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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

We present our work on the halo evolution of sulfur, based on observations of the S I lines around 9220 A for ten stars for which the S abundance was obtained previously from much weaker S I lines at 8694 A. We cannot confirm the rise and…

Astrophysics · Physics 2007-05-23 Nils Ryde , David L. Lambert

We present the analysis of the FLAMES dataset targeting the central 25 arcmin region of the Sextans dSph. This dataset is the third major part of the high resolution spectroscopic section of the ESO large program 171.B-0588(A) obtained by…

Astrophysics of Galaxies · Physics 2020-10-21 R. Theler , P. Jablonka , R. Lucchesi , C. Lardo , P. North , M. Irwin , G. Battaglia , V. Hill , E. Tolstoy , K. Venn , A. Helmi , A. Kaufer , F. Primas , M. Shetrone

We have determined the O/H and N/O of a sample of 122751 SFGs from the DR7 of the SDSS. For all these galaxies we have also determined their morphology and their SFH using the code STARLIGHT. The comparison of the chemical abundance with…

Cosmology and Nongalactic Astrophysics · Physics 2015-06-05 J. P. Torres-Papaqui , R. Coziol , R. A. Ortega-Minakata , D. M. Neri-Larios

We measure oxygen and nitrogen abundances for 14 star-forming emission line galaxies (ELGs) at 0.11<z<0.5 using Keck/LRIS optical spectroscopy. The targets exhibit a range of metallicities from slightly metal-poor like the LMC to…

Astrophysics · Physics 2009-10-30 Henry A. Kobulnicky , Dennis Zaritsky

From exploratory studies and theoretical expectations it is known that simplifying approximations in spectroscopic analysis (LTE, 1D) lead to systematic biases of stellar parameters and abundances. These biases depend strongly on surface…

Solar and Stellar Astrophysics · Physics 2017-10-04 Maria Bergemann , Remo Collet , Ralph Schoenrich , Rene Andrae , Mikhail Kovalev , Gregory Ruchti , Camilla J. Hansen , Zazralt Magic

We study the detailed properties of the radial metallicity gradient in the stellar disk of our Galaxy to constrain its chemical and structural evolution. For this purpose we select and analyze $\sim$ 18,500 disk stars taken from two…

Astrophysics of Galaxies · Physics 2015-06-19 Daisuke Toyouchi , Masashi Chiba

We gathered more than 1130 high-resolution optical spectra for more than 250 Galactic classical Cepheids. The spectra were collected with different optical spectrographs: UVES at VLT, HARPS at 3.6m, FEROS at 2.2m MPG/ESO, and STELLA. To…

The Spitzer Space Telescope is devoting a significant fraction of the observing time to multi-wavelength cosmological surveys of different depths in various low-background sky regions. Several tens of thousand mid-IR galaxies have been…

Astrophysics · Physics 2007-05-23 A. Franceschini , M. Vaccari , S. Berta , G. Rodighiero , C. Lonsdale

The characteristics of the stellar populations in the Galactic Bulge inform and constrain the Milky Way's formation and evolution. The metal-poor population is particularly important in light of cosmological simulations, which predict that…

We present elemental abundances for eight unevolved extremely metal-poor stars with $T_{\rm eff}>5500\,\mathrm{K}$, among which seven have $[\mathrm{Fe/H}]<-3.5$. The sample is selected from the Sloan Digital Sky Survey / Sloan Extension…

Solar and Stellar Astrophysics · Physics 2017-07-26 Tadafumi Matsuno , Wako Aoki , Timothy C. Beers , Young Sun Lee , Satoshi Honda

Extremely metal-poor stars are keys to understand the early evolution of our Galaxy. The ESO large programme TOPoS has been tailored to analyse a new set of metal-poor turn-off stars, whereas most of the previously known extremely…

LTE abundances of light elements in extremely metal-poor (EMP) stars have been previously derived from high quality spectra. New derivations, free from the NLTE effects, will better constrain the models of the Galactic chemical evolution…

Astrophysics of Galaxies · Physics 2015-05-14 S. M. Andrievsky , Monique Spite , S. A. Korotin , F. Spite , P. Bonifacio , R. Cayrel , P. François , V. Hill

Photospheric abundances are presented for 27 elements from carbon to europium in 181 F-G dwarfs from a differential LTE analysis of high-resolution and high signal-to-noise spectra. Stellar $T_{\rm eff}$ were adopted from an infrared flux…

Astrophysics · Physics 2009-11-07 Bacham E. Reddy , Jocelyn Tomkin , David L. Lambert , Carlos Allende Prieto

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

By means of chemo-photometric models for galaxies of different morhological types, we have carried out a detailed study of the history of element production by spheroidal and dwarf irregular galaxies. Spheroidal galaxies suffer a strong and…

Astrophysics · Physics 2009-11-11 Francesco Calura , Francesca Matteucci

Understanding the chemical enrichment of different elements is crucial to gaining a complete picture of galaxy chemical evolution. In this study, we present a new sample of 46 low-redshift, low-mass star-forming galaxies at $M_*\sim…

ABRIDGED: To compare the chemistries of stars in the Milky Way dSph galaxies with stars in the Galaxy, we have compiled a large sample of Galactic stellar abundances from the literature. As found in previous studies, the [alpha/Fe] ratios…

Astrophysics · Physics 2009-11-10 K. A. Venn , M. Irwin , M. D. Shetrone , C. A. Tout , V. Hill , E. Tolstoy

We measure the relationship between stellar mass and stellar metallicity, the stellar mass--metallicity relation (MZR), for 1336 star-forming galaxies at $1.6\le z\le3.0$ (<z>=2.2) using rest-frame far-ultraviolet spectra from the…

When searching for exoplanets and ultimately considering their habitability, it is necessary to consider the planet's composition, geophysical processes, and geochemical cycles in order to constrain the bioessential elements available to…

Earth and Planetary Astrophysics · Physics 2020-09-02 Natalie R. Hinkel , Hilairy E. Hartnett , Patrick A. Young
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