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The Milky Way's metal-poor stars are nearby ancient objects that are used to study early chemical evolution and the assembly and structure of the Milky Way. Here we present reliable metallicities of $\sim280,000$ stars with $-3.75 \lesssim$…

Astrophysics of Galaxies · Physics 2021-06-09 Anirudh Chiti , Anna Frebel , Mohammad K. Mardini , Tatsuya W. Daniel , Xiaowei Ou , Anastasiia V. Uvarova

In intermediate-temperature (T = 2.5 - 4.5 keV) galaxy clusters, abundance measurements are almost-equally driven by Fe K and L transitions, at $\sim$ 6.7 keV and 0.9 - 1.3 keV, respectively. While K-shell-derived measurements are…

Cosmology and Nongalactic Astrophysics · Physics 2022-09-14 G. Riva , S. Ghizzardi , S. Molendi , I. Bartalucci , S. De Grandi , F. Gastaldello , C. Grillo , M. Rossetti

We have determined Be abundances in 50 F and G dwarfs in the mass range of 0.9 $\leq$ M$_\odot$ $\leq$ 1.1 as determined by Lambert & Reddy. The effective temperatures are 5600 to 6400 K and metallicities from $-$0.65 to +0.11. The spectra…

Astrophysics · Physics 2015-05-13 Ann Merchant Boesgaard , Julie A. Krugler

We have computed a grid of high resolution synthetic spectra for cool stars (2500<Teff<6000 K) in the wavelength range 6000 -- 10200A, by employing an updated line list of atomic and molecular lines, together with state-of-the-art model…

Astrophysics · Physics 2009-10-30 Ricardo P. Schiavon , Beatriz Barbuy

In this work we present and discuss the observations of the Mn abundances for 247 FGK dwarfs, located in the Galactic disc with metallicity -1<Fe/H]<+0.3. The observed stars belong to the substructures of the Galaxy thick and thin discs,…

Astrophysics of Galaxies · Physics 2015-10-14 T. Mishenina , T. Gorbaneva , M. Pignatari , F. -K. Thielemann , S. A. Korotin

We report the statistical properties of stars and brown dwarfs obtained from four radiation hydrodynamical simulations of star cluster formation, the metallicities of which span a range from 1/100 to 3 times the solar value. Unlike previous…

Solar and Stellar Astrophysics · Physics 2019-01-15 Matthew R. Bate

In this study, photometric metallicity and absolute magnitude calibrations were derived using F-G spectral type main-sequence stars in the Solar neighbourhood with precise spectroscopic, photometric and Gaia astrometric data for UBV…

Astrophysics of Galaxies · Physics 2019-10-23 M. Celebi , S. Bilir , S. Ak , T. Ak , Z. F. Bostanci , T. Yontan

The CM Draconis system comprises two eclipsing mid-M dwarfs of nearly equal mass in a 1.27-day orbit. This well-studied eclipsing binary has often been used for benchmark tests of stellar models, since its components are amongst the lowest…

We used moderately high-resolution, high S/N spectra to study the chemical composition of 10 field ab-type RR Lyrae stars. A new temperature scale was determined from literature Infrared Flux Method measures of subdwarfs and the Kurucz…

Astrophysics · Physics 2009-11-24 G. Clementini , E. Carretta , R. Gratton , R. Merighi , J. R. Mould , J. K. McCarthy

Deriving the metallicity, [Fe/H], in low-resolution spectra of carbon-enhanced metal-poor (CEMP) stars is a tedious task that, owing to the large number of line blends, often leads to uncertainties on [Fe/H] exceeding 0.25dex. The CEMP…

Solar and Stellar Astrophysics · Physics 2020-02-12 D. Singh , C. J. Hansen , J. S. Byrgesen , M. Reichert , H. M. Reggiani

We present the results of determination of the barium abundance considering the non-LTE (NLTE) effects in 172 dwarf stars in the metallicity range of -1< [Fe/H] <+0.3, assigned to different Galactic substructures by kinematic criteria. We…

Solar and Stellar Astrophysics · Physics 2015-05-27 S. Korotin , T. Mishenina , T. Gorbaneva , C. Soubiran

We present gas-phase metallicity measurements for 583 emission line galaxies at $0.3<z<0.85$, including 388 dwarf galaxies with $log(M_{\star}/M_{\odot}) < 9.5$, and explore the dependence of the metallicity on the stellar mass and star…

The current classification system of M stars on the main sequence distinguishes three metallicity classes (dwarfs - dM, subdwarfs - sdM, and extreme subdwarfs - esdM). The spectroscopic definition of these classes is based on the relative…

Astrophysics · Physics 2009-11-13 Sebastien Lepine , R. Michael Rich , Michael M. Shara

In Chen et al., 2023 (C23; arXiv:2304.09898), we introduced a new method to directly measure temperature fluctuations and applied it to a nearby dwarf galaxy, Mrk 71, finding a temperature fluctuation parameter $t^2 = 0.008\pm 0.043$. This…

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

We use a sample of 37 H II regions with high quality spectra to study the behavior of the relative abundances of several elements as a function of metallicity. The sample includes spectra for eight H II regions of the Magellanic Clouds,…

Astrophysics of Galaxies · Physics 2019-06-06 G. Domínguez-Guzmán , M. Rodríguez , C. Esteban , J. García-Rojas

This study is an attempt to determine the metallicities of WUMa-type binary stars using spectroscopy. ~4,500 spectra collected at the David Dunlap Observatory were subject to the same Broadening Function processing to determine the combined…

Solar and Stellar Astrophysics · Physics 2015-06-16 Slavek M. Rucinski , Theodor Pribulla , Jan Budaj

The mean metallicity of the Milky Way thin disc in the solar neighbourhood is still a matter of debate, and has recently been subject to upward revision (Haywood, 2001). Our star sample was drawn from a set of solar neighbourhood dwarfs…

Astrophysics · Physics 2009-11-07 M. Haywood

We report on the discovery of seven low-metallicity stars selected from the Hamburg/ESO Survey, six of which are extremely metal-poor ([Fe/H]<-3.0), with four having [Fe/H]<-3.5. Chemical abundances or upper limits are derived for these…

We present detailed chemical analyses for a sample of twelve stars selected from the CH star catalogue of Bartkevicius (1996). The sample includes two confirmed binaries, four objects that are known to show radial velocity variations and…

Solar and Stellar Astrophysics · Physics 2014-12-12 Drisya Karinkuzhi , Aruna Goswami