Related papers: Metallicity Effects on RR Lyrae Variables
On the basis of an extended set of nonlinear convective RR Lyrae pulsation models we derive the first theoretical light curves in the Gaia bands and the corresponding intensity-weighted mean magnitudes and pulsation amplitudes. The effects…
The relation between the Fourier coefficients determined by the light curves of RR Lyrae variables in the Sculptor dwarf galaxy, the M5 cluster, and the unique globular cluster omega-Centauri is investigated. A couple of recent papers claim…
Context. RR Gem is one of the few Blazhko RR Lyrae that has photometric observations available extended enough to study the long-term courses of its pulsation and modulation properties in detail. Aims. We investigate the pulsation and…
A theoretical investigation of the pulsation behavior of so-named ``anomalous'' Cepheids is presented. The study is based on nonlinear convective pulsation models with $Z$=0.0001 and 0.0004, mass in the range 1.3-2.2 Mo and various…
Companion stars exposed to high energy radiation from a primary neutron star or accreting black hole can experience significant spallation of their heavy elements, so that their atmospheres would be extremely rich in lithium, beryllium, and…
We perform a thorough theoretical analysis of resonance effects when an arbitrarily polarized plane monochromatic wave is incident onto a double periodically modulated metal film sandwiched by two different transparent media. The proposed…
Understanding electrical resistivity in metals remains a central challenge in quantifying charge transport at finite temperature. Current first-principles calculations based on the Boltzmann transport equation often match experiments, yet…
We report the discovery of a new group of double-periodic RR Lyrae stars from the analysis of the OGLE-IV Galactic bulge photometry. In 11 stars identified in the OGLE catalog as first overtone pulsators (RRc stars) we detect additional…
We present some recent findings concerning the use of RR Lyrae as distance indicators and stellar tracers. We outline pros and cons of field and cluster RR Lyrae stars and discuss recent theoretical findings concerning the use of the Bailey…
The additional signals observed in the frequency spectra of the first-overtone RR Lyrae stars, that form a period ratio around 0.61 with the period of the first overtone, are a common phenomenon for RRc and RRd stars, as well as for…
We have revisited the problem of metallicity prediction of RR Lyrae stars from their near-infrared light curves in the Cousins I waveband. Our study is based on high-quality time-series photometry and state-of-the-art high-resolution…
We analysed the light curve of four, apparently extremely metal-rich fundamental-mode RR Lyrae stars. We identified two stars, MT Tel and ASAS J091803-3022.6 as RRc (first-overtone) pulsators that were misclassified as RRab ones in the ASAS…
The compilation of the metallicity values of $\omega$~Centauri stars led to detection of spatial asymmetry in the metallicity distribution of the bright giants. It was found that the most and least metal-poor objects are separated along…
Electromagnetic waves impinging on three-dimensional helical metallic metamaterials have been shown to exhibit chiral effects of large magnitude both theoretically and in experimental realizations. Chirality here describes different…
In this paper we revisit observational data concerning RR Lyrae stars in Galactic globular clusters, presenting frequency histograms of fundamentalized periods for the 32 clusters having more than 12 pulsators with well recognized period…
The effects of rotation on low-metallicity stellar models are twofold: first, the models reach break-up during main sequence and may lose mass by mechanical process; second, strong internal mixing brings freshly synthesized elements towards…
We examined the complete short cadence sample of Kepler RR Lyrae stars to further investigate the recently discovered dynamical effects such as period doubling and additional modes. Here we present the findings on four stars. V450 Lyr may…
The stellar parameters of RR Lyrae stars vary considerably over a pulsation cycle, and their determination is crucial for stellar modelling. We present a detailed spectroscopic analysis of the pulsating star RR Lyr, the prototype of its…
We present preliminary results of an observational campaign devoted at establishing the influence of chemical composition on the Cepheid Period-Luminosity relation. The data are in good agreement with theoretical predictions based on…
With the aid of stellar atmosphere models, we derive iron abundances [Fe/H] from the OGLE B, V, I photometry on the Magellanic Cloud Cepheids. We show that in both clouds the average metallicities of the first overtone variables are lower…