The remarkable visual binary system VW Arietis: Chemical composition of its components

1995 ◽  
Vol 107 ◽  
pp. 219 ◽  
Author(s):  
S. M. Andrievsky ◽  
I. V. Chernyshova ◽  
I. A. Usenko ◽  
V. V. Kovtyukh ◽  
V. E. Panchuk ◽  
...  

1993 ◽  
Vol 137 ◽  
pp. 554-556
Author(s):  
Timothy M. Brown ◽  
Jørgen Christensen-Dalsgaard ◽  
Barbara W. Mihalas

AbstractPulsation frequency separations, combined with other observations, can constrain the structural parameters of Sun-like stars. As an example, we treat a hypothetical visual binary system resembling α Cen.



1996 ◽  
Vol 281 (3) ◽  
pp. 1001-1015 ◽  
Author(s):  
R. D. Jeffries ◽  
D. A. H. Buckley ◽  
D. J. James ◽  
J. R. Stauffer






1992 ◽  
Vol 104 ◽  
pp. 1539 ◽  
Author(s):  
Erika Boehm-Vitense


1985 ◽  
Vol 90 ◽  
pp. 346 ◽  
Author(s):  
R. L. Walker ◽  
C. R. Chambliss


2021 ◽  
Author(s):  
Suhail G. Masda ◽  
A. R. Khan ◽  
J. M. Pathan


Astrophysics ◽  
2018 ◽  
Vol 61 (4) ◽  
pp. 444-457 ◽  
Author(s):  
E. V. Polyakov ◽  
O. O. Vasilkova ◽  
D. L. Gorshanov ◽  
M. A. Pogodin ◽  
N. A. Shakht


1998 ◽  
Vol 11 (1) ◽  
pp. 390-390
Author(s):  
V. Leushin ◽  
V. Chuvenkov ◽  
L. Snezhko

A model of internal structure and evolution of the peculiar binary system v Sgr is presented. The model corresponds well to the observed chemical composition of the main component atmosphere (10-4 H, 0.844 He, 0.013 C, 0.042 N by mass). It is supposed that about 5 million years ago the main component passed the stage of hydrogen nuclear burning in the shell over the helium core where the helium-carbon reactions took place. Because of convective mixing, the synthesized carbon diffusing into the hydrogen burning zone was catalyzing the reactions of the CN - cycle. This has resulted in anomalies in the chemical composition, particularly high nitrogen abundance in the layer observed now as the atmosphere of the main component since external layers were thrown off during the evolution. Following the calculated results, the quantitative restrictions of temperature and density in the layers and values of mixing parameters are obtained. It is shown that the best agreement with observations exists if the mass of the matter penetrating from the zone of helium-carbon reactions into the helium layer is 0.25 of the helium-carbon core mass. Moreover, the ratio of mass concentration He/C in this matter should equal 2, and the mass share diffusing into the layer of hydrogen burning should be in the range 0.25 - 0.30 of the layer mass.



1993 ◽  
Vol 138 ◽  
pp. 192-196
Author(s):  
L.S. Lyubimkov ◽  
T.M. Rachkovskaya

Duplicity is a very widespread phenomenon among Am-stars. For instance, Abt (1961) investigating 25 such stars found out that 22 of them are spectroscopic binaries. However this important phenomenon is ignored usually in chemical composition investigations of Am-stars. Consequently some “mean” element abundances are determined, which can noticeably differ from real abundances in atmospheres of components. Moreover false chemical anomalies can appear, as shown by the theoretical modelling of spectra of binary stars (Lyubimkov, 1989, 1992). Meanwhile accurate data on chemical composition of Am-stars must be considered as observational test for any hypothesis suggested for explanation of these objects.



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