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During the late stages of gravitational core-collapse of massive stars, extreme isospin asymmetries are reached within the core. Due to the lack of microscopic calculations of electron capture (EC) rates for all relevant nuclei, in general…

Nuclear Theory · Physics 2017-02-22 Ad. R. Raduta , F. Gulminelli , M. Oertel

We investigated the dynamical evolution of clusters of galaxies in virial equilibrium using Fokker-Planck models and self-consistent N-body models. In particular, we focused on the growth of a common halo, which is a cluster-wide halo…

Astrophysics · Physics 2015-06-24 K. Takahashi , T. Sensui , Y. Funato , J. Makino

A number of globular clusters appear to have undergone core collapse, in the sense that their predicted collapse time is much shorter than their current age. Simulations using gas models and Fokker-Planck approximation have shown that the…

Astrophysics · Physics 2009-10-28 Junichiro Makino

We study the dynamical evolution of globular clusters using our new 2-D Monte Carlo code, and we calculate the lifetimes of clusters in the Galactic environment. We include the effects of a mass spectrum, mass loss in the Galactic tidal…

Astrophysics · Physics 2015-06-24 Kriten J. Joshi , Cody P. Nave , Frederic A. Rasio

Models of self-gravitating gas in the early stages of pressure-free collapse are compared for initial states which are equilibrium layers, cylinders, and Bonnor-Ebert spheres. For each geometrical case the density profile has an inner…

Astrophysics · Physics 2009-11-10 Philip C. Myers

A model is developed for an idealised spherical galaxy evolving from a uniform mass distribution at the epoch of galactic separation until attaining an equilibrium state through gravitational collapse. The final theoretical radial surface…

Astrophysics of Galaxies · Physics 2024-05-14 John H Marr

We study the dynamical evolution of globular clusters using our H\'enon-type Monte Carlo code for stellar dynamics including all relevant physics such as two-body relaxation, single and binary stellar evolution, Galactic tidal stripping,…

Astrophysics of Galaxies · Physics 2015-06-05 Sourav Chatterjee , Stefan Umbreit , John M. Fregeau , Frederic A. Rasio

A novel way of looking at the evolution of star clusters is presented. With a dynamical temperature, given by the mean kinetic energy of the cluster stars, and a dynamical luminosity, which is defined as the kinetic energy of the stars…

Astrophysics · Physics 2009-11-13 Andreas H. W. Kuepper , Pavel Kroupa , Holger Baumgardt

We perform a systematic combined photometric and kinematic analysis of a sample of globular clusters under different relaxation conditions, based on their core relaxation time (as listed in available catalogs), by means of two well-known…

Astrophysics of Galaxies · Physics 2015-03-19 A. Zocchi , G. Bertin , A. L. Varri

We have developed a two-dimensional orbit averaged Fokker-Planck model of stellar clusters which expands on spherically symmetric one-dimensional models to include rotation and ellipticity. Physical effects such as collisions, finite…

Astrophysics · Physics 2007-05-23 J. Girash

The relaxation time at the half-mass radius of Galactic globular clusters (GGCs) is typically within a few Gyr. Hence, the majority of GGCs are expected to be well relaxed systems, given their age is around 12-13 Gyr. So any initial radial…

Astrophysics of Galaxies · Physics 2018-12-31 Valery V. Kravtsov

The influence of rotation on the dynamical evolution of collisional stellar systems is investigated by solving the orbit-averaged Fokker-Planck equation in (E,J_z)-space. We find that large amounts of initial rotation drive the system into…

Astrophysics · Physics 2007-05-23 Ch. Einsel , R. Spurzem

We investigate the 1D stellar evolution of a 16.5 M$_{\odot}$ zero-age main-sequence star having different initial rotations. Starting from the pre-main-sequence, the models evolve up to the onset of the core collapse stage. The collapse of…

High Energy Astrophysical Phenomena · Physics 2024-09-30 Amar Aryan , Shashi Bhushan Pandey , Rahul Gupta , Amit Kumar Ror , A. J. Castro-Tirado

We present core radii for 54 Milky Way globular clusters determined by fitting King-Michie models to cumulative projected star count distributions. We find that fitting star counts rather than surface brightness profiles produces results…

Astrophysics of Galaxies · Physics 2015-06-16 Ryan Goldsbury , Jeremy Heyl , Harvey Richer

The study of star cluster evolution necessitates modeling how their density profiles develop from their natal gas distribution. Observational evidence indicates that many star clusters follow a Plummer-like density profile. However, most…

It has recently been suggested that high-density clusters have stellar age distributions narrower than that of the Orion Nebula Cluster, indicating a possible trend of narrower age distributions for denser clusters. We show this effect to…

Solar and Stellar Astrophysics · Physics 2015-06-22 Genevieve Parmentier , Susanne Pfalzner , Eva K. Grebel

We predict the survival time of initially bound star clusters in the solar neighbourhood taking into account: (1) stellar evolution, (2) tidal stripping, (3) shocking by spiral arms and (4) encounters with giant molecular clouds. We find…

Astrophysics · Physics 2016-08-30 Henny J. G. L. M. Lamers , Mark Gieles

We summarize the current status of the turbulent model of star formation in turbulent molecular clouds. In this model, clouds, clumps and cores form a hierarchy of nested density fluctuations caused by the turbulence, and either collapse or…

Astrophysics · Physics 2007-05-23 Enrique Vazquez-Semadeni

We introduce version two of the fast star cluster evolution code Evolve Me A Cluster of StarS (EMACSS). The first version (Alexander & Gieles) assumed that cluster evolution is balanced for the majority of the life-cycle, meaning that the…

Astrophysics of Galaxies · Physics 2015-06-17 Mark Gieles , Poul Alexander , Henny Lamers , Holger Baumgardt

Mass segregation is seen in many star clusters, but whether massive stars form in the center of a cluster or migrate there dynamically is still debated. N-body simulations have shown that early dynamical mass segregation is possible when…