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Stars in an open cluster are assumed to have formed from a broadly homogeneous distribution of gas, implying that they should be chemically homogeneous. Quantifying the level to which open clusters are chemically homogeneous can therefore…

Astrophysics of Galaxies · Physics 2024-09-05 Amaya Sinha , Gail Zasowski , Peter Frinchaboy , Katia Cunha , Diogo Souto , Jamie Tayar , Keivan Stassun

We investigate the production sites and the enrichment history of $r$-process elements in the Galaxy, as traced by the [Eu/Fe] ratio, using the high resolution, cosmological zoom-in simulation `Eris'. At $z=0$, Eris represents a close…

Astrophysics of Galaxies · Physics 2015-07-15 Sijing Shen , Ryan Cooke , Enrico Ramirez-Ruiz , Piero Madau , Lucio Mayer , Javiera Guedes

Binary star systems are assumed to be co-natal and coeval, thus to have identical chemical composition. In this work we aim to test the hypothesis that there is a connection between observed element abundance patterns and the formation of…

Solar and Stellar Astrophysics · Physics 2021-09-06 Fan Liu , Bertram Bitsch , Martin Asplund , Bei-Bei Liu , Michael T. Murphy , David Yong , Yuan-Sen Ting , Sofia Feltzing

We study turbulent gas diffusion affects on $r$-process abundances in Milky Way stars, by a combination of an analytical approach and a Monte Carlo simulation. Higher $r$-process event rates and faster diffusion, lead to more efficient…

High Energy Astrophysical Phenomena · Physics 2020-06-24 Paz Beniamini , Kenta Hotokezaka

Milky Way-mass galaxies in the FIRE-2 simulations demonstrate two main modes of star formation. At high redshifts star formation occurs in a series of short and intense bursts, while at low redshifts star formation proceeds at a steady rate…

Millimeter sized dust grains experience radial velocities exceeding the gas velocities by orders of magnitude. The viscous evolution of the accretion disk adds disk material onto the central star's convective envelope, influencing its…

Earth and Planetary Astrophysics · Physics 2023-08-15 León-Alexander Hühn , Bertram Bitsch

Abundance observations indicate the presence of often surprisingly large amounts of neutron capture (i.e., s- and r-process) elements in old Galactic halo and globular cluster stars. These observations provide insight into the nature of the…

Accurate stellar parameters and precise elemental abundances are vital pieces to correctly characterize discovered planetary systems, better understand planet formation, and trace galactic chemical evolution. We have performed a uniform…

Solar and Stellar Astrophysics · Physics 2018-08-29 John M. Brewer , Debra A. Fischer

Stellar chemical element ratios have well-defined systematic trends as a function of abundance, with an excellent correlation of these trends with stellar populations defined kinematically. This is remarkable, and has significant…

Astrophysics · Physics 2007-05-23 Gerry Gilmore , Rosemary F. G. Wyse

The current knowledge of the abundance structure in the Milky Way is reviewed. Special emphasis is put on recent results for stars with kinematics typical of the thin and the thick disks, respectively, and how these results can, apart from…

Astrophysics · Physics 2007-05-23 Sofia Feltzing

We present preliminary results of a detailed chemical abundance analysis for a sample of solar-type stars known to exhibit excess infrared emission associated with dusty debris disks. Our sample of 28 stars was selected based on results…

Solar and Stellar Astrophysics · Physics 2015-06-17 Adam M. Ritchey , Guillermo Gonzalez , Myra Stone , George Wallerstein

We present a model to explain the wide range of abundances for heavy r-process elements (mass number A > 130) at low [Fe/H]. This model requires rapid star formation and/or an initial population of supermassive stars in the earliest…

Astrophysics · Physics 2009-10-31 G. J. Wasserburg , Y. -Z. Qian

We use data of $\sim$13,000 stars from the SDSS/APOGEE survey to study the shape of the bulge MDF within the region $|\ell|\leq11^\circ$ and $|b|\leq13^\circ$, and spatially constrained to ${\rm R_{GC}\leq3.5}$ kpc. We apply Gaussian…

Neutron star mergers (NSMs) are promising astrophysical sites for the rapid neutron-capture ("$r$-") process, but can their integrated yields explain the majority of heavy-element material in the Galaxy? One method to address this question…

Recent observations of heavy elements produced by rapid neutron capture (r-process) in the halo have shown a striking and unexpected behavior: within a single star, the relative abundances of r-process elements heavier than Eu are the same…

Astrophysics · Physics 2009-11-06 Brian D. Fields , James W. Truran , John J. Cowan

The evolution of C and O abundances in the Milky Way can impose strong constraints on stellar nucleosynthesis and help understanding the formation and evolution of our Galaxy. The aim is to review the measured C and O abundances in the disk…

Astrophysics of Galaxies · Physics 2015-05-13 G. Cescutti , F. Matteucci , A. McWilliam , C. Chiappini

We study the abundance patterns and the radial gradients of s-process elements (Y, Zr, Ba, La and Ce), r-process elements (Eu) and mixed-process elements (Mo, Nd and Pr) in the Galactic thin disc by means of a detailed two-infall chemical…

ABRIDGED: METHODS: We have conducted a high-resolution spectroscopic study of 714 F and G dwarf and subgiant stars in the Solar neighbourhood. The star sample has been kinematically selected to trace the Galactic thin and thick disks to…

Astrophysics of Galaxies · Physics 2015-06-17 T. Bensby , S. Feltzing , M. S. Oey

We apply for the first time fission yields determined across the chart of nuclides from the macroscopic-microscopic theory of the Finite Range Liquid Drop Model to simulations of rapid neutron capture ($r$-process) nucleosynthesis. With the…

High Energy Astrophysical Phenomena · Physics 2020-06-22 Nicole Vassh , Matthew R. Mumpower , Gail C. McLaughlin , Trevor M. Sprouse , Rebecca Surman

In this paper we adopt a chemical evolution model, which is an improved version of the Chiappini, Matteucci and Gratton (1997) model, assuming two main accretion episodes for the formation of the Galaxy. The present model takes into account…

Astrophysics · Physics 2009-11-06 Cristina Chiappini , Francesca Matteucci , Donatella Romano