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Ionization Feedback In Massive Star Formation
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Book Synopsis Ionization Feedback in Massive Star Formation by : Thomas Peters
Download or read book Ionization Feedback in Massive Star Formation written by Thomas Peters and published by Sudwestdeutscher Verlag Fur Hochschulschriften AG. This book was released on 2010-11 with total page 152 pages. Available in PDF, EPUB and Kindle. Book excerpt: Understanding the origin of high-mass stars is central to modern astrophysics. We shed light on this problem using novel radiation-hydrodynamic simulations that consistently follow the gravitational collapse of a massive molecular cloud, the subsequent build-up and fragmentation of the accretion disk surrounding the nascent star, and, for the first time, the interaction between its intense UV radiation field and the infalling material. We show that ionization feedback can neither stop protostellar mass growth nor suppress fragmentation. We present a consistent picture of the formation and evolution of H II regions that explains the observed morphology, time variability, and ages of ultracompact H II regions, solving the long-standing lifetime problem.
Book Synopsis Observational Signatures of Massive Star Formation by : Katharine Grace Johnston
Download or read book Observational Signatures of Massive Star Formation written by Katharine Grace Johnston and published by . This book was released on 2011 with total page 179 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Book Synopsis Introduction to Stellar Winds by : Henny J. G. L. M. Lamers
Download or read book Introduction to Stellar Winds written by Henny J. G. L. M. Lamers and published by Cambridge University Press. This book was released on 1999-06-17 with total page 456 pages. Available in PDF, EPUB and Kindle. Book excerpt: The first comprehensive introduction to the observations and theories of stellar winds; a long-awaited graduate textbook, written by two founders of the field.
Book Synopsis Very Massive Stars in the Local Universe by : Jorick S. Vink
Download or read book Very Massive Stars in the Local Universe written by Jorick S. Vink and published by Springer. This book was released on 2014-10-25 with total page 277 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book presents the status of research on very massive stars in the Universe. While it has been claimed that stars with over 100 solar masses existed in the very early Universe, recent studies have also discussed the existence and deaths of stars up to 300 solar masses in the local Universe. This represents a paradigm shift for the stellar upper-mass limit, which may have major implications far beyond the field of stellar physics. The book comprises 7 chapters, which describe this discipline and provide sufficient background and introductory content for graduate (PhD) students and researchers from different branches of astronomy to be able to enter this exciting new field of very massive stars.
Book Synopsis Star Formation in Molecular Clouds Associated with HII Regions by : Mohaddesseh Azimlu Shanjani
Download or read book Star Formation in Molecular Clouds Associated with HII Regions written by Mohaddesseh Azimlu Shanjani and published by . This book was released on 2010 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:
Book Synopsis Galaxy Formation and Mergers with Stars and Massive Black Holes by : Chi-hun Kim
Download or read book Galaxy Formation and Mergers with Stars and Massive Black Holes written by Chi-hun Kim and published by Stanford University. This book was released on 2011 with total page 189 pages. Available in PDF, EPUB and Kindle. Book excerpt: While mounting observational evidence suggests the coevolution of galaxies and their embedded massive black holes (MBHs), a comprehensive astrophysical understanding which incorporates both galaxies and MBHs has been missing. To tackle the nonlinear processes of galaxy formation, we develop a state-of-the-art numerical framework which self-consistently models the interplay between galactic components: dark matter, gas, stars, and MBHs. Utilizing this physically motivated tool, we present an investigation of a massive star-forming galaxy hosting a slowly growing MBH in a cosmological LCDM simulation. The MBH feedback heats the surrounding gas and locally suppresses star formation in the galactic inner core. In simulations of merging galaxies, the high-resolution adaptive mesh allows us to observe widespread starbursts via shock-induced star formation, and the interplay between the galaxies and their embedding medium. Fast growing MBHs in merging galaxies drive more frequent and powerful jets creating sizable bubbles at the galactic centers. We conclude that the interaction between the interstellar gas, stars and MBHs is critical in understanding the star formation history, black hole accretion history, and cosmological evolution of galaxies. Expanding upon our extensive experience in galactic simulations, we are well poised to apply this tool to other challenging, yet highly rewarding tasks in contemporary astrophysics, such as high-redshift quasar formation.
