Not So Simple Stellar Populations In Star Clusters

This book focuses on understanding the stellar populations of massive star clusters and aims to investigate the origin, evolution and properties of binary systems, their collision products, as well as the general characteristics (e.g. ages, metal content) of stellar population(s) in star clusters. It introduces the basic background knowledge of various stellar populations in star clusters as well as their formation, interaction and evolution and offers high impact observational results on our understanding of the formation and evolution mode of star clusters. Based on these discoveries, this book proposes a series of future projects that can shed light on these topics. The research introduced in this book reveals key features of star clusters formation and by extension how all stars formed in our universe.

A comprehensive survey of stellar populations traces them from initial mass function and star formation histories through the chemical history of galaxies and their observed evolution.

The book discusses the theoretical path to decoding the information gathered from observations of old stellar systems. It focuses on old stellar systems because these are the fossil record of galaxy formation and provide invaluable information ont he evolution of cosmic structures and the universe as a whole. The aim is to present results obtained in the past few years for theoretical developments in low mass star research and in advances in our knowledge of the evolution of old stellar systems. A particularly representative case is the recent discovery of multiple stellar populations in galactic globular clusters that represents one of the hottest topics in stellar and galactic astrophysics and is discussed in detail. Santi Cassisi has authored about 270 scientific papers, 150 of them in peer-reviewed journals, and the title Evolution of Stars and Stellar Populations.

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.

This up-to-date reference on stellar populations and development models includes coverage of distant galaxies, chemical evolution and supernovae. Written by highly acclaimed authorities in the field, the book makes use of specific problems to reveal the "kitchen secrets."

The formation of the first stars (Pop III stars) and galaxies is one of the great outstanding challenges in modern astrophysics and cosmology. The first stars are likely key drivers for early cosmic evolution and will be at the center of attention over the next decade. The best available space and ground-based telescopes like the Hubble Space Telescope probe the Universe to high redshifts and provide us with tantalizing hints; but they cannot yet directly detect the first generation of stars and the formation of the first galaxies. This is left as key science for future telecopes like the James Webb Space Telescope. This book is based in part on classroom tested lectures related to Pop III stars, but also draws from the author's review articles of the main physical principles involved. The book will thus combine pedagogical introductory chapters with more advanced ones to survey the cutting-edge advances from the frontier of research. It covers the theory of first star formation, the relation between first stars and dark matter, their impact on cosmology, their observational signatures, the transition to normal star formation as well as the assembly of the first galaxies. It will prepare students for interpreting observational findings and their cosmological implications.

The detection of radial and non-radial solar-like oscillations in thousands of G-K giants with CoRoT and Kepler is paving the road for detailed studies of stellar populations in the Galaxy. The available average seismic constraints allow largely model-independent determination of stellar radii and masses, and can be used to determine the position and age of thousands of stars in different regions of the Milky Way, and of giants belonging to open clusters. Such a close connection between stellar evolution, Galactic evolution, and asteroseismology opens a new very promising gate in our understanding of stars and galaxies. This book represents a natural progression from the collection of review papers presented in the book 'Red Giants as Probes of the Structure and Evolution of the Milky Way', which appeared in the Astrophysics and Space Science Proceedings series in 2012. This sequel volume contains review papers on spectroscopy, seismology of red giants, open questions in Galactic astrophysics, and discusses first results achieved by combining photometric/spectroscopic and seismic constraints on populations of stars observed by CoRoT and Kepler. The book also reports on discussions between expert researchers in Galactic evolution, specialists in stellar structure and asteroseismology, and key representatives of extensive ground-based spectroscopic surveys such as APOGEE and the ESO-GAIA Spectroscopic Survey, which would serve as a roadmap for future endeavours in this field of research.