New constraints on the chemical evolution of the solar neighbourhood and galactic disc(s) - improved astrophysical parameters for the Geneva-Copenhagen Survey
Luca Casagrande,Ralph Schönrich,Martin Asplund,Santi Cassisi,I. Ramirez,Jorge Melendez,Thomas Bensby,Sofia Feltzing +7 more
TLDR
In this article, the Geneva-Copenhagen survey was used for a re-analysis of the spectral properties of the stars in the solar neighborhood and the results showed that the stars are on average 100 K hotter and 0.1 dex more metal rich, which shifted the peak of the metallicity distribution function around the solar value.Abstract:
We present a re-analysis of the Geneva-Copenhagen survey, which benefits from the infrared flux method to improve the accuracy of the derived stellar effective temperatures and uses the latter to build a consistent and improved metallicity scale. Metallicities are calibrated on high-resolution spectroscopy and checked against four open clusters and a moving group, showing excellent consistency. The new temperature and metallicity scales provide a better match to theoretical isochrones, which are used for a Bayesian analysis of stellar ages. With respect to previous analyses, our stars are on average 100 K hotter and 0.1 dex more metal rich, which shift the peak of the metallicity distribution function around the solar value. From Stromgren photometry we are able to derive for the first time a proxy for [alpha/Fe] abundances, which enables us to perform a tentative dissection of the chemical thin and thick disc. We find evidence for the latter being composed of an old, mildly but systematically alpha-enhanced population that extends to super solar metallicities, in agreement with spectroscopic studies. Our revision offers the largest existing kinematically unbiased sample of the solar neighbourhood that contains full information on kinematics, metallicities, and ages and thus provides better constraints on the physical processes relevant in the build-up of the Milky Way disc, enabling a better understanding of the Sun in a Galactic context. (Less)read more
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Intrinsic Colors, Temperatures, and Bolometric Corrections of Pre-Main Sequence Stars
Mark J. Pecaut,Eric E. Mamajek +1 more
TL;DR: In this article, the intrinsic colors and temperatures of 5-30 Myr old pre-main sequence (pre-MS) stars were analyzed using optical spectra taken with the SMARTS 1.5m telescope.
Journal ArticleDOI
The Galaxy in Context: Structural, Kinematic, and Integrated Properties
TL;DR: In this paper, the authors review the key integrated, structural and kinematic parameters of the Galaxy, and point to uncertainties as well as directions for future progress, and show that the Galaxy is a luminous (L⋆) barred spiral with a central box/peanut bulge, a dominant disk, and a diffuse stellar halo.
Journal ArticleDOI
Exploring the Milky Way stellar disk - A detailed elemental abundance study of 714 F and G dwarf stars in the solar neighbourhood
TL;DR: In this paper, a high-resolution spectroscopic study of 714 F and G dwarfs and subgiant stars in the Solar neighbourhood was conducted, where the star sample has been kinematically selected to trace the Galactic thin and thick disks to their extremes, the metal-rich stellar halo, sub-structures in velocity space such as the Hercules stream and the Arcturus moving group, as well as stars that cannot be associated with either the thin disk or the thick disk.
Journal ArticleDOI
Nucleosynthesis in Stars and the Chemical Enrichment of Galaxies
TL;DR: In this article, the authors review the recent results of the nucleosynthesis yields of mainly massive stars for a wide range of stellar masses, metallicities, and explosion energies, and provide yields tables and examine how those yields are affected by some hydrodynamical effe...
Journal ArticleDOI
The GALAH survey: scientific motivation
G. M. De Silva,G. M. De Silva,Kenneth C. Freeman,Joss Bland-Hawthorn,Sarah L. Martell,E. Wylie de Boer,Martin Asplund,Stefan Keller,Sanjib Sharma,Daniel B. Zucker,Tomaž Zwitter,Borja Anguiano,Carlos Bacigalupo,Daniel Bayliss,M.A. Beavis,Maria Bergemann,Simon Campbell,Russell D. Cannon,Daniela Carollo,Luca Casagrande,Andrew R. Casey,G. S. Da Costa,Valentina D'Orazi,Valentina D'Orazi,Aaron Dotter,Ly Duong,Alexander Heger,Alexander Heger,Alexander Heger,Michael J. Ireland,Prajwal R. Kafle,Janez Kos,John C. Lattanzio,Geraint F. Lewis,J. Lin,Karin Lind,Ulisse Munari,David M. Nataf,Simon J. O'Toole,Quentin A. Parker,Warren A. Reid,Katharine J. Schlesinger,Andrew I. Sheinis,Jeffrey D. Simpson,Dennis Stello,Yuan-Sen Ting,Gregor Traven,Fred G. Watson,Robert A. Wittenmyer,David Yong,M. Žerjal +50 more
TL;DR: The Galactic Archaeology with HERMES (GALAH) survey is a large high-resolution spectroscopic survey using the newly commissioned High Efficiency and Resolution Multi-element Spectrograph (HERMES) on the Anglo-Australian Telescope as discussed by the authors.
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