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200 papers

We performed an extensive non-LTE analysis of the neutral sodium lines of Na {\sc i} 5683/5688, 5890/5896, 6154/6161, and 8183/8195 for disk/halo stars of F--K type covering a wide metallicity range ($-4 \la$ [Fe/H] $\la 0.4$), based on our…

Astrophysics · Physics 2014-10-13 Yoichi Takeda , Gang Zhao , Masahide Takada-Hidai , Yu-Qin Chen , Yu-ji Saito , Hua-Wei Zhang

We present oxygen abundances for 72 F and G dwarf stars in the solar neighbourhood. Using the kinematics of the stars we divide them into two sub-samples with space velocities that are typical for the thick and thin disks, respectively. The…

Astrophysics · Physics 2009-11-10 T. Bensby , S. Feltzing , I. Lundstrom

We present a study of the chemical abundances of Solar neighbourhood stars associated to dynamical structures in the Milky Way's (thick) disk. These stars were identified as overdensity in the eccentricity range 0.3< ecc < 0.5 in the…

Astrophysics of Galaxies · Physics 2015-06-22 Amina Helmi , Mary Williams , K. C. Freeman , J. Bland-Hawthorn , G. De Silva

We have determined carbon abundances or upper limits from the forbidden [C I] line at 8727.13 A for 85 F and early G type main sequence stars, with metallicities ranging between [Fe/H] = -1.0 and [Fe/H] = +0.25. The [C I] line has not been…

Astrophysics · Physics 2007-05-23 Helena Andersson , Bengt Edvardsson

We present first results from a program to measure the chemical abundances of a large (N>30) sample of thick disk stars with the principal goal of investigating the formation history of the Galactic thick disk. Our analysis confirms…

We report on the HI content of an isolated, compact group of 6 dwarf galaxies at a distance of 145 Mpc. The distribution and kinematics of the HI, including multiple gaseous bridges, indicate the group is a gravitationally bound system. The…

We present a new version of the compiled catalogue of nearby stars for which was published the spectoscopically determined effective temperatures, surface gravities, and abundances of iron, magnesium, calcium, silicon, and titanium.…

Astrophysics · Physics 2007-10-25 T. V. Borkova , M. S. Katchieva , B. A. Marsakov , D. M. Pitkina

Chlorine abundances are reported in 15 evolved giants and one M dwarf in the solar neighborhood. The Cl abundance was measured using the vibration-rotation 1-0 P8 line of H$^{35}$Cl at 3.69851 $\mu$m. The high resolution L-band spectra were…

Solar and Stellar Astrophysics · Physics 2016-12-05 Z. G. Maas , C. A. Pilachowski , K. Hinkle

Initial C/O ratios of circumstellar disks have been obtained in solar-type stars by differential photospheric abundance analysis with respect to the Sun. We present C/O ratios of M dwarfs obtained by absolute abundance analysis derived from…

Solar and Stellar Astrophysics · Physics 2016-10-26 Tadashi Nakajima , Satoko Sorahana

Abundances of C, O, and Fe are determined for F and G main-sequence stars in the solar neighborhood in order to study trends and systematic differences in the C/Fe, O/Fe, and C/O ratios for stellar populations. Carbon abundances are…

Solar and Stellar Astrophysics · Physics 2014-09-05 P. E. Nissen , Y. Q. Chen , L. Carigi , W. J. Schuster , G. Zhao

We study the metal abundances of F and G type stars in the Galactic disk and halo using the Canada-France-Hawaii Telescope Legacy Survey D4 field. For a sample of stars within 7 kpc of the Galactic plane, we derive mean abundance values of…

Astrophysics · Physics 2009-11-13 Y. Karatas , M. Kilic , O. Gunes , F. Limboz

We present a non-local thermodynamic equilibrium abundance analysis of the resonance doublet Li I at 6707.8 A for 55 Galactic F and G supergiants and bright giants. The derived lithium abundances log \epsilon(Li) may be considered in three…

We present metallicity and photometric parallax calibrations for the F and G type dwarfs with photometric, astrometric and spectroscopic data. The sample consists of 168 dwarf stars covering the colour, iron abundance and absolute magnitude…

Astrophysics of Galaxies · Physics 2016-06-15 S. Tuncel Guctekin , S. Bilir , S. Karaali , S. Ak , T. Ak , Z. F. Bostanci

We present a chemical composition analysis of 36 giant stars in the mildly metal-poor globular cluster M5 (NGC 5904). The analysis makes use of high resolution data acquired at the Keck I telescope as well as a re-analysis of high…

We present alpha to iron abundance ratios for 226 individual red giant branch stars in nine dwarf galaxies of the Andromeda (M 31) satellite system. The abundances are measured from the combined signal of Mg, Si, Ca, and Ti lines in…

Astrophysics of Galaxies · Physics 2015-06-19 Luis C. Vargas , Marla C. Geha , Erik J. Tollerud

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 abundances and orbital parameters for 235 F- and G-type intermediate- and low- mass stars in the Galaxy is analyzed. We found that there are abundance gradients in the thin disk in both radial and vertical…

Astrophysics of Galaxies · Physics 2015-05-30 Chenzhou Cui , Yuqin Chen , Gang Zhao , Yongheng Zhao

Lithium abundances are presented for 91 dwarf and subgiant stars in the Galactic bulge. The analysis is based on line synthesis of the 7Li line at 6707 {\AA} in high-resolution spectra obtained during gravitational microlensing events, when…

Astrophysics of Galaxies · Physics 2020-02-26 T. Bensby , S. Feltzing , J. C. Yee , J. A. Johnson , A. Gould , M. Asplund , J. Meléndez , S. Lucatello

We investigated almost 500 stars distributed among 193 binary or multiple systems made of late-F, G-, or early-K primaries and late-K or M dwarf companion candidates. For all of them, we compiled or measured coordinates, J-band magnitudes,…

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