scholarly journals Nomenclature for Multiple Systems Containing Close Binaries

2005 ◽  
Vol 13 ◽  
pp. 1000-1005
Author(s):  
C.D. Scarfe
Keyword(s):  
Complex System ◽  
Close Binaries ◽  
Multiple Systems

AbstractI would like to discuss the difficulty of developing and maintaining a hierarchical designation scheme for components of multiple systems, when components are found by more than one method. Such a sequence of discoveries can easily lead to conflict between the initial nomenclature, which gets established in the literature, and that based on a scheme that is in broader use, or is more physically representative, or both. I will describe as an example a hypothetical complex system whose hierarchical description depends on the sequence in which discoveries are made, and whose designation in discovery order is ambiguous. In the end I urge flexibility in designations.

scholarly journals Origin of Binary Systems

1992 ◽  
Vol 151 ◽  
pp. 9-19
Author(s):  
Peter Bodenheimer
Keyword(s):  
Angular Momentum ◽  
Binary Systems ◽  
Theoretical Calculations ◽  
Pressure Effects ◽  
Close Binaries ◽  
Rotating Stars ◽  
Multiple Systems ◽  
The Individual ◽  
Protostellar Collapse ◽  
Three Body

Recent observational studies of the properties of binary systems among young stars indicate that the majority of binaries are formed very early in the history of a star, perhaps during the protostellar collapse. Major observational facts to be explained include the overall binary frequency, the non-negligible occurrence of multiple systems, and the distributions of period, eccentricity, and mass ratio among the individual binaries. Theoretical calculations of the collapse of rotating protostars during the isothermal phase indicate instability to fragmentation into multiple systems. This process in general produces systems with periods greater than a few hundred years, although somewhat shorter periods are possible. Fragmentation during later, optically thick, phases of collapse tends to be suppressed by pressure effects. Therefore, major theoretical problems remain concerning the origin of close binaries. Fission of rapidly rotating stars, tidal capture, and three-body capture have been shown to be improbable mechanisms for formation of close binaries. Mechanisms currently under study include gravitational instabilities in disks, orbital interactions and disk-induced captures in fragmented multiple systems, hierarchical fragmentation, and orbital decay of long-period systems. Single stars, on the other hand, could result by escape from multiple systems or by the collapse of clouds of low angular momentum, coupled with angular momentum transport after disk formation.

scholarly journals The Formation of Multiple Systems by Dynamical Interaction in Clusters

1977 ◽  
Vol 33 ◽  
pp. 199-206
Author(s):  
S. J. Aarseth
Keyword(s):  
Large Fraction ◽  
Close Binaries ◽  
Formation Mechanisms ◽  
Dynamical Interaction ◽  
Multiple Systems ◽  
Triple Systems ◽  
Hyades Cluster ◽  
Binary Formation ◽  
Formation And Evolution ◽  
Three Body

AbstractThis review is mainly devoted to a discussion of binary formation and evolution in stellar systems, as described by N-body techniques. The simplest formation mechanisms consist of ejection from bound triple systems and capture arising from hyperbolic three-body encounters. However, the large number of astrophysically close binaries cannot be accounted for in this way unless most stars are formed in compact groups. Numerical calculations show that the evolution of clusters containing several hundred members is invariably dominated by one central binary which absorbs a large fraction of the total energy. It is suggested that a visual binary in the core of the Hyades cluster may have been associated with this process.

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 A high binary fraction for the most massive close-in giant planets and brown dwarf desert members

2019 ◽  
Vol 485 (4) ◽  
pp. 4967-4996 ◽  
Author(s):  
C Fontanive ◽  
K Rice ◽  
M Bonavita ◽  
E Lopez ◽  
K Mužić ◽  
...  
Keyword(s):  
Giant Planets ◽  
Close Binaries ◽  
Brown Dwarf ◽  
Multiple Systems ◽  
Binary Separation ◽  
Short Period ◽  
Formation And Evolution ◽  
Gaia Dr2 ◽  
Independent Confirmation

