Different evolutionary pathways for the two subtypes of contact binaries

2020 ◽  
Vol 492 (3) ◽  
pp. 4112-4119 ◽  
Author(s):  
Xu-Dong Zhang ◽  
Sheng-Bang Qian ◽  
Wen-Ping Liao
Keyword(s):  
Density Distribution ◽  
Main Sequence ◽  
Evolutionary Relationship ◽  
Interior Structure ◽  
Radial Density ◽  
Main Sequence Stars ◽  
Radial Density Distribution ◽  
Type Contact ◽  
Contact Binaries ◽  
Evolutionary Pathways

ABSTRACT Secondary components of W UMa-type contact binaries (CBs) have many special properties, two of them are excess in radius and luminosity. In order to make these specialties clear, we propose radial density distribution to roughly detect the interior structure of the secondaries in CBs. By comparing the radial density distribution between secondary components of CBs and main-sequence stars, we find the radial density distribution of secondaries in A-subtype CBs are similar to main-sequence stars whose masses higher than 1.8 Msun, which suggests that these two kinds of stars may have some evolutionary relationship. While secondary components of W-subtype CBs are closely connected with stars whose masses lower than 1.8 Msun. Then, we investigate the mass–luminosity relation of secondaries in CBs, the big differences between two subtypes suggests that the overluminosity of secondaries in these two subtypes are caused by two different reasons. Overluminosity in A-subtype is because the secondary components are evolved from initial more massive stars, while in W-subtype is due to energy transfer.

Radial Density Distribution and Field Fluctuation of Magnetized Positive Column in Turbulence

1970 ◽  
Vol 29 (5) ◽  
pp. 1397-1397 ◽  
Author(s):  
Takeshi Takashima ◽  
Hiroshi Sato ◽  
Michio Matsumoto ◽  
Yoshiei Nakano
Keyword(s):  
Density Distribution ◽  
Positive Column ◽  
Radial Density ◽  
Field Fluctuation ◽  
Radial Density Distribution

scholarly journals Calculation of Radial Density Distribution Function for main orbital of Carbon atom and Carbon like ions

2014 ◽  
Vol 11 (4) ◽  
pp. 1455-1458
Author(s):  
Baghdad Science Journal
Keyword(s):  
Distribution Function ◽  
Carbon Atom ◽  
Density Distribution ◽  
Computer Software ◽  
Negative Ion ◽  
Radial Density ◽  
Density Distribution Function ◽  
Hartree Fock ◽  
Radial Density Distribution ◽  
Nitrogen Ion

Radial density distribution function of one particle D(r1) was calculated for main orbital of carbon atom and carbon like ions (N+ and B- ) by using the Partitioning technique .The results presented for K and L shells for the Carbon atom and negative ion of Boron and positive ion for nitrogen ion . We observed that as atomic number increases the probability of existence of electrons near the nucleus increases and the maximum of the location r1 decreases. In this research the Hartree-fock wavefunctions have been computed using Mathcad computer software .

scholarly journals Emission Line Profiles in RY Scuti: A Massive Binary in a Pre-WR Stage?

1991 ◽  
Vol 143 ◽  
pp. 261-262
Author(s):  
D. de Martino ◽  
A. A. Vittone ◽  
C. Rossi ◽  
F. Giovannelli
Keyword(s):  
Velocity Field ◽  
Main Sequence ◽  
Log P ◽  
Velocity Gradients ◽  
Evolutionary Phase ◽  
Mass Outflow ◽  
Blue Component ◽  
Type Contact ◽  
Contact Binaries ◽  
The Masses

RY Scuti (HD 169515) is a massive 9thmag eclipsing binary (Porb = 11.12d) surrounded by a peculiar nebula. High resolution spectroscopic observations in Hα, He I (λ5876), [N II] (λλ6548, 6584), [A III] (λ7136) and [S III] (λλ9069, 9532) are presented. All emission lines show a complex profile with two main structures: a sharp and strong red component and a very broad fainter complex blue one in which at least three sub-components can be detected. We have analysed these profiles in order to derive information on the velocity field in the nebula. Permitted and forbidden lines show the same velocity field indicating a common line forming region. The presence of a multi-structured blue component in all profiles gives evidence that velocity gradients are present within the nebula. Systemic corrected expansion velocities of + 30 and −45,−30,−9 Km/s are found for the red and the three blue components respectively. Weaker emission structures, reflecting the same asymmetries of the strong emissions, are observed close to the permitted lines at larger velocities (Vb = −189 Km/s and Vr = 158 K m/s). The observed velocity field indicates an asymmetric mass outflow from the system very likely through the second Lagrange point rather than via stellar wind. The system should loose mass during the mass exchange phase. Using the masses (M1 = 39M⊙, M2 = 49M⊙) and radii (R1 = 37R⊙, R2 = 41R⊙) of the two components (Milano et al., 1981), and locating RY Scuti in the [log R, log M] diagram for early type contact binaries from Leung and Schneider (1979), we find that this system has just evolved-off the Terminal Age Main Sequence. Moreover, placing RY Scuti in the [log P, log M1/M2] diagram for O+O and WR+OB binaries of Massey (1981) we find that it is in an evolutionary phase just preceeding a WR+OB stage.

Radial Density Distribution in Irradiated FBR MOX Fuel Pellets

2015 ◽  
Vol 189 (3) ◽  
pp. 312-317 ◽  
Author(s):  
Akihiro Ishimi ◽  
Kozo Katsuyama ◽  
Hirofumi Nakamura ◽  
Takeo Asaga ◽  
Hirotaka Furuya
Keyword(s):  
Density Distribution ◽  
Radial Density ◽  
Fuel Pellets ◽  
Mox Fuel ◽  
Radial Density Distribution
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