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We have derived Mn abundances for more than 200 stars in 19 globular clusters. In addition, Mn abundance determinations have been made for a comparable number of halo field and disk stars possessing an overlapping range of metallicities and…

This work presents the medium-resolution ($R \sim 1,500$) spectroscopic follow-up of 522 low-metallicity star candidates from the Southern Photometric Local Universe Survey (S-PLUS). The objects were selected from narrow-band photometry,…

We present a spectral analysis of the binary G 224-58 AB that consists of the coolest M extreme subdwarf (esdM5.5) and a brighter primary (esdK5). This binary may serve as a benchmark for metallicity measurement calibrations and as a…

Solar and Stellar Astrophysics · Physics 2015-10-21 Ya. V. Pavlenko , Z. H. Zhang , M. C. Gálvez-Ortiz , I. O. Kushniruk , H. R. A. Jones

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

The study of stellar parameters of planet-hosting stars, such as metallicity and chemical abundances, help us to understand the theory of planet formation and stellar evolution. Here, we present a catalogue of accurate stellar atmospheric…

Solar and Stellar Astrophysics · Physics 2015-03-11 S. Alves , L. Benamati , N. C. Santos , V. Zh. Adibekyan , S. G. Sousa , G. Israelian , J. R. De Medeiros , C. Lovis , S. Udry

Infrared OH lines at 1.5 - 1.7 um in the H band were obtained with the NIRSPEC high-resolution spectrograph at the 10m Keck Telescope for a sample of seven metal-poor stars. Detailed analyses have been carried out, based on optical…

Astrophysics · Physics 2009-11-07 Jorge Melendez , Beatriz Barbuy

The young $\sigma$-Orionis cluster is an important location for understanding the formation and evolution of stars, brown dwarfs, and planetary-mass objects. Its metallicity, although being a fundamental parameter, has not been well…

The abundance of iron is measured from emission line complexes at 6.65 keV (Fe line) and 8 keV (Fe/Ni line) in {\em RHESSI} X-ray spectra during solar flares. Spectra during long-duration flares with steady declines were selected, with an…

Solar and Stellar Astrophysics · Physics 2015-06-03 K. J. H. Phillips , B. R. Dennis

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…

We present low-resolution MMT Hectospec spectroscopy of 594 candidate Monoceros stream member stars. Based on strong color-magnitude diagram overdensities, we targeted three fields within the stream's footprint, with 178 deg < l < 203 deg…

Astrophysics of Galaxies · Physics 2012-08-28 Aaron M. Meisner , Anna Frebel , Mario Juric , Douglas P. Finkbeiner

We determine the metallicity distribution function (MDF) of the Galactic halo by means of a sample of 1638 metal-poor stars selected from the Hamburg/ESO objective-prism survey (HES). The sample was corrected for minor biases introduced by…

In an attempt of clarifying the [S/Fe] behavior with the run of [Fe/H] in the metal-poor regime which has been a matter of debate, an extensive non-LTE analysis of near-IR S I triplet lines (multiplet 3) at 1.046 micron was carried out for…

Solar and Stellar Astrophysics · Physics 2015-05-19 Yoichi Takeda , Masahide Takada-Hidai

Stellar chromospheric activity serves as a valuable proxy for estimating stellar ages, though its applicable range and accurate functional form are still debated. In this study, utilizing the LAMOST spectra we compiled a catalog of open…

Solar and Stellar Astrophysics · Physics 2026-01-27 Henggeng Han , Song Wang , Xue Li , Chuanjie Zheng , Jiahui Wang , Jifeng Liu

HARPS-N spectra with S/N > 250 and MARCS model atmospheres were used to derive abundances of C, O, Na, Mg, Al, Si, Ca, Ti, Cr, Fe, Ni, Zn, and Y in ten stars from the Kepler LEGACY sample (including the binary pair 16 Cyg A and B) selected…

Solar and Stellar Astrophysics · Physics 2017-12-13 P. E. Nissen , V. Silva Aguirre , J. Christensen-Dalsgaard , R. Collet , F. Grundahl , D. Slumstrup

We present the results of a spectroscopic survey of the Ca II H & K core strengths in a sample of 60 solar-type stars that are members of the solar-age and solar-metallicity open cluster M67. We adopt the HK index, defined as the summed H+K…

Astrophysics · Physics 2008-11-26 Mark S. Giampapa , Jeffrey C. Hall , Richard R. Radick , Sallie L. Baliunas

Context. Searching for extrasolar planets through radial velocity measurements relies on the stability of stellar photospheres. Aims. We aim at characterizing the statistical properties of magnetic activity cycles, and studying their impact…

Solar and Stellar Astrophysics · Physics 2011-07-28 C. Lovis , X. Dumusque , N. C. Santos , F. Bouchy , M. Mayor , F. Pepe , D. Queloz , D. Ségransan , S. Udry

We study the metallicity distribution and kinematic properties of 4,680 A/F/G/K-type giant stars with $|z|>$ 5 kpc selected from the LAMOST spectroscopic survey. The metallicity distribution of giant stars with 5 $<|z|\leqslant$ 15 kpc can…

Astrophysics of Galaxies · Physics 2018-08-15 Shuai Liu , Cuihua Du , Heidi Jo Newberg , Yuqin Chen , Zhenyu Wu , Jun Ma , Xu Zhou , Zihuang Cao , Yonghui Hou , Yuefei Wang , Yong Zhang

We present chemical abundances for 21 elements (from Li to Eu) in 150 metal-poor Galactic stars spanning $-$4.1 $<$ [Fe/H] $<$ $-$2.1. The targets were selected from the SkyMapper survey and include 90 objects with [Fe/H] $\le$ $-$3 of…

Based on the Beijing-Arizona-Taiwan-Connecticut (BATC) and Sloan Digital Sky Survey (SDSS) photometric data, we adopt SEDs fitting Method to evaluate the metallicity distribution for \sim40,000 main-sequence stars in the Galaxy. According…

Astrophysics of Galaxies · Physics 2015-06-03 Xiyan Peng , Cuihua Du , Zhenyu Wu

The estimation of stellar atmospheric parameters for large-scale samples, particularly metal-poor stars, is a cornerstone of Galactic archaeology. In this work, we optimized a photometric filter design tailored to measuring stellar…

Solar and Stellar Astrophysics · Physics 2026-04-24 Ruifeng Shi , Yang Huang , Kai Xiao , Chuanjie Zheng , Bowen Zhang , Hongrui Gu , Xinyi Li , Huiling Chen
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