Download or read book Nova Outburst Modeling and Its Application to the Recurrent Nova Phenomenon written by and published by . This book was released on 1985 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: The thermonuclear runaway (TNR) theory for the cause of the common novae is reviewed. Numerical simulations of this theory were performed using an implicit hydrodynamic Lagrangian computer code. Relevant physical phenomena are explained with the simpler envelope-in-place calculations. Next the models that include accretion are discussed. The calculations agree very well with observations of common novae. The observational differences between common novae and recurrent novae are examined. We propose input parameters to the TNR model which can give the outburst characteristics of RS Ophiuchi and discuss the implications. This review is concluded with a brief discussion of two current topics in novae research: shear mixing on the white dwarf and Neon novae. 36 refs., 4 figs.
Download or read book RS Ophiuchi 1985 and the Recurrent Nova Phenomenon written by M. F. Bode and published by VSP. This book was released on 1987-12 with total page 276 pages. Available in PDF, EPUB and Kindle. Book excerpt: This international conference brought together over 50 astronomers from around the world. The meeting centred around a single object, the reccurent nova RS Ophiuchi, a star which had undergone four recorded outbursts before the latest event in 1985. Observations of previous outbursts (discussed in detail in one of the review talks) already indicated that RS Ophiuchi is a unique object of great astronomical significance. The outburst mechanism is probably similar to that of classical novae, but the interaction of the ejecta with a pre-existing shell of material give it the characteristics of a young supernova remnant. However, unlike supernova remnants, the evolution occurs 'before our very eyes'. Following the latest outburst, a frenzy of activity ensued, resulting in the acquisition of detailed observations from the radio (where rapidly expanding jets were discovered) to the X-ray (where RS Ophiuchi turned out to be one of the brightest soft X-ray sources yet observed). The Proceedings report the many exciting and unexpected observational results right across the electromagnetic spectrum in both RS Ophiuchi and related objects. Theoretical work on the cause of the outburst, and remnant evolution is also given prominence. The result is a much fuller understanding of RS Ophiuchi and its important standing in several branches of astrophysical research.
Download or read book RS Ophiuchi 2006 and the Recurrent Nova Phenomenon written by Aneurin Evans and published by . This book was released on 2008 with total page 400 pages. Available in PDF, EPUB and Kindle. Book excerpt: "On 12 February 2006, the recurrent nova RS Ophiuchi erupted for the first time since 1985, its 6th (at least!) known eruption. This event triggered an intensive multi-wavelength observational campaign, from the radio to gamma-rays, and theoreticians have been presented with a wealth of high-quality data. A workshop was held at Keele University, UK, from 12-14 June 2007 to discuss the observations, their interpretation, and where RS Ophiuchi sits in the wider astrophysical picture. The workshop brought together observers, from gamma-ray to radio wavelengths, theoreticians, and workers in closely related areas. The workshop considered not only the 2006 eruption of RS Oph but also the implications that this has had for our understanding of other much broader areas of astrophysics. It was wide ranging, taking in the environments of red giants; supernova progenitors; accretion, thermonuclear processes and evolution of close binary systems; and shocks of jets, as well as recurrent novae and related objects. The proceedings contain 15 invited reviews, 38 contributed talks and posters, and 3 specially commissioned papers which we hope will enhance the value of the workshop for the wider astrophysical community."--Publisher's website
Download or read book Scientific and Technical Aerospace Reports written by and published by . This book was released on 1995 with total page 652 pages. Available in PDF, EPUB and Kindle. Book excerpt: Lists citations with abstracts for aerospace related reports obtained from world wide sources and announces documents that have recently been entered into the NASA Scientific and Technical Information Database.
Download or read book Publications written by United States. National Bureau of Standards and published by . This book was released on 1991 with total page 480 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Literature 1987 Part 1 written by S. Böhme and published by Springer Science & Business Media. This book was released on 2013-11-11 with total page 1300 pages. Available in PDF, EPUB and Kindle. Book excerpt: Astronomy and Astrophysics Abstracts aims to present a comprehensive documen tation of the literature concerning all aspects of astronomy, astrophysics, and their border fields. It is devoted to the recording, summarizing, and indexing of the relevant publications throughout the world. Astronomy and Astrophysics Abstracts is prepared by a special department of the Astronomisches Rechen-Institut under the auspices of the International Astronomical Union. Volume 43 records literature published in 1987 and received before August 15, 1987. Some older documents which we received late and which are not surveyed in earlier volumes are included too. We acknowledge with thanks contributions of our colleagues all over the world. We also express our gratitude to all organiza tions, observatories, and publishers which provide us with complimentary copies of their publications. Starting with Volume 33, all the recording, correction, and data processing work was done by means of computers. The recording was done by our technical staff members Ms. Helga Ballmann, Ms. Beate Gobel, Ms. Monika Kohl, Ms. Sylvia Matyssek, Ms. Doris Schmitz-Braunstein, Ms. Utta-Barbara Stegemann. Mr. Jochen Heidt and Mr. Kristopher Polzine supported our task by careful proof reading. It is a pleasure to thank them all for their encouragement. Heidelberg, October 1987 The Editors Contents Introduction . . . . . . . . . . . 1 Concordance Relation: PHYS-AAA 3 Abbreviations 5 Periodicals, Proceedings, Books, Activities 001 Periodicals . . . . . . . . . . . 10 002 Bibliographical Publications, Documentation, Catalogues, Data Bases 50 003 Books ...... .
