Download or read book Tidal Disruption and Accretion of Planets and Brown Dwarfs Inside Giant Stars written by Gabriel Guidarelli and published by . This book was released on 2022 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: "A significant fraction of isolated white dwarfs host strong magnetic fields that range from a few to a thousand Megagauss. These high-field magnetic white dwarfs (HFMWDs) comprise ∼10% of all isolated white dwarfs. Remarkably, not a single close and detached binary system that is composed of a white dwarf and a low-mass-main-sequence star contains a HFMWD. If the origin of magnetic fields in white dwarfs were independent of binary interactions, then the observed distribution of isolated white dwarfs should be similar to those in detached binaries, yet they are not. Unless there is a mechanism by which distant companions prevent the formation of a strong magnetic field, a more plausible explanation is that highly magnetized white dwarfs became that way by engulfing (and removing) their companions. When a member of a binary system extends past its Roche-Lobe, mass transfer and tidal torques serve to distribute material in a circumbinary ‘envelope’ enclosing the system. This process causes the orbit to decay as the ambient material dynamically drags on the binary components. This interaction is referred to as common envelope evolution and is thought to be the primary channel for producing short-period binaries in the Universe. Using three-dimensional numerical simulations, we investigate common envelope events between an Asymptotic Giant Branch (AGB) star and low-mass companions that are expected to result in mergers. As a companion approaches the AGB core, it tidally disrupts. The disrupted material forms an accretion disk which may amplify, transport and anchor the magnetic field onto the proto-white dwarf. At the end of the AGB phase, a HFMWD would emerge."--Abstract.
Download or read book The Exoplanet Handbook written by Michael Perryman and published by Cambridge University Press. This book was released on 2018-08-30 with total page 973 pages. Available in PDF, EPUB and Kindle. Book excerpt: With the discovery of planets beyond our solar system 25 years ago, exoplanet research has expanded dramatically, with new state-of-the-art ground-based and space-based missions dedicated to their discovery and characterisation. With more than 3,500 exoplanets now known, the complexity of the discovery techniques, observations and physical characterisation have grown exponentially. This Handbook ties all these avenues of research together across a broad range of exoplanet science. Planet formation, exoplanet interiors and atmospheres, and habitability are discussed, providing in-depth coverage of our knowledge to date. Comprehensively updated from the first edition, it includes instrumental and observational developments, in-depth treatment of the new Kepler mission results and hot Jupiter atmospheric studies, and major updates on models of exoplanet formation. With extensive references to the research literature and appendices covering all individual exoplanet discoveries, it is a valuable reference to this exciting field for both incoming and established researchers.
Download or read book Exoplanets Compositions Mineralogy Evolution written by Natalie R. Hinkel and published by Walter de Gruyter GmbH & Co KG. This book was released on 2024-09-02 with total page 612 pages. Available in PDF, EPUB and Kindle. Book excerpt: The focus for RiMG volume 90 is on rocky exoplanets because the search for truly Earth-like planets is of special interest. The goal is to motivate communication between the disciplines so as to make the best use possible of existing data and data yet to be collected by the James Webb and the Nancy Grace Roman Space Telescopes, since the astronomy community is gathering data on stars and exoplanets at an accelerating rate. Such data now include exoplanet size and mass (i.e., density) as well as their atmospheric compositions, which are collectively telltale of mineralogy and evolution. Much of what is published may still fall in the realm of educated speculation, but our conjectures are metamorphosing into testable hypotheses. There is now a remarkably large amount of astronomical data (with even more on the way) that geochemists and petrologists can make much use of. But just as astronomers may benefit from geologic insights, geologists need our colleagues in astronomy to help interpret their data and their underlying implications to better understand its astronomical context. Our hopes for this volume will be fulfilled if readers initiate their own analyses of what at present may seem like novel or unusual data, and if new collaborations between academic departments and subfields are forged.
