An R-process enhanced star in the dwarf galaxy Tucana III

Abstract

Chemically peculiar stars in dwarf galaxies provide a window for exploring the birth environment of stars with varying chemical enrichment. We present a chemical abundance analysis of the brightest star in the newly discovered ultra-faint dwarf galaxy candidate Tucana III. Because it is particularly bright for a star in an ultra-faint Milky Way satellite, we are able to measure the abundance of 28 elements, including 13 neutron-capture species. This star, DES J235532.66$-$593114.9 (DES J235532), shows a mild enhancement in neutron-capture elements associated with the $r$-process and can be classified as an $r$-I star. DES J235532 is the first $r$-I star to be discovered in an ultra-faint satellite, and Tuc III is the second extremely low-luminosity system found to contain $r$-process enriched material, after Reticulum II. Comparison of the abundance pattern of DES J235532 with $r$-I and $r$-II stars found in other dwarf galaxies and in the Milky Way halo suggests a common astrophysical origin for the neutron-capture elements seen in all $r$-process enhanced stars. We explore both internal and external scenarios for the $r$-process enrichment of Tuc III and show that with abundance patterns for additional stars it should be possible to distinguish between them.

12 pages, 5 figures. Accepted for publication in ApJ

References in corpus (22)

• The Dartmouth Stellar Evolution Database
• Magnetorotationally driven Supernovae as the origin of early galaxy $r$-process elements?
• Beasts of the Southern Wild: Discovery of nine Ultra Faint satellites in the vicinity of the Magellanic Clouds
• Carbon Enhanced Metal-Poor Stars. I. Chemical Compositions of 26 Stars
• A Search for Stars of Very Low Metal Abundance. VI. Detailed Abundances of 313 Metal-Poor Stars
• The Tidal Evolution of Local Group Dwarf Spheroidals
• Carbon-Enhanced Metal-Poor Star Frequencies in the Galaxy: Corrections for the Effect of Evolutionary Status on Carbon Abundances
• CH in stellar atmospheres: an extensive linelist
• Nucleosynthesis-relevant conditions in neutrino-driven supernova outflows. I. Spherically symmetric hydrodynamic simulations
• A high resolution VLT/FLAMES study of individual stars in the centre of the Fornax dwarf spheroidal galaxy
• The Chemical Evolution of the Draco Dwarf Spheroidal Galaxy
• Complete element abundances of nine stars in the r-process galaxy Reticulum II
• VLT/FLAMES spectroscopy of red giant branch stars in the Fornax dwarf spheroidal galaxy
• The first carbon-enhanced metal-poor star found in the Sculptor dwarf spheroidal
• Nucleosynthesis in Magnetically Driven Jets from Collapsars
• Detailed Abundances of Two Very Metal-Poor Stars in Dwarf Galaxies
• High-resolution abundance analysis of very metal-poor r-I stars
• Nine New Metal-Poor Stars on the Subgiant and Red Horizontal Branches with High Levels of r-process Enhancement
• Enrichment history of r-process elements shaped by a merger of neutron star pairs
• Chemical Signatures of the First Supernovae in the Sculptor Dwarf Spheroidal Galaxy
• Contribution of Neutron Star Mergers to the R-process Chemical Evolution in the Hierarchical Galaxy Formation
• Chemical Feature of Eu abundance in the Draco dwarf spheroidal galaxy

Cited by in corpus (49)

