The elliptical motion of stars in close binary systems with a conservative mass exchange

2013 ◽  
Vol 68 (1) ◽  
pp. 76-81
Author(s):  
A. A. Medvedeva
Keyword(s):  
Mass Exchange ◽  
Binary Systems ◽  
Close Binary ◽  
Close Binary Systems ◽  
Elliptical Motion

scholarly journals Observational Evidence for Mass Exchange in Close Binary Systems

1977 ◽  
Vol 42 ◽  
pp. 371-382
Author(s):  
Horst Drechsel ◽  
Jürgen Rahe ◽  
Gudrun Wolfschmidt ◽  
Yoji Kondo ◽  
George E. McCluskey
Keyword(s):  
Northern Hemisphere ◽  
Mass Exchange ◽  
Binary Systems ◽  
Variable Stars ◽  
Observational Evidence ◽  
Close Binary ◽  
Wide Angle ◽  
Close Binary Systems ◽  
The Individual

In 1925 a photographic search for new variable stars was begun at the Remeis-Observatory in Bamberg. Initially the sky patrol covered only the northern hemisphere, but in 1964 it was also extended to the southern sky. At the individual observing stations, the sky is systematically photographed with several wide-angle patrol cameras which are attached to the same mounting, and which have f/6 Tessar lenses of 4-inch aperture. Each camera covers a 13-by-13 degree field. The plates are usually exposed for one hour and a photographic magnitude of 14m is reached.

scholarly journals Two Types of Evolution of Massive Close Binary Systems

1976 ◽  
Vol 73 ◽  
pp. 27-34 ◽  
Author(s):  
C. De Loore ◽  
J. P. De Greve
Keyword(s):  
Mass Exchange ◽  
Binary Systems ◽  
Supernova Explosion ◽  
Close Binary ◽  
Helium Burning ◽  
Primary Star ◽  
Close Binary Systems ◽  
First Case ◽  
Initial Chemical Composition ◽  
Massive Close Binary

It is well known that the outcome of case B evolution of the primaries of massive close binary systems (M1 ≥ 9 M⊙) depends on the initial primary mass. The most massive primaries finally ignite carbon, form iron cores and presumably end in a supernova explosion, whereas the lighter ones presumably end as white dwarfs, without carbon ignition. This paper derives an estimate of the mass boundary separating these two kinds of evolution.As an example of the first case, the evolution of a 20 M⊙ + 14 M⊙ system was computed; after the mass exchange, the primary star (with M = 5.43 M⊙) evolves through the helium-burning (Wolf-Rayet) stage towards a supernova explosion; finally the system evolves into an X-ray binary (BWRX-evolution).As a representative for the second case the evolution of a 10 M⊙ + 8 M⊙ system was examined. After the first stage of mass exchange, the primary (with a mass of 1.66 M⊙) approaches the helium main sequence; during later phases of helium burning the radius increases again, and a second stage of mass transfer starts; after this the star (with a mass of 1.14 M⊙) again evolves towards the left in the Hertzsprung-Russell diagram and ends as a white dwarf (BSWD-evolution). A system of 15 M⊙ + 8 M⊙ is found to evolve very similar to the 20 M⊙ + 14 M⊙ system. The mass Mu, separating the two types of evolution, must therefore be situated between 10 and 15 solar masses. An initial chemical composition X = 0.70, Z = 0.03 was used for all systems.

scholarly journals A Review of Early-Type Close Binary Systems

1984 ◽  
Vol 80 ◽  
pp. 237-237
Author(s):  
K. C. Leung
Keyword(s):  
Mass Exchange ◽  
Binary Systems ◽  
Close Binary ◽  
Early Type ◽  
Close Binary Systems ◽  
Two Systems ◽  
V729 Cyg ◽  
Photometric Solution ◽  
Roche Model ◽  
Absolute Dimensions

AbstractThis is a review of close binary systems with very early spectral types (B, O, Of, and WR stars). We limit our selection to systems with Roche model photometric solution only. There are 10 contact systems known at present. Three of them (V701 Sco, BH Cen, and RZ Pyx) are located in the vicinity of the zero-age contact (ZC) according to a Spectral Type - Period diagram. Only the first two systems have absolute dimensions available. Both of these fall into the ZC zone in the logP - logm diagram and the logm - logR diagram. The system TU Mus was thought to be a ZC system is located in the evolved contact zone (EC) in the above diagrams. Both V701 Sco and BH Cen were thought to be having mass ratios about unity. With the much improved light curves of BH Cen and new analysis the mass ratio has been revised to 0.84! This result may favor Shu's model for early-type zero-age contact systems. The evolved systems might be undergone Case A mass exchange except for two systems (V729 Cyg and RY Set) which might be from Case B. The systems V367 Cyg was classified by Plavec as a W Ser system may be a evolved contact system.It is interesting to note that V729 Cyg (07f + Ofla), UW CMa(07f + O) and CQ Cep(WN7 + O) are all highly evolved contact systems. The Max II of UW CMa and CQ Cep are displaced to 0.78 and 0.80 phase, respectively. The displacement for V729 Cyg is not known due to poor coverage at this phase. The most distinct feature going from Of to Wolf-Rayet stars is the increasing domination of emission lines. It is suspected that this phaseshifts reflect the increasing activity of mass-flow in the common envelope.There are 8 semidetached systems with reliable absolute dimensions. It is believed that 6 of them are derived from Case A while the remaining 2 are from Case B mass exchange.

scholarly journals White Dwarfs in Close Binary Systems

1968 ◽  
Vol 1 ◽  
pp. 414-419
Author(s):  
Alfred Weigert
Keyword(s):  
Mass Exchange ◽  
White Dwarf ◽  
Final Stage ◽  
Binary Systems ◽  
Main Sequence ◽  
Small Mass ◽  
Close Binary ◽  
Main Sequence Stars ◽  
Single Star ◽  
Close Binary Systems

While it has not yet been possible to give a detailed step-by-step treatment of the evolution of a single star from the main sequence to the white-dwarf stage, such a treatment is available for close binary systems. It has been shown that by calculating the evolution including mass exchange in a system of main-sequence stars of small mass and relatively large separation, one can follow the system to its final stage of a white dwarf and a more massive main-sequence star. This type of evolution arises when the original primary has exhausted its central hydrogen content when mass exchange starts, and the mass of its helium core is small enough so that electron degeneracy prevents the ignition of helium.

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