Download or read book The Nature and Evolution of Disks Around Hot Stars written by Richard Ignace and published by . This book was released on 2005 with total page 400 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Protostars and Planets VI written by Henrik Beuther and published by University of Arizona Press. This book was released on 2014-12-18 with total page 945 pages. Available in PDF, EPUB and Kindle. Book excerpt: Proceedings of a conference held in Heidelberg, Germany, July 15-20, 2013.
Download or read book The Astrophysics of Emission Line Stars written by Tomokazu Kogure and published by Springer Science & Business Media. This book was released on 2010-05-05 with total page 544 pages. Available in PDF, EPUB and Kindle. Book excerpt: Emission line stars are attractive to many people because of their spectacular phenomena and their amazing varieties and variability. This book offers general information on emission line stars, starting from a brief introduction to stellar astrophysics and then moving to a broad overview of emission line stars including early and late type stars as well as pre-main sequence stars.
Download or read book New Worlds New Horizons in Astronomy and Astrophysics written by National Research Council and published by National Academies Press. This book was released on 2011-02-04 with total page 324 pages. Available in PDF, EPUB and Kindle. Book excerpt: Driven by discoveries, and enabled by leaps in technology and imagination, our understanding of the universe has changed dramatically during the course of the last few decades. The fields of astronomy and astrophysics are making new connections to physics, chemistry, biology, and computer science. Based on a broad and comprehensive survey of scientific opportunities, infrastructure, and organization in a national and international context, New Worlds, New Horizons in Astronomy and Astrophysics outlines a plan for ground- and space- based astronomy and astrophysics for the decade of the 2010's. Realizing these scientific opportunities is contingent upon maintaining and strengthening the foundations of the research enterprise including technological development, theory, computation and data handling, laboratory experiments, and human resources. New Worlds, New Horizons in Astronomy and Astrophysics proposes enhancing innovative but moderate-cost programs in space and on the ground that will enable the community to respond rapidly and flexibly to new scientific discoveries. The book recommends beginning construction on survey telescopes in space and on the ground to investigate the nature of dark energy, as well as the next generation of large ground-based giant optical telescopes and a new class of space-based gravitational observatory to observe the merging of distant black holes and precisely test theories of gravity. New Worlds, New Horizons in Astronomy and Astrophysics recommends a balanced and executable program that will support research surrounding the most profound questions about the cosmos. The discoveries ahead will facilitate the search for habitable planets, shed light on dark energy and dark matter, and aid our understanding of the history of the universe and how the earliest stars and galaxies formed. The book is a useful resource for agencies supporting the field of astronomy and astrophysics, the Congressional committees with jurisdiction over those agencies, the scientific community, and the public.
Download or read book High Angular Resolution Studies of the Structure and Evolution of Protoplanetary Disks written by Joshua Eisner and published by Universal-Publishers. This book was released on 2005 with total page 240 pages. Available in PDF, EPUB and Kindle. Book excerpt: 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.
Download or read book The Multi Messenger Approach to High Energy Gamma Ray Sources written by Josep M. Paredes and published by Springer Science & Business Media. This book was released on 2007-11-12 with total page 496 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book provides a theoretical and observational overview of the state of the art of gamma-ray astrophysics, and their impact and connection with the physics of cosmic rays and neutrinos. With the aim of shedding new and fresh light on the problem of the nature of the gamma-ray sources, particularly those yet unidentified, this book summarizes contributions to a workshop that continues today.
Download or read book The Formation and Early Evolution of Protostellar Disks Around Low Mass Stars written by Stefanie Walch and published by . This book was released on 2008 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt:
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 Stars with the B e Phenomenon written by Michaela Kraus and published by . This book was released on 2006 with total page 434 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Asteroseismology written by C. Aerts and published by Springer Science & Business Media. This book was released on 2010-01-19 with total page 872 pages. Available in PDF, EPUB and Kindle. Book excerpt: Understanding the stars is the bedrock of modern astrophysics. Stars are the source of life. The chemical enrichment of our Milky Way and of the Universe withallelementsheavierthanlithiumoriginatesintheinteriorsofstars.Stars arethe tracersofthe dynamics ofthe Universe,gravitationallyimplying much more than meets the eye. Stars ionize the interstellar medium and re-ionized the early intergalactic medium. Understanding stellar structure and evolution is fundamental. While stellar structure and evolution are understood in general terms, we lack important physical ingredients, despite extensive research during recent decades.Classicalspectroscopy,photometry,astrometryandinterferometryof stars have traditionally been used as observational constraints to deduce the internal stellar physics. Unfortunately, these types of observations only allow the tuning of the basic common physics laws under stellar conditions with relatively poor precision. The situation is even more worrisome for unknown aspects of the physics and dynamics in stars. These are usually dealt with by using parameterised descriptions of, e.g., the treatments of convection, rotation,angularmomentumtransport,theequationofstate,atomicdi?usion andsettlingofelements,magneto-hydrodynamicalprocesses,andmore.There is a dearth of observational constraints on these processes, thus solar values areoftenassignedtothem.Yetitishardtoimaginethatonesetofparameters is appropriate for the vast range of stars.
Download or read book Aperture Synthesis written by Swapan Kumar Saha and published by Springer Science & Business Media. This book was released on 2010-10-17 with total page 482 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book deals with the fundamentals of stellar interferometry with emphasis on aperture synthesis using sparse array of telescopes particularly at optical/IR wavelengths, the origin, properties, and optical effects of turbulence in the Earth's atmosphere, techniques developed to overcome image degradation. Studded with more than one hundred and fifty illustrations and tens of footnotes, it addresses the basic tricks of trade, current trend, motivation, methods, and path to future promise of true interferometry both from the ground and space. Also discussed are the technical challenge involved, such as beam transportation and recombination, detecting fringes using modern sensors, and image synthesis. Astronomical science that benefits from aperture synthesis imaging are highlighted as well.