Download or read book The Tidal Disruption of Stars by Massive Black Holes written by Peter G. Jonker and published by Springer. This book was released on 2021-11-19 with total page 589 pages. Available in PDF, EPUB and Kindle. Book excerpt: This volume provides an overview of the fast-developing field of tidal disruption events. For several decades, astronomers speculated that a hapless star could wander too close to a massive black hole and be torn apart by tidal forces. Yet it is only with the recent advent of wide-field transient surveys that such events have been detected. Written by a team of prominent researchers, the chapters detail the discoveries made so far in this burgeoning field of study across the entire electromagnetic spectrum, from gamma-rays through X-rays, ultra-violet, optical, infrared, and radio. In addition, they show how tidal disruption events can be used to study the properties of otherwise undetectable supermassive black holes; the populations and dynamics of stars in galactic nuclei; the physics of black hole accretion, including the potential to detect relativistic effects near a SMBH; and the physics of (radio) jet formation and evolution in a pristine environment. Finally, the book outlines important outstanding questions about TDEs. With more than 100 color images, the volume will be useful to researchers and others interested in learning more about this promising area of astrophysics. Previously published in Space Science Reviews in the Topical Collection “The Tidal Disruption of Stars by Massive Black Holes”
Download or read book Accretion Processes in Star Formation written by Lee Hartmann and published by Cambridge University Press. This book was released on 2000-11-15 with total page 260 pages. Available in PDF, EPUB and Kindle. Book excerpt: This first comprehensive account of the dynamical processes in the formation of stars and disks from which planets ultimately form.
Download or read book Accretion and Ejection Properties of Young Low mass Stars and Brown Dwarfs written by Elisabetta Rigliaco and published by . This book was released on 2010 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book New Light on Dark Stars written by Neill I. Reid and published by Springer Science & Business Media. This book was released on 2013-11-27 with total page 492 pages. Available in PDF, EPUB and Kindle. Book excerpt: Perhaps the most common question that a child asks when he or she sees the night sky from a dark site for the first time is: 'How many stars are there?' This happens to be a question which has exercised the intellectual skills of many astronomers over the course of most of the last century, including, for the last two decades, one of the authors of this text. Until recently, the most accurate answer was 'We are not certain, but there is a good chance that almost all of them are M dwarfs. ' Within the last three years, results from new sky-surveys - particularly the first deep surveys at near infrared wavelengths - have provided a breakthrough in this subject, solidifying our census of the lowest-mass stars and identifying large numbers of the hitherto almost mythical substellar-mass brown dwarfs. These extremely low-luminosity objects are the central subjects of this book, and the subtitle should be interpreted accordingly. The expression 'low-mass stars' carries a wide range of meanings in the astronomical literature, but is most frequently taken to refer to objects with masses comparable with that of the Sun - F and G dwarfs, and their red giant descendants. While this definition is eminently reasonable for the average extragalactic astronomer, our discussion centres on M dwarfs, with masses of no more than 60% that of the Sun, and extends to 'failed stars' - objects with insufficient mass to ignite central hydrogen fusion.
Download or read book From Giant Planets to Cool Stars written by Caitlin A. Griffith and published by . This book was released on 2000 with total page 400 pages. Available in PDF, EPUB and Kindle. Book excerpt: Annotation Contains papers from a June 1999 workshop addressing the emerging interdisciplinary field of brown dwarfs and extrasolar giant planets. Principal topics discussed are atmospheric structure and chemistry, dynamics, condensation, interior structure, and the evolution of extra-solar planets and brown dwarfs. Some specific topics include the nature and origin of low-mass companions to stars, discovering T dwarfs with 2MASS, the exotic atmospheres of substellar-mass objects, narrow-band near infrared photometry of brown dwarfs, and photochemistry in giant-planet atmospheres. Griffith is affiliated with Northern Arizona University. Marley is affiliated with New Mexico State University. Lacks a subject index. Annotation c. Book News, Inc., Portland, OR (booknews.com)
Download or read book Handbook of Exoplanets written by Hans J. Deeg and published by Springer. This book was released on 2018-06-15 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: This state-of-the-art reference work includes over 15 sections dealing with all aspects of exoplanets and exobiology research, including historic aspects, the Solar System as a template, objects at the planet-to-star transition, exoplanet detection and characterization with related instrumentation, technology and software tools, planet and planet-system statistics with recent and planned surveys, their atmosphere and formation and evolution processes, habitability and exobiology implications, and outlooks for future exploration and science development, including visionary contributions. Each section has 10-20 contributions written by the top experts in their subject, including both senior researchers as well as young, smart researchers who represent the future of the discipline. All in all, this handbook comprehensively tackles one of the most challenging and dynamic fields of modern astronomy and astrophysics.
