Stellar substructures in the solar neighbourhood IV. Kinematic Group 1 in the Geneva-Copenhagen survey

Abstract

We determine detailed elemental abundances in stars belonging to the so-called Group 1 of the Geneva-Copenhagen survey (GCS) and compare the chemical composition with the Galactic thin- and thick-disc stars, with the GCS Group 2 and Group 3 stars, as well as with several kinematic streams of similar metallicities. The aim is to search for chemical signatures that might give information about the formation history of this kinematic group of stars. High-resolution spectra were obtained with the Fibre-fed Echelle Spectrograph (FIES) spectrograph at the Nordic Optical Telescope, La Palma, and were analysed with a differential model atmosphere method. Comparison stars were observed and analysed with the same method. The average value of [Fe/H] for the 37 stars of Group 1 is -0.20 +- 0.14 dex. Investigated Group 1 stars can be separated into three age subgroups. Along with the main 8- and 12-Gyr-old populations, a subgroup of stars younger than 5 Gyr can be separated as well. Abundances of oxygen, alpha-elements, and r-process dominated elements are higher than in Galactic thin-disc dwarfs. This elemental abundance pattern has similar characteristics to that of the Galactic thick disc and differs slightly from those in Hercules, Arcturus, and AF06 stellar streams. The similar chemical composition of stars in Group 1, as well as in Group 2 and 3, with that in stars of the thick disc might suggest that their formation histories are linked. The chemical composition pattern together with the kinematic properties and ages of stars in the investigated GCS groups provide evidence of their common origin and possible relation to an ancient merging event. A gas-rich satellite merger scenario is proposed as the most likely origin.

arXiv comment17 pages, 13 figures, accepted for publication in Astronomy & Astrophysics, 2015

References in corpus (99)

