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Related papers: The M dwarf problem: Fe and Ti abundances in a vol…

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With abundances and 2{\sigma} upper limits of fluorine (F) in seven metal-poor field giants, nucleosynthesis of stellar F at low metallicity is discussed. The measurements are derived from the HF(1-0) R9 line at 23358{\AA} using…

Astrophysics of Galaxies · Physics 2013-02-19 H. N. Li , H. -G. Ludwig , E. Caffau , N. Christlieb , G. Zhao

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 an abundance analysis based on high resolution spectra of 8 stars selected to span the full range in metallicity in the Draco dwarf spheroidal galaxy. We find [Fe/H] for the sample stars ranges from -1.5 to -3.0 dex. Combining…

Astrophysics of Galaxies · Physics 2009-08-05 Judith G. Cohen , Wenjin Huang

Deriving metallicities for solar-like stars follows well-established methods, but for cooler stars such as M dwarfs, the determination is much more complicated due to forests of molecular lines that are present. Several methods have been…

The consistency of the metallicity distributions of F, G and K dwarfs is studied. We present a new metallicity distribution for K dwarfs using metallicities determined from uvby photometry. There is a remarkable paucity of metal-poor K…

Astrophysics · Physics 2007-05-23 H. J. Rocha-Pinto , W. J. Maciel

The origin and evolution of fluorine in the Milky Way galaxy is still in debate. In particular, the increase of the [F/Fe] in metal-rich stars found from near-IR HF-lines is challenging to explain theoretically. We determine the fluorine…

Astrophysics of Galaxies · Physics 2023-08-09 G. Nandakumar , N. Ryde , G. Mace

A metal-rich environment facilitates planet formation, making metal-rich stars the most favorable targets for surveys seeking to detect new exoplanets. Using this advantage to identify likely low-mass planet hosts, however, has been…

Solar and Stellar Astrophysics · Physics 2012-03-15 Barbara Rojas-Ayala , Kevin R. Covey , Philip S. Muirhead , James P. Lloyd

We attempt to constrain the efficiency of additional transport or mixing processes that reduce the effect of atomic diffusion in stellar atmospheres. We apply spectral synthesis methods to spectra observed with the GIRAFFE spectrograph on…

Evolutionary models for massive stars, accounting for rotational mixing effects, do not predict any core-processed material at the surface of B dwarfs with low rotational velocities. Contrary to theoretical expectations, we present a…

Astrophysics · Physics 2009-11-13 T. Morel , S. Hubrig , M. Briquet

High-resolution HST ultra-violet spectra for five B-type stars in the Magellanic Bridge and in the Large and Small Magellanic Clouds have been analysed to estimate their iron abundances. Those for the Clouds are lower than estimates…

Astrophysics · Physics 2009-06-23 P. L. Dufton , R. S. I. Ryans , H. M. A. Thompson , R. A. Street

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 report results from the high resolution spectral analysis of the 107 metal rich (mostly [Fe/H]$\ge$7.67 dex) target stars from the Calan-Hertfordshire Extrasolar Planet Search program observed with HARPS. Using our procedure of finding…

Solar and Stellar Astrophysics · Physics 2017-05-10 Oleksiy M. Ivanyuk , James S. Jenkins , Yakiv V. Pavlenko , Hugh R. A. Jones , David J. Pinfield

Aims. In this work we develop a technique to obtain high precision determinations of both metallicity and effective temperature of M dwarfs in the optical. Methods. A new method is presented that makes use of the information of 4104 lines…

Solar and Stellar Astrophysics · Physics 2014-09-05 V. Neves , X. Bonfils , N. C. Santos , X. Delfosse , T. Forveille , F. Allard , S. Udry

The determination of the stellar parameters of M dwarfs is of prime importance in the fields of galactic, stellar and planetary astronomy. M stars are the least studied galactic component regarding their fundamental parameters. Yet, they…

Solar and Stellar Astrophysics · Physics 2015-05-27 V. Neves , X. Bonfils , N. C. Santos

Parameters and abundances for 1002 stars of spectral types F, G, and K of luminosity class IV and V have been derived. After culling the sample for rotational velocity and effective temperature, 867 stars remain for discussion. Twenty-eight…

Solar and Stellar Astrophysics · Physics 2016-12-28 R. Earle Luck

We describe observations and abundance analysis of a high-resolution, high-S/N survey of 168 stars, most of which are metal-poor dwarfs. We follow a self-consistent LTE analysis technique to determine the stellar parameters and abundances,…

Astrophysics · Physics 2009-10-31 Jon P. Fulbright

We present the results from a five-year campaign to gather multi-epoch, high-resolution spectra of a volume-complete sample of 413 M dwarfs with masses 10-30% that of the Sun that lie within 15 parsecs. We report weighted mean systemic…

We have obtained high-resolution spectroscopy of ten red giants in the Carina dwarf spheroidal (dSph) with UVES at the ESO/VLT. Here we present the abundances of O,Na,Mg,Si,Ca,Ti and Fe. By comparing the iron abundances [Fe/H] with calcium…

Abundances of five elements, Na, Mg, Al, Si, and Sr, are investigated for 44 very metal-poor stars (-4.0 < [Fe/H] < -1.5) in the Galactic halo system based on an Local Thermodinamic Equilibrium (LTE) analysis of high-resolution…