Download or read book International Aerospace Abstracts written by and published by . This book was released on 1999 with total page 934 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Explaining Lithium Enriched Red Giant Branch Stars written by Claudia Aguilera-Gómez and published by Springer. This book was released on 2018-11-28 with total page 131 pages. Available in PDF, EPUB and Kindle. Book excerpt: This thesis provides new insights into the seemingly anomalous ubiquity of lithium-rich red giant stars. The theory of stellar evolution, one of the most successful models of modern astrophysics, predicts that red giant stars should display negligible levels of lithium (Li) on their surfaces. However, Li-rich giants, defined as those showing more than three times the Li content of the Sun, are found everywhere astronomers look in apparent defiance of established theory. The author addresses this problem, analyzing the different possible explanations for such an anomaly, which include interaction with a binary companion, the production of Li in the interior of the star with its subsequent transport to stellar exteriors, and the stellar interaction with planets. The author focuses on this last possibility, where the Li enrichment may be due to the ingestion of planets or brown dwarfs as the stars in question grew in size while becoming giants. She shows that this process is indeed able to explain an important fraction of giants with Li levels above the three times solar threshold, but that some other mechanism is needed to explain the remaining fraction. While this is an important discovery in its own right, the result that makes this thesis groundbreaking is its demonstration that the threshold between Li-normal and Li-rich is mass dependent rather than a fixed proportion of the Sun’s content. This corrects a fundamental misapprehension of the phenomenon and opens up a new framework in which to understand and solve the problem. Finally, the author presents interesting observational applications and samples with which to test this new approach to the problem of Li enrichment in giants.
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 Infrared Space Interferometry Astrophysics the Study of Earth Like Planets written by C. Eiroa and published by Springer Science & Business Media. This book was released on 2012-12-06 with total page 333 pages. Available in PDF, EPUB and Kindle. Book excerpt: The past year has produced some of the most exciting results in the history of astronomy, particularly in the area of planets outside our solar system. Only a half-year before our meeting in Toledo, Spain, the first unambiguous detection of planet-sized masses orbiting main sequence stars were reported. Since that time, evidence for a new exo planet has been reported almost at the rate of about once per month. Some of these objects are likely to turn out to be very low-mass stars, but something like half show characteristics - Jupiter-like mass and near-zero orbital eccentricity - which appear to be unique to planets. Almost at the same time that giant planets were being discovered regularly, the two major space agencies, ESA and NASA, have iden tified searches for and detailed study of Earth-like planets as a major priority for the future. In ESA's "Horizon 2000 Plus" programme, an infrared interferometer has been proposed as a possible future Cor nerstone mission. Similarly, scientists in the US produced the "Road Map for the Exploration of Neighboring Planetary Systems (ExNPS)", which provided NASA with a long-term plan which leads also to an infrared interferometer in space to study hypothetical Earth-like worlds beyond our Solar System. Such an observatory is designed to search for the thermal emission from a family of planets, using interferometric nulling to remove the contaminating light from the central star.
