Author: Kazi Lucie Jessica RyglPublisher:
ISBN:
Category :
Languages : en
Pages : 166
Book Description
Massive Star-forming Regions Across the Galaxy
Author: Kazi Lucie Jessica RyglPublisher:
ISBN:
Category :
Languages : en
Pages : 166
Book Description
On the Formation of the Most Massive Stars in the Galaxy
Author: Roberto J. Galván-MadridPublisher: Springer Science & Business Media
ISBN: 1461433088
Category : Science
Languages : en
Pages : 131
Book Description
The most massive stars in the galaxy - those with more than 15 to 20 solar masses - are lilkely to ionize their surroundings before they reach their final mass. How can they accrete in spite of the presence of over-pressurized gas? This thesis presents results of Submillimeter Array (SMA) and Very Large Array (VLA) studies of massive star formation regions in the early stages of ionization, as well as an analysis of numerical simulations of the evolution of these young HII regions. The results favor a picture in which very massive stars form in accretion flows that are partially ionized and that keep accreting material from their environment.
An Introduction to Star Formation
Author: Derek Ward-ThompsonPublisher: Cambridge University Press
ISBN: 1139494473
Category : Science
Languages : en
Pages : 229
Book Description
Guiding the reader through all the stages that lead to the formation of a star such as our Sun, this advanced textbook provides students with a complete overview of star formation. It examines the underlying physical processes that govern the evolution from a molecular cloud core to a main-sequence star, and focuses on the formation of solar-mass stars. Each chapter combines theory and observation, helping readers to connect with and understand the theory behind star formation. Beginning with an explanation of the interstellar medium and molecular clouds as sites of star formation, subsequent chapters address the building of typical stars and the formation of high-mass stars, concluding with a discussion of the by-products and consequences of star formation. This is a unique, self-contained text with sufficient background information for self-study, and is ideal for students and professional researchers alike.
Galaxies and Cosmology
Author: Vittorio CanutoPublisher: CRC Press
ISBN: 9780677221502
Category : Science
Languages : en
Pages : 898
Book Description
This is a treatment of the fundamentals of cosmology and galaxies discussed from theoretical, experimental and observational perspectives and providing a basic reference source for both specialists and non-specialists. Articles from non-equilibrium relativistic cosmology to the evolution of galaxies are included.
Study of Galactic Clumps with Millimeter
Author: Manuel Antonio Merello FerradaPublisher:
ISBN:
Category :
Languages : en
Pages : 460
Book Description
Massive stars play a key role in the evolution of the Galaxy; hence they are important objects of study in astrophysics. Although they are rare compared to low mass stars, they are the principal source of heavy elements and UV radiation, affecting the process of formation of stars and planets, and the physical, chemical, and morphological structure of galaxies. Star clusters form in dense "clumps" (~few parsecs in size) within giant molecular clouds, while individual stars form in cores (subparsec scale). An important step in the observational study of massive star formation is the identification and characterization of clumps. More detailed studies can then show how these clumps fragment into cores. Studies of clumps in our Galaxy will provide fundamental guidelines for the analysis of other galaxies, where individual clumps and cores cannot be resolved, and provide a catalog of interesting sources for observations of the Milky Way with a new generation of instruments, such as the Atacama Large Millimeter/Submillimeter Array. Large-scale blind surveys of the Galactic plane at millimeter and submillimeter wavelengths have recently been completed, allowing us to identify star forming clumps and improve our understanding of the early stages of massive stars. One of these studies, the Bolocam Galactic Plane Survey (BGPS), mapped the continuum emission at 1.1 mm over a large region of the northern Galactic plane at a resolution of 33'', identifying 8559 compact sources throughout the Galaxy. In this dissertation, I present observations of a sample of sources from the BGPS catalog, obtained with the Submillimeter High Angular Resolution Camera II (SHARC-II). I present in this work 107 continuum emission maps at 350 microns at high angular resolution (8.5'') toward clump-like sources and construct a catalog of BGPS substructures. I estimate clump properties such as temperatures and multiplicity of substructures, and compare my results with 350 microns continuum maps from the Hi-GAL survey. I also present a detailed analysis, using molecular line and dust continuum observations, of the region G331.5-0.1, one of the most luminous regions of massive star formation in the Milky Way, located at the tangent region of the Norma spiral arm. Molecular line and millimeter continuum emission maps reveal the presence of six compact and luminous molecular clumps, with physical properties consistent with values found toward other massive star forming sources. This work includes the discovery of one of the most energetic and luminous molecular outflows known in the Galaxy, G331.512-0.103. For this high-speed outflow, I present ALMA observations that reveal a very compact, extremely young bipolar outflow and a more symmetric outflowing shocked shell surrounding a very small region of ionized gas. The source is one of the youngest examples of massive molecular outflows associated with the formation of a high-mass star.
