Star Formation at High Angular Resolution

Star Formation at High Angular Resolution PDF Author: International Astronomical Union. Symposium
Publisher: Astronomical Society of the Pacific
ISBN:
Category : Science
Languages : en
Pages : 568

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Star Formation at High Angular Resolution

Star Formation at High Angular Resolution PDF Author: International Astronomical Union. Symposium
Publisher: Astronomical Society of the Pacific
ISBN:
Category : Science
Languages : en
Pages : 568

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Book Description


Galaxies at High Redshift

Galaxies at High Redshift PDF Author: I. PĂ©rez-Fournon
Publisher: Cambridge University Press
ISBN: 9780521825917
Category : Science
Languages : en
Pages : 302

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Book Description
This volume presents lectures of the XI Canary Islands Winter School of Astrophysics written by experts in the field.

High Angular Resolution in Astrophysics

High Angular Resolution in Astrophysics PDF Author: A. Lagrange
Publisher: Springer Science & Business Media
ISBN: 9400900414
Category : Science
Languages : en
Pages : 404

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Book Description
Over the last decade many efforts have been made to develop high angular resolution techniques in astrophysics. Combined with imaging facilities, they have rapidly proved their efficiency and have already led to major astrophysical results. During the decade to come, astronomers will be offered new, even more sophisticated high angular resolution tools, especially in the IR and optical domains, coupled with much bigger telescopes, either on the ground or in space. In such a context of rapidly evolving techniques and a growing need for higher angular resolution to test theories or discover new objects, the present book reviews both instrumental and scientific aspects. The main questions addressed are: what kind of science will benefit from high angular resolution techniques? How can they best be used? Audience: The book is accessible to students and research workers in both instrumental and astrophysical aspects.

The Birth of Star Clusters

The Birth of Star Clusters PDF Author: Steven Stahler
Publisher: Springer
ISBN: 3319228013
Category : Science
Languages : en
Pages : 205

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Book Description
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.

High Angular Resolution Studies of the Structure and Evolution of Protoplanetary Disks

High Angular Resolution Studies of the Structure and Evolution of Protoplanetary Disks PDF Author: Joshua Eisner
Publisher: Universal-Publishers
ISBN: 1581122802
Category : Science
Languages : en
Pages : 240

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Book Description
Young stars are surrounded by massive, rotating disks of dust and gas, which supply a reservoir of material that may be incorporated into planets or accreted onto the central star. In this dissertation, I use high angular resolution observations at a range of wavelengths to understand the structure, ubiquity, and evolutionary timescales of protoplanetary disks. First, I describe a study of Class I protostars, objects believed to be at an evolutionary stage between collapsing spherical clouds and fully-assembled young stars surrounded by protoplanetary disks. I use a Monte Carlo radiative transfer code to model new 0.9 micron scattered light images, 1.3 mm continuum images, and broadband spectral energy distributions. This modeling shows that Class I sources are probably surrounded by massive protoplanetary disks embedded in massive infalling envelopes. For the best-fitting models of the circumstellar dust distributions, I determine several important properties, including envelope and disk masses, mass infall rates, and system inclinations, and I use these results to constrain the evolutionary stage of these objects. Second, I discuss observations of the innermost regions of more evolved disks around T Tauri and Herbig Ae/Be stars, obtained with the Palomar Testbed and Keck Interferometers. I constrain the spatial and temperature structure of the circumstellar material at sub-AU radii, and demonstrate that lower-mass stars are surrounded by inclined disks with puffed-up inner edges 0.1-1 AU from the star. In contrast, the truncated inner disks around more massive stars may not puff-up, indicating that disk structure depends on stellar properties. I discuss the implications of these results for disk accretion, terrestrial planet formation and giant planet migration. Finally, I put these detailed studies of disk structure into a broader context by constraining the mass distribution and evolutionary timescales of circumstellar disks. Using the Owens Valley Millimeter Array, I mapped the millimeter continuum emission toward >300 low-mass stars in the NGC 2024 and Orion Nebula clusters. These observations demonstrate that the average disk mass in each cluster is comparable to the "minimum-mass protosolar nebula," and that there may be disk evolution on one million year timescales.

