scholarly journals Binary Interactions in Star Clusters

1988 ◽  
Vol 126 ◽  
pp. 669-670
Author(s):  
Stephen L. W. McMillan
Keyword(s):  
Numerical Experiments ◽  
Binary Systems ◽  
Star Clusters ◽  
Stellar Dynamics ◽  
Single Star ◽  
The Past

Over the past decade, a very considerable amount of effort in stellar dynamics has gone into the study of interactions between binary systems and other stars. The asymptotic analytic results obtained by Heggie (1975) for binary-single star encounters have been largely confirmed and extended by later numerical experiments (Hills 1975, Hut and Bahcall 1983). Binary-binary interactions have been studied by Mikkola (1983).

scholarly journals Test of the Accuracy of Approximate Methods to Handle Distant Binary-Single Star Encounters

2007 ◽  
Vol 3 (S246) ◽  
pp. 469-470
Author(s):  
Yoko Funato ◽  
D.C. Heggie ◽  
P. Hut ◽  
Jun Makino
Keyword(s):  
Numerical Experiments ◽  
Star Clusters ◽  
Floating Point ◽  
Direct Integration ◽  
Single Particles ◽  
Approximate Methods ◽  
Single Star ◽  
Distant Interactions ◽  
Weak Perturbation ◽  
Multiple Precision

AbstractIn the numerical simulations of evolution of star clusters, binary-single star interactions frequently take place. Since the direct integration of them is time consuming, distant interactions between binaries and field stars are often integrated by using some approximations. Traditionally the effect of the error caused by the approximated treatment is regarded as small enough to be ignored. However, if we have a binary-dominated core, the energy drift is large. In this study, we perform numerical experiments to evaluate the effect of neglecting the weak perturbation from distant single particles. We developed an N-body integrator which can manipulate multiple precision floating point numbers.

scholarly journals Star Cluster Simulations Including Stellar Evolution

2003 ◽  
Vol 208 ◽  
pp. 131-144
Author(s):  
Stephen L. W. McMillan
Keyword(s):  
Stellar Evolution ◽  
Binary Systems ◽  
Stellar Dynamics ◽  
Star Cluster ◽  
The Past ◽  
Large Numbers ◽  
Evolution Dynamics ◽  
Binary Evolution ◽  
First Time ◽  
Made In

The past few years have seen dramatic improvements in the scope and realism of star cluster simulations. Accurate treatments of stellar evolution, coupled with robust descriptions of all phases of binary evolution, have been incorporated self-consistently into several dynamical codes, allowing for the first time detailed study of the interplay between stellar dynamics and stellar physics. The coupling between evolution, dynamics, and the observational appearance of the cluster is particularly strong in young systems and those containing large numbers of primordial binary systems, and important inroads have been made in these areas, particularly in N-body simulations. I discuss some technical aspects of the current generation of N-body integrators, and describe some recent results obtained using these codes.

Bence-albee after 25 years: A new superior α-factor correction procedure for the quantitative analysis of oxides and silicates

1992 ◽  
Vol 50 (2) ◽  
pp. 1744-1745
Author(s):  
John T. Armstrong
Keyword(s):  
Quantitative Analysis ◽  
Electron Microprobe ◽  
Binary Systems ◽  
Correction Procedure ◽  
Geological Samples ◽  
The Past ◽  
Large Matrix ◽  
Computational Speed ◽  
Microprobe Data ◽  
Geological Sciences

One of the most cited papers in the geological sciences has been that of Albee and Bence on the use of empirical " α -factors" to correct quantitative electron microprobe data. During the past 25 years this method has remained the most commonly used correction for geological samples, despite the facts that few investigators have actually determined empirical α-factors, but instead employ tables of calculated α-factors using one of the conventional "ZAF" correction programs; a number of investigators have shown that the assumption that an α-factor is constant in binary systems where there are large matrix corrections is incorrect (e.g, 2-3); and the procedure’s desirability in terms of program size and computational speed is much less important today because of developments in computing capabilities. The question thus exists whether it is time to honorably retire the Bence-Albee procedure and turn to more modern, robust correction methods. This paper proposes that, although it is perhaps time to retire the original Bence-Albee procedure, it should be replaced by a similar method based on compositiondependent polynomial α-factor expressions.

scholarly journals Dynamics and Binary (Trans)formation in Globular Clusters

1996 ◽  
Vol 165 ◽  
pp. 377-388
Author(s):  
Piet Hut
Keyword(s):  
Globular Clusters ◽  
Stellar Dynamics ◽  
Diagnostic Tools ◽  
Reaction Products ◽  
Exchange Reactions ◽  
Blue Stragglers ◽  
The Past ◽  
X Ray Binaries ◽  
Triple Star ◽  
Made In

Globular clusters form ideal laboratories for studying the interactions between stellar evolution and stellar dynamics. In the past, highly exceptional systems such as X-ray binaries and later millisecond pulsars have provided us with useful diagnostic tools. However, the fate of the bulk of the more normal stars has remained less clear. At present, rapid progress is being made in our understanding of the distributions of normal stars and primordial binaries, as well as their most abundant reaction products: blue stragglers and binaries that are produced through exchange encounters with other single stars or binaries. The complexity of the network of exchange reactions is illustrated through some specific examples, such as a formation scenario for the hierarchical triple system containing the millisecond pulsar PSR B1620-26 in M4, the first triple star system ever detected in a globular cluster.

