相关论文: Toward more accurate RR Lyrae metallicities

The properties of RR Lyrae variables make them excellent probes of the formation and evolution of a stellar population. The mere presence of such stars necessitates an age greater than ~10 Gyr while their periods and amplitudes can be used…

We present new period-luminosity and period-luminosity-metallicity relations for Galactic RR Lyrae stars based on a sample of 28 pulsators located at distances up to $1.5$ kpc from the Sun. Near-infrared photometry was obtained at the Cerro…

We introduce a new photometric catalog of RR Lyrae variables (RRLs, $\sim$300,000) mainly based on data available in public datasets. We also present the largest and most homogeneous spectroscopic dataset of RRLs and Blue Horizontal Branch…

We constructed new sets of He-enhanced (Y = 0.30, Y = 0.40) nonlinear, time-dependent convective hydrodynamical models of RR Lyrae (RRL) stars covering a broad range in metal abundances (Z from 0.0001 to 0.02). The increase in He content…

We have analysed 1455 fundamental mode RR Lyrae stars of the Galactic field, using the All Sky Automated Survey (ASAS) data. The sample covers 75% of the sky and contains objects in the close neighbourhood of the Sun, within 4 kpc distance.…

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,…

A grid of synthetic horizontal-branch (SHB) models based on HB evolutionary tracks with improved physics has been constructed to reconsider the theoretical calibration of the dependence of M_v(RR) on metallicity in globular clusters, and…

We use the calibrations by Calamida et al. and by Hilker et al., and the standardised synthetic photometry in the v, b, and y Stromgren passbands from Gaia DR3 BP/RP spectra, to obtain photometric metallicities for a selected sample of…

We report new statistical equilibrium calculations for Fe I and Fe II in the atmosphere of Late-Type stars. We used atomic models for Fe I and Fe II having respectively 256 and 190 levels, as well as 2117 and 3443 radiative transitions.…

RR Lyrae variables are excellent population II distance indicators thanks to their well-defined period-luminosity relations (PLRs) at infrared wavelengths. We present results of near-infrared (NIR) monitoring of Galactic globular clusters…

We describe and employ a stacking procedure to investigate abundances derived from the low S/N spectra obtained in the Carnegie RR Lyrae Survey (CARRS; Kollmeier et al. 2013). We find iron metallicities that extend from [Fe/H] ~ -2.5 to…

88 dwarfs, covering the colour index interval 0.37 <(B-V)o <= 1.07 mag, with metallicities -2.70 <= [Fe/H] <= +0.26 dex have been taken from three different sources for new metallicity calibration. The catalogue of Cayrel de Stroble et al.…

RR Lyrae (RRL) variable stars are cornerstone distance indicators. In particular, double-mode RR Lyrae (RRd) stars enable period--luminosity relations (PLRs) that are less sensitive to metallicity, reducing systematic biases in distance…

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…

Recent radiative lifetime measurements accurate to +/- 5% (Stockett et al. 2007, J. Phys. B 40, 4529) using laser-induced fluorescence (LIF) on 8 even-parity and 62 odd-parity levels of Er II have been combined with new branching fractions…

The study of chemical abundances in stars with planets is an important ingredient for the models of formation and evolution of planetary systems. In order to determine accurate abundances, it is crucial to have a reliable set of atmospheric…

In an era of extensive photometric observations, the catalogs of RR Lyr type variable stars number tens of thousands of objects. The relation between the iron abundance [Fe/H] and the Fourier parameters of the stars light curve allows us to…

We present a calibration of the metallicity and physical parameters (temperature, luminosity, gravity, mass, radius) for RR Lyrae stars using the ugriz SDSS photometric system. Our work is based on calculations of synthetic horizontal…

We present a revised catalog of 2106 Galactic stars, selected without kinematic bias, and with available radial velocities, distance estimates, and metal abundances in the range 0.0 <= [Fe/H] <= -4.0. This update of the Beers and…

We present element-to-element abundance ratios measured from high dispersion spectra for 150 field subdwarfs and early subgiants with accurate Hipparcos parallaxes (errors <20%). For 50 stars new spectra were obtained with the UVES on…