scholarly journals Dynamical Evolution of Rotating Globular Clusters

1996 ◽  
Vol 174 ◽  
pp. 375-376
Author(s):  
P.-Y. Longaretti ◽  
C. Lagoute
Keyword(s):  
Angular Momentum ◽  
Stellar Evolution ◽  
Globular Cluster ◽  
Globular Clusters ◽  
Dynamical Evolution

We have computed simplified globular cluster evolutionary tracks which take into account the effects of internal relaxation, of the cluster rotation, of the galactic tidal field, and, in a cruder way, of stellar evolution and of gravitational shocking. The objectives are first to quantify the influence of rotation in the dynamical evolution of globular clusters; and second, to investigate the evolution of globular cluster angular momentum and flattening (Lagoute and Longaretti 1995a, Longaretti and Lagoute 1995b,c).

scholarly journals Dynamical Evolution of the Mass Function of the Globular Cluster System from Fokker-Planck Calculations: Preliminary Results

2006 ◽  
Vol 2 (S235) ◽  
pp. 110-110
Author(s):  
Jihye Shin ◽  
Sungsoo S. Kim
Keyword(s):  
Stellar Evolution ◽  
Globular Cluster ◽  
Globular Clusters ◽  
Dynamical Evolution ◽  
Mass Function ◽  
Cluster System ◽  
Dynamical Friction ◽  
Luminosity Functions ◽  
Globular Cluster System ◽  
Fokker Planck

AbstractUsing anisotropic Fokker-Planck models, we calculate the evolution of mass and luminosity functions of the Galactic globular cluster system. Our models include two-body relaxation, binary heating, tidal shocks, dynamical friction, and stellar evolution. We perform Fokker-Planck simulations for a large number of virtual globular clusters and synthesize these results to study the relation between the initial and present GCMFs.

scholarly journals Contribution of White Dwarfs to Cluster Masses

1998 ◽  
Vol 11 (1) ◽  
pp. 430-432
Author(s):  
Ted Von Hippel
Keyword(s):  
Stellar Evolution ◽  
Mass Fraction ◽  
Globular Clusters ◽  
White Dwarfs ◽  
Literature Search ◽  
Galactic Disk ◽  
Dynamical Evolution ◽  
Open Clusters ◽  
Solar Neighborhood ◽  
Current Evidence

The study of cluster white dwarfs (WDs) has been invigorated recently bythe Hubble Space Telescope (HST). Recent WD studies have been motivated by the new and independent cluster distance (Renzini et al. 1996), age (von Hippel et al. 1995; Richer et al. 1997), and stellar evolution (Koester & Reimers 1996) information that cluster WDs can provide. An important byproduct of these studies has been an estimate of the WD mass contribution in open and globular clusters. The cluster WD mass fraction is of importance for understanding the dynamical state and history of star clusters. It also bears an important connection to the WD mass fractions of the Galactic disk and halo. Current evidence indicates that the open clusters (e.g. von Hippel et al. 1996; Reid this volume) have essentially the same luminosity function (LF) as the solar neighborhood population. The case for the halo is less clear, despite the number of very good globular cluster LFs down to nearly 0.1 solar masses (e.g. Cool et al. 1996; Piotto, this volume), as the field halo LF is poorly known. For most clusters dynamical evolution should cause evaporation of the lowest mass members, biasing clusters to have flatter present-day mass functions (PDMFs) than the disk and halo field populations. Dynamical evolution should also allow cluster WDs to escape, though not in the same numbers as the much lower mass main sequence stars. The detailed connection between cluster PDMFs and the field IMF awaits elucidation from observations and the new combined N-body and stellar evolution models (Tout, this volume). Nevertheless, the WD mass fraction of clusters already provides an estimate for the WD mass fraction of the disk and halo field populations. A literature search to collect cluster WDs and a simple interpretive model follow. This is a work in progress and the full details of the literature search and the model will be published elsewhere.

