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Evaporative evolution of stellar clusters is shown to be relaxation limited when the number of stars satisfies $N>>N_c$, where $N_c\simeq 1600$. For a Maxwell velocity distribution that extends beyond the escape velocity, this process is…

Astrophysics of Galaxies · Physics 2015-06-03 Maurice H. P. M. van Putten

In order to develop a complete theory of star formation, one essentially needs to know two things: what collapses, and how long it takes. This is the second paper in a series, where we query how long a parcel of gas takes to collapse and…

Astrophysics of Galaxies · Physics 2024-06-13 David C. Collins , Dan K. Le , Luz L. Jimenez Vela

A model of core-clump accretion with equally likely stopping describes star formation in the dense parts of clusters, where models of isolated collapsing cores may not apply. Each core accretes at a constant rate onto its protostar, while…

Astrophysics of Galaxies · Physics 2015-05-30 Philip C. Myers

We present new models of the evolution and dissolution of star clusters evolving under the combined influence of internal relaxation and external tidal fields, using the anisotropic gaseous model based on the Fokker-Planck approximation,…

Astrophysics · Physics 2009-11-10 R. Spurzem , M. Giersz , K. Takahashi , A. Ernst

We report results of N-body simulations of isolated star clusters, performed up to the point where the clusters are nearly completely dissolved. Our main focus is on the post-collapse evolution of these clusters. We find that after core…

Astrophysics · Physics 2009-11-07 Holger Baumgardt , Piet Hut , Douglas C. Heggie

We developed a mathematical model to derive time scales and the presence of BS stars. The model is based on the variation of mass through a circle into the cluster defined by a radius, and at a time; this mass cross is translated into a…

Solar and Stellar Astrophysics · Physics 2022-11-22 Félix Llorente de Andrés , Carmen Morales-Durán

We study the rate of escape of stars (``evaporation'') from tidally-limited postcollapse globular clusters having a power-law distribution of stellar masses. We use a multi-mass Fokker-Planck code and assume a steady tidal field.…

Astrophysics · Physics 2007-05-23 Hyung Mok Lee , Jeremy Goodman

We describe results from large numbers of $N$-body simulations containing from $250$ to $1000$ stars each. The distribution of stellar masses is a power law, and the systems are isolated. While the collapse of the core exhibits the expected…

Astrophysics · Physics 2015-06-24 Mirek Giersz , Douglas C. Heggie

Motivated by recent observations that suggest a low density of old stars around the Milky Way supermassive black hole, models for the nuclear star cluster are considered that have not yet reached a steady state under the influence of…

Astrophysics of Galaxies · Physics 2014-11-20 David Merritt

Supermassive black holes at the centres of galaxies are often surrounded by dense star clusters. For a wide range of cluster properties and orbital radii the resonant relaxation times in these clusters are much shorter than the Hubble time.…

Astrophysics of Galaxies · Physics 2020-02-19 Scott Tremaine

The evolution of star clusters is studied using N-body simulations in which the evolution of single stars and binaries are taken self-consistently into account. Initial conditions are chosen to represent relatively young Galactic open…

The supermassive black holes found at the centers of galaxies are often surrounded by dense star clusters. The ages of these clusters are generally longer than the resonant-relaxation time and shorter than the two-body relaxation time over…

Astrophysics of Galaxies · Physics 2019-12-18 Scott Tremaine

We report on the results of a direct N-body simulation of a star cluster that started with N = 200 000, comprising 195 000 single stars and 5 000 primordial binaries. The code used for the simulation includes stellar evolution, binary…

Astrophysics of Galaxies · Physics 2015-06-11 Jarrod R. Hurley , Michael M. Shara

We discuss the lifetimes and evolution of clumps and cores formed as turbulent density fluctuations in nearly isothermal molecular clouds. In the non-magnetic case, clumps are unlikely to reach a hydrostatic state, and instead are expected…

We present a unified model for molecular core formation and evolution, based on numerical simulations of converging, supersonic flows. Our model applies to star formation in GMCs dominated by large-scale turbulence, and contains four main…

Solar and Stellar Astrophysics · Physics 2009-06-25 Hao Gong , Eve C. Ostriker

Two-component (normal and degenerate stars) models are the simplest realization of clusters with a mass spectrum because high mass stars evolve quickly into degenerates, while low mass stars remain on the main-sequence for the age of the…

Astrophysics · Physics 2015-06-24 Sungsoo S. Kim , Hyung Mok Lee , Jeremy Goodman

This is the third paper of a series of our works on the self-similar orbit-averaged Fokker-Planck (OAFP) equation. The first paper provided an accurate spectral solution of the equation for isotropic pre-collapse star clusters and the…

Astrophysics of Galaxies · Physics 2021-06-23 Yuta Ito

We present the first post core collapse models of initially rotating star clusters, using the numerical solution of an orbit-averaged 2D Fokker-Planck equation. Based on the code developed by Einsel & Spurzem (1999), we have improved the…

Astrophysics · Physics 2009-11-07 Eunhyeuk Kim , Christian Einsel , Hyung Mok Lee , Rainer Spurzem , Myung Gyoon Lee

Star clusters - open and globulars - experience dynamical evolution on time scales shorter than their age. Consequently, open and globular clusters provide us with unique dynamical laboratories for learning about two-body relaxation, mass…

Astrophysics · Physics 2007-05-23 Georges Meylan

This is the second paper of a series of our works on the self-similar orbit-averaged Fokker-Planck (OAFP) equation and details physical properties of isotropic pre-collapse solution. The fundamental core collapse process at the late stage…

Astrophysics of Galaxies · Physics 2020-05-04 Yuta Ito