The Dynamical Evolution of Young Star Clusters

The Dynamical Evolution of Young Star Clusters
Author: Richard James Allison
Publisher:
Total Pages:
Release: 2010
Genre:
ISBN:

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Stars form in large clouds of cold, dense molecular gas. In these clouds the majority of stars do not form in isolation, but instead form in clusters. The formation of stars and their hos~ clusters are intrinsically linked, and thus to fully understand how stars form we must also understand the formation and early evolution of stellar clusters. The formation of stars is thought to be governed by the turbulent conditions inside these molecular clouds, and due to this the initial conditions of star formation are likely to be spatially complex and dynamically cool. In this Thesis we use fractal spatial distributions (D = 1.6,2.0,2.6 and 3.0) to mimic the complex initial conditions of star formation to investigate how the dynamical evolution of star clusters is affected by variations in the amount of primordial structure. We also use varying initial virial ratios (Q = 0.3, 0.4 and 0.5) to investigate what affect the initial kinematics have on a clusters dynamical evolution. I present a new method, based on the minimum spanning tree, which is able to determine and quantify the presence of mass segregation. The method is applied to observations of the ONe, ,vhich we find to be complexly mass segregated, with different levels of mass segregation depending on stellar mass. We find, contrary to common belief, that mass segregation can occur through purely dynamical processes on a short timescale (rv the initial cluster crossing time). We also find that the amount of dynamical mass segregation that occurs is dependant on both the initial structure and virial ratio, where cooler and more structured initial conditions tend to lead to more dramatic dynamical evolution. Additionally, we find that the clumpy and cool initial conditions also lead to the dynamical formation of high-mass multiple systems, which in turn can lead to the ejection of high-mass stars and the destruction of the host cluster itself.

Dynamics of Young Star Clusters and Associations

Dynamics of Young Star Clusters and Associations
Author: Cathie Clarke
Publisher: Springer
Total Pages: 356
Release: 2015-09-11
Genre: Science
ISBN: 3662472902

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Where do most stars (and the planetary systems that surround them) in the Milky Way form? What determines whether a young star cluster remains bound (such as an open or globular cluster), or disperses to join the field stars in the disc of the Galaxy? These questions not only impact understanding of the origins of stars and planetary systems like our own (and the potential for life to emerge that they represent), but also galaxy formation and evolution, and ultimately the story of star formation over cosmic time in the Universe. This volume will help readers understand our current views concerning the answers to these questions as well as frame new questions that will be answered by the European Space Agency's Gaia satellite that was launched in late 2013. The book contains the elaborated notes of lectures given at the 42nd Saas-Fee Advanced Course “Dynamics of Young Star Clusters & Associations" by Cathie Clarke (University of Cambridge) who presents the theory of star formation and dynamical evolution of stellar systems, Robert Mathieu (University of Wisconsin) who discusses the kinematics of star clusters and associations, and I. Neill Reid (S pace Telescope Science Institute) who provides an overview of the stellar populations in the Milky Way and speculates on from whence came the Sun. As part of the Saas-Fee Advanced Course Series, the book offers an in-depth introduction to the field serving as a starting point for Ph.D. research and as a reference work for professional astrophysicists.

Dynamics of Young Star Clusters and Associations

Dynamics of Young Star Clusters and Associations
Author: Cathie Clarke
Publisher:
Total Pages:
Release: 2015
Genre:
ISBN: 9783662472910

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Where do most stars (and the planetary systems that surround them) in the Milky Way form? What determines whether a young star cluster remains bound (such as an open or globular cluster), or disperses to join the field stars in the disc of the Galaxy? These questions not only impact understanding of the origins of stars and planetary systems like our own (and the potential for life to emerge that they represent), but also galaxy formation and evolution, and ultimately the story of star formation over cosmic time in the Universe. This volume will help readers understand our current views concerning the answers to these questions as well as frame new questions that will be answered by the European Space Agency's Gaia satellite that was launched in late 2013. The book contains the elaborated notes of lectures given at the 42nd Saas-Fee Advanced Course "Dynamics of Young Star Clusters & Associations" by Cathie Clarke (University of Cambridge) who presents the theory of star formation and dynamical evolution of stellar systems, Robert Mathieu (University of Wisconsin) who discusses the kinematics of star cluster s and associations, and I. Neill Reid (Space Telescope Science Institute) who provides an overview of the stellar populations in the Milky Way and speculates on from whence came the Sun. As part of the Saas-Fee Advanced Course Series, the book offers an in-depth introduction to the field serving as a starting point for Ph.D. research and as a reference work for professional astrophysicists.

The Birth of Star Clusters

The Birth of Star Clusters
Author: Steven Stahler
Publisher: Springer
Total Pages: 205
Release: 2017-11-04
Genre: Science
ISBN: 3319228013

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All stars are born in groups. The origin of these groups has long been a key question in astronomy, one that interests researchers in star formation, the interstellar medium, and cosmology. This volume summarizes current progress in the field, and includes contributions from both theorists and observers. Star clusters appear with a wide range of properties, and are born in a variety of physical conditions. Yet the key question remains: How do diffuse clouds of gas condense into the collections of luminous objects we call stars? This book will benefit graduate students, newcomers to the field, and also experienced scientists seeking a convenient reference.

Multi-scale Approach of the Formation and Evolution of Star Clusters

Multi-scale Approach of the Formation and Evolution of Star Clusters
Author: Julien Dorval
Publisher:
Total Pages: 0
Release: 2016
Genre:
ISBN:

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Young star clusters are substructured and undergo a dynamical evolution erasing this substructure to form relaxed spherical clusters. I present a new method to generate realistic initial conditions to perform N-body simulations of this process: the Hubble-Lemaitre fragmentation. By expanding an initially uniform sphere, I allow spontaneous overdensities to grow, creating a realistic model for young clumpy stellar systems. This method is validated by analysing the distribution and content of the clumps and comparing them to hydrodynamical simulations of star formation as well as observations of star forming regions. These systems undergo a softer collapse than uniform ones. I injected binary stars in the fragmented models and found they were heavily processed when substructure was present. I also found extreme short and tight binaries, down to 0.01 AU, to formin the models. The method has a lot of potential, such as the generation of mock observations of star-forming regions.

Dynamical Evolution of Star Clusters - Confrontation of Theory and Observations

Dynamical Evolution of Star Clusters - Confrontation of Theory and Observations
Author: Piet Hut
Publisher: Springer
Total Pages: 0
Release: 1996-06-30
Genre: Science
ISBN: 9780792340706

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This volume reviews recent progress in the study of dynamics of star clusters. The meeting focused on the enormous progress of both the observation and the theoretical modeling of star clusters. New results from the refurbished Hubble Space Telescope (HST) include the mass function down to the hydrogen burning limits, white dwarf sequence, and central density profiles of `post-collapse' clusters by star counts. On the theoretical side, this symposium saw the first direct evidence of gravothermal oscillation through N-body simulation, which was made possible by GRAPE-4, the dedicated special-purpose computer for N-body simulation. Numerical techniques to combine stellar evolution and dynamical evolution of the cluster were presented. The book will be of primary interest to astrophysicists.