Globular cluster tidal interactions and mergers in the Galactic disc

2019 ◽  
Vol 14 (S351) ◽  
pp. 442-446
Author(s):  
Alessandra Mastrobuono-Battisti ◽  
Sergey Khoperskov ◽  
Paola Di Matteo ◽  
Misha Haywood
Keyword(s):  
Globular Cluster ◽  
Iron Content ◽  
Globular Clusters ◽  
Dynamical Evolution ◽  
Stellar Populations ◽  
Cluster System ◽  
Galactic Disc ◽  
Tidal Interactions ◽  
Globular Cluster System ◽  
Shed Light

AbstractThe Galactic globular cluster system went and is still going through dynamical processes that require to be explored in detail. Here we illustrate how primordial massive globular clusters born in the Milky Way’s disc evolved by stripping material from each other or even merging very early during their lives. These processes might explain the puzzling presence of star-by-star spreads in iron content observed in massive globular clusters and should be taken into account when studying globular cluster stellar populations. In this context, we show how the direct comparison between the predictions provided by our direct N-body simulations and observations can shed light on the origin and chemo-dynamical evolution of globular clusters.

scholarly journals Dynamical evolution of rotating globular clusters with embedded black holes

2006 ◽  
Vol 2 (S238) ◽  
pp. 363-364 ◽  
Author(s):  
José Fiestas ◽  
Rainer Spurzem
Keyword(s):  
Black Holes ◽  
Angular Momentum ◽  
Globular Clusters ◽  
Structural Parameters ◽  
Dynamical Evolution ◽  
Meridional Plane ◽  
Angular Momentum Transport ◽  
Dimensional Distribution ◽  
Velocity Diffusion ◽  
Parent Galaxy

AbstractEvolution of rotating globular clusters with embedded black holes is presented. The interplay between velocity diffusion due to relaxation and black hole star accretion is followed together with cluster rotation, using 2-dimensional, in energy and z-component of angular momentum, Fokker Planck numerical methods. Gravogyro and gravothermal instabilities drive the system to a faster evolution leading to shorter collapse times and a faster cluster dissolution in the tidal field of a parent galaxy.Angular momentum transport and star accretion support the development of central rotation in relaxation time scales. Two-dimensional distribution (in the meridional plane) of kinematical and structural parameters (density, dispersions, rotation) are reproduced, with the aim to enable the use of set of models for comparison with observational data.

scholarly journals Observational Constraints on the Formation and Evolution of Globular Cluster Systems

2007 ◽  
Vol 3 (S246) ◽  
pp. 394-402
Author(s):  
Stephen E. Zepf
Keyword(s):  
Globular Cluster ◽  
Globular Clusters ◽  
Dynamical Evolution ◽  
Mass Function ◽  
Cluster System ◽  
Host Galaxy ◽  
Cluster Systems ◽  
Cluster Mass ◽  
Formation And Evolution ◽  
Globular Cluster System

AbstractThis paper reviews some of the observational properties of globular cluster systems, with a particular focus on those that constrain and inform models of the formation and dynamical evolution of globular cluster systems. I first discuss the observational determination of the globular cluster luminosity and mass function. I show results from new very deep HST data on the M87 globular cluster system, and discuss how these constrain models of evaporation and the dynamical evolution of globular clusters. The second subject of this review is the question of how to account for the observed constancy of the globular cluster mass function with distance from the center of the host galaxy. The problem is that a radial trend is expected for isotropic cluster orbits, and while the orbits are observed to be roughly isotropic, no radial trend in the globular cluster system is observed. I review three extant proposals to account for this, and discuss observations and calculations that might determine which of these is most correct. The final subject is the origin of the very weak mass-radius relation observed for globular clusters. I discuss how this strongly constrains how globular clusters form and evolve. I also note that the only viable current proposal to account for the observed weak mass-radius relation naturally effects the globular cluster mass function, and that these two problems may be closely related.

scholarly journals On the survivability of planets in young massive clusters and its implication of planet orbital architectures in globular clusters

2019 ◽  
Vol 489 (3) ◽  
pp. 4311-4321 ◽  
Author(s):  
Maxwell X Cai ◽  
S Portegies Zwart ◽  
M B N Kouwenhoven ◽  
Rainer Spurzem
Keyword(s):  
Globular Cluster ◽  
Time Scale ◽  
Globular Clusters ◽  
Semimajor Axis ◽  
Stellar System ◽  
Dynamical Evolution ◽  
The Other ◽  
Crossing Time ◽  
Massive Clusters ◽  
Full Investigation

