scholarly journals Mass Transfer Characterization in Close Binary Stars

1992 ◽  
Vol 151 ◽  
pp. 337-340
Author(s):  
J. M. García ◽  
A. Giménez

A method for estimating representative values of the parameters that characterize the loss of mass and angular momentum occurred during the evolution of a close binary star is considered. Absolute dimensions previous to mass-transfer stage have been obtained for a select group of 43 semidetached systems adopting a grid of values of mass loss, angular momentum loss and initial mass ratio. Our study reveals a highly non-conservative scenario for the evolution towards an Algol-type system.

1987 ◽  
Vol 93 ◽  
pp. 675-679
Author(s):  
V.G. Karetnikov

AbstractFrom the values of period changes for 6 close binary stars the mass transfer rate was calculated. Comparing these values Mt with the values of shell masses Msh, the expressionwas derived. The analysis of this expression points out the initial character of the outflow of matter, and one may determine the time interval of the substitution of the shell matter. So one may conclude that for a certain mass transfer rate, a certain amount of matter accumulates in the nearby regions of the system.


1992 ◽  
Vol 151 ◽  
pp. 245-252
Author(s):  
E. F. Guinan

A review of IAU Symposium 151 on Interacting Binary Stars is given along with discussions of the present and future prospects of research in close binary stars.


Author(s):  
Zhao Guo

The study of stellar oscillations allows us to infer the properties of stellar interiors. Meanwhile, fundamental parameters such as mass and radius can be obtained by studying stars in binary systems. The synergy between binarity and asteroseismology can constrain the parameter space of stellar properties and facilitate the asteroseismic inference. On the other hand, binarity also introduces additional complexities such tides and mass transfer. From an observational perspective, we briefly review the recent advances in the study of tidal effects on stellar oscillations, focusing on upper main sequence stars (F-, A-, or OB- type). The effect can be roughly divided into two categories. The first one concerns the tidally excited oscillations (TEOs) in eccentric binaries where TEOs are mostly due to resonances between dynamical tides and gravity modes of the star. TEOs appear as orbital-harmonic oscillations on top of the eccentric ellipsoidal light curve variations (the “heartbeat” feature). The second category is regarding the self-excited oscillations perturbed by static tides in circularized and synchronized close binaries. It includes the tidal deformation of the propagation cavity and its effect on eigenfrequencies, eigenfunctions, and the pulsation alignment. We list binary systems that show these two types of tidal effect and summarize the orbital and pulsation observables. We also discuss the theoretical approaches used to model these tidal oscillations and relevant complications such as non-linear mode coupling and resonance locking. Further information can be extracted from the observations of these oscillations which will improve our understanding of tides. We also discuss the effect of mass transfer, the extreme result of tides, on stellar oscillations. We bring to the readers' attention: (1) oscillating stars undergoing mass accretion (A-, F-, and OB type pulsators and white dwarfs), for which the pulsation properties may be changed significantly by accretion; (2) post-mass transfer pulsators, which have undergone a stable or unstable Roche-Lobe overflow. These pulsators have great potential in probing detailed physical processes in stellar interiors and mass transfer, as well as in studying the binary star populations.


1980 ◽  
Vol 88 ◽  
pp. 149-153 ◽  
Author(s):  
Jon K. West ◽  
Kwan-Yu Chen

Conventional computer models of close binary star systems usually start with at least one component on the main sequence. Models of premain sequence binaries have been computed to study mass transfer (Yamasaki 1971). However no pre-main sequence computations have been published that follow the evolutionary tracks of a binary system onto the main sequence, even though some observed systems appear to be premain sequence (Field 1969). The main purpose of this investigation is the evaluation of individual close binaries with a pre-main sequence model. The evaluation will be accomplished by comparing the positions of the observed binary on the Hertzsprung-Russell diagram with the evolutionary tracks generated by the pre-main sequence model. If both components appear to have the same age and fall near the tracks of the model, then the system is possibly pre-main sequence. Eleven semidetached binaries were considered, each with a total mass between 2.5 and 6 solar masses and with a period between 0.9 and 3.4 days.


