Related papers: Physical Parameters for RR Lyrae Stars in the SDSS…
We discuss an alternative approach to constrain the absolute bolometric luminosity of Zero Age Horizontal Branch structures by using the observational pulsational properties of ab type RR Lyrae stars and theoretical expectations concerning…
The visually close binary system HD25811 is analyzed to estimate its physical and geometrical parameters in addition to its spectral type and luminosity class. The method depends on obtaining the best fit between the entire observational…
We investigate the physical and morphological properties of LBGs at z ~2.5 to ~3.5, to determine if and how they depend on the nature and strength of the Lyalpha emission. We selected U-dropout galaxies from the z-detected GOODS MUSIC…
We combine LAMOST DR7 spectroscopic data and Gaia EDR3 photometric data to construct high-quality giant (0.7 $< (BP-RP) <$ 1.4) and dwarf (0.5 $< (BP-RP) < $ 1.5) samples in the high Galactic latitude region, with precise corrections for…
We have revisited and updated the $uvby$ Str\"omgren colour and colour-index distributions of A, F and early G-type main sequence stars. For this aim, we selected 7054 dwarf stars along with 65 MK standard stars within the same spectral…
We analyze a sample of tens of thousands of spectra of halo turnoff stars, obtained with the optical spectrographs of the Sloan Digital Sky Survey (SDSS), to characterize the stellar halo population "in situ" out to a distance of a few tens…
A low-latitude anticenter field (l=189, b=+21) is investigated by using the full calibration tools of RGU photometry. The observed RGU data are reduced to the standard system and the separation of dwarfs and evolved stars is carried out by…
We present a new detailed abundance study of field red horizontal branch (RHB) and blue horizontal branch (BHB) non-variable stars. High resolution and high S/N echelle spectra of 11 RHB and 12 BHB were obtained with the McDonald 2.7 m…
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 predicted relations connecting pulsational and evolutionary parameters, as based on a wide set of convective pulsating models of RR Lyrae stars with Z=0.001, Y=0.24 and mass and luminosity suitable for the ``old'' (age $>$ 8 Gyr)…
[Fe/H] - phi_31 - log P relations are found for c-type RR Lyrae stars in globular clusters. The relations are analogous to that found by Jurcsik & Kovacs (1996) for field ab-type RR Lyrae stars, where a larger period correlates with lower…
Knowledge of stellar atmospheric parameters ($T_{\rm eff}$, $\log{g}$, [Fe/H]) of M dwarfs can be used to constrain both theoretical stellar models and Galactic chemical evolutionary models, and guide exoplanet searches, but their…
The China Space Station Telescope (CSST) will conduct a deep and wide imaging survey in the NUV-, u-, g-, r-, i-, z-, and y-bands. In this work, using theoretical data synthesized from the BOSZ spectra of Bohlin et al. (2017), along with…
Photospheric abundances of C, N, O, and Na were determined by applying the synthetic spectrum-fitting technique to 34 snap-shot high-dispersion spectra of 22 RR Lyr stars covering a metallicity range of -1.8 <[Fe/H] < 0.0, with an aim of…
Due to the importance of accurate Fourier parameters, we devise a method that is more appropriate for deriving these parameters on low-quality data than the traditional Fourier fitting. Based on the accurate light curves of 248 fundamental…
We describe a standard star catalog constructed using multiple SDSS photometric observations (at least four per band, with a median of ten) in the $ugriz$ system. The catalog includes 1.01 million non-variable unresolved objects from the…
The spectra of emission-line galaxies (ELGs) from the extended Baryon Oscillation Spectroscopic Survey (eBOSS) of the Sloan Digit Sky Survey (SDSS) are used to study the mass-metallicity relation (MZR) at $z\sim0.8$. The selected sample…
We present a detailed light curve analysis of RR Lyrae variables at multiple wavelengths using Fourier decomposition method. The time-series data for RR Lyrae variables in the Galactic bulge and the Magellanic Clouds are taken from the…
Getting spectra at good signal-to-noise ratios takes orders of magnitudes more time than photometric observations. Building on the technique developed for photometric redshift estimation of galaxies, we develop and demonstrate a…
We present an analysis of VI CCD time-series photometry of the globular cluster NGC 6171. The main goal is to determine individual physical parameters for single-mode RR Lyrae stars present in the field of view of our images, by means of…