• PARSEC: stellar tracks and isochrones with the PAdova and TRieste Stellar Evolution Code
• A grid of MARCS model atmospheres for late-type stars I. Methods and general properties
• The Geneva-Copenhagen survey of the Solar neighbourhood: Ages, metallicities, and kinematic properties of 14,000 F and G dwarfs
• Star Formation Histories, Abundances and Kinematics of Dwarf Galaxies in the Local Group
• SEGUE: A Spectroscopic Survey of 240,000 stars with g=14-20
• Exploring the Milky Way stellar disk. A detailed elemental abundance study of 714 F and G dwarf stars in the Solar neighbourhood
• GAIA: Composition, Formation and Evolution of the Galaxy
• Tracing Galaxy Formation with Stellar Halos I: Methods
• The Radial Velocity Experiment (RAVE): first data release
• The Field of Streams: Sagittarius and its Siblings
• Elemental Abundance Survey of The Galactic Thick Disk
• New constraints on the chemical evolution of the solar neighbourhood and Galactic disc(s). Improved astrophysical parameters for the Geneva-Copenhagen Survey
• The Chemical Compositions of Galactic Disk F and G Dwarfs
• alpha-, r-, and s-process element trends in the Galactic thin and thick disks
• The remnants of galaxy formation from a panoramic survey of the region around M31
• A giant stream of metal-rich stars in the halo of the galaxy M31
• The Geneva-Copenhagen Survey of the Solar neighbourhood III. Improved distances, ages, and kinematics
• The age structure of stellar populations in the solar vicinity. Clues of a two-phase formation history of the Milky Way disk
• The Effect of the Outer Lindblad Resonance of the Galactic Bar on the Local Stellar Velocity Distribution
• Local kinematics of K and M giants from Coravel/Hipparcos/Tycho-2 data. Revisiting the concept of superclusters
• The Galactic Thick Disk Stellar Abundances
• A Low Latitude Halo Stream around the Milky Way
• The Emergence of the Thick Disk in a CDM Universe
• Beyond Inside-Out Growth: Formation and Evolution of Disk Outskirts
• Stellar Iron Abundances: non-LTE Effects
• Origin and structure of the Galactic disc(s)
• A 2MASS All-Sky View of the Sagittarius Dwarf Galaxy: IV. Modeling the Sagittarius Tidal Tails
• Multi-Element Abundance Measurements from Medium-Resolution Spectra. III. Metallicity Distributions of Milky Way Dwarf Satellite Galaxies
• Cold Dark Matter Substructure and Galactic Disks I: Morphological Signatures of Hierarchical Satellite Accretion
• Uncovering Extremely Metal-Poor Stars in the Milky Way's Ultra-Faint Dwarf Spheroidal Satellite Galaxies
• High-Resolution Spectroscopy of Extremely Metal-Poor Stars in the Least Evolved Galaxies: Ursa Major II and Coma Berenices
• Galaxy Disks
• The Radial Velocity Experiment (RAVE): second data release
• One Ring to Encompass them All: A giant stellar structure that surrounds the Galaxy
• Chemodynamical evolution of the Milky Way disk II: Variations with Galactic radius and height above the disk plane
• Lambda-Cold Dark Matter, Stellar Feedback, and the Galactic Halo Abundance Pattern
• Velocity trends in the debris of Sagittarius and the shape of the dark-matter halo of the Galaxy
• Chemical Abundance Distributions of Galactic Halos and their Satellite Systems in a Lambda CDM Universe
• Chemodynamics of the Milky Way. I. The first year of APOGEE data
• Segue 2: A Prototype of the Population of Satellites of Satellites
• Order and chaos in the local disc stellar kinematics induced by the Galactic bar
• The Gaia-ESO Survey: radial metallicity gradients and age-metallicity relation of stars in the Milky Way disk
• A comprehensive model for the Monoceros tidal stream
• The Merging History of the Milky Way
• Pieces of the puzzle: Ancient substructure in the Galactic disk
• Deciphering The Last Major Invasion of the Milky Way Galaxy
• Abundance trends in kinematical groups of the Milky Way's disk
• Constraining the thick disc formation scenario of the Milky Way
• Extremely metal-poor stars in classical dwarf spheroidal galaxies: Fornax, Sculptor and Sextans
• The ghost of a dwarf galaxy: fossils of the hierarchical formation of the nearby spiral galaxy NGC 5907
• Experimental f-value and isotopic structure for the Ni I line blended with [OI] at 6300A
• The dominant epoch of star formation in the Milky Way formed the thick disc
• The Stellar Populations of the Carina Dwarf Spheroidal Galaxy: I. a New Color-Magnitude Diagram for the Giant and Horizontal Branches
• Is the Milky Way ringing? The hunt for high velocity streams
• Constraints on the Galactic Bar from the Hercules stream as traced with RAVE across the Galaxy
• Disentangling the Hercules stream
• Phase-Space Distributions of Chemical Abundances in Milky Way-type Galaxy Halos
• The Gaia-ESO Survey: the chemical structure of the Galactic discs from the first internal data release
• The orbits of open clusters in the Galaxy
• Origin and evolution of moving groups I. Characterization in the observational kinematic-age-metallicity space
• Chemical Abundances and Kinematics in Globular Clusters and Local Group Dwarf Galaxies and Their Implications for Formation Theories of the Galactic Halo
• The Extragalactic Origin of the Arcturus Group
• The Emergence of the Thick Disk in a CDM Universe II: Colors and Abundance Patterns
• Abundances of neutron-capture elements in stars of the galactic disk substructures
• Galactic Archaeology. The dwarfs that survived and perished
• Orbital Eccentricity as a probe of Thick Disk Formation Scenarios
• 3D kinematics of white dwarfs from the SPY project
• Kinematics of the Outer Stellar Halo
• Chaos caused by resonance overlap in the solar neighborhood -- Spiral structure at the Bar's 2:1 outer Lindblad resonance
• Halo streams in the 7th SDSS data release
• Identifying stellar streams in the 1st RAVE public data release
• In the thick of it: metal-poor disc stars in RAVE
• Further Evidence for a Merger Origin for the Thick Disk: Galactic Stars Along Lines-of-sight to Dwarf Spheroidal Galaxies
• Signatures of minor mergers in Milky Way-like disc kinematics: Ringing revisited
• Fine structure in the phase space distribution of nearby subdwarfs
• Kinematic groups beyond the Solar neighbourhood with RAVE
• Is Ursa Major II the Progenitor of the Orphan Stream?
• Analysis of old very metal rich stars in the solar neighbourhood
• A Comparison of the Chemical Evolutionary Histories of the Galactic Thin Disk and Thick Disk Stellar Populations
• Searching for the metal-weak thick disc in the solar neighbourhood
• Testing formation mechanisms of the Milky Way's thick disc with RAVE
• Why the Canis Major overdensity is not due to the Warp: analysis of its radial profile and velocities
• Simulations of minor mergers. II. The phase-space structure of thick discs
• Stellar halo streams in the Solar neighbourhood
• The formation of a thick disk through the heating of a thin disk: Agreement with orbital eccentricities of stars in the solar neighborhood
• Europium abundances in F and G disk dwarfs
• Probing the Galaxy's bars via the Hercules stream
• The Chemical Evolution of the Milky Way: the Three Infall Model
• Observational Evidence from SDSS for a Merger Origin of the Milky Way's Thick Disk
• Through thick and thin: Structure of the Galactic thick disc from extragalactic surveys
• Chemical compositions of stars in two stellar streams from the Galactic thick disk
• Analysis of Peculiarities of the Stellar Velocity Field in the Solar Neighborhood
• Signatures of star streams in the phase space distribution of nearby halo stars
• Classification of field dwarfs and giants in RAVE and its use in stellar stream detection
• Analysis of the Velocity Field of F and G Dwarfs in the Solar Neighborhood as a Function of Age
• Stellar substructures in the solar neighbourhood. I. Kinematic group 3 in the Geneva-Copenhagen survey
• More pieces of the puzzle: Chemistry and substructures in the Galactic thick disk
• Stellar substructures in the solar neighbourhood. III. Kinematic group 2 in the Geneva-Copenhagen survey
• Stellar substructures in the solar neighbourhood. II. Abundances of neutron-capture elements in the kinematic Group 3 of the Geneva-Copenhagen survey

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