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We present a determination of the thick disk iron abundance distribution obtained from an in situ sample of F/G stars. These stars are faint, $15 \simlt V \simlt 18$, selected on the basis of color, being a subset of the larger survey of…

Astrophysics · Physics 2009-10-22 Gerard Gilmore , Rosemary F. G. Wyse , J. Bryn Jones

Most of our current knowledge on planet formation is still based on the analysis of main-sequence, solar-type stars. Conversely, detailed chemical studies of large samples of M-dwarf planet hosts are still missing. We develop for the first…

Ancient, very metal-poor stars offer a window into the earliest epochs of galaxy formation and assembly. We combine data from the H3 Spectroscopic Survey and Gaia to measure metallicities, abundances of $\alpha$ elements, stellar ages, and…

The main goal of this work is to study element ratios that are important for the formation of planets of different masses. We study potential correlations between the existence of planetary companions and the relative elemental abundances…

Earth and Planetary Astrophysics · Physics 2015-09-09 V. Adibekyan , N. C. Santos , P. Figueira , C. Dorn , S. G. Sousa , E. Delgado-Mena , G. Israelian , A. A. Hakobyan , C. Mordasini

This work presents a homogeneous derivation of atmospheric parameters and iron abundances for a sample of giant and subgiant stars which host giant planets, as well as a control sample of subgiant stars not known to host giant planets. The…

Solar and Stellar Astrophysics · Physics 2010-11-23 L. Ghezzi , K. Cunha , S. C. Schuler , V. V. Smith

The well-known correlation between stellar metallicity and planet occurrence is strongest for giant planets, but weaker for smaller planets, suggesting that detailed elemental patterns beyond [Fe/H] may be relevant. Using abundances from…

Earth and Planetary Astrophysics · Physics 2026-02-11 N. Sussholz , S. Zucker , R. Helled , D. Bashi

We performed a detailed study of the ratio of low-{\alpha} to high-{\alpha} stars in the Galactic halo as observed by the Gaia-ESO Survey. Using a sample of 381 metal-poor stars from the second internal data release, we found that the value…

Around 16% of the solar-like stars in our neighbourhood show IR-excesses due to debris discs and a fraction of them are known to host planets. We aim to determine in a homogeneous way the metallicity of a sample of stars with known debris…

Earth and Planetary Astrophysics · Physics 2015-06-04 J. Maldonado , C. Eiroa , E. Villaver , B. Montesinos , A. Mora

In this paper we present a study of chemical abundances in six star-forming regions. Stellar parameters and metallicities are derived using high-resolution, high S/N spectra of weak-line T-Tauri stars in each region. The results show that…

Astrophysics · Physics 2009-11-13 N. C. Santos , C. Melo , D. J. James , J. F. Gameiro , J. Bouvier , J. I. Gomes

Studies of the early chemical evolution of some larger dwarf galaxies ( $>10^7$ solar masses) are limited by the small number of stars known at low metallicities in these systems. Here we present metallicities and carbon abundances for…

Astrophysics of Galaxies · Physics 2020-10-14 Anirudh Chiti , Kylie Y. Hansen , Anna Frebel

The relationship between the compositions of giant planets and their host stars is of fundamental interest in understanding planet formation. The solar system giant planets are enhanced above solar composition in metals, both in their…

Earth and Planetary Astrophysics · Physics 2019-12-11 Johanna K. Teske , Daniel Thorngren , Jonathan J. Fortney , Natalie Hinkel , John M. Brewer

We present a detailed elemental abundance study of 90 F and G dwarf, turn-off and subgiant stars in the Galactic bulge. Based on high-resolution spectra acquired during gravitational microlensing events, stellar ages and abundances for 11…

We present Keck/HIRES observations of six metal-poor stars in two of the ultra-faint dwarf galaxies orbiting the Milky Way, Ursa Major II and Coma Berenices. These observations include the first high-resolution spectroscopic observations of…

Astrophysics of Galaxies · Physics 2009-12-17 Anna Frebel , Joshua D. Simon , Marla Geha , Beth Willman

Correlations between stellar properties and the occurrence rate of exoplanets can be used to inform the target selection of future planet search efforts and provide valuable clues about the planet formation process. We analyze a sample of…

Earth and Planetary Astrophysics · Physics 2015-05-19 John Asher Johnson , Kimberly M. Aller , Andrew W. Howard , Justin R. Crepp

Probing the connection between a star's metallicity and the presence and properties of any associated planets offers an observational link between conditions during the epoch of planet formation and mature planetary systems. We explore this…

We studied a sample of high proper motion, old and metal-rich dwarf stars, selected from the NLTT catalogue. The low pericentric distances and eccentric orbits of these solar neighbourhood stars indicate that they might have originated in…

Solar and Stellar Astrophysics · Physics 2014-10-15 M. Trevisan , B. Barbuy

The most metal-poor stars in dwarf spheroidal galaxies (dSphs) can show the nucleosynthetic patterns of one or a few supernovae. These supernovae could have zero metallicity, making metal-poor dSph stars the closest surviving links to…

Astrophysics of Galaxies · Physics 2012-11-12 Evan N. Kirby , Judith G. Cohen

Thin and Thick disk metallicities overlap, but alpha(Fe) relations differ; there is also a hiatus in time before the first thin-disk stars, with a minimum metallicity [Fe/H] = -0.6. Thus there are two `G-dwarf' problems. We fit metallicity…

Astrophysics · Physics 2016-11-03 B. E. J. Pagel

The abundance patterns of the most metal-poor stars in the Galactic halo and small dwarf galaxies provide us with a wealth of information about the early Universe. In particular, these old survivors allow us to study the nature of the first…

Astrophysics of Galaxies · Physics 2010-06-15 Anna Frebel

We have derived abundances of O, Na, Mg, Al, Si, Ca, Sc, Ti, V, Cr, Fe, Ni and Ba for 43 metal-poor field stars in the solar neighbourhood with iron abundances [Fe/H] ranging from -0.4 to -3.0. Total abundance errors are estimated to about…