Book Synopsis Radiative Feedback and Massive Star Formation by : R. G. Edgar
Download or read book Radiative Feedback and Massive Star Formation written by R. G. Edgar and published by . This book was released on 2003 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:
Book Synopsis Star Formation from the Galaxy to the Cosmos by : Jonathan Charles Tan
Download or read book Star Formation from the Galaxy to the Cosmos written by Jonathan Charles Tan and published by . This book was released on 2001 with total page 464 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Book Synopsis Ionization Impact on Molecular Clouds and Star Formation by : Pascal Tremblin
Download or read book Ionization Impact on Molecular Clouds and Star Formation written by Pascal Tremblin and published by . This book was released on 2013 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:
Book Synopsis The Interplay Between Massive Star Formation, the ISM and Galaxy Evolution by : D. Kunth
Download or read book The Interplay Between Massive Star Formation, the ISM and Galaxy Evolution written by D. Kunth and published by Atlantica Séguier Frontières. This book was released on 1996 with total page 668 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book The First Stars written by Volker Bromm and published by Springer. This book was released on 2016-09-07 with total page 240 pages. Available in PDF, EPUB and Kindle. Book excerpt: 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.
Book Synopsis Mass Loss from Stars and the Evolution of Stellar Clusters by : Alex de Koter
Download or read book Mass Loss from Stars and the Evolution of Stellar Clusters written by Alex de Koter and published by . This book was released on 2008 with total page 512 pages. Available in PDF, EPUB and Kindle. Book excerpt: "In the spring of 2006 a four day international workshop was held in Lunteren, The Netherlands, in honor of the formal retirement of Prof. Henny Lamers. These proceedings provide a comprehensive overview of mass loss in massive stars and of the dynamical fate of clusters. The dynamical evolution of clusters is affected by stellar winds, mass loss outbursts and supernova explosions as well as by the loss of stars in dynamical interactions, thus linking the two central themes of the workshop. It is becoming clear that mass loss by radiation pressure on spectral lines is not only at work in normal O, B, and A stars but also in Luminous Blue Variables and Wolf-Rayet stars. The importance of these line-driven winds relative to outbursts in the Luminous Blue Variable phase of evolution is under debate. A central issue in this discussion is the importance of small and possibly large scale structure in stellar winds and its implications for the measured mass loss rates. These proceedings report on progress establishing wind properties, on theoretical predictions of mass loss and wind structure as a function of stellar properties, and on the effects of mass loss on the evolution of massive stars. As a result of dynamical interactions, clusters may dissolve completely over time. Observational studies of cluster dissolution timescales as a function of cluster formation history and cluster and environmental properties, are at the focus of cluster studies in the last decade. A key topic discussed in this book is whether the old globular clusters we observe today were once similar to present-day massive young clusters. The mass function of the two types of clusters is observed to be different. Is this a result of dynamical evoltuion or were the mass functions different at formation? The 12 invited reviews, 18 contributed talks, 48 poster papers, and two discussion sessions combine to provide and in-depth assessment of both observational and theoretical issues. The book is suitable for researchers and graduate students interested in stellar astrophysics and cluster dynamics."--Provided by publisher.
Book Synopsis The First Galaxies in the Universe by : Abraham Loeb
Download or read book The First Galaxies in the Universe written by Abraham Loeb and published by Princeton University Press. This book was released on 2013-01-15 with total page 572 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book provides a comprehensive, self-contained introduction to one of the most exciting frontiers in astrophysics today: the quest to understand how the oldest and most distant galaxies in our universe first formed. Until now, most research on this question has been theoretical, but the next few years will bring about a new generation of large telescopes that promise to supply a flood of data about the infant universe during its first billion years after the big bang. This book bridges the gap between theory and observation. It is an invaluable reference for students and researchers on early galaxies. The First Galaxies in the Universe starts from basic physical principles before moving on to more advanced material. Topics include the gravitational growth of structure, the intergalactic medium, the formation and evolution of the first stars and black holes, feedback and galaxy evolution, reionization, 21-cm cosmology, and more. Provides a comprehensive introduction to this exciting frontier in astrophysics Begins from first principles Covers advanced topics such as the first stars and 21-cm cosmology Prepares students for research using the next generation of large telescopes Discusses many open questions to be explored in the coming decade
Book Synopsis The Formation of Stars by : Steven W. Stahler
Download or read book The Formation of Stars written by Steven W. Stahler and published by John Wiley & Sons. This book was released on 2008-07-11 with total page 865 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book is a comprehensive treatment of star formation, one of the most active fields of modern astronomy. The reader is guided through the subject in a logically compelling manner. Starting from a general description of stars and interstellar clouds, the authors delineate the earliest phases of stellar evolution. They discuss formation activity not only in the Milky Way, but also in other galaxies, both now and in the remote past. Theory and observation are thoroughly integrated, with the aid of numerous figures and images. In summary, this volume is an invaluable resource, both as a text for physics and astronomy graduate students, and as a reference for professional scientists.
