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Accurate determinations of metallicity for large, complete stellar samples are essential for advancing various studies of the Milky Way. In this paper, we present a data-driven algorithm that leverages photometric data from the KiDS and the…

Astrophysics of Galaxies · Physics 2025-02-11 Bao-Kun Sun , Bing-Qiu Chen , Xiao-Wei Liu

We report photometric estimates of effective temperature, $T_{\rm eff}$, metallicity, [Fe/H], carbonicity, [C/Fe], and absolute carbon abundances, $A{\rm (C)}$, for over 700,000 stars from the Southern Photometric Local Universe Survey…

We derive new empirical calibrations for strong-line diagnostics of gas phase metallicity in local star forming galaxies by uniformly applying the Te method over the full metallicity range probed by the Sloan Digital Sky Survey (SDSS). To…

Astrophysics of Galaxies · Physics 2016-11-02 M. Curti , G. Cresci , F. Mannucci , A. Marconi , R. Maiolino , S. Esposito

We present new calibrations of stellar parameters of O stars at solar metallicity taking non-LTE, wind, and line-blanketing effects into account. Gravities and absolute visual magnitudes are derived from results of recent spectroscopic…

Astrophysics · Physics 2009-05-29 F. Martins , D. Schaerer , D. J. Hillier

We present atmospheric parameters for about 300 stars of different chemical composition, whose spectra will be used to study the galactic enrichment of Fe and light elements. These parameters were derived using an homogenous iterative…

Astrophysics · Physics 2007-05-23 R. G. Gratton , E. Carretta , F. Castelli

Relative abundances of the five stable isotopes of titanium (^46Ti to ^50Ti) are measured for 11 M dwarfs belonging to the thin disk (four stars), thick disk (three stars), the halo (one star), and either the thick or the thin disk (three…

Solar and Stellar Astrophysics · Physics 2009-07-24 J. Chavez , D. L. Lambert

We present a series of systematic abundance measurements for a group of hot DA white dwarfs in the temperature range 20,000-75,000K, based on far-UV spectroscopy with STIS on HST, IUE and FUSE. Using our latest heavy element blanketed…

The fraction of binary stars (fb) is one of most valuable tool to probe the star formation and evolution of multiple systems in the Galaxy. We focus on the relationship between fb and stellar metallicity ([Fe/H]) by employing the…

Solar and Stellar Astrophysics · Physics 2017-05-31 Shuang Gao , He Zhao , Hang Yang , Ran Gao

Stellar metallicity strongly correlates with the presence of planets and their properties. To check for new correlations between stars and the existence of an orbiting planet, we determine precise stellar parameters for a sample of…

Solar and Stellar Astrophysics · Physics 2015-05-20 Sérgio G. Sousa , Nuno C. Santos , Garik Israelian , C. Lovis , Michel Mayor , Pedro B. Silva , Stephane Udry

In this paper, we use the Mappings photoionization code to explore the physical parameters that impact on the measurement of electron temperature and abundance in HII regions. In the previous paper we presented observations and measurements…

Astrophysics of Galaxies · Physics 2015-06-19 David C. Nicholls , Michael A. Dopita , Ralph S. Sutherland , Helmut Jerjen , Lisa J. Kewley , Hassan Basurah

We present NIR synthetic spectra based on PHOENIX stellar atmosphere models of typical early and mid M dwarfs with varied C and O abundances. We apply multiple recently published methods for determining M dwarf metallicity to our models to…

Solar and Stellar Astrophysics · Physics 2016-09-21 Mark J. Veyette , Philip S. Muirhead , Andrew W. Mann , France Allard

We provide the whole set of Lick indices from CN1 to TiO2 of Simple Stellar Population models with, for the first time, variable element abundance ratios, [alpha/Fe]=0.0, 0.3, 0.5, [alpha/Ca]=-0.1, 0.0, 0.2, 0.5, and [alpha/N]=-0.5, 0.0.…

Astrophysics · Physics 2009-11-07 Daniel Thomas , Claudia Maraston , Ralf Bender

We present a recalibration of the luminosity-metallicity relation for gas-rich, star-forming dwarfs to magnitudes as faint as M$_R$ ~ -13. We use the Dopita et al. (2013) metallicity calibrations to calibrate the relation for all of the…

We present the effective temperatures ($T_{\rm eff}$), metallicities, and colours in SDSS, 2MASS, and WISE filters, of a sample of 3834 late-K and early-M dwarfs selected from the Sloan Digital Sky Survey APOGEE spectroscopic survey ASPCAP…

Solar and Stellar Astrophysics · Physics 2016-07-27 Sarah J. Schmidt , Erika L. Wagoner , Jennifer A. Johnson , James R. A. Davenport , Keivan G. Stassun , Diogo Souto , Jian Ge

We are now in an era of large spectroscopic surveys of OB-type stars. Quantitative spectroscopic analysis of these modern datasets is enabling us to review the physical properties of blue massive stars with robust samples, not only…

Solar and Stellar Astrophysics · Physics 2014-10-22 S. Simón-Díaz , A. Herrero , C. Sabín-Sanjulián , F. Najarro , M. Garcia , J. Puls , N. Castro , C. J. Evans

Using classical model atmospheres and an LTE analysis, Mg isotope ratios 24Mg:25Mg:26Mg are measured in 32 Hyades dwarfs covering 4000K < Teff < 5000K. We find no significant trend in any isotope ratio versus Teff and the mean isotope ratio…

Astrophysics · Physics 2009-11-10 David Yong , David L. Lambert , Carlos Allende Prieto , Diane B. Paulson

Elemental abundances of Sun-like stars are crucial for understanding the detailed properties of their planets. However, measuring elemental abundances in M stars is challenging due to their faintness and pervasive molecular features in…

Solar and Stellar Astrophysics · Physics 2024-08-28 Haiyang S. Wang , Sascha P. Quanz , Suvrath Mahadevan , Morgan Deal

With the dual aims of enlarging the list of extremely metal-poor stars identified in the Galaxy, and boosting the numbers of moderately metal-deficient stars in directions that sample the rotational properties of the thick disk, we have…

The research focuses on determining the metallicity ([Fe/H]) predicted in the solar twin stars by using various regression modeling techniques which are, Random Forest, Linear Regression, Decision Tree, Support Vector, and Gradient…

Solar and Stellar Astrophysics · Physics 2024-10-10 Sathwik Narkedimilli , Satvik Raghav , Sujith Makam , Prasanth Ayitapu , Aswath Babu H

Using previous measurements and quantum chemical calculations to derive the molecular properties of the TiH molecule, we obtain new values for its ro-vibrational constants, thermochemical data, spectral line lists, line strengths, and…

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