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Related papers: High- and Low-$\alpha$ Disk Stars Separate Dynamic…

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The growth and properties of galaxies are thought to be closely connected to the ones of their host dark matter halos. Despite the importance of this so-called galaxy-halo connection, the potential role of dark matter halos in regulating…

Astrophysics of Galaxies · Physics 2022-02-16 Laura Scholz-Diaz , Ignacio Martin-Navarro , Jesus Falcon-Barroso

We derive age constraints for 1639 red giants in the APOKASC sample for which seismic parameters from Kepler, as well as effective temperatures, metallicities and [alpha/Fe] values from APOGEE DR12 are available. We investigate the relation…

Stellar systems composed of single, double, triple or high-order systems are rightfully regarded as the fundamental building blocks of the Milky Way. Binary stars play an important role in formation and evolution of the Galaxy. Through…

The age and chemical characteristics of the Galactic bulge link to the formation and evolutionary history of the Galaxy. Data-driven methods and large surveys enable stellar ages and precision chemical abundances to be determined for vast…

Solar and Stellar Astrophysics · Physics 2020-08-31 Tawny Sit , Melissa Ness

We explore the origin of the observed decline in [O/Fe] (and [Mg/Fe]) with Galactocentric distance for high-metallicity stars ([Fe/H] > -1.1), based on a sample of halo stars selected within the Apache Point Observatory Galactic Evolution…

Context: The chemical composition of stars is intimately linked to the Galaxy formation and evolution. Aims: We aim to trace the chemical evolution of the Galactic disk through the inspection of the [X/Fe]-age relations of 24 species from C…

Solar and Stellar Astrophysics · Physics 2016-10-05 L. Spina , J. Meléndez , A. I. Karakas , I. Ramírez , T. R. Monroe , M. Asplund , D. Yong

We investigate, using the Gaia-ESO Survey internal Data-Release 2, the properties of the double sequence of the Milky Way discs (defined chemically as the high-alpha and low-alpha populations), and discuss their compatibility with discs…

Using a sample of red giant stars from the Apache Point Observatory Galactic Evolution Experiment (APOGEE) Data Release 16, we infer the conditional distribution $p([\alpha/\text{Fe}]\,|\,[\text{Fe/H}])$ in the Milky Way disk for the…

Astrophysics of Galaxies · Physics 2021-10-13 Fiorenzo Vincenzo , David H. Weinberg , Andrea Miglio , Richard R. Lane , Alexandre Roman-Lopes

A scenario for the formation of the bi-modality in the chemical space [$\alpha$/Fe] vs [Fe/H] of the Milky Way was recently proposed in which $\alpha$-enhanced stars are produced early and quickly in clumps. Besides accelerating the…

Astrophysics of Galaxies · Physics 2020-02-12 Leandro Beraldo e Silva , Victor P. Debattista , Tigran Khachaturyants , David Nidever

RR Lyrae stars in the Milky Way are good tracers to study the kinematic behaviour and spatial distribution of older stellar populations. A recently established well documented sample of 217 RR Lyr stars with V<12.5 mag, has been used to…

Astrophysics · Physics 2009-11-11 Gisela Maintz , Klaas S. de Boer

We exploit the [Mg/Mn]-[Al/Fe] chemical abundance plane to help identify nearby halo stars in the 14th data release from the APOGEE survey that have been accreted on to the Milky Way. Applying a Gaussian Mixture Model, we find a `blob' of…

Astrophysics of Galaxies · Physics 2020-02-12 Payel Das , Keith Hawkins , Paula Jofre

We have for the first time identified the early stellar disk in the Milky Way by using a combination of elemental abundances and kinematics. Using data from APOGEE DR17 and Gaia we select stars in the Mg-Mn-Al-Fe plane with elemental…

Astrophysics of Galaxies · Physics 2023-06-28 Sofia Feltzing , Diane Feuillet

HARPS spectra with signal-to-noise ratios S/N > 600 at 6000 A were analysed with MARCS model atmospheres to obtain 1D LTE abundances of C, O, Na, Mg, Al, Si, Ca, Ti, Cr, Fe, Ni, Sr, and Y for 72 nearby solar-type stars with metallicities in…

Solar and Stellar Astrophysics · Physics 2020-08-19 P. E. Nissen , J. Christensen-Dalsgaard , J. R. Mosumgaard , V. Silva Aguirre , E. Spitoni , K. Verma.

Trends in the enrichment of elements with stellar ages are a powerful avenue to identify unexplained origins of the elements. We investigate the stellar abundance trends of low to intermediate-mass stars using the GALAH DR3 high-resolution…

Astrophysics of Galaxies · Physics 2024-10-15 Evans K. Owusu , Sven Buder , Ashley J. Ruiter , Ivo R. Seitenzahl , Nicolás Rodríguez-Segovia

The halo and disc globular cluster population can be used as a tracer of the primordial epochs of the Milky Way formation. In this work, literature data of globular clusters ages, chemical abundances, and structural parameters are studied,…

Astrophysics of Galaxies · Physics 2018-12-26 Alejandra Recio-Blanco

Stellar masses are a fundamental property to understand models of pre-main sequence evolution, but their values derived from Hertzsprung-Russell (HR) diagrams are strongly model dependent. We benchmark pre-main sequence stellar evolutionary…

We use 297 042 main sequence turn-off stars selected from the LSS-GAC to determine the radial and vertical gradients of stellar metallicity of the Galactic disk in the anti-center direction. We determine ages of those turn-off stars by…

We study the different patterns of interannual magnetic variability in stars on or near the lower main sequence, approximately solar-type (G-K dwarf) stars in time series of 36 years from the Mount Wilson Observatory Ca\,{\sc ii}\,H\&K…

Solar and Stellar Astrophysics · Physics 2016-06-22 K. Oláh , Zs. Kővári , K. Petrovay , W. Soon , S. Baliunas , Z. Kolláth , K. Vida

We present results from a photometric H-alpha survey of 22 nuclear rings, aiming to provide insight into their star formation properties, including age distribution, dynamical timescales, star formation rates, and galactic bar influence. We…

Astrophysics · Physics 2009-11-13 Lisa M. Mazzuca , Johan H. Knapen , Sylvain Veilleux , Michael W. Regan

The analysis of the distribution of stars in open clusters may yield important information on the star formation process and early dynamical evolution of stellar clusters. Here we address this issue by systematically characterizing the…

Solar and Stellar Astrophysics · Physics 2011-02-11 Nestor Sanchez , Emilio J. Alfaro
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