Isotopic fractionation study towards massive star-forming regions across the Galaxy
Author: Laura ColziPublisher: Firenze University Press
ISBN: 8855183796
Category : Science
Languages : en
Pages : 232
Book Description
One of the most important tools to investigate the chemical history of our Galaxy and our own Solar System is to measure the isotopic fractionation of chemical elements. In the present study new astronomical observations devoted to the study of hydrogen and nitrogen fractionation (D/H and 14N/15N ratios) of molecules, towards massive star-forming regions in different evolutionary phases, have been presented. Moreover, a new detailed theoretical study of carbon fractionation, 12C/13C ratios, has been done. One of the main results was the confirmation that the 14N/15N ratio increases with the galactocentric distance, as predicted by stellar nucleosynthesis Galactic chemical evolution models. This work gives new important inputs on the understanding of local chemical processes that favor the production of molecules with different isotopes in star-forming regions.
Ultraviolet Astronomy and the Quest for the Origin of Life
Author: Ana I. Gomez de CastroPublisher: Elsevier
ISBN: 0128191716
Category : Science
Languages : en
Pages : 178
Book Description
Ultraviolet Astronomy and the Quest for the Origin of Life addresses the use of astronomical observations in the ultraviolet range to better understand the generation of complex, life-precursor molecules. The origin of RNA is still under debate but seems to be related to the generation of pools of complex organic molecules submitted to heavy cycles of solution in water and drying. This book investigates whether these cycles require a planetary surface or may occur in space by examining both the theoretical and observational aspects of the role of UV radiation in the origin of life. This book offers the latest advances in these studies for astronomers, astrobiologists and planetary scientists. Addresses both the theoretical and observational aspects of the role of Ultraviolet (UV) radiation in the origin of life Builds on the requirements to produce prebiotic molecules in space and the implications for the origin of RNA Investigates the use of ultraviolet observations related to planetary system formation, the evolution of young planetary disks, and the interaction of stars with planetary atmospheres
Galaxies at High Redshift
Author: I. Pérez-FournonPublisher: Cambridge University Press
ISBN: 9780521825917
Category : Science
Languages : en
Pages : 302
Book Description
This volume presents lectures of the XI Canary Islands Winter School of Astrophysics written by experts in the field.
Massive Stars in Starbursts
Author: Claus LeithererPublisher: Cambridge University Press
ISBN: 9780521404655
Category : Science
Languages : en
Pages : 354
Book Description
This book reviews the importance of massive stars in several areas of astrophysics. Massive stars are objects that are 10-100 times the mass of our Sun. Above ten solar masses, loss through stellar winds begins to have a major impact on the evolution of a star. The upper limit of 100 solar masses is derived from observations. Significant progress has now been achieved in massive star research. New models, along with high quality observations, have improved our understanding of the formation, structure, atmosphere, and evolution of these massive objects. They are formed in violent bursts of star formation and are probably related to the phenomena observed in active galactic nuclei. The workshop at the Space Telescope Science Institute examined the interplay between the astrophysics of massive stars and their location in extragalactic starburst regions. There are eighteen chapters by leading researchers. Each has been carefully edited to ensure that the book is a comprehensive introduction to the theory and observation of massive stars in starburst regions.
Author: Nicole L. Homeier