We determine the metallicity and detailed chemical abundances (α, iron-peak and neutron-capture elements) for the almost complete (18/24) sample of Galactic double mode Cepheids (also called beat Cepheids). Double mode Cepheids are Cepheids that pulsate in two modes simultaneously. We calibrate a new relation between their metallicity and their period ratio P₁/P₀. This linear relation allows to determine the metallicity of bimodal Cepheids with an accuracy of 0.03 dex in the range of [Fe/H] from +0.2 to −0.5 dex. By extrapolating the relation to Magellanic Clouds beat Cepheids, we provide their metallicity distribution function. Moreover, by using this relation, we also provide the first metallicity estimate for two double-mode F/1O Cepheids located in and beyond the Galactic bulge. Finally, we report the discovery of a super-Lithium rich double mode Cepheid V371 Per which has a Lithium abundance of logA(Li) = 3.54 ± 0.09 dex. Along with V1033 Cyg (which is an ordinary classical Cepheid), it is the second known Cepheid of such type in the Galaxy.

Using three independent theoretical approaches (CA, HFR + CP, AUTOSTRUCTURE), oscillator strengths have been calculated for a set of Tc ii transitions

Using high-dispersion spectral observations of HD 101065 (Przybylski's star) we have identified the lines of heavy radioactive elements with atomic numbers from 84 to 99 in the spectrum of the star. We found the lines of all these elements except At (Z=85) and Fr (Z=87). We try to explain a presence of such heavy species in the atmosphere of this star as a result of radioactive decay of Th and U nuclei and neutron capture process producing some transuranium isotopes. The necessary conditions for these processes to work may appear due to atomic diffusion and favorable accumulation of the thorium and uranium nuclei in the upper of the PS atmosphere.To search for other articles by the author(s) go to: http://adsabs.harvard.edu/abstract_service.html

Chemical Composition of RR Lyn - an Eclipsing Binary System with Am and λ Boo Type Components stars;eclipsing binaries (RR Lyn);individual (RR Lyn);abundances;accretion;chemically peculiar; High-resolution spectroscopic observations of the eclipsing binary system RR Lyn were made using the 1.8 m telescope at the Bohuynsan Optical Astronomical Observatory in Korea. The spectral resolving power was R = 82,000, with a signal to noise ratio of S/N > 150. We found the effective temperatures and surface gravities of the primary and secondary components to be equal to $T_{eff}$ = 7,920 & 7,210 K and log(g) = 3.80 & 4.16, respectively. The abundances of 34 and 17 different chemical elements were found in the atmospheric components. Correlations between the derived abundances with condensation temperatures and the second ionization potentials of these elements are discussed. The primary component is a typical metallic line star with the abundances of light and iron group elements close to solar values, while elements with atomic numbers Z > 30 are overabundant by 0.5-1.5 dex with respect to solar values. The secondary component is a ${\lambda}$ Boo type star. In this type of stars, CNO abundances are close to solar values, while the abundance pattern shows a negative correlation with condensation temperatures.

We investigated the chemical composition of the planetary host halo star HD47536 via high-resolution spectral observations recorded using a 1.5 meter Cerro Tololo Inter-American Observatory (CTIO) telescope (Chile). Furthermore, we determined the abundances of 38 chemical elements. Both light and heavy elements were overabundant compared to the iron group elements. The abundance pattern of HD47536 was similar to that of halo-type stars, with an enrichment of heavy elements. We analyzed the relationships between the relative abundances of chemical elements and their second ionization potentials and condensation temperatures. We demonstrated that the interplay of charge-exchange reactions owing to the accretion of interstellar matter and the gas-dust separation mechanism can influence the initial abundances and can be used to qualitatively explain the abundance patterns in the atmosphere of HD47536.