scholarly journals Dynamical Evolution of Mass-Segregated Clusters

2007 ◽  
Vol 3 (S246) ◽  
pp. 181-185
Author(s):  
Enrico Vesperini ◽  
Steve McMillan ◽  
Simon Portegies Zwart
Keyword(s):  
Mass Loss ◽  
Density Profile ◽  
Stellar Evolution ◽  
Star Clusters ◽  
Dynamical Evolution ◽  
Mass Function ◽  
Initial Mass Function ◽  
Initial Evolution ◽  
Stellar Initial Mass Function ◽  
Mass Segregation

AbstractWe present the results of a survey of N-body simulations aimed at exploring the implications of primordial mass segregation on the dynamical evolution of star clusters. We show that, in a mass-segregated cluster, the effect of early mass loss due to stellar evolution is, in general, more destructive than for an unsegregated cluster with the same density profile and leads to shorter lifetimes, a faster initial evolution toward less concentrated structure and flattening of the stellar initial mass function.

scholarly journals The Mass Function of Young Star Clusters in our Galaxy and Nearby Galaxies: Is It Universal?

2002 ◽  
Vol 207 ◽  
pp. 515-524
Author(s):  
Ram Sagar
Keyword(s):  
Star Clusters ◽  
Dynamical Evolution ◽  
Mass Function ◽  
Young Star ◽  
Initial Mass Function ◽  
Galactocentric Distance ◽  
Photometric Observations ◽  
Nearby Galaxies ◽  
Mass Segregation ◽  
Young Star Clusters

Mass functions (MFs) derived from photometric observations of young star clusters of our Galaxy, the Magellanic Clouds (MCs), M31 and M33 have been used to investigate the question of universality of the initial mass function and presence of mass segregation in these systems. Observational determination of the MF slope of young star clusters have an inherent uncertainty of at least ∼ 1.0 dex in the Milky Way and of ∼ 0.4 dex in the MCs. There is no obvious dependence of the MF slope on either galactocentric distance or age of the young star clusters or on the spatial concentration of the stars formed or on the galactic characteristics including metallicity. Effects of mass segregation have been observed in a good number of young stellar groups of our Galaxy and MCs. As their ages are much smaller than their dynamical evolution times, star formation processes seem to be responsible for the observed mass segregation in them.

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 Young massive star clusters: achievements and challenges

2009 ◽  
Vol 5 (S266) ◽  
pp. 49-57 ◽  
Author(s):  
Richard de Grijs
Keyword(s):  
Massive Star ◽  
Initial Conditions ◽  
Cluster Formation ◽  
Star Clusters ◽  
Dynamical Evolution ◽  
Mass Function ◽  
Large Magellanic Cloud ◽  
Initial Mass Function ◽  
Ongoing Research ◽  
Mass Segregation

AbstractIn spite of significant recent and ongoing research efforts, most of the early evolution and long-term fate of young massive star clusters remain clouded in uncertainties. Here, I discuss our understanding of the initial conditions of star cluster formation and the importance of initial substructure for the subsequent dynamical-evolution and mass-segregation timescales. I also assess our current understanding of the (initial) binary fraction in star clusters and the shape of the stellar initial mass function at the low-mass end in the low-metallicity environment of the Large Magellanic Cloud. Finally, I question the validity of our assumptions leading to dynamical cluster mass estimates. I conclude that it seems imperative that observers, modellers and theorists combine efforts and exchange ideas and data freely for the field to make a major leap forward.

scholarly journals Quantifying the universality of the stellar initial mass function in old star clusters

2012 ◽  
Vol 422 (2) ◽  
pp. 1592-1600 ◽  
Author(s):  
Nathan Leigh ◽  
Stefan Umbreit ◽  
Alison Sills ◽  
Christian Knigge ◽  
Guido de Marchi ◽  
...  
Keyword(s):  
Star Clusters ◽  
Mass Function ◽  
Initial Mass Function ◽  
Initial Mass ◽  
Stellar Initial Mass Function

scholarly journals Stellar initial mass function variation in massive early-type galaxies: the potential role of the deuterium abundance

2020 ◽  
Vol 498 (3) ◽  
pp. 4051-4059 ◽  
Author(s):  
Timothy A Davis ◽  
Freeke van de Voort
Keyword(s):  
Mass Loss ◽  
Cosmic Time ◽  
Mass Function ◽  
Stellar Mass ◽  
Initial Mass Function ◽  
Initial Mass ◽  
Early Type ◽  
Root Cause ◽  
Stellar Initial Mass Function ◽  
Low Mass

ABSTRACT The observed stellar initial mass function (IMF) appears to vary, becoming bottom-heavy in the centres of the most massive, metal-rich early-type galaxies. It is still unclear what physical processes might cause this IMF variation. In this paper, we demonstrate that the abundance of deuterium in the birth clouds of forming stars may be important in setting the IMF. We use models of disc accretion on to low-mass protostars to show that those forming from deuterium-poor gas are expected to have zero-age main-sequence masses significantly lower than those forming from primordial (high deuterium fraction) material. This deuterium abundance effect depends on stellar mass in our simple models, such that the resulting IMF would become bottom-heavy – as seen in observations. Stellar mass loss is entirely deuterium free and is important in fuelling star formation across cosmic time. Using the Evolution and Assembly of GaLaxies and their Environments (EAGLE) simulation we show that stellar mass-loss-induced deuterium variations are strongest in the same regions where IMF variations are observed: at the centres of the most massive, metal-rich, passive galaxies. While our analysis cannot prove that the deuterium abundance is the root cause of the observed IMF variation, it sets the stage for future theoretical and observational attempts to study this possibility.

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.

scholarly journals Dynamical evolution of star clusters with top-heavy IMF

2019 ◽  
Vol 14 (S351) ◽  
pp. 447-450
Author(s):  
Hosein Haghi ◽  
Ghasem Safaei ◽  
Akram H. Zonoozi ◽  
Pavel Kroupa
Keyword(s):  
Globular Clusters ◽  
Milky Way ◽  
Massive Stars ◽  
Star Clusters ◽  
Dynamical Evolution ◽  
Mass Function ◽  
Initial Mass Function ◽  
Dissolution Time ◽  
Theoretical Studies ◽  
Cloud Density

AbstractSeveral observational and theoretical studies suggest that the initial mass function (IMF) slope for massive stars in globular clusters (GCs) depends on the initial cloud density and metallicity, such that the IMF becomes increasingly top-heavy with decreasing metallicity and increasing the gas density of the forming object. Using N-body simulations of GCs starting with a top-heavy IMF and undergo early gas expulsion within a Milky Way-like potential, we show how such a cluster would evolve. By varying the degree of top-heaviness, we calculate the dissolution time and the minimum cluster mass needed for the cluster to survive after 12 Gyr of evolution.

scholarly journals Age Determination of HII Regions of the LMC and SMC

1984 ◽  
Vol 108 ◽  
pp. 383-384
Author(s):  
M. V. Copetti ◽  
H. A. Dottori ◽  
E. L. Bica ◽  
M. G. Pastoriza
Keyword(s):  
Mass Loss ◽  
Stellar Evolution ◽  
Age Determination ◽  
Hii Regions ◽  
Mass Function ◽  
Initial Mass Function ◽  
Mass Limit ◽  
Hii Region ◽  
Image Position

HII region models were constructed which take into account: ) A burst for the formation of the ionizing association; ) Different Salpeter's initial mass function () and upper stellar mass limit Models of stellar evolution with and without mass loss (Maeder, 1980, Hellings et al. 1981).

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