Book Synopsis Disruption of Giant Molecular Clouds by Massive Star Clusters by : Elizabeth Harper-Clark
Download or read book Disruption of Giant Molecular Clouds by Massive Star Clusters written by Elizabeth Harper-Clark and published by . This book was released on 2011 with total page 510 pages. Available in PDF, EPUB and Kindle. Book excerpt: The lifetime of a Giant Molecular Cloud (GMC) and the total mass of stars that form within it are crucial to the understanding of star formation rates across a whole galaxy. In particular, the stars within a GMC may dictate its disruption and the quenching of further star formation. Indeed, observations show that the Milky Way contains GMCs with extensive expanding bubbles while the most massive stars are still alive. Simulating entire GMCs is challenging, due to the large variety of physics that needs to be included, and the computational power required to accurately simulate a GMC over tens of millions of years. Using the radiative-magneto-hydrodynamic code Enzo, I have run many simulations of GMCs. I obtain robust results for the fraction of gas converted into stars and the lifetimes of the GMCs: (A) In simulations with no stellar outputs (or "feedback''), clusters form at a rate of 30% of GMC mass per free fall time; the GMCs were not disrupted but contained forming stars. (B) Including ionization gas pressure or radiation pressure into the simulations, both separately and together, the star formation was quenched at between 5% and 21% of the original GMC mass. The clouds were fully disrupted within two dynamical times after the first cluster formed. The radiation pressure contributed the most to the disruption of the GMC and fully quenched star formation even without ionization. (C) Simulations that included supernovae showed that they are not dynamically important to GMC disruption and have only minor effects on subsequent star formation. (D) The inclusion of a few micro Gauss magnetic field across the cloud slightly reduced the star formation rate but accelerated GMC disruption by reducing bubble shell disruption and leaking. These simulations show that new born stars quench further star formation and completely disrupt the parent GMC. The low star formation rate and the short lifetimes of GMCs shown here can explain the low star formation rate across the whole galaxy.
Book Synopsis Massive Star Formation by : Álvaro Sánchez Monge
Download or read book Massive Star Formation written by Álvaro Sánchez Monge and published by . This book was released on 2011 with total page 265 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Book Synopsis Outflow Feedback Regulated Massive Star Formation in Parsec-Scale Cluster Forming Clumps by :
Download or read book Outflow Feedback Regulated Massive Star Formation in Parsec-Scale Cluster Forming Clumps written by and published by . This book was released on 2010 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: We investigate massive star formation in turbulent, magnetized, parsec-scale clumps of molecular clouds including protostellar outflow feedback using three dimensional numerical simulations of effective resolution 20483. The calculations are carried out using a block structured adaptive mesh refinement code that solves the ideal MHD equations including self-gravity and implements accreting sink particles. We find that, in the absence of regulation by magnetic fields and outflow feedback, massive stars form readily in a turbulent, moderately condensed clump of ≈ 1,600 M{sub {circle_dot}} (containing ≈ 102 initial Jeans masses), along with a cluster of hundreds of lower mass stars. The massive stars are fed at high rates by (1) transient dense filaments produced by large-scale turbulent compression at early times, and (2) by the clump-wide global collapse resulting from turbulence decay at late times. In both cases, the bulk of the massive star's mass is supplied from outside a 0.1 pc-sized 'core' that surrounds the star. In our simulation, the massive star is clump-fed rather than core-fed. The need for large-scale feeding makes the massive star formation prone to regulation by outflow feedback, which directly opposes the feeding processes. The outflows reduce the mass accretion rates onto the massive stars by breaking up the dense filaments that feed the massive star formation at early times, and by collectively slowing down the global collapse that fuel the massive star formation at late times. The latter is aided by a moderate magnetic field of strength in the observed range (corresponding to a dimensionless clump mass-to-flux ratio [lambda] ≈ a few); the field allows the outflow momenta to be deposited more efficiently inside the clump. We conclude that the massive star formation in our simulated turbulent, magnetized, parsec-scale clump is outflow-regulated and clump-fed (ORCF for short). An important implication is that the formation of low-mass stars in a dense clump can affect the formation of massive stars in the same clump, through their outflow feedback on the clump dynamics. In a companion paper, we discuss the properties of the lower mass cluster members formed along with the massive stars, including their mass distribution and spatial clustering.