Phase space complexity of star clusters: Fresh observables for old and new questions

2019 ◽  
Vol 14 (S351) ◽  
pp. 389-394
Author(s):  
Anna Lisa Varri ◽  
Philip G. Breen ◽  
Douglas C. Heggie
Keyword(s):  
Phase Space ◽  
Globular Clusters ◽  
Star Clusters ◽  
Stellar Dynamics ◽  
Stellar Systems ◽  
Internal Dynamics ◽  
The Rich ◽  
Evolving Context ◽  
New Generation ◽  
Precision Astrometry

AbstractThe blooming era of precision astrometry for Galactic studies truly brings the rich internal dynamics of globular clusters to the centre stage. But several aspects of our current understanding of fundamental collisional stellar dynamics cannot match such new-generation data and the theoretical ambitions they trigger. This rapidly evolving context offers the stimulus to address a number of old and new questions concerning the phase space properties of this class of stellar systems.

scholarly journals Numerical Experiments in Collisionless Systems

1971 ◽  
Vol 10 ◽  
pp. 73-90
Author(s):  
R. H. Miller
Keyword(s):  
Numerical Experiments ◽  
Stellar Dynamics ◽  
Computational Speed

Gravitational n-body calculations handling 105 particles have become routine in the last three or four years. The plasma physicists have also run calculations with comparable numbers of particles – you will hear of these from Dawson this afternoon. In the stellar dynamics area, two groups have been making these calculations – our own group with Kevin Prendergast and William Quirk, and the competition, the group that formed when Roger Hockney and Frank Hohl merged (and later parted ways). Our calculation is described in Miller and Prendergast (1968); theirs is best described by Hohl and Hockney (1969), and some very thorough discussions of computational speed of force calculations by Hockney (1970).

scholarly journals Type IIb supernovae by the grazing envelope evolution

2019 ◽  
Author(s):  
Binyamin V Naiman ◽  
Efrat Sabach ◽  
Avishai Gilkis ◽  
Noam Soker
Keyword(s):  
Mass Loss ◽  
Binary Systems ◽  
The Other ◽  
Primary Star ◽  
Single Star ◽  
Common Envelope ◽  
Secondary Star ◽  
The Core ◽  
Free Parameters ◽  
Binary Evolution

Abstract We simulate the evolution of binary systems with a massive primary star of 15M⊙ where we introduce an enhanced mass loss due to jets that the secondary star might launch, and find that in many cases the enhanced mass loss brings the binary system to experience the grazing envelope evolution (GEE) and form a progenitor of Type IIb supernova (SN IIb). The jets, the Roche lobe overflow (RLOF), and a final stellar wind remove most of the hydrogen-rich envelope, leaving a blue-compact SN IIb progenitor. In many cases without this jet-driven mass loss the system enters a common envelope evolution (CEE) and does not form a SN IIb progenitor. We use the stellar evolutionary code MESA binary and mimic the jet-driven mass loss with a simple prescription and some free parameters. Our results show that the jet-driven mass loss, that some systems have during the GEE, increases the parameter space for stellar binary systems to form SN IIb progenitors. We estimate that the binary evolution channel with GEE contributes about a quarter of all SNe IIb, about equal to the contribution of each of the other three channels, binary evolution without a GEE, fatal CEE (where the secondary star merges with the core of the giant primary star), and the single star channel.

scholarly journals Glimpses of Be Binary Evolution

2000 ◽  
Vol 175 ◽  
pp. 668-680 ◽  
Author(s):  
Douglas R. Gies
Keyword(s):  
Neutron Stars ◽  
Binary Systems ◽  
Rotational Velocity ◽  
Close Binary ◽  
Be Stars ◽  
Star System ◽  
Single Star ◽  
X Ray ◽  
Binary Evolution ◽  
X Ray Binaries

AbstractModels of close binary evolution predict that mass gainers will be spun up to speeds close to the critical rotational velocity while the mass donors will appear as stripped down He stars, white dwarfs, or neutron stars. I argue here that the mass gainers are closely related to the Be stars. I present a list of the known Be binary systems which consists of those with bright, Roche-filling companions and those with faint or undetected companions. Notably absent are Be + B systems which are expected if the Be phase is a stage in the life of a single star. We now have the first example of a Be + He star system in the binary, ϕ Per, and taken together with the well known Be X-ray binaries, there is clear evidence that some fraction of Be stars are created in binaries; whether all such rapid rotators are so formed remains unknown.

scholarly journals Surface Differential Rotation of Evolved Fast Rotators

2004 ◽  
Vol 215 ◽  
pp. 294-299
Author(s):  
P. Petit ◽  
J.-F. Donati ◽  
G. A. Wade ◽  
J. D. Landstreet ◽  
T.A.A. Sigut ◽  
...  
Keyword(s):  
Differential Rotation ◽  
Surface Brightness ◽  
Binary Systems ◽  
Temporal Evolution ◽  
Doppler Imaging ◽  
Short Term ◽  
Single Star ◽  
Magnetic Structures ◽  
Tidal Forces ◽  
Rotational Shear

Zeeman-Doppler Imaging enables one to estimate the short term temporal evolution of surface brightness and magnetic structures, under the effect of differential rotation. We present here spectropolarimetric observations secured between 1998 and 2002 for two evolved active stars: the K1 subgiant of the RS CVn system HR 1099 and the single FK Com giant HD 199178. Differential rotation is detected both from brightness and magnetic images, indicating that the rotational shear, roughly solar in magnitude for the single star, is significantly weaker in the binary system. This result suggests that tidal forces, rather than stellar evolution, could be responsible for the lower rotational shear and thus the longer spot lifetime reported for binary systems.

“Undisturbed” Evolution in Binaries

1989 ◽  
Vol 8 ◽  
pp. 145-148
Author(s):  
J. Andersen
Keyword(s):  
Binary Systems ◽  
Single Star ◽  
Future Work

AbstractThe use of binary systems as tools for testing models for single-star (“undisturbed”) evolution is briefly reviewed. Recent successes and directions for future work are discussed.

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