Download or read book Physical and Chemical Properties During High mass Star Formation written by Caroline Gieser and published by . This book was released on 2022 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Chemistry as a Diagnostic of Star Formation written by National Research Council Canada and published by NRC Research Press. This book was released on 2003 with total page 510 pages. Available in PDF, EPUB and Kindle. Book excerpt: This publication contains presentations & poster papers of a conference that focussed on the many aspects of astrochemistry related to star formation. Topics covered include: the next generation of telescopes & detectors; studies of fundamental chemical processes both in the lab & in the field; an exploration of the connections between chemistry & physics in star-forming regions; the unique problems of high-mass star formation; the formation of hydrogen; deuterated molecules; molecular depletion; observations & modelling of embedded protostars; accretion disks & circumstellar disks; interstellar dust; and the chemistry, physical conditions, & structure of dark clouds. Includes indexes of subjects, authors, & astronomical objects.
Download or read book The Chemistry of Warm Cores in Low mass Star Forming Regions written by Z. M. A.-H. Awad and published by . This book was released on 2010 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: My thesis deals with the investigation of the chemical and physical properties of the gas and dust involved in the formation of low mass stars. As the stars form, warm cores (or 'hot corinos') are detected in molecular emission. The study of such emissions allows us to get an insight on the physical conditions of low-mass star formation, and trace its various evolutionary stages. Through out this thesis I make use of a chemical model originally developed for the study of high mass star forming regions. I have adapted this model for the study of low mass stars and first applied it to explore the sensitivity of the chemistry of hot corinos to the changes in the physical conditions of the surrounding environment. It is found that the chemical trends of these cores does not qualitatively differ much from that of hot cores (remnant of high mass star formation) leading us to conclude that, at least in some cases, the formation of low-mass stars may be a scaled-down version of that of massive stars. One of the most studied hot corinos is that surrounding IRAS 16293-2422: in order to validate my model, I compare the predicted chemical abundances to the molecular emission from this object and find a relatively good match. Observations of warm cores also revealed that they are rich in deuterium content. I enlarge our chemical network to include all the possible mono-deuterated species, as well as D2CO. In this study, I look into the chemical evolution of the deuterated species, and aim to identify a set of deuterated molecules as evolutionary indicators for the protostellar stage of the core. A very debated issue when validating chemical models is that of whether the initial chemical conditions of the gas affect the chemical evolution of the star forming cores. I investigate this issue by running a large grid of dark and dense cloud models where the initial conditions are varied, in particular I investigate whether a pre-processed gas (e.g. 'left over' from a previous star formation event) may affect subsequent star formation processes and find that in general the initial chemical composition of the gas is in fact irrelevant. Finally, I took part of a study, led by Dr Bayet, where the chemistry of deuterated species in extragalactic environments is investigated and in this thesis I highlight my contribution to this work.
Download or read book Earliest Phases of Star Formation written by Nils Lippok and published by . This book was released on 2014 with total page 116 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book The Earliest Stages of Massive Clustered Star Formation Fragmentation of Infrared Dark Clouds written by Ke Wang and published by Springer. This book was released on 2014-11-03 with total page 160 pages. Available in PDF, EPUB and Kindle. Book excerpt: 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.
Download or read book Cosmic Matter written by Siegfried Röser and published by John Wiley & Sons. This book was released on 2008-09-26 with total page 426 pages. Available in PDF, EPUB and Kindle. Book excerpt: This 20th volume in the series contains 16 invited reviews and highlight contributions presented during the 2007 International Scientific Conference of the German Astronomical Society on the topic of "Cosmic Matter", held in Würzburg, Germany. The papers published here discuss a wide range of hot topics, including cosmology, high-energy astrophysics, astroparticle physics gravitational waves, extragalactic and stellar astronomy -- together representing the roadmap for astroparticle physics in Europe.
Download or read book Isotopic fractionation study towards massive star forming regions across the Galaxy written by Laura Colzi and published by Firenze University Press. This book was released on 2022 with total page 232 pages. Available in PDF, EPUB and Kindle. Book excerpt: 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.
