Enrichment by Extragalactic First Stars in the Large Magellanic Cloud

Abstract

The Large Magellanic Cloud (LMC) is the Milky Way's most massive satellite galaxy, which only recently (~2 billion years ago) fell into our Galaxy. Since stellar atmospheres preserve their natal cloud's composition, the LMC's recent infall makes its most ancient, metal-deficient ("low-metallicity") stars unique windows into early star formation and nucleosynthesis in a formerly distant region of the high-redshift universe. Previously, identifying such stars in the LMC was challenging. But new techniques have opened this window, now enabling tests of whether the earliest element enrichment and star formation in distant, extragalactic proto-galaxies deviated from what occurred in the proto-Milky Way. Here we present the elemental abundances of 10 stars in the LMC with iron-to-hydrogen ratios ranging from ~1/300th to ~1/12,000th of the Sun. Our most metal-deficient star is 50 times more metal-deficient than any in the LMC with available detailed chemical abundance patterns, and is likely enriched by a single extragalactic first star supernova. This star lacks significant carbon-enhancement, as does our overall sample, in contrast with the lowest metallicity Milky Way stars. This, and other abundance differences, affirm that the extragalactic early LMC experienced diverging enrichment processes compared to the early Milky Way. Early element production, driven by the earliest stars, thus appears to proceed in an environment-dependent manner.

arXiv commentThe final version of this paper has been published in Nature Astronomy on March 20, 2024 at https://www.nature.com/articles/s41550-024-02223-w. Free read-only access at https://rdcu.be/dBRPn. The arxiv version is the submitted manuscript, but we note arXiv:2312.12793

References in corpus (64)

