The Galactic Stellar Disc

Abstract

The study of the Milky Way stellar discs in the context of galaxy formation is discussed. In particular we explore the properties of the Milky Way disc using a new sample of about 550 dwarf stars for which we have recently obtained elemental abundances and ages based on high resolution spectroscopy. For all the stars we also have full kinematic information as well as information about their stellar orbits. We confirm results from previous studies that the thin and the thick disc have distinct abundance patterns. But we also explore a larger range of orbital parameters than what has been possible in our previous studies. Several new results are presented. We find that stars that reaches high above the galactic plane and have eccentric orbits show remarkably tight abundance trends. This implies that these stars formed out of well mixed gas that had been homogenized over large volumes. We find some evidence that point to that the event that most likely caused the heating of this stellar population happened a few billion years ago. Through a simple, kinematic exploration of stars with super-solar [Fe/H] we show that the solar neighbourhood contains metal-rich, high velocity stars that very likely are associated with the thick disc. Additionally, the HR1614 moving group and the Hercules and Arcturus stellar streams are discussed and it is concluded that, probably, a large fraction of the so far identified groups and streams in the disc are the result of evolution and interactions within the stellar disc rather than being dissolved stellar clusters or engulfed dwarf galaxies.

20 pages, Review talk at the conference "A stellar journey", A symposium in celebration of Bengt Gustafsson's 65th birthday, held in Uppsala, June 2008, In press in Physica Scripta, eds. Paul Barklem, Andreas Korn, and Bertrand Plez

References in corpus (31)

• The Geneva-Copenhagen survey of the Solar neighbourhood: Ages, metallicities, and kinematic properties of 14,000 F and G dwarfs
• The New Galaxy: Signatures of its Formation
• Radial Mixing in Galactic Discs
• Elemental Abundance Survey of The Galactic Thick Disk
• Clumps and streams in the local dark matter distribution
• The large-scale structure of the Universe
• Stellar Chemical Signatures And Hierarchical Galaxy Formation
• The Chemical Compositions of Galactic Disk F and G Dwarfs
• Local kinematics of K and M giants from Coravel/Hipparcos/Tycho-2 data. Revisiting the concept of superclusters
• The Geneva-Copenhagen Survey of the Solar neighbourhood II. New uvby calibrations and rediscussion of stellar ages, the G dwarf problem, age-metallicity diagram, and heating mechanisms of the disk
• The YY Isochrones for alpha-element Enhanced Mixtures
• The Distribution of Nearby Stars in Velocity Space Inferred from Hipparcos Data
• Structural Parameters of Thin and Thick Disks in Edge-On Disk Galaxies
• Thin, thick and dark discs in LCDM
• Kinemetry of SINS High-Redshift Star-Forming Galaxies: Distinguishing Rotating Disks from Major Mergers
• O/Fe in metal-poor main sequence and subgiant stars
• Oxygen trends in the Galactic thin and thick disks
• Evidence for Solar Metallicities in Massive Star-forming Galaxies at z>~2
• Abundance trends in kinematical groups of the Milky Way's disk
• Tracing the Galactic thick disk to Solar metallicities
• Abundances for metal-poor stars with accurate parallaxes II. alpha-elements in the halo
• Disentangling the Hercules stream
• Origin and evolution of moving groups I. Characterization in the observational kinematic-age-metallicity space
• Chemically Tagging the HR1614 Moving Group
• The Radical Consequences of Realistic Satellite Orbits for the Heating and Implied Merger Histories of Galactic Disks
• Simulations of the heating of the Galactic stellar disc
• Lick Indices in the Thin and Thick Disks of Edge-On Disk Galaxies
• Fine structure in the phase space distribution of nearby subdwarfs
• A Disk Galaxy of Old Stars at z ~ 2.5
• Chemical evolution of the Milky Way and its Satellites
• Clues to Radial Migration from the Properties of Outer Disks

Cited by in corpus (19)

• Exploring the Milky Way stellar disk. A detailed elemental abundance study of 714 F and G dwarf stars in the Solar neighbourhood
• New constraints on the chemical evolution of the solar neighbourhood and Galactic disc(s). Improved astrophysical parameters for the Geneva-Copenhagen Survey
• A temperate rocky super-Earth transiting a nearby cool star
• On the angular momentum evolution of fully-convective stars: rotation periods for field M-dwarfs from the MEarth transit survey
• A rocky planet transiting a nearby low-mass star
• Characterizing the Cool KOIs III. KOI-961: A Small Star with Large Proper Motion and Three Small Planets
• Verifying asteroseismically determined parameters of Kepler stars using hipparcos parallaxes: self-consistent stellar properties and distances
• Measuring the vertical age structure of the Galactic disc using asteroseismology and SAGA
• Towards stellar effective temperatures and diameters at one per cent accuracy for future surveys
• A dark matter disc in three cosmological simulations of Milky Way mass galaxies
• A possible signature of terrestrial planet formation in the chemical composition of solar analogs
• Discovery of a stripped red giant core in a bright eclipsing binary system
• The relation between chemical abundances and kinematics of the Galactic disc with RAVE
• Observational Evidence from SDSS for a Merger Origin of the Milky Way's Thick Disk
• High- and Low-$\alpha$ Disk Stars Separate Dynamically at all Ages
• Photometric rotation periods for 107 M dwarfs from the APACHE survey
• Deceleration of kicked objects due to the Galactic potential
• Mapping the Asymmetric Thick Disk: III. The Kinematics and Interaction with the Galactic Bar
• The Spheroidal Bulge of the Milky Way: Chemodynamically Distinct from the Inner-Thick Disc and Bar