Jets from Young Stars II

Jets from Young Stars II PDF Author: Francesca Bacciotti
Publisher: Springer
ISBN: 9783642087684
Category : Science
Languages : en
Pages : 0

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Book Description
This volume offers a background in modern high spatial resolution techniques, illustrating how such methods have impacted on our understanding of young stars. It provides hands-on insight into observing from space as well as the ground, the use of interferometers at millimeter and infrared wavelengths, image analysis and spectral diagnostic techniques, and High Angular Resolution studies of the inner regions of circumstellar disks that play a fundamental role in jet launching.

Cosmic Rays in Star-Forming Environments

Cosmic Rays in Star-Forming Environments PDF Author: Diego F. Torres
Publisher: Springer Science & Business Media
ISBN: 3642354106
Category : Science
Languages : en
Pages : 500

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Book Description
These are the proceedings of the Sant Cugat Forum 2nd Workshop on Cosmic-ray Induced Phenomenology in Stellar Environments, held April 16-19, 2012. The aim of this Workshop was to address the current knowledge and challenges of high-energy emission from stellar environments at all scales and provide a comprehensive review of the state of the field from the observational to the theoretical perspectives. In the meeting, the prospects for possible observations with planned instruments across the multi-wavelength spectrum were analyzed and also how they impact on our understanding of these systems.

The Physics of Star Formation and Early Stellar Evolution

The Physics of Star Formation and Early Stellar Evolution PDF Author: Charles J. Lada
Publisher: Springer Science & Business Media
ISBN: 9401136424
Category : Science
Languages : en
Pages : 779

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Book Description
The origin of stars is one of the principle mysteries of nature. During the last two decades advances in technology have enabled more progress to be made in the quest to understand stellar origins than at any other time in history. The study of star formation has developed into one of the most important branches of mod ern astrophysical research. A large body of observational data and a considerable literat ure now exist concerning this topic and a 1arge community of international astronomers and physicists devote their efforts attempting to decipher the secrets of stellar birth. Yet, the young astronomerjphysicist or more advanced researcher desiring to obtain a basic background in this area of research must sift through a very diverse and sometimes bewildering literature. A literature which includes research in many discip1ines and sub discip1ines of classical astrophysics from stel lar structure to the interstellar medium and encompasses the entire range of the electromagnetic spectrum from radio to gamma rays. Often, the reward of a suc cessfu1 foray through the current literature is the realization that the results can be obsolete and outdated as soon as the ink is dry in the journal or the conference proceeding in which they are published.

The Earliest Stages of Massive Clustered Star Formation: Fragmentation of Infrared Dark Clouds

The Earliest Stages of Massive Clustered Star Formation: Fragmentation of Infrared Dark Clouds PDF Author: Ke Wang
Publisher: Springer
ISBN: 3662449692
Category : Science
Languages : en
Pages : 160

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Book Description
This thesis presents an in-depth, high-resolution observational study on the very beginning of the formation process: the fragmentation of dense molecular clouds known as infrared dark clouds (IRDCs). Using the Submillimeter Array (SMA) and Very Large Array (VLA) radio interferometers, the author has discovered a common picture of hierarchical fragmentation that challenges some of the leading theoretical models and suggests a new, observation-driven understanding of how massive star formation in clustered environments may begin: it is initiated by the hierarchical fragmentation of a dense filament from 10 pc down to 0.01 pc, and the stellar mass buildup is simultaneously fed by hierarchical accretion at similar scales. The new scenario points out the importance of turbulence and filamentary structure, which are now receiving increasing attention and further tests from both observers and theorists.

Astrophysical Masers and Their Environments (IAU S242)

Astrophysical Masers and Their Environments (IAU S242) PDF Author: International Astronomical Union. Symposium
Publisher: Cambridge University Press
ISBN: 9780521874649
Category : Nature
Languages : en
Pages : 564

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Book Description
Astrophysical masers, naturally occurring microwave and radio-wave emissions, provide an important tool to investigate astrophysical environments. Several thousand maser sources have been observed in the interstellar medium and star formation regions, in the expanding winds from evolved stars, in the compressed shells of supernovae remnants, in comets and in the centers of galaxies. Masers are also useful for studying the structure and dynamics of our own galaxy, while masers in other galaxies are now used for cosmological studies and studies of galactic nuclei. This volume contains the latest research on the topic as presented at IAU Symposium 242, only the third international symposium on astrophysical masers. Over 125 astronomers from 18 different countries gathered in Alice Spring, Australia, for discussions on maser research.