• Proper Motions, Orbits, and Tidal Influences of Milky Way Dwarf Spheroidal Galaxies
• Post-merger Mass Ejection of Low-mass Binary Neutron Stars
• Revised and new proper motions for confirmed and candidate Milky Way dwarf galaxies
• Magnetorotational supernovae: A nucleosynthetic analysis of sophisticated 3D models
• Galactic Archaeology with Gaia
• RAVE J203843.2-002333: The first highly r-process-enhanced star identified in the RAVE survey
• A deep survey of short GRB host galaxies over $z\sim 0-2$: implications for offsets, redshifts, and environments
• Detailed Abundances in the Ultra-faint Magellanic Satellites Carina II and III
• Dynamically Tagged Groups of Very Metal-poor Halo Stars from the HK and Hamburg/ESO Surveys
• A stellar stream remnant of a globular cluster below the metallicity floor
• Simulating Neutron Star Mergers as r-process Sources in Ultra Faint Dwarf Galaxies
• Chemical Abundance Analysis of Three $\alpha$-Poor, Metal-Poor Stars in the Ultra-Faint Dwarf Galaxy Horologium I
• Enrichment in r-process elements from multiple distinct events in the early Draco dwarf spheroidal galaxy
• Double Neutron Star Formation: Merger Times, Systemic Velocities, and Travel Distances
• The Most Metal-poor Stars in the Magellanic Clouds are $r$-process Enhanced
• Evidence for the accretion origin of halo stars with an extreme r-process enhancement
• The Pristine survey -- XII: Gemini-GRACES chemo-dynamical study of newly discovered extremely metal-poor stars in the Galaxy
• The R-Process Alliance: The Peculiar Chemical Abundance Pattern of RAVE J183013.5-455510
• The Cosmic Hunt for Members in the Outskirts of Ultra Faint Dwarf Galaxies: Ursa Major I, Coma Berenices, and Boötes I
• Neutron star mergers as the astrophysical site of the r-process in the Milky Way and its satellite galaxies
• Dark matter halo cores and the tidal survival of Milky Way satellites
• Chemical Analysis of the Ultra-Faint Dwarf Galaxy Grus~II. Signature of high-mass stellar nucleosynthesis
• Detailed chemical abundances of stars in the outskirts of the Tucana II ultra-faint dwarf galaxy
• The R-Process Alliance: Abundance Universality among Some Elements at and between the First and Second R-Process Peaks
• Timing the r-Process Enrichment of the Ultra-Faint Dwarf Galaxy Reticulum II
• Origin of highly $r$-process-enhanced stars in a cosmological zoom-in simulation of a Milky Way-like galaxy
• Chemical Complexity in the Eu-enhanced Monometallic Globular Cluster NGC 5986
• How much metals did the first stars provide to the ultra-faint dwarfs?
• R-process-rich stellar streams in the Milky Way
• $r$-process nucleosynthesis from compact binary mergers
• Ursa Major III/UNIONS 1: the darkest galaxy ever discovered?
• Highly r-process enhanced stars in ultra-faint dwarf galaxies
• Possibilities and Limitations of Kinematically Identifying Stars from Accreted Ultra-Faint Dwarf Galaxies
• The SAMI-Fornax Dwarfs Survey III: Evolution of [$\alpha$/Fe] in dwarfs, from Galaxy Clusters to the Local Group
• Extremely metal-poor stars in the Fornax and Carina dwarf spheroidal galaxies
• $S^5$: The destruction of a bright dwarf galaxy as revealed by the chemistry of the Indus stellar stream
• The Pristine Inner Galaxy Survey (PIGS) X. Probing the early chemical evolution of the Sagittarius dwarf galaxy with carbon abundances
• Chemical evolution of ultra-faint dwarf galaxies: testing the IGIMF
• The formation of the Milky Way halo and its dwarf satellites: a NLTE-1D abundance analysis. IV. Segue 1, Triangulum II, and Coma Berenices UFDs
• Metal-Poor Stars Observed with the Southern African Large Telescope II. An Extended Sample
• Empirical Constraints on Core Collapse Supernova Yields using Very Metal Poor Damped Lyman Alpha Absorbers
• A Nuclear Equation of State Inferred from Stellar r-process Abundances
• A second-generation star in a relic dwarf galaxy
• Understanding Stellar Mass-Metallicity and Size Relations in Simulated Ultra-Faint Dwarf Galaxies
• Cosmological insights into the early accretion of r-process-enhanced stars II. Dynamical identification of lost members of Reticulum II
• The impact of rare events on the chemical enrichment in dwarf galaxies
• An Alternative Formation Scenario for Uranium-rich Giants: Engulfing a Earth-like Planet
• Mantle Degassing Lifetimes through Galactic Time and the Maximum Age Stagnant-lid Rocky Exoplanets can Support Temperate Climates
• An ancient system hidden in the Galactic plane?