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We calculate the evolution of heavy element abundances from C to Zn in the solar neighborhood adopting our new nucleosynthesis yields. Our yields are calculated for wide ranges of metallicity (Z=0-Z_\odot) and the explosion energy (normal…

Astrophysics · Physics 2008-11-26 C. Kobayashi , H. Umeda , K. Nomoto , N. Tominaga , T. Ohkubo

We show that the low ratios of $\alpha$ elements (Mg, Si, and Ca) to Fe recently found for a small fraction of extremely metal-poor stars can be naturally explained with the nucleosynthesis yields of core-collapse supernovae, i.e.,…

Astrophysics of Galaxies · Physics 2015-06-19 Chiaki Kobayashi , Miho N. Ishigaki , Nozomu Tominaga , Ken'ichi Nomoto

The supernova yields of several heavy elements including alpha-, iron-group, and r-process elements are obtained as a function of the mass of their progenitor main-sequence stars M_ms from the abundance patterns of extremely metal-poor…

Astrophysics · Physics 2009-10-31 Takuji Tsujimoto , Toshikazu Shigeyama

We present new analytic solutions for one-zone (fully mixed) chemical evolution models and explore their implications. In contrast to existing analytic models, we incorporate a realistic delay time distribution for Type Ia supernovae (SNIa)…

Astrophysics of Galaxies · Physics 2017-03-22 David H. Weinberg , Brett H. Andrews , Jenna Freudenburg

In this paper we study the very early phases of the evolution of our Galaxy by means of a chemical evolution model which reproduces most of the observational constraints in the solar vicinity and in the disk. We have restricted our analysis…

Astrophysics · Physics 2016-08-30 Cristina Chiappini , Francesca Matteucci , Timothy Beers , Ken'ichi Nomoto

We report the results of a coherent study of three chemically anomalous metal-poor ([Fe/H] ~ -2) stars. These objects exhibit unusually low abundances of Mg, Si, Ca (alpha-elements) and Sr, Y, and Ba (neutron-capture elements). Our analyses…

At present none of Galactic chemical evolution (GCE) models provides a self-consistent description of observed trends for all iron-peak elements with metallicity simultaneously. The question is whether the discrepancy is due to deficiencies…

Solar and Stellar Astrophysics · Physics 2015-05-14 Maria Bergemann , Thomas Gehren

We have attributed the elements from Sr through Ag in stars of low metallicities ([Fe/H] < -1.5) to charged-particle reactions (CPR) in neutrino-driven winds, which are associated with neutron star formation in low-mass and normal…

Astrophysics · Physics 2008-09-18 G. J. Wasserburg , Y. -Z. Qian

We present new observations of copper and zinc abundances in 90 metal-poor stars, belonging to the metallicity range -3< [Fe/H] < -0.5. The present study is based on high resolution spectroscopic measurements collected at the Haute Provence…

Astrophysics · Physics 2009-11-07 T. V. Mishenina , V. V. Kovtyukh , C. Soubiran , C. Travaglio , M. Busso

The aim of this paper is to characterise the abundance patterns of five iron-peak elements (Mn, Fe, Ni, Cu, and Zn) for which the stellar origin and chemical evolution are still debated. We automatically derived iron peak (Mn, Fe, Ni, Cu,…

Solar and Stellar Astrophysics · Physics 2017-10-10 Š. Mikolaitis , P. de Laverny , A. Recio-Blanco , V. Hill , C. C. Worley , M. de Pascale

Inhomogeneous chemical evolution models of galaxies which try to reproduce the scatter seen in element-to-iron ratios of metal-poor halo stars are heavily dependent on theoretical nucleosynthesis yields of core-collapse supernovae. Hence…

Astrophysics · Physics 2009-11-06 D. Argast , M. Samland , F. -K. Thielemann , O. E. Gerhard

The evolution and explosion of metal-free stars with masses 10--100 solar masses are followed, and their nucleosynthetic yields, light curves, and remnant masses determined. When the supernova yields are integrated over a Salpeter initial…

Astrophysics · Physics 2011-02-11 Alexander Heger , S. E. Woosley

The heaviest iron-peak element, Zn has been used as an important tracer of cosmic chemical evolution. Spectroscopic observations of the metal-poor stars in Local Group galaxies show that an increasing trend of [Zn/Fe] ratios toward lower…

Astrophysics of Galaxies · Physics 2018-03-21 Yutaka Hirai , Takayuki R. Saitoh , Yuhri Ishimaru , Shinya Wanajo

We calculate nucleosynthesis in core-collapse explosions of massive Pop III stars, and compare the results with abundances of metal-poor halo stars to constrain the parameters of Pop III supernovae. We focus on iron-peak elements and, in…

Astrophysics · Physics 2011-02-11 Hideyuki Umeda , Ken'ichi Nomoto

A model for Galactic chemical evolution, driven by supernova-induced star formation, is formulated and used to examine the nature of the Galactic halo at early epochs. In this model, new stars are formed following each supernova event, thus…

Astrophysics · Physics 2009-10-31 Takuji Tsujimoto , Toshikazu Shigeyama , Yuzuru Yoshii

I present a review of chemical evolution models of the solar neighborhood. I give special attention to the necessary ingredients to reproduce the observed [Xi/Fe] ratios in nearby metal and super metal rich stars, and to the chemical…

Astrophysics · Physics 2007-05-23 L. Carigi

We explore the effects on nucleosynthesis in Type II supernovae of various parameters (mass cut, neutron excess, explosion energy, progenitor mass) in order to explain the observed trends of the iron-peak element abundance ratios ([Cr/Fe],…

We investigate the chemical evolution of odd-numbered elements such as sodium (Na) and aluminum (Al) during the early epochs of the Galactic halo with the use of a model that reproduces the observed box-shaped distribution of extremely…

Astrophysics · Physics 2009-11-07 Takuji Tsujimoto , Toshikazu Shigeyama , Yuzuru Yoshii

Isotope ratios have opened a new window into the study of the details of stellar evolution, supernovae, and galactic chemical evolution. We present the evolution of the isotope ratios of elemental abundances (from C to Zn) in the solar…

Astrophysics of Galaxies · Physics 2015-05-27 Chiaki Kobayashi , Amanda I. Karakas , Hideyuki Umeda

Early phases of the chemical evolution and formation history of extremely metal poor (EMP) stars are investigated using hierarchical galaxy formation models. We build a merger tree of the Galaxy according to the extended Press-Schechter…

Astrophysics of Galaxies · Physics 2015-05-28 Yutaka Komiya
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