Download or read book The Physics of Star Formation and Early Stellar Evolution written by Charles J. Lada and published by Springer Science & Business Media. This book was released on 2012-12-06 with total page 779 pages. Available in PDF, EPUB and Kindle. Book excerpt: 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.
Download or read book Formation Of The Solar System The Theories Old And New 2nd Edition written by Michael Mark Woolfson and published by World Scientific. This book was released on 2014-09-11 with total page 441 pages. Available in PDF, EPUB and Kindle. Book excerpt: This fully-updated second edition remains the only truly detailed exploration of the origins of our Solar System, written by an authority in the field. Unlike other authors, Michael Woolfson focuses on the formation of the solar system, engaging the reader in an intelligent yet accessible discussion of the development of ideas about how the Solar System formed from ancient times to the present.Within the last five decades new observations and new theoretical advances have transformed the way scientists think about the problem of finding a plausible theory. Spacecraft and landers have explored the planets of the Solar System, observations have been made of Solar-System bodies outside the region of the planets and planets have been detected and observed around many solar-type stars. This new edition brings in the most recent discoveries, including the establishment of dwarf planets and challenges to the ‘standard model’ of planet formation — the Solar Nebula Theory.While presenting the most up-to-date material and the underlying science of the theories described, the book avoids technical jargon and terminology. It thus remains a digestible read for the non-expert interested reader, whilst being detailed and comprehensive enough to be used as an undergraduate physics and astronomy textbook, where the formation of the solar system is a key part of the course.Michael Woolfson is Emeritus Professor of Theoretical Physics at University of York and is an award-winning crystallographer and astronomer.
Download or read book Protoplanetary Dust written by Dániel Apai and published by Cambridge University Press. This book was released on 2010-01-21 with total page 397 pages. Available in PDF, EPUB and Kindle. Book excerpt: The first comprehensive overview of planet formation for students and researchers in astronomy, cosmochemistry, laboratory astrophysics and planetary sciences.
Download or read book Angular Momentum and Mass Loss for Hot Stars written by L.A. Willson and published by Springer Science & Business Media. This book was released on 2012-12-06 with total page 366 pages. Available in PDF, EPUB and Kindle. Book excerpt: Fundamental unsolved problems of stellar astrophysics include the effects of angular momentum on stellar structure and evolution, the nature and efficiency of the processes by which angular momentum is redistributed within and lost from stars, and the role that stellar rotation plays in enhancing or driving stellar mass loss. There appears to be a qualitative change in the nature and efficiency of these mechanisms near spectral type FO: hotter (more massive) stars typically retain more angular momentum at least until they reach the main sequence, while cooler stars typically spin down quickly. For the hotter stars, recent work suggests a strong link between the type of pulsation behavior, the mass loss rates, and the rotation velocity. If the same mechanisms are able to drive mass loss from the main sequence A stars, as has recently been proposed, then the current interpretations of a number of observations will be drastically affected: e. g. the ages of clusters may be incorrect by up to a factor of two, and the surface abundances of isotopes of He, Li and Be may no longer give constraints on cosmological nucleosynthesis. There are also effects on the evolution of the abundances of elements in the interstellar medium and on the general evolution of populations of stars. Thus the questions of the mechanisms of angular momentum and mass loss of stars more massive than the sun is important not only for stellar studies but for the foundations of much of modern astrophysics.
Download or read book Reports on Astronomy 2003 2005 IAU XXVIA written by Oddbjorn Engvold and published by Cambridge University Press. This book was released on 2007-05-10 with total page 416 pages. Available in PDF, EPUB and Kindle. Book excerpt: Transactions XXVIA of the International Astronomical Union (IAU) provides a comprehensive and authoritative review of what has been achieved in astronomy during the years 2003 to 2005. The insightful and up-to-date reviews are written by the Presidents and Chairpersons of the IAU's different Divisions, Commissions and Working Groups and each focuses on a different subject area. Topics covered in this wide-ranging volume include: fundamental astronomy; the Sun and heliosphere; planetary systems sciences; stars; variable stars; interstellar matter; the Galactic system; galaxies and the Universe; optical and infrared techniques; radio astronomy; space and high energy astrophysics; and other IAU activities. The reviews are written at a level suitable for colleagues in the same field, but they will also be useful for students and researchers wishing to gain an overview beyond their own research area.
Download or read book The Early Evolution of Solids in Protoplanetary Disks written by Carey Louise Weisberg and published by . This book was released on 2019 with total page 84 pages. Available in PDF, EPUB and Kindle. Book excerpt: The Early Evolution of Solids in Protoplanetary Disks By Carey Louise Weisberg Observations at millimeter wavelengths can directly probe the existence of mm/ cm-sized pebbles in the disks around forming stars and thereby reveal information about the dust evolution that leads to planet formation. 24 disks in the Upper Scorpius starforming region were observed at a wavelength of 2.87 mm with the Atacama Large Millimeter/Submillilmeter Array (ALMA) of radio antennas. Disk images were analyzed with the Common Astronomy Software Application (CASA) to determine the amount of radiation per unit area. By combining these observations with the detections obtained for the same disks at a wavelength of 0.88 mm, we measured for the first time the amount of radiation per unit wavelength of disks toward the end of their lifetime, i.e. 5-10 million years. This wavelength-dependence of dust emissivity depends on the size of the particles. Mm/cm-sized particles have been observed in the outer regions of younger disks. These observations will reveal whether these particles are still present near the end of a disk's lifetime, which would indicate that some kind of trapping mechanism is preventing them from accreting inwards.