ABSTRACT As of 2019 August, among the more than 4000 confirmed exoplanets, only one has been detected in a globular cluster (GC) M4. The scarce of exoplanet detections motivates us to employ direct N-body simulations to investigate the dynamical stability of planets in young massive clusters (YMC), which are potentially the progenitors of GCs. In an N = 128 k cluster of virial radius 1.7 pc (comparable to Westerlund-1), our simulations show that most wide-orbit planets (a ≥ 20 au) will be ejected within a time-scale of 10 Myr. Interestingly, more than $70{{\ \rm per\ cent}}$ of planets with a < 5 au survive in the 100 Myr simulations. Ignoring planet–planet scattering and tidal damping, the survivability at t Myr as a function of initial semimajor axis a0 in au in such a YMC can be described as fsurv(a0, t) = −0.33log10(a0)(1 − e−0.0482t) + 1. Upon ejection, about $28.8{{\ \rm per\ cent}}$ of free-floating planets (FFPs) have sufficient speeds to escape from the host cluster at a crossing time-scale. The other FFPs will remain bound to the cluster potential, but the subsequent dynamical evolution of the stellar system can result in the delayed ejection of FFPs from the host cluster. Although a full investigation of planet population in GCs requires extending the simulations to multiGyr, our results suggest that wide-orbit planets and free-floating planets are unlikely to be found in GCs.

scholarly journals A Candidate for the Recovered Nova of 1938 in the Globular Cluster M 14

1988 ◽  
Vol 126 ◽  
pp. 585-586
Author(s):  
Michael M. Shara ◽  
Michael Potter ◽  
Anthony F. J. Moffat ◽  
Helen Sawyer Hogg ◽  
Amelia Wehlau
Keyword(s):  
Globular Cluster ◽  
Globular Clusters ◽  
Dynamical Evolution ◽  
Close Binaries ◽  
Dwarf Novae ◽  
X Ray ◽  
Negative Results ◽  
Classical Nova ◽  
M 14

Although close binaries are believed to be of importance in the dynamical evolution of globular clusters, searches for such binaries have produced mostly negative results, aside from x-ray sources. Two dwarf novae which are possible cluster members are known (Margon and Downes 1983) and two classical nova candidates have been found. The crowded field around the nova observed in 1860 close to the center of M80 makes ground-based recovery of that star impossible with present techniques. Here we report on our attempt to recover the star which erupted in 1938 about 30″ (0.8 core radii) from the center of M14.

Dynamical evolution of globular clusters: Recent developments

2017 ◽  
Vol 26 (09) ◽  
pp. 1730017
Author(s):  
Marco Merafina
Keyword(s):  
Globular Cluster ◽  
Globular Clusters ◽  
Milky Way ◽  
Structural Parameters ◽  
Dynamical Evolution ◽  
Limit Value ◽  
Tidal Forces ◽  
The Galaxy ◽  
Recent Developments ◽  
Theoretical Results

We analyze structural parameters of the globular clusters belonging to the Milky Way system which were listed in the latest edition of the Harris Catalogue. We search for observational evidences of the effect of tidal forces induced by the Galaxy on the dynamical and thermodynamical evolution of a globular cluster. The behavior for the [Formula: see text] distribution exhibited by the globular cluster population seems to be in contrast with theoretical results in literature about gravothermal instability, and suggest a new limit value smaller than the previous one.

scholarly journals Globular cluster ages from main sequence fitting and detached, eclipsing binaries: The case of 47 Tuc

2008 ◽  
Vol 4 (S258) ◽  
pp. 171-176 ◽  
Author(s):  
Aaron Dotter ◽  
Janusz Kaluzny ◽  
Ian B. Thompson
Keyword(s):  
Stellar Evolution ◽  
Globular Cluster ◽  
Globular Clusters ◽  
Main Sequence ◽  
Eclipsing Binaries ◽  
Eclipsing Binary ◽  
Age Constraints

AbstractAge constraints are most often placed on globular clusters by comparing their CMDs with theoretical isochrones. The recent discoveries of detached, eclipsing binaries in such systems by the Cluster AgeS Experiment (CASE) provide new insights into their ages and, at the same time, provide much-needed tests of stellar evolution models. We describe efforts to model the properties of the detached, eclipsing binary V69 in 47 Tuc and compare age constraints derived from stellar evolution models of V69A and B with ages obtained from fitting isochrones to the cluster CMD. We determine whether or not, under reasonable assumptions of distance, reddening, and metallicity, it is possible to simultaneously constrain the age and He content of 47 Tuc.

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