• Maps of Dust IR Emission for Use in Estimation of Reddening and CMBR Foregrounds
• Gaia Data Release 3: Summary of the content and survey properties
• A grid of MARCS model atmospheres for late-type stars I. Methods and general properties
• The Dartmouth Stellar Evolution Database
• First stars V - Abundance patterns from C to Zn and supernova yields in the early Galaxy
• Nucleosynthesis Yields of Core-Collapse Supernovae and Hypernovae, and Galactic Chemical Evolution
• Nucleosynthesis and Evolution of Massive Metal-Free Stars
• Are the Magellanic Clouds on their First Passage about the Milky Way?
• SkyMapper and the Southern Sky Survey
• Near-Field Cosmology with Metal-Poor Stars
• Third-Epoch Magellanic Cloud Proper Motions I: HST/WFC3 data and Orbit Implications
• The Stellar Abundances for Galactic Archeology (SAGA) Database - Compilation of the Characteristics of Known Extremely Metal-Poor Stars
• An extremely primitive halo star
• 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 Abundances of Neutron Capture Species in the Very Metal-Poor Globular Cluster M15: An Uniform Analysis of RGB and RHB Stars
• CH in stellar atmospheres: an extensive linelist
• Tango for three: Sagittarius, LMC, and the Milky Way
• The Pristine survey I: Mining the Galaxy for the most metal-poor stars
• Observational Constraints on First-Star Nucleosynthesis. I. Evidence for Multiple Progenitors of CEMP-no Stars
• Complete element abundances of nine stars in the r-process galaxy Reticulum II
• Star formation, supernovae, iron, and alpha: consistent cosmic and Galactic histories
• Line lists for the A2PI-X2Sigma+ (red) and {B2Sigma+-X2Sigma} (violet) Systems of CN, 13C14N, and 12C15N, and Application to Astronomical Spectra
• The $R$-Process Alliance: First Release from the Southern Search for $r$-Process-Enhanced Stars in the Galactic Halo
• Line strengths and updated molecular constants for the C2 Swan system
• The R-Process Alliance: First Release from the Northern Search for r-Process Enhanced Metal-Poor Stars in the Galactic Halo
• The First Population II Stars Formed in Externally Enriched Mini-halos
• A Population of Accreted SMC Stars in the LMC
• Connecting the first galaxies with ultra faint dwarfs in the Local Group: chemical signatures of Population~III stars
• Chemical abundances in LMC stellar populations. II. The bar sample
• A Review of the Distance and Structure of the Large Magellanic Cloud
• The Chemical Evolution of the Ursa Minor Dwarf Spheroidal Galaxy
• Deriving Stellar Effective Temperatures of Metal-Poor Stars with the Excitation Potential Method
• The Lazy Giants: APOGEE Abundances Reveal Low Star Formation Efficiencies in the Magellanic Clouds
• Extremely metal-poor stars from the cosmic dawn in the bulge of the Milky Way
• VLT/FLAMES high-resolution chemical abundances in Sculptor: a textbook dwarf spheroidal galaxy
• Measuring the Mass of the Large Magellanic Cloud with Stellar Streams Observed by $S^5$
• The Caterpillar Project: A Large Suite of Milky Way Sized Halos
• All-Sky Dynamical Response of the Galactic Halo to the Large Magellanic Cloud
• The $R$-Process Alliance: Fourth Data Release from the Search for $r$-Process-Enhanced Stars in the Galactic Halo
• Chemical Abundances in the Ultra-Faint Dwarf Galaxies Grus I and Triangulum II: Neutron-Capture Elements as a Defining Feature of the Faintest Dwarfs
• $S^5$: Probing the Milky Way and Magellanic Clouds potentials with the 6-D map of the Orphan-Chenab stream
• Gaia Data Release 3: The Galaxy in your preferred colours. Synthetic photometry from Gaia low-resolution spectra
• The R-process Alliance: First Magellan/MIKE Release from the Southern Search for R-Process-enhanced Stars
• The Southern Stellar Stream Spectroscopic Survey (S5): Chemical Abundances of Seven Stellar Streams
• The first stars: CEMP--no stars and signatures of spinstars
• Preserving chemical signatures of primordial star formation in the first low-mass stars
• Predicting the locations of possible long-lived low-mass first stars: Importance of satellite dwarf galaxies
• Detailed Abundances in the Ultra-faint Magellanic Satellites Carina II and III
• The SkyMapper DR1.1 Search for Extremely Metal-Poor Stars
• Tracing the first stars and galaxies of the Milky Way
• The Atari Disk, a Metal-Poor Stellar Population in the Disk System of the Milky Way
• 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
• Stellar Metallicities from SkyMapper Photometry II: Precise photometric metallicities of $\sim$280,000 giant stars with [Fe/H] $<-0.75$ in the Milky Way
• SPLUSJ210428.01-004934.2: An Ultra Metal-Poor Star Identified from Narrowband Photometry
• Stellar metallicities from SkyMapper photometry I: A study of the Tucana II ultra-faint dwarf galaxy
• 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 chemical abundance pattern of the extremely metal-poor thin disk star 2MASS J1808-5104 and its origins
• Tracing Pop III supernovae with extreme energies through the Sculptor dwarf spheroidal galaxy
• Discovery of 18 stars with -3.10 < [Fe/H] < -1.45 in the Sagittarius dwarf galaxy
• Formation and fate of low metallicity stars in IllustrisTNG50
• The SkyMapper search for extremely metal-poor stars in the Large Magellanic Cloud

Cited by in corpus (8)

• Discovery of an $[Fe/H]\sim -4.8$ Star in $Gaia$ XP Spectra
• The Pristine Inner Galaxy Survey (PIGS) X. Probing the early chemical evolution of the Sagittarius dwarf galaxy with carbon abundances
• Mapping the Distant and Metal-Poor Milky Way with SDSS-V
• A second-generation star in a relic dwarf galaxy
• Cosmological insights into the early accretion of r-process-enhanced stars II. Dynamical identification of lost members of Reticulum II
• The chemical DNA of the Magellanic Clouds V. R-process dominates neutron capture elements production in the oldest SMC stars
• HE0144-4657: A Carbon-Enhanced Ultra Metal-Poor Star ([Fe/H] ~ -4.1) from the Helmi Stream Disrupted Dwarf Galaxy
• The metal-poor tail of the APOGEE survey I. Uncovering [Fe/H] < -2.5 stars from the inner Galaxy to the Magellanic Clouds