scholarly journals Mass-Loss Timescale of Star Clusters in an External Tidal Field. II. Effect of Mass Profile of Parent Galaxy

2010 ◽  
Vol 62 (5) ◽  
pp. 1215-1230 ◽  
Author(s):  
Ataru Tanikawa ◽  
Toshiyuki Fukushige
Keyword(s):  
Mass Loss ◽  
Star Clusters ◽  
Mass Profile ◽  
Parent Galaxy

scholarly journals Mass-Loss Timescale of Star Cluster in External Tidal Field

2007 ◽  
Vol 3 (S246) ◽  
pp. 191-192
Author(s):  
T. Fukushige ◽  
A. Tanikawa
Keyword(s):  
Mass Loss ◽  
Coriolis Force ◽  
Density Profile ◽  
Star Clusters ◽  
Star Cluster ◽  
Cluster Models ◽  
Parent Galaxy

AbstractWe investigate evolution of star clusters in steady external tidal field by means of N-body simulations. We followed several sets of cluster models whose strength and Coriolis's contribution of the external tidal field are different. We found that the mass loss timescale due to the escape of stars, t_mloss, and its dependence on the two-body relaxation timescale, trh,i, are determined by the strength of the tidal field. The logarithmic slope [≡ dln(tmloss)/dln(trh,i)] approaches unity for the cluster models in weaker tidal fields. We also found that stronger Coriolis force against others, produced by parent galaxy whose density profile is shallower, makes the mass loss timescale longer. This is due to the fact that a fraction of stars whose orbit are nearly regular increases as the Coriolis force becomes stronger.

scholarly journals Evolution of 1–5 Mm⊙ Stars by Mass Loss

1993 ◽  
Vol 155 ◽  
pp. 478-478
Author(s):  
E. Vassiliadis ◽  
P.R. Wood
Keyword(s):  
Mass Loss ◽  
Loss Rate ◽  
Main Sequence ◽  
Mass Loss Rate ◽  
Star Clusters ◽  
Magellanic Clouds ◽  
Pulsation Period ◽  
Agb Stars ◽  
Loss Formula ◽  
Loss Rates

Stars of mass 1–5 MM⊙ and composition Y=0.25 and Z=0.016 have been evolved from the main-sequence to the white dwarf stage with an empirical mass loss formula based on observations of mass loss rates in AGB stars. This mass loss formula (Wood 1990) causes the mass loss rate to rise exponentially with pulsation period on the AGB until superwind rates are achieved, where these rates correspond to radiation pressure driven mass loss rates. The formula was designed to reproduce the maximum periods observed for optically-visible LPVs and it also reproduces extremely well the maximum AGB luminosities observed in star clusters in the Magellanic Clouds (see Vassiliadis and Wood 1992 for details).

scholarly journals Building Dwarf Galaxies out of Merged Young Star Clusters

2002 ◽  
Vol 207 ◽  
pp. 730-732
Author(s):  
Michael Fellhauer
Keyword(s):  
Star Clusters ◽  
Young Star ◽  
Matter Content ◽  
Interacting Galaxies ◽  
Dynamical Friction ◽  
Dwarf Spheroidal Galaxies ◽  
Tidal Heating ◽  
Destructive Processes ◽  
Young Star Clusters ◽  
Parent Galaxy

Young star clusters in interacting galaxies are often found in groups or clusters of star clusters containing up to 100 single clusters. In our project we study the future fate of these clusters of star clusters. We find that the star clusters merge on time scales of a few dynamical crossing times of the super-cluster. The resulting merger object has similarities with observed dwarf ellipticals (dE). Furthermore, if destructive processes like tidal heating, dynamical friction or interaction with disc or bulge of the parent galaxy are taken into account our merger objects may evolve into objects resembling dwarf spheroidal galaxies (dSph), without the need of a high dark matter content.

scholarly journals Pre-Collapse Evolution of Galactic Globular Clusters

1996 ◽  
Vol 174 ◽  
pp. 365-366
Author(s):  
Toshiyuki Fukushige ◽  
Douglas C. Heggie
Keyword(s):  
Mass Spectrum ◽  
Mass Loss ◽  
Stellar Evolution ◽  
Globular Clusters ◽  
Star Clusters ◽  
Early Evolution ◽  
Initial Structure ◽  
Spherically Symmetric ◽  
Order Of Magnitude ◽  
Model Star

We investigated collisionless aspects of the early evolution of model star clusters. The effects of mass loss through stellar evolution and of a steady tidal field are modelled using N-body simulations. Our results (which depend on the assumed initial structure and the mass spectrum) agree qualitatively with those of Chernoff & Weinberg (1990), who used a Fokker-Planck model with a spherically symmetric tidal cutoff. For those systems which are disrupted, the lifetime to disruption generally exceeds that found by Chernoff & Weinberg, sometimes by as much as an order of magnitude.