Download or read book Chemical Evolution of Galaxies written by Francesca Matteucci and published by Springer Science & Business Media. This book was released on 2012-01-05 with total page 237 pages. Available in PDF, EPUB and Kindle. Book excerpt: The term “chemical evolution of galaxies” refers to the evolution of abundances of chemical species in galaxies, which is due to nuclear processes occurring in stars and to gas flows into and out of galaxies. This book deals with the chemical evolution of galaxies of all morphological types (ellipticals, spirals and irregulars) and stresses the importance of the star formation histories in determining the properties of stellar populations in different galaxies. The topic is approached in a didactical and logical manner via galaxy evolution models which are compared with observational results obtained in the last two decades: The reader is given an introduction to the concept of chemical abundances and learns about the main stellar populations in our Galaxy as well as about the classification of galaxy types and their main observables. In the core of the book, the construction and solution of chemical evolution models are discussed in detail, followed by descriptions and interpretations of observations of the chemical evolution of the Milky Way, spheroidal galaxies, irregular galaxies and of cosmic chemical evolution. The aim of this book is to provide an introduction to students as well as to amend our present ideas in research; the book also summarizes the efforts made by authors in the past several years in order to further future research in the field.
Download or read book Case Studies in Star Formation written by Duncan MacKay and published by Cambridge University Press. This book was released on 2023-03-31 with total page 339 pages. Available in PDF, EPUB and Kindle. Book excerpt: A succinct overview of our current understanding in the molecular astronomy of star formation for graduate students and early researchers.
Download or read book Study of Galactic Clumps with Millimeter written by Manuel Antonio Merello Ferrada and published by . This book was released on 2014 with total page 460 pages. Available in PDF, EPUB and Kindle. Book excerpt: 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.
Download or read book The Molecular Universe IAU S280 written by José Cernicharo and published by Cambridge University Press. This book was released on 2012-01-19 with total page 528 pages. Available in PDF, EPUB and Kindle. Book excerpt: Astrochemistry, the study of molecules and their chemistry in astrophysical objects throughout the Universe, is experiencing a true golden age. Astronomical observations of molecules are crucial in contributing to our understanding of the physical conditions in many different astrophysical environments, from the Solar System and extrasolar planets to stars, interstellar clouds and galaxies. Concurrently, laboratory experiments and theoretical studies can provide basic information about the often exotic chemical processes taking place in the Universe. IAU Symposium 280 contains outstanding reviews on the advances in observational, laboratory, theoretical and modelling studies, carried out by leading scientists worldwide. This volume provides researchers and graduate students with an indispensable account of the current state of astrochemistry, its recent successes and the immense possibilities of this fascinating field for future growth.
Download or read book The Early Stages of Massive Star Formation written by Hannah Calcutt and published by . This book was released on 2015 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Violent Star Formation written by G. Tenorio-Tagle and published by Cambridge University Press. This book was released on 1994-09-22 with total page 452 pages. Available in PDF, EPUB and Kindle. Book excerpt: A valuable overview and a timely update on all aspects of violent star formation in a host of objects, for graduate students and researchers across a broad range of research interests.
Download or read book Protostars and Planets V written by Bo Reipurth and published by University of Arizona Press. This book was released on 2007 with total page 994 pages. Available in PDF, EPUB and Kindle. Book excerpt: 'Protostars and Planets V' builds on the latest results from recent advances in ground and space-based astronomy and in numerical computing techniques to offer the most detailed and up-to-date picture of star and planet formation - including the formation and early evolution of our own solar system.
Download or read book The Early Stages of Massive Star Formation written by and published by . This book was released on 2015 with total page 380 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Scientific and Technical Aerospace Reports written by and published by . This book was released on 1994 with total page 892 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Star Formation Galaxies and the Interstellar Medium written by Jose Franco and published by Cambridge University Press. This book was released on 1993-06-10 with total page 418 pages. Available in PDF, EPUB and Kindle. Book excerpt: The enormously powerful phenomena of starbursts are examined in this book. These spectacular star-forming events are seen on large scales in some galaxies, often triggered by galactic interactions. An intriguing implication of starburst research is that active galactic nuclei (AGN) may not be powered by accreting black holes. Instead theories are presented where compact powerhouses of dust-enshrouded star formation lie at the core of AGN, with supernovae exploding roughly once per year within massive nuclear concentrations of gas. This book collects articles from a timely international conference in Elba, Italy, in 1992; these comprise a thorough review of the most important developments in galactic-scale star formation since the starburst revolution of the late 1980s. This text will introduce graduate students to this exciting area and keep experts apace with rapid developments in it.
