Some evolutionary aspects of the binary stellar systems containing neutron star

The obvious lack of the binary stellar systems that contain neutron stars (NS) is observed at present. Partly it is caused by the fact that it is very difficult to detect neutron star in a binary system if this relativistic component does not manifest itself as a radio pulsar. Among 1879 pulsars that are listed in the ATNF pulsar catalogue, only 141 pulsars are known to be the companions in binary systems. Only 81 objects having median mass estimation of more than 0.2 $M_{\odot}$ constitute the binary systems with pulsars. Nevertheless, such systems should be much more numerous and their investigation is of the great interest because thier structure and evolution can certainly help in our understanding of many unique properties that are seen in some stars.Comment: Accepted to published in the Odessa Astronomical Publications, 2012, vol. 25/1, p.35-3

Some Statistical Picture of Magnetic CP Stars Evolution

We discuss some statistical results on the evolution of magnetic CP stars in the framework of the supposition about their binary nature.Comment: 3 pages, 3 figure

Analysis of the spectral energy distribution of the coolest RCrB type carbon star DY Per

We analyse the spectral energy distribution of the evolved carbon giant DY Per with a spectral synthesis technique. The red giant shows the photometric features of R CrB type stars. We derive the atmospheric parameters of DY Per using three variants of molecular line lists. We estimate Teff to be in the range 2900 < Teff < 3300 K. We adopted log g = 0. The star may be metal deficient and hydrogen deficient. The maximum possible carbon abundance in the star, [C]=0.94, provides the following atmospheric parameters: Tef=3100 K, [Fe/H] = 0, log(C/O)=0.6, [N/Fe] = 0, [H/He] = 0, with Jorgensen's line lists for the molecules C2 and CN.Comment: 4 pages, 2 tables, 3 figs, accepted by Odessa asronomical observatory Publ., 200

Effects of spot structure of lines of rare earths and non-LTE effects on lithium abundance estimates for two roAp stars

Taking into account blending of the lithium 6108 Å line profile by adjacent rare-earth lines together with their spotted surface structure does not appreciably affect lithium abundance estimates for the atmospheres of HD 83368 and HD 60435 but provides a better fit of the observed and stimulated line profiles. Our computed non-LTE corrections reduce the lithium abundance estimates by 0.1-0.2 dex for both stars. Given the uncertainties in the lithium abundances, it is not possible to be certain whether the lithium abundances in map stars, or at least in their spots, exceed the cosmic (primordial) value. © 2002 MAIK "Nauka/Interperiodica"