scholarly journals Central Densities of Star Clusters in the Magellanic Clouds

1996 ◽  
Vol 174 ◽  
pp. 335-336 ◽  
Author(s):  
M. Kontizas ◽  
D. Gouliermis ◽  
E. Kontizas
Keyword(s):  
Total Mass ◽  
Star Clusters ◽  
Star Cluster ◽  
Magellanic Clouds ◽  
Cluster System ◽  
Galactocentric Distance ◽  
Cluster Systems ◽  
Image Position ◽  
Young Old ◽  
Parent Galaxy

The way star cluster systems in galaxies are forming and survive seem to depend on the relation of the central density ρ (at half mass radius) of each cluster with its galactocentric distance Rgc. It is found that this relation takes the form of: The cluster systems of our Galaxy and of the two Magellanic Clouds, have been investigated. We have taken the cluster system of the conventional globulars of our Galaxy whereas the young and old systems of clusters in the LMC and SMC were treated separately. The radial distributions of central densities and half mass radii were found for all these systems showing a definite trend which depends on: (α) The total mass of the parent galaxy & (β) The age of the cluster system (young - old). It therefore appears that the total mass and/or the morphology of the parent galaxy plays a major role on the loci where clusters survive and form.

scholarly journals The e-MERLIN Cyg OB2 radio survey (COBRaS)

2010 ◽  
Vol 6 (S272) ◽  
pp. 306-307
Author(s):  
Raman K. Prinja ◽  
Danielle Fenech
Keyword(s):  
Thermal Radiation ◽  
Mass Loss ◽  
Northern Hemisphere ◽  
Globular Clusters ◽  
Massive Stars ◽  
Star Clusters ◽  
Formation Dynamics ◽  
Super Star Clusters ◽  
Massive Clusters ◽  
Radio Survey

AbstractThe e-MERLIN Cyg OB2 Radio Survey (COBRaS) is designed to exploit e-MERLIN's enhanced capabilities to conduct uniquely probing, targeted deep-field mapping of the massive Cyg OB2 association in our Galaxy. The project aims to deliver (between 2010 to 2013) the most detailed radio census for the most massive OB association in the northern hemisphere, offering direct comparison to not only massive clusters in general, but also young globular clusters and super star clusters. With the COBRaS Legacy project we will assemble a uniform dataset of lasting value that is critical for advancing our understanding of current astrophysical problems in the inter-related core themes of (i) mass loss and evolution of massive stars, (ii) the formation, dynamics and content of massive OB associations, and (iii) the frequency of massive binaries and the incidence of non-thermal radiation.

scholarly journals N-body Simulations of Star Clusters

2007 ◽  
Vol 3 (S246) ◽  
pp. 187-188
Author(s):  
Peter Anders ◽  
Henny J. G. L. M. Lamers ◽  
Holger Baumgardt
Keyword(s):  
Mass Loss ◽  
Star Clusters ◽  
List Type ◽  
Type Number ◽  
Body Studies ◽  
Mass Segregation

AbstractTwo aspects of our recent N-body studies of star clusters are presented: 1)What impact does mass segregation and selective mass loss have on integrated photometry?2)How well do results compare from N-body simulations using NBODY4 and STARLAB/KIRA?

scholarly journals Young Star Clusters in the LMC

1992 ◽  
Vol 45 (4) ◽  
pp. 407
Author(s):  
KC Freeman
Keyword(s):  
Mass Loss ◽  
Globular Clusters ◽  
Star Clusters ◽  
Dynamical Evolution ◽  
Mass Function ◽  
Young Star ◽  
Stellar Mass ◽  
Initial Mass Function ◽  
Initial Mass ◽  
Young Star Clusters

The young globular star clusters in the LMC offer us insights into the formation and early dynamical evolution of globular clusters which are unobtainable from the old globular clusters in our Galaxy. Because these young clusters are so young and populous, they provide an opportunity to measure the upper end of the initial mass function by direct means and also through the dynamical effects of stellar mass loss on the structure of the clusters.

scholarly journals Star clusters as laboratories for stellar and dynamical evolution

2010 ◽  
Vol 368 (1913) ◽  
pp. 755-782 ◽  
Author(s):  
Jason S. Kalirai ◽  
Harvey B. Richer
Keyword(s):  
Mass Loss ◽  
Stellar Evolution ◽  
First Generation ◽  
Main Sequence ◽  
Star Clusters ◽  
Dynamical Evolution ◽  
Stellar Populations ◽  
Stellar Mass ◽  
Theoretical Studies ◽  
Chemical Enrichment

Open and globular star clusters have served as benchmarks for the study of stellar evolution owing to their supposed nature as simple stellar populations of the same age and metallicity. After a brief review of some of the pioneering work that established the importance of imaging stars in these systems, we focus on several recent studies that have challenged our fundamental picture of star clusters. These new studies indicate that star clusters can very well harbour multiple stellar populations, possibly formed through self-enrichment processes from the first-generation stars that evolved through post-main-sequence evolutionary phases. Correctly interpreting stellar evolution in such systems is tied to our understanding of both chemical-enrichment mechanisms, including stellar mass loss along the giant branches, and the dynamical state of the cluster. We illustrate recent imaging, spectroscopic and theoretical studies that have begun to shed new light on the evolutionary processes that occur within star clusters.

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