2004 ◽  
Vol 191 ◽  
pp. 235-238
Author(s):  
S. Cuevas ◽  
A. Iriarte ◽  
L.A. Martínez ◽  
F. Garfias ◽  
L. Sánchez ◽  
...  

AbstractGuieloa is the adaptive optics system project for the 2.1-m SPM telescope. This is a 19 sub-apertures curvature-type system. It corrects 8 Zernike terms. Guieloa is very similar to PUEO, the CFHT adaptive optics system and compensates the atmospheric turbulence from the R band to the K band. Among the planned applications of Guieloa are the study of OB binary systems, the detection of close binary stars, and the study of disks, jets and other phenomena associated with young stars.


2020 ◽  
Vol 499 (1) ◽  
pp. L121-L125
Author(s):  
F Lagos ◽  
M R Schreiber ◽  
S G Parsons ◽  
B T Gänsicke ◽  
N Godoy

ABSTRACT In spite of their importance for modern astronomy, we do not fully understand how close binary stars containing at least one white dwarf form from main-sequence binary stars. The discovery of EL CVn binaries, close pre-white dwarfs with A/F main-sequence star companions, offers now the unique possibility to test models of close compact binary star formation. Binary evolution theories predict that these EL CVn stars descend from very close main-sequence binaries with orbital periods shorter than 3 d. If this is correct, nearly all EL CVn stars should be inner binaries of hierarchical triples because more than 95 per cent of very close main-sequence binaries (the alleged progenitor systems) are found to be hierarchical triples. We here present SPHERE/IRDIS observations of five EL CVn binaries, finding in all of them tertiary objects, as predicted. We conclude that EL CVn systems are inner binaries of hierarchical triples and indeed descend from very close main-sequence binaries that experience stable mass transfer.


2005 ◽  
Vol 13 ◽  
pp. 455-455 ◽  
Author(s):  
Ron W. Hilditch ◽  
Tim J. Harries ◽  
Ian D. Howarth

The OGLE survey of the SMC has discovered ~1500 eclipsing binaries thereby providing an excellent platform to study the evolution of close binary systems through case A and case B mass-exchange processes. The complementary spectroscopic radial-velocity studies of these binaries are now in progress and are revealing many interesting systems which challenge current theoretical models of close binary star evolution. These studies also provide excellent direct determinations of distances to these binary stars leading to an improved understanding of the mean distance to the SMC and its 3-D structure. Comparisons between these binary-star distances and other methods of determining the mean distance to the SMC will also be made.


2018 ◽  
Vol 27 (11) ◽  
pp. 1850093 ◽  
Author(s):  
V. V. Sargsyan ◽  
H. Lenske ◽  
G. G. Adamian ◽  
N. V. Antonenko

The evolution of close binary stars in mass asymmetry (transfer) coordinate is considered. The conditions for the formation of stable symmetric binary stars are analyzed. The role of symmetrization of asymmetric binary star in the transformation of potential energy into internal energy of star and the release of a large amount of energy is revealed.


2019 ◽  
Vol 50 (3) ◽  
pp. 507
Author(s):  
V.V. Sargsyan ◽  
H. Lenske ◽  
G.G. Adamian ◽  
N.V. Antonenko

2018 ◽  
Vol 27 (07) ◽  
pp. 1850063 ◽  
Author(s):  
V. V. Sargsyan ◽  
H. Lenske ◽  
G. G. Adamian ◽  
N. V. Antonenko

Applying the microscopic nuclear physics ideas to macroscopic stellar systems, we study the evolution of the compact di-stars in mass asymmetry (transfer) coordinate. Depending on the internal structure of constituent stars, the initial mass asymmetry, total mass, and orbital angular momentum, the close di-star system can either exist in symmetric configuration or fuse into mono-star. The limitations for the formation of stable symmetric binary stars are analyzed.


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