Download or read book Energy Research Abstracts written by and published by . This book was released on 1986 with total page 504 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Publications of the National Institute of Standards and Technology Catalog written by National Institute of Standards and Technology (U.S.) and published by . This book was released on 1991 with total page 480 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book The Nova Outburst written by and published by . This book was released on 1999 with total page 6 pages. Available in PDF, EPUB and Kindle. Book excerpt: Observational and theoretical studies of the outbursts of classical novae have provided critical insights into a broad range of astrophysical phenomena. Thermonuclear runaways (TNRs) in accreted hydrogen-rich envelopes on the white dwarf (WD) components of close binary systems constitute not only the outburst mechanism for a classical nova explosion, but also the recurrent novae and a fraction of the symbiotic novae explosions. Studies of the general characteristics of these explosions, both in our own galaxy and in neighboring galaxies of varying metallicity, can teach us about binary stellar evolution, while studies of the evolution of nova binary systems can constrain models for the (as yet unidentified) progenitors of Type Ia supernovae. Further, the empirical relation between the peak luminosity of a nova and the rate of decline, which presents a challenge to theoretical models, allows novae to be utilized as standard candles for distance determinations out to the Virgo Cluster. E xtensive studies of novae with IUE and the resulting abundance determinations have revealed the existence of oxygen-neon white dwarfs in some systems. The high levels of enrichment of novae ejecta in elements ranging from carbon to sulfur confirm that there is significant dredge-up of matter from the core of the underlying white dwarf and enable novae to contribute to the chemical enrichment of the interstellar medium. Observations of the epoch of dust formation in the expanding shells of novae allow important constraints to be placed on the dust formation process and confirm that graphite, SiC, and SiO2 grains are formed by the outburst. It is possible that grains from novae were injected into the pre-solar nebula and can be identified with some of the pre-solar grains or ''stardust'' found in meteorites. Finally, g-ray observations during the first several years of their outburst, using the next generation of satellite observatories, could confirm the presence of decays from 7Be and 22Na.
Download or read book The Symbiotic Phenomenon written by Joanna Mikolajewska and published by Springer Science & Business Media. This book was released on 2012-12-06 with total page 356 pages. Available in PDF, EPUB and Kindle. Book excerpt: Symbiotic stars were identified spectroscopically as M giants with a very strong He II 4686 emission line. After five decades of study by many astronomers, the first internatioinal meetings devoted to symbiotics were held at the University of Colorado (Boulder) and at the Haute Provence Observatory during the Summer of 1981. These conferences emphasized exciting new results obtained by modern satellite (EINSTEIN, IUE) and ground-based observatories. Although the vast majority of the participants were already fairly sure that symbiotics are almost certainly interacting binary systems, and not extremely peculiar single stars, it was not clear exactly which types of physical processes were needed to be invoked to explain their observed behaviour. Many were even worried that it might not be possible to clearly define a class of "symbiotic stars" , and thus establish a unique model applicable to any system. Since the publication of the Haute-Provence proceedings, our understanding of the physical processes occuring in symbiotic stars (and in related objects such as cataclysmic variables and compact planetary nebulae) has greatly improved. We now speak confidently of a "symbiotic phenomenon" , in which an evolved red giant and a hot companion object (usually thought to be an accreting main sequence star or a luminous white dwarf star) happily coexist.
Download or read book Frontiers Of Space And Ground Based Astronomy written by Willem Wamsteker and published by Springer Science & Business Media. This book was released on 1994-08-31 with total page 794 pages. Available in PDF, EPUB and Kindle. Book excerpt: ROSAT Observations G. HASINGER Max-Planck-Institut flir extraterrestrische Physik, D-85740 Garching, Germany Abstract. This review describes the most recent advances in the study of the extragalactic soft X-ray background and what we can learn about its constituents. The deepest pointed observations with the ROSAT PSPC are discussed. The logN-logS relation is presented, which reaches to the faintest X-ray fluxes and to the highest AGN surface densities ever achieved. The N(>S) relation shows a 2 density in excess of 400 deg- at the faintest fluxes and a flattening below the Einstein Deep Survey limit. About 60% of the extragalactic background has been resolved in the deepest field. Detailed source spectra and first optical and radio identifications will be discussed. The results are put into perspective of the higher energy X -ray background. Key words: X-rays, background radiations, active galactic nuclei. 1. Introduction The extragalactic X-ray background (XRB), discovered about 30 years ago, has been studied extensively with many X-ray experiments, in particular with the satel lites HEAO I and II (see ego Boldt 1987) and with ROSAT (e. g. Hasinger et aI. , 1993). Figure 1 shows a compilation of some of the most recent spectral measure ments for the X-ray background. Over the energy range from 3 to about 100 keY its spectrum can be well approximated by an optically thin thermal bremsstrahlung model with kT