scholarly journals 42. Close Binary Stars (Etoiles Binaires Serrees)

1991 ◽  
Vol 21 (1) ◽  
pp. 479-504 ◽  
Author(s):  
Robert H. Koch
Keyword(s):  
Binary Stars ◽  
Eclipsing Binaries ◽  
Spectroscopic Binaries ◽  
Close Binary ◽  
Close Binaries ◽  
Draft Report ◽  
New Members ◽  
Close Binary Stars ◽  
Personal Appreciation ◽  
Mean Trend

By the end of the XXth General Assembly in Baltimore, the number of Commission 42 members had increased to 305. Subsequently, D. Ya. Martynov has died and 11 new members have been added.The last Draft Report showed a healthy rate of growth in citations of Sections 117 (Close Binaries), 119 (Eclipsing Binaries), and 120 (Spectroscopic Binaries) of Astronomy and Astrophysics Abstracts from 1982 through 1986. The number of these citations has continued the mean trend with 976 and 1015 references for 1987 and 1988, respectively. As the Past-President remarked, these counts are considerable underestimates of the total literature concerning close binaries (hereafter, CB’s). A personal appreciation of the total corpus of work is that quality remains very high and content has become much richer as more and more associations have been made with generalized stellar studies. In part, this may be traced to the everincreasing awareness by the general community of the experiments in stellar evolution which Nature runs in CB’s.

scholarly journals Close-In Substellar Companions and the Formation of sdB-Type Close Binary Stars

2015 ◽  
Vol 2 (1) ◽  
pp. 183-187 ◽  
Author(s):  
L. Y. Zhu ◽  
S. B. Qian ◽  
E.-G. Zhao ◽  
E. Fernández Lajús ◽  
Z.-T. Han
Keyword(s):  
Binary Stars ◽  
Eclipsing Binaries ◽  
Close Binary ◽  
Close Binaries ◽  
Close Binary Stars ◽  
Cataclysmic Binaries ◽  
Low Mass ◽  
Substellar Companions ◽  
Orbital Periods

The sdB-type close binaries are believed to have experienced a common-envelope phase and may evolve into cataclysmic binaries (CVs). About 10% of all known sdB binaries are eclipsing binaries consisting of very hot subdwarf primaries and low-mass companions with short orbital periods. The eclipse profiles of these systems are very narrow and deep, which benefits the determination of high precise eclipsing times and makes the detection of small and close-in tertiary bodies possible. Since 2006 we have monitored some sdB-type eclipsing binaries to search for the close-in substellar companions by analyzing the light travel time effect. Here some progresses of the program are reviewed and the formation of sdB-type binary is discussed.

42. Close Binary Stars (Etoiles Binaires Serrees)

1988 ◽  
Vol 20 (01) ◽  
pp. 569-594
Author(s):  
J. Smak ◽  
R.H. Koch ◽  
K.D. Abhyankar ◽  
J. Andersen ◽  
A.H. Batten ◽  
...  
Keyword(s):  
Binary Stars ◽  
Binary Systems ◽  
Spectroscopic Binaries ◽  
Close Binary ◽  
Close Binaries ◽  
Stellar Winds ◽  
Space Instruments ◽  
Close Binary Stars ◽  
Nuclear Burning ◽  
Astronomy And Astrophysics

During the XlXth General Assembly of the IAU in Delhi the number of members of Cotrmission 42 increased to 260. This simply reflects the growing interest and importance of our field. Growing is not only the number of astronomers involved in research on CBS but also the number of papers resulting from that activity. As an example one can quote the numbers of papers listed during the last few years in Sections 117 (Close Binaries), 119 (Eelipsing Binaries), and 120 (Spectroscopic Binaries) of theAstronomy and Astrophysics Abstracts:705(1982), 775(1983), 836(1984), 1080(1985), and 911(1986); note that many additional references could be added to these numbers from other sections. Naturally, such numbers alone do not reflect the quality and even less so the position and significance of the CBS field. Here one could perhaps mention an impressive record of successful research proposals involving requests for the observing time on large, ground based telescopes and on space instruments. Indeed, in spite of a very strong competition from other fields, programs involving CBS are usually placed very high on the priority lists (cf. Sections 2D and 2E). Obviously, the close binary systems, their evolution, and the physical processes which occur in them (accretion, stellar winds, nuclear burning, etc) appear interesting and important not only to those who are involved in their studies but also to astronomers from other fields.

scholarly journals Close binary models for Luminous Blue Variable stars

1989 ◽  
Vol 113 ◽  
pp. 185-194
Author(s):  
J. S. Gallagher
Keyword(s):  
Mass Loss ◽  
Binary Stars ◽  
Mass Loss Rate ◽  
Variable Stars ◽  
High Mass ◽  
Close Binary ◽  
Close Binaries ◽  
System A ◽  
Close Binary Stars ◽  
High Mass Loss

AbstractThe evolution of massive close binary stars inevitably involves mass exchange between the two stellar components as well as mass loss from the system. A combination of these two processes could produce the stellar wind-modulated behavior seen in LB Vs. The possibility that LBVs are powered by accretion is examined, and does not appear to be a satisfactory general model. Instead, identification of LBVs with close binaries in high mass-loss rate or common envelope evolutionary phases shows promise.

scholarly journals Statistical Properties of Solar-Type Close Binaries

2004 ◽  
Vol 191 ◽  
pp. 20-27
Author(s):  
J.-L. Halbwachs ◽  
M. Mayor ◽  
S. Udry ◽  
F. Arenou
Keyword(s):  
Binary Stars ◽  
Equal Mass ◽  
Open Clusters ◽  
Statistical Properties ◽  
Spectroscopic Binaries ◽  
Close Binary ◽  
Close Binaries ◽  
Multiple Systems ◽  
Short Period ◽  
Mass Ratios

AbstractTwo Coravel radial velocity surveys dedicated to F7-K field dwarfs and to open clusters are merged in order to investigate the statistical properties of binaries with periods up to 10 years. Thanks to the accurate trigonometric parallaxes provided by Hipparcos, an unbiased sample of spectroscopic binaries (SB) is selected. After correction for the uncertainties of the measurements, the following results are obtained: 1. The distribution of mass ratios exhibits a peak for equal-mass binaries (twins), which is higher for short-period binaries than for long-period binaries. 2. Apart from the twins, the distribution of mass ratios exhibits a broad peak from 0.2 to 0.6. 3. The orbital eccentricities of twins are slightly smaller than those of other binaries. 4. An excess of SB is observed with periods shorter than about 50 days in comparison with the Duquennoy and Mayor log-normal distribution of periods. These features suggest that close binary stars are generated by two different processes. A possible difference could come from the accretion onto the binary, for instance from a common envelope or from a circumbinary disk. Alternatively, twins could come from dynamic evolution of multiple systems. It is not clear whether the formation models are already sufficiently elaborated to reproduce our statistics.

scholarly journals Non-Stability in Close Binary Stars

1957 ◽  
Vol 3 ◽  
pp. 159-164
Author(s):  
V. A. Krat
Keyword(s):  
Physical Properties ◽  
Binary Stars ◽  
Eclipsing Binaries ◽  
Close Binary ◽  
Close Binary Stars

Those eclipsing binaries whose components are non-stable stars deserve particular attention not only owing to the fact that in such cases the physical properties of the stars may be studied in greater detail, but also since the mechanism of the ejection of gases from the atmospheres of the components may then be established with some certainty.

scholarly journals COMMISSION 42: CLOSE BINARY STARS

2008 ◽  
Vol 4 (T27A) ◽  
pp. 260-266
Author(s):  
Slavek M. Rucinski ◽  
Ignasi Ribas ◽  
Alvaro Giménez ◽  
Petr Harmanec ◽  
Ronald W. Hilditch ◽  
...  
Keyword(s):  
Binary Stars ◽  
Close Binary ◽  
Close Binaries ◽  
Evolutionary Processes ◽  
Spring Meeting ◽  
Close Binary Stars ◽  
Multiple Stars ◽  
Short Period ◽  
Binary And Multiple Stars ◽  
Full Day

Two meetings of interest to close binaries took place during the reporting period: A full day session on short-period binary stars – mostly CV's – (Milone et al. 2008) during the 2006 AAS Spring meeting in Calgary and the very broadly designed IAU Symposium No. 240 on Binary Stars as Critical Tools and Tests in Contemporary Astrophysics in Prague, 2006, with many papers on close binaries [Hartkopf et al. 2007]. In addition, the book by Eggleton (2006), which is a comprehensive summary of evolutionary processes in binary and multiple stars, was published.

scholarly journals Asteroseismology of Close Binary Stars

2006 ◽  
Vol 2 (S240) ◽  
pp. 432-441 ◽  
Author(s):  
Conny Aerts
Keyword(s):  
Binary Stars ◽  
Review Paper ◽  
Stellar Structure ◽  
Structure Theory ◽  
Close Binary ◽  
Close Binaries ◽  
Basic Principles ◽  
Stellar Oscillations ◽  
Close Binary Stars ◽  
Near Future

AbstractIn this review paper, we summarise the goals of asteroseismic studies of close binary stars. We first briefly recall the basic principles of asteroseismology, and highlight how the binarity of a star can be an asset, but also a complication, for the interpretation of the stellar oscillations. We discuss a few sample studies of pulsations in close binaries and summarise some case studies. This leads us to conclude that asteroseismology of close binaries is a challenging field of research, but with large potential for the improvement of current stellar structure theory. Finally, we highlight the best observing strategy to make efficient progress in the near future.

scholarly journals Eclipsing Spectroscopic Binaries in the SMC

2005 ◽  
Vol 13 ◽  
pp. 455-455 ◽  
Author(s):  
Ron W. Hilditch ◽  
Tim J. Harries ◽  
Ian D. Howarth
Keyword(s):  
Binary Stars ◽  
Binary Systems ◽  
Binary Star ◽  
Theoretical Models ◽  
Eclipsing Binaries ◽  
Spectroscopic Binaries ◽  
Close Binary ◽  
Exchange Processes ◽  
The Mean ◽  
Close Binary Star

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.

scholarly journals The evolution of close binary stars: conditions in the winds

1995 ◽  
Vol 163 ◽  
pp. 291-299
Author(s):  
J.P. de Greve
Keyword(s):  
Mass Transfer ◽  
Binary Stars ◽  
Internal State ◽  
Close Binary ◽  
Close Binaries ◽  
Close Binary Stars ◽  
Wind Characteristics ◽  
Wind Regimes

The influence of mass transfer in an OB-type binary on the colliding wind characteristics of the following phase of WR binary is examined. We look to the changes in composition and orbital characteristics. Special attention is given to the formation of WR+OB systems and the colliding wind characteristics. The mass-luminosity behaviour after mass transfer is examined. We discuss the influence of the internal state, the composition of the wind, and rotational effects on the mass gainer. Recent models of both single stars and close binaries allow us to derive the dependence of these characteristics on the initial masses of the components. From this, constraints for the wind regimes at the WR+OB stage result.

scholarly journals Surveying Planetary Nebulae Central Stars for Close Binaries: Constraining Evolution of Central Stars Based on Binary Parameters

Galaxies ◽  
2018 ◽  
Vol 6 (3) ◽  
pp. 85 ◽  
Author(s):  
Todd Hillwig
Keyword(s):  
Binary Stars ◽  
Planetary Nebula ◽  
Planetary Nebulae ◽  
Close Binary ◽  
Close Binaries ◽  
Common Envelope ◽  
Close Binary Stars ◽  
Red Giant ◽  
The Relationship ◽  
Central Stars

The increase in discovered close binary central stars of planetary nebulae is leading to a sufficiently large sample to begin to make broader conclusions about the effect of close binary stars on common envelope evolution and planetary nebula formation. Herein I review some of the recent results and conclusions specifically relating close binary central stars to nebular shaping, common envelope evolution off the red giant branch, and the total binary fraction and double degenerate fraction of central stars. Finally, I use parameters of known binary central stars to explore the relationship between the proto-planetary nebula and planetary nebula stages, demonstrating that the known proto-planetary nebulae are not the precursors of planetary nebulae with close binary central stars.

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