Download or read book Astrophysics in a Nutshell written by Dan Maoz and published by Princeton University Press. This book was released on 2016-02-23 with total page 310 pages. Available in PDF, EPUB and Kindle. Book excerpt: The ideal one-semester astrophysics introduction for science undergraduates—now expanded and fully updated Winner of the American Astronomical Society's Chambliss Award, Astrophysics in a Nutshell has become the text of choice in astrophysics courses for science majors at top universities in North America and beyond. In this expanded and fully updated second edition, the book gets even better, with a new chapter on extrasolar planets; a greatly expanded chapter on the interstellar medium; fully updated facts and figures on all subjects, from the observed properties of white dwarfs to the latest results from precision cosmology; and additional instructive problem sets. Throughout, the text features the same focused, concise style and emphasis on physics intuition that have made the book a favorite of students and teachers. Written by Dan Maoz, a leading active researcher, and designed for advanced undergraduate science majors, Astrophysics in a Nutshell is a brief but thorough introduction to the observational data and theoretical concepts underlying modern astronomy. Generously illustrated, it covers the essentials of modern astrophysics, emphasizing the common physical principles that govern astronomical phenomena, and the interplay between theory and observation, while also introducing subjects at the forefront of modern research, including black holes, dark matter, dark energy, and gravitational lensing. In addition to serving as a course textbook, Astrophysics in a Nutshell is an ideal review for a qualifying exam and a handy reference for teachers and researchers. The most concise and current astrophysics textbook for science majors—now expanded and fully updated with the latest research results Contains a broad and well-balanced selection of traditional and current topics Uses simple, short, and clear derivations of physical results Trains students in the essential skills of order-of-magnitude analysis Features a new chapter on extrasolar planets, including discovery techniques Includes new and expanded sections and problems on the physics of shocks, supernova remnants, cosmic-ray acceleration, white dwarf properties, baryon acoustic oscillations, and more Contains instructive problem sets at the end of each chapter Solutions manual (available only to professors)
Download or read book Saturn in the 21st Century written by Kevin H. Baines and published by Cambridge University Press. This book was released on 2018-12-06 with total page 495 pages. Available in PDF, EPUB and Kindle. Book excerpt: A detailed overview of Saturn's formation, evolution and structure written by eminent planetary scientists involved in the Cassini Orbiter mission.
Download or read book Ultraviolet Astronomy and the Quest for the Origin of Life written by Ana I. Gomez de Castro and published by Elsevier. This book was released on 2021-03-27 with total page 178 pages. Available in PDF, EPUB and Kindle. Book excerpt: 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
Download or read book Meteorologies of Brown Dwarfs and Extrasolar Giant Planets written by and published by . This book was released on 2006 with total page 276 pages. Available in PDF, EPUB and Kindle. Book excerpt: This dissertation explores the consequences of atmospheric dynamics for observations of substellar mass objects (SMOs). Discussed first is the growth of cloud particles of various compositions in brown dwarfs of different surface gravities and effective temperatures. The structure of these objects is calculated with a one-dimensional radiative transfer model. To determine particle sizes, the timescales for microphysical growth processes, including nucleation, coagulation, and coalescence, are compared to the timescale for gravitational sedimentation. The model also allows for sustained uplifting of condensable vapor in convective regions. The results show that particle sizes vary greatly over the range of objects studied. In most cases, clouds on brown dwarfs do not dominate the opacity. Rather, they smooth the emergent spectrum and partially redistribute the radiative energy. The focus then shifts to extrasolar giant planets (EGPs). Results are presented from a three-dimensional model of atmospheric dynamics on the transiting Jupiter-like planet HD 209458b. As a close-in orbiter (known as a r̀̀oaster''), HD 209458b is super-heated on its dayside. Due to tidal locking of the interior, the dayside hemisphere faces the star in perpetuity, which leads to very different dynamics than is seen on Jupiter. The flow is characterized by an eastward supersonic jet (u ̃4 km/s) extending from the equator to the mid-latitudes. Temperature contrasts are 5̃00 K at the photosphere. At 220 mbar, winds blow the hottest regions downstream from the substellar point by 60 degrees, with direct implications for the infrared light curve. These simulations are extended to the study of carbon chemistry in HD 209458b's atmosphere by coupling the CO/CH4 reaction kinetics to the dynamics. Disequilibrium results from slow reaction rates at low temperatures and pressures. Effective vertical quenching near the 3 bar level leads to uniformly high concentrations ofCO at the photosphere, even in cool regions where CH4 is strongly favored thermodynamically. Observations are underway to detect these signatures of meteorology on HD 209458b and similar planets.
