Related papers: Metallicity Effects on RR Lyrae Variables
We present the first results from MMT and Keck spectroscopy for a large sample of $0.1\leq z\leq1$ emission-line galaxies selected from our narrow-band imaging in the Subaru Deep Field. We measured the weak [OIII]$\lambda$4363 emission line…
Several classes of pulsating stars are now known to undergo slow changes in amplitude; these include pulsating red giants and supergiants, and yellow supergiants. We have used visual observations from the AAVSO International Database, and…
The search for materials displaying a large magnetoelectric effect has occupied researchers for many decades. The rewards could include not only advanced electronics technologies, but also fundamental insights concerning the dielectric and…
The relations for the polarizability of the metallic nanoparticles, coated with the shell of cyanine dyes, are obtained in the article. The frequency dependencies for light absorption and scattering efficiencies, the heating of the…
We investigate the effect of strong magnetic fields on the adiabatic radial oscillations of hadronic stars. We describe magnetized hadronic matter within the framework of the relativistic nonlinear Walecka model and integrate the equations…
Accurate relative abundances have been obtained for a sample of 21 mildly metal-poor stars from the analysis of high resolution and high signal-to-noise spectra. With these accurate results, correlations between relative abundances have…
It is well known that Raman scattering and fluorescence can be enhanced by the presence of metallic nanoparticles. Here, we derive simple equations to analyse the influence of metallic nanoparticles on upconversion processes such as…
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…
The recently published spectroscopic metallicities of RR Lyrae stars in M3 (Sandstrom, K., Pilachowski, C. A., and Saha, A. 2001, AJ 122, 3212) though show a relatively wide range of the [Fe/H] values, the conclusion that no metallicity…
This srudy investigates the influence of relativistic effects on some properties of the halogen group and gold atoms, including their ions. The analysis covers radii, orbital's energy, first and second ionization energies, electron…
We present the results of a new study investigating the relationship between observed Ly$\alpha$ equivalent width ($W_{\lambda}$(Ly$\alpha$)) and the metallicity of the ionizing stellar population ($Z_{\star}$) for a sample of $768$…
We present newly-calibrated period-$\phi_{31}$-[Fe/H] relations for fundamental mode RR Lyrae stars in the optical and, for the first time, mid-infrared. This work's calibration dataset provides the largest and most comprehensive span of…
The large charge-transfer anisotropy of quasi-one- and quasi-two-dimensional crystalline organic metals means that magnetoresistance is one of the most powerful tools for probing their bandstructure and interesting phase diagrams. Here we…
The knowledge of accurate stellar parameters is a keystone in several fields of stellar astrophysics, such as asteroseismology and stellar evolution. Although the fundamental parameters can be derived both from spectroscopy and multicolour…
We have shown that alloying a noble metal (gold) with another metal (cadmium), which can contribute two electrons per atom to a free electron gas, can significantly improve the metals optical properties in certain wavelength ranges and make…
Up to now, it seemed that the additional frequencies in the fundamental mode (RRab) and in the overtone mode pulsating (RRc and RRd) RR Lyrae stars have different nature. RRab stars show frequencies associated with periodic doubling, as…
Accurate metallicities of RR Lyrae are extremely important in constraining period-luminosity-metallicity relationships (PLZ), particularly in the near-infrared. We analyse 69 high-resolution spectra of Galactic RR Lyrae stars from the…
The influence of the electromagnetic irradiation pressure on a spheroidal metallic nanoparticle at the frequencies close to the surface plasmon vibrations has been considered. With the action of the radiation pressure, the polarizability of…
We study the linewidth of the surface plasmon resonance in the optical absorption spectrum of metallic nanoparticles, when the decay into electron-hole pairs is the dominant channel. Within a semiclassical approach, we find that the…
We discuss the effects of surfaces on bulk plasma oscillations in a metallic film of thickness $L$. The leading corrections to the plasma frequencies due to the surfaces are proportional to $L^{-1}$. dispersion relation of bulk modes,…