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Related papers: Cosmic variance in [O/Fe] in the Galactic disk

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Galactic disk warp has been widely characterized by stellar distributions and stellar kinematics but has not been traced by stellar chemistry. Here, we use a sample with over 170,000 red clump (RC) stars selected from LAMOST and APOGEE…

Astrophysics of Galaxies · Physics 2024-12-18 Weixiang Sun , Han Shen , Biwei Jiang , Xiaowei Liu

The Apache Point Observatory Galactic Evolution Experiment (APOGEE) has observed $\sim$600 transiting exoplanets and exoplanet candidates from \textit{Kepler} (Kepler Objects of Interest, KOIs), most with $\geq$18 epochs. The combined…

Understanding the evolution of carbon and iron in the Milky Way's halo is of importance because these two elements play crucial roles constraining star formation, Galactic assembly, and chemical evolution in the early Universe. Here, we…

The analysis of the APOGEE DR16 data suggests the existence of a clear distinction between two sequences of disc stars at different Galactocentric distances in the [$\alpha$/Fe] vs. [Fe/H] abundance ratio space: the so-called high-$\alpha$…

Astrophysics of Galaxies · Physics 2021-03-10 E. Spitoni , K. Verma , V. Silva Aguirre , F. Vincenzo , F. Matteucci , B. Vaičekauskaitė , M. Palla , V. Grisoni , F. Calura

For the first time, we present an extensive study of stars with individual non-local thermodynamic equilibrium (NLTE) abundances for 17 chemical elements from Li to Eu in a sample of stars uniformly distributed over the $-2.62 \le$ [Fe/H]…

Age-metallicity relation for the Galactic disc is a crucial tool and to constrain the Galactic chemical evolution models. We investigate the age-metallicity relation of the Galactic disc using the red giant branch stars in the Solar…

Astrophysics of Galaxies · Physics 2023-05-01 S. Doner , S. Ak , O. Onal Tas , O. Plevne

We present oxygen abundances derived from both the permitted and forbidden oxygen lines for 55 subgiants and giants with [Fe/H] values between -2.7 and solar with the goal of understanding the discrepancy in the derived abundances. A first…

Astrophysics · Physics 2009-11-10 Jon P. Fulbright , Jennifer A. Johnson

Observations of nearby massive galaxies have revealed that they are older and richer in metals and magnesium than their low-mass counterparts. In particular, the overabundance of magnesium compared to iron, [Mg/Fe], is interpreted to…

Astrophysics of Galaxies · Physics 2024-07-17 Emilie Pernet , Alina Böcker , Ignacio Martín-Navarro

The Galactic bulge has a bimodal metallicity distribution function: different kinematic, spatial, and, potentially, age distributions characterize the metal-poor and metal-rich components. Despite this observed dichotomy, which argues for…

Astrophysics of Galaxies · Physics 2019-05-07 A. Rojas-Arriagada , M. Zoccali , M. Schultheis , A. Recio-Blanco , G. Zasowski , D. Minniti , H. Jönsson , R. E. Cohen

The abundance ratio N/O is a useful tool to study the interplay of galactic processes, e.g. star formation efficiency, time-scale of infall and outflow loading factor We aim to trace log(N/O) versus [Fe/H] in the Milky Way and to compare it…

We present a kinematic analysis of a sample of 23,908 G- and K-type dwarfs in the Galactic disk. Based on the $\alpha$-abundance ratio, [$\alpha$/Fe], we separated our sample into low-$\alpha$ thin-disk and high-$\alpha$ thick-disk stars.…

Astrophysics of Galaxies · Physics 2020-06-17 Doo Ri Han , Young Sun Lee , Young Kwang Kim , Timothy C. Beers

We use the EAGLE simulations to study the oxygen abundance gradients of gas discs in galaxies within the stellar mass range [10^9.5, 10^10.8]Mo at z=0. The estimated median oxygen gradient is -0.011 (0.002) dex kpc^-1, which is shallower…

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…

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

We present the first fluorine measurements in 12 normal giants belonging to the Galactic thin and thick disks using spectra obtained with the Phoenix infrared spectrometer on the 2.1m telescope at Kitt Peak. Abundances are determined from…

Astrophysics of Galaxies · Physics 2024-06-06 K. E. Brady , C. A. Pilachowski , V. Grisoni , Z. G. Maas , K. A. Nault

Based on the LAMOST survey and Sloan Digital Sky Survey (SDSS), we use low-resolution spectra of 130,043 F/G-type dwarf stars to study the kinematics and metallicity properties of the Galactic disk. Our study shows that the stars with…

Astrophysics of Galaxies · Physics 2016-10-12 Yingjie Jing , Cuihua Du , Jiayin Gu , Yunpeng Jia , Xiyan Peng , Yuqin Chen , Zhenyu Wu , Jun Ma , Xu Zhou , Zihuang Cao , Yonghui Hou , Yuefei Wang , Yong Zhang

The accurate O, Mg and Fe abundances derived in previous papers of this series from a homogenous reanalysis of high quality data for a large sample of stars are combined with stellar kinematics in order to discuss the history of star…

Astrophysics · Physics 2007-05-23 Raffaele Gratton , Eugenio Carretta , Francesca Matteucci , Chris Sneden

AIMS: We spectroscopically characterize the Galactic Bulge to infer its star formation timescale, compared to the other Galactic components, through the chemical signature on its individual stars. METHODS: We derived iron and oxygen…

Astrophysics · Physics 2010-01-07 M. Zoccali , A. Lecureur , B. Barbuy , V. Hill , A. Renzini , D. Minniti , Y. Momany , A. Gomez , S. Ortolani

The distribution of metals within a galaxy traces the baryon cycle and the buildup of galactic disks, but the detailed gas phase metallicity distribution remains poorly sampled. We have determined the gas phase oxygen abundances for 7,138…

We explore the correlations between velocity and metallicity and the possible distinct chemical signatures of the velocity over-densities of the local Galactic neighbourhood. We use the large spectroscopic survey RAVE and the Geneva…