86 research outputs found
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 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 Γ
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. Β© 2002 MAIK "Nauka/Interperiodica"
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