculptor'-ing the Galaxy? The Chemical Compositions of Red Giants in the Sculptor Dwarf Spheroidal Galaxy
• Binarity in Carbon-Enhanced Metal-Poor stars
• The Star Formation & Chemical Evolution History of the Sculptor Dwarf Spheroidal Galaxy
• Line lists for the A2PI-X2Sigma+ (red) and {B2Sigma+-X2Sigma} (violet) Systems of CN, 13C14N, and 12C15N, and Application to Astronomical Spectra
• Linking dwarf galaxies to halo building blocks with the most metal-poor star in Sculptor
• First Stars II. Elemental abundances in the extremely metal-poor star CS 22949--037: A diagnostic of early massive supernovae
• First stars IX -Mixing in extremely metal-poor giants. Variation of the 12C/13C, [Na/Mg] and [Al/Mg] ratios
• Carbon-enhanced Metal-poor Stars in SDSS/SEGUE. I. Carbon Abundance Estimation and Frequency of CEMP Stars
• Extremely metal-poor stars in classical dwarf spheroidal galaxies: Fornax, Sculptor and Sextans
• Multi-Element Abundance Measurements from Medium-Resolution Spectra. I. The Sculptor Dwarf Spheroidal Galaxy
• Neutron-capture elements in the very metal-poor star HD88609: another st ar with excesses of light neutron-capture elements
• Abundances of Cu and Zn in metal-poor stars: clues for Galaxy evolution
• NLTE determination of the aluminium abundance in a homogeneous sample of extremely metal-poor stars
• NLTE determination of the sodium abundance in a homogeneous sample of extremely metal-poor stars
• New Extremely Metal-Poor Stars in the Galactic Halo
• Ultra faint dwarfs: probing early cosmic star formation
• The Chemical Composition of Carbon-Rich, Very Metal-Poor Stars: A New Class of Mildly Carbon-Rich Objects Without Excess of Neutron-Capture Elements
• Carbon Stars in the Hamburg/ESO Survey: Abundances
• Uncovering the Chemical Signature of the First Stars in the Universe
• Non-LTE abundances of Mg and K in extremely metal-poor stars and the evolution of [O/Mg], [Na/Mg], [Al/Mg] and [K/Mg] in the Milky Way
• First stars X. The nature of three unevolved Carbon-Enhanced Metal-Poor stars
• Chemical Composition of the Carbon-rich, Extremely Metal-Poor Star CS 29498--043: A New Class of Extremely Metal-Poor Stars with Excesses of Magnesium and Silicon
• The Araucaria Project. The Distance to the Sculptor dwarf spheroidal galaxy from infrared photometry of RR Lyrae stars
• The extremely low-metallicity tail of the Sculptor dwarf spheroidal galaxy
• The [Fe/H], [C/Fe], and [alpha/Fe] distributions of the Bootes I Dwarf Spheroidal Galaxy
• Decoding the stellar fossils of the dusty Milky Way progenitors
• The r-process in the early Galaxy
• Elemental abundances and classification of CEMP stars
• Carbon-Enhanced Metal-Poor Stars: Relics from the Dark Ages
• Explaining the Ba, Y, Sr, and Eu abundance scatter in metal-poor halo stars: constraints to the r-process
• Detailed Abundances of Two Very Metal-Poor Stars in Dwarf Galaxies
• Enrichment history of r-process elements shaped by a merger of neutron star pairs
• Oxygen Overabundance in the Extremely Iron-Poor Star CS29498-043
• Deep Wide-Field Imaging down to the oldest Main Sequence Turnoffs in the Sculptor dwarf spheroidal galaxy
• First Stars XIV. Sulfur abundances in extremely metal-poor (EMP) stars
• First stars in Damped Lyman Alpha systems
• Enrichment of Heavy Elements in the red giant S15-19 in the Sextans Dwarf Spheroidal Galaxy
• Chemical Compositions of Four Metal-poor Giants
• Near-infrared spectroscopy of AGB star candidates in Fornax, Sculptor and NGC 6822

Cited by in corpus (66)

• The Pristine survey I: Mining the Galaxy for the most metal-poor stars
• TOPoS: II. On the bimodality of carbon abundance in CEMP stars. Implications on the early chemical evolution of galaxies
• Carbon, oxygen, and iron abundances in disk and halo stars. Implications of 3D non-LTE spectral line formation
• JINAbase: A database for chemical abundances of metal-poor stars
• An R-process enhanced star in the dwarf galaxy Tucana III
• Descendants of the first stars: the distinct chemical signature of second generation stars
• VLT/FLAMES high-resolution chemical abundances in Sculptor: a textbook dwarf spheroidal galaxy
• The Impact of Modeling Assumptions in Galactic Chemical Evolution Models
• Limits on Pop III star formation with the most iron-poor stars
• Chemical Abundances in the Ultra-Faint Dwarf Galaxies Grus I and Triangulum II: Neutron-Capture Elements as a Defining Feature of the Faintest Dwarfs
• Carbon-enhanced metal-poor stars in dwarf galaxies
• Stellar Abundances for Galactic Archaeology Database IV - Compilation of Stars in Dwarf Galaxies
• The Southern Stellar Stream Spectroscopic Survey (S5): Chemical Abundances of Seven Stellar Streams
• The oldest and most metal poor stars in the APOSTLE Local Group simulations
• The early days of the Sculptor dwarf spheroidal galaxy
• Carbon in Red Giants in Globular Clusters and Dwarf Spheroidal Galaxies
• The formation of the Milky Way halo and its dwarf satellites; a NLTE-1D abundance analysis. II. Early chemical enrichment
• Magnetorotational supernovae: A nucleosynthetic analysis of sophisticated 3D models
• Detailed Abundances in the Ultra-faint Magellanic Satellites Carina II and III
• From actinides to zinc: Using the full abundance pattern of the brightest star in Reticulum II to distinguish between different r-process sites
• Chemical Signatures of the First Supernovae in the Sculptor Dwarf Spheroidal Galaxy
• Variable stars in Local Group Galaxies - II. Sculptor dSph
• Abundances and kinematics of carbon-enhanced metal-poor stars in the Galactic halo*; A new classification scheme based on Sr and Ba
• Zero-metallicity hypernova uncovered by an ultra metal-poor star in the Sculptor dwarf spheroidal galaxy
• The Pristine survey III: Spectroscopic confirmation of an efficient search for extremely metal-poor stars
• Ultra-faint dwarf galaxies: unveiling the minimum mass of the first stars
• Zinc in the Sculptor dwarf spheroidal galaxy
• The evolution of CNO elements in galaxies
• Chemical abundances of damped Lyman alpha systems in the XQ-100 survey
• Detection of a population of carbon-enhanced metal-poor stars in the Sculptor dwarf spheroidal galaxy
• The Origin of r-process Enhanced Metal-Poor Halo Stars In Now-Destroyed Ultra-Faint Dwarf Galaxies
• Probing the early chemical evolution of the Sculptor dSph with purely old stellar tracers
• Enrichment of Zinc in galactic chemodynamical evolution models
• A CEMP-no star in the ultra-faint dwarf galaxy Pisces II
• The S2 Stream: the shreds of a primitive dwarf galaxy
• Origin of the CEMP-no Group Morphology in the Milky Way
• Spectroscopic study of CEMP-(s & r/s) stars- Revisiting classification criteria and formation scenarios, highlighting i-process nucleosynthesis
• Detailed chemical abundances of stars in the outskirts of the Tucana II ultra-faint dwarf galaxy
• The Pristine Inner Galaxy Survey (PIGS) III: carbon-enhanced metal-poor stars in the bulge
• The R-Process Alliance: J1521-3538, a very metal-poor, extremely r-process-enhanced star with [Eu/Fe]=+2.2, and the class of r-III stars
• Tracing Pop III supernovae with extreme energies through the Sculptor dwarf spheroidal galaxy
• Carbon and nitrogen abundances of individual stars in the Sculptor dwarf spheroidal galaxy
• Carbon-Enhanced Metal-Poor star candidates from BP/RP Spectra in $Gaia$ DR3
• Neutron-capture elements in dwarf galaxies II: Challenges for the s- and i-processes at low metallicity
• Identification of a Group III CEMP-no Star in the Dwarf Spheroidal Galaxy Canes Venatici I
• Sulphur in the Sculptor dwarf spheroidal galaxy - Including NLTE corrections
• Unusual neutron-capture nucleosynthesis in a carbon-rich Galactic bulge star
• The energy distribution of the first supernovae
• A 3D view of dwarf galaxies with Gaia and VLT/FLAMES I. The Sculptor dwarf spheroidal
• Abundance analysis of a CEMP-no star in the Carina dwarf spheroidal galaxy
• The chemical connection between damped Lyman-α systems and Local Group dwarf galaxies
• Extremely metal-poor stars in the Fornax and Carina dwarf spheroidal galaxies
• Extending the Chemical Reach of the H3 Survey: Detailed Abundances of the Dwarf-galaxy Stellar Stream Wukong/LMS-1
• Homogeneity in the early chemical evolution of the Sextans dwarf Spheroidal galaxy
• Evidence for multiple nucleosynthetic processes from carbon enhanced metal-poor stars in the Carina dwarf spheroidal galaxy
• A chemical signature from fast-rotating low-metallicity massive stars: ROA 276 in omega Centauri
• On the dearth of C-enhanced metal-poor stars in the Galactic bulge
• The Occurrence and Impact of Carbon-Oxygen Shell Mergers in Massive Stars
• The Pristine Inner Galaxy Survey (PIGS) X. Probing the early chemical evolution of the Sagittarius dwarf galaxy with carbon abundances
• Scl-1013644: a CEMP-s star in the Sculptor Dwarf Spheroidal Galaxy
• Carbon-enhanced metal-poor stars in the SDSS-APOGEE database
• Probing the nucleosynthetic contribution of low-metallicity, low-mass star companions of CEMP stars
• Carbon-enhanced metal-poor stars in different environments
• The impact of rare events on the chemical enrichment in dwarf galaxies
• Four-hundred Very Metal-poor Stars Studied with LAMOST and Subaru. IV. Heavy Element Enhanced Stars
• Carbon measurements in two ultra-faint dwarf galaxies: Grus II and Tucana IV