ABSTRACT Stellar multiplicity is believed to influence planetary formation and evolution, although the precise nature and extent of this role remain ambiguous. We present a study aimed at testing the role of stellar multiplicity in the formation and/or evolution of the most massive, close-in planetary and substellar companions. Using past and new direct imaging observations, as well as the Gaia DR2 catalogue, we searched for wide binary companions to 38 stars hosting massive giant planets or brown dwarfs (M > 7 MJup) on orbits shorter than ∼1 au. We report the discovery of a new component in the WASP-14 system, and present an independent confirmation of a comoving companion to WASP-18. From a robust Bayesian statistical analysis, we derived a binary fraction of $79.0^{+13.2}_{-14.7}$ per cent between 20 and 10 000 au for our sample, twice as high as for field stars with a 3σ significance. This binary frequency was found to be larger than for lower-mass planets on similar orbits, and we observed a marginally higher binary rate for inner companions with periods shorter than 10 d. These results demonstrate that stellar companions greatly influence the formation and/or evolution of these systems, suggesting that the role played by binary companions becomes more important for higher-mass planets, and that this trend may be enhanced for systems with tighter orbits. Our analysis also revealed a peak in binary separation at 250 au, highlighting a shortfall of close binaries among our sample. This indicates that the mechanisms affecting planet and brown dwarf formation or evolution in binaries must operate from wide separations, although we found that the Kozai–Lidov mechanism is unlikely to be the dominant underlying process. We conclude that binarity plays a crucial role in the existence of very massive short-period giant planets and brown dwarf desert inhabitants, which are almost exclusively observed in multiple systems.

scholarly journals New Observational Clues on Binary Formation in the Galaxy

1989 ◽  
Vol 8 ◽  
pp. 103-107
Author(s):  
David W. Latham
Keyword(s):  
Strong Dependence ◽  
Stellar Populations ◽  
Close Binaries ◽  
Major Influence ◽  
Solar Mass ◽  
Multiple Systems ◽  
Binary Formation ◽  
The Galaxy ◽  
Low Mass ◽  
Formation And Evolution

AbstractNew observations of binaries are beginning to provide new clues on the formation and evolution of binary and multiple systems in a variety of stellar populations in the Galaxy. New orbital determinations are shedding light on the frequency and orbital characteristics of binaries in the disk and the halo of our Galaxy, both in clusters and the field. These results support the view that the formation of binaries involving solar-mass stars is relatively independent of the stellar environment. Evolutionary effects can have a major influence for close binaries with periods up to at least ten days, with a strong dependence on the age of the population. Progress towards determining the frequency of low-mass companions and planetary systems is promising but still very limited.

scholarly journals The Evolution of Massive Stars — The Production of Binary WR Stars

1982 ◽  
Vol 99 ◽  
pp. 343-358 ◽  
Author(s):  
C. de Loore
Keyword(s):  
Massive Stars ◽  
Galactic Disk ◽  
Close Binaries ◽  
Multiple Systems ◽  
Total Fraction

A large part of the stars of the galactic disk are binaries. Abt and Levy (1976,1978) estimate that more than 50% of B type stars are members of binary or multiple systems, and about 50% are close binaries. According to Conti et al. (1980) the total fraction of certain or probable binaries among O stars is about 36 percent. This means that during the evolution their components can fill their Roche volumes, and consequently have to lose mass in order to keep the star within the allowed surface. Several review papers dealing with the evolution of binaries were published recently: Paczynski (1971,1980), van den Heuvel (1976), de Loore (1980,1981), Webbink (1979).

scholarly journals The Distribution of Separations of Wide Binaries of Different Ages

2004 ◽  
Vol 191 ◽  
pp. 49-57
Author(s):  
Arcadio Poveda ◽  
Christine Allen
Keyword(s):  
Proper Motion ◽  
Circumstellar Disks ◽  
Close Binaries ◽  
Orion Nebula ◽  
Multiple Systems ◽  
Multiple Stars ◽  
The Galaxy ◽  
Double And Multiple Stars ◽  
Major Semiaxes ◽  
Low Metallicity

AbstractFor the purpose of understanding how the distribution of major semiaxes of double and multiple stars has evolved from the earliest ages up to the ages of the oldest systems, we have studied a number of different groups of such systems. We review and expand our previous work on the following groups of stars: (a) The wide binaries in the IDS; (b) Luyten’s common proper motion pairs (the LDS catalogue), (c) Our catalogue of nearby wide binaries divided into two groups: the youngest and the oldest; (d) The common proper motion pairs in the Orion Nebula cluster; (e) Our sample of high velocity, low metallicity binaries that represents a population of very old systems. From the very young binaries (Orion Nebula Cluster) to the oldest (thick disk and halo), all groups show a distribution of major semiaxes following Oepik, i.e., f(a) da ∝ da/a (where a is the major semiaxis), valid over an interval of a between 60 AU and am(t), am(t) being a maximum semiaxis which depends on the age of the binaries as well as on the number density and velocities of the massive objects they encounter as they travel in the Galaxy. Strong gravitational encounters in recently formed multiple systems were found to produce an Oepik distribution, which at small separations (a ≤ 40 − 60 AU) gets truncated by circumstellar disks and close binaries, and at large separations gets depleted by encounters with massive objects.

scholarly journals Dusty Disks in the Multiple Systems UZ Tau and GG Tau

1992 ◽  
Vol 135 ◽  
pp. 66-66
Author(s):  
M. Simon ◽  
S. Guilloteau
Keyword(s):  
Triple System ◽  
Thermal Emission ◽  
Close Binary ◽  
Close Binaries ◽  
Strong Emission ◽  
Multiple Systems ◽  
System A ◽  
T Tauri ◽  
Dusty Disks

AbstractInterferometric observations of the 2.6 mm dust thermal emission around the T Tauri triple system UZ Tau show that most of it is equally divided between UZ Tau W (the close binary) and UZ Tau E. The emission is at least partially optically thick at 2.6 mm which implies an origin in disks of size ~ 13 AU and mass ~ 0.024 M⊙. The 2.6 mm emission of the GG Tau system, a hierarchical quadruple, is partially resolved. Strong emission extended over ~ 3″ × 5″ is associated with the close binary GG Tau. Weak emission is detected at GG Tau/c, also a close binary. Evidently extensive dusty disks can survive in the environment of close binaries for at least ~ 105 y, and their structure can vary markedly from system to system.

scholarly journals Growth and Development: A possible systemic understanding

2020 ◽  
Vol 3 ◽  
pp. 83-94
Author(s):  
Gianfranco Minati
Keyword(s):  
Complex System ◽  
Complex Systems ◽  
Growth And Development ◽  
Emergent Property ◽  
Logistic Growth ◽  
Growth Processes ◽  
Multiple Systems ◽  
Systemic Understanding

Approaches for representing quantitative processes of growth for single systems are considered focussing especially upon logistic growth processes. Attention is then extended to processes of growth for complex systems such as Multiple Systems comprising components belonging to more than one system. Complex system populations of growth processes are considered in an attempt to gain an understanding of their growth. We consider in this regard various possible approaches for understanding development and its being an emergent property. We present some possible ways of understanding emergent development which can not be suitably considered as being reducible to the properties of sequences of processes of growth.

scholarly journals Statistics Of Multiple Stars

2004 ◽  
Vol 191 ◽  
pp. 7-14 ◽  
Author(s):  
A. Tokovinin
Keyword(s):  
Stability Limit ◽  
Orbital Evolution ◽  
Close Binaries ◽  
Stellar Systems ◽  
Hierarchical Systems ◽  
Momentum Exchange ◽  
Multiple Systems ◽  
Multiple Stars ◽  
Short Period ◽  
Low Mass

AbstractThe statistics of stellar systems of multiplicity three and higher is reviewed. They are frequent, 0.15−0.25 of all stellar systems. Some 700 multiples are expected among the 3383 stars of spectral type F, G, and K within 50 pc, while only 76 of them are actually known. Many (if not all) close binaries have distant tertiary components, indicating that angular momentum exchange within multiple systems was probably critical in forming short-period binaries. The ratio of outer to inner periods in the best-studied nearby multiples and in low-mass pre-main sequence multiples does not exceed 104 at the formation epoch; larger ratios are produced by subsequent orbital evolution. All multiples with well-defined orbits are dynamically stable, the eccentricities of outer orbits obey the empirical stability limit Pout(1 – eout)3/Pin > 5 that is more strict than current theoretical limits. Relative orientation of orbits in triple stars shows some degree of alignment, especially in weakly-hierarchical systems. The statistics support the idea that most multiple stars originated from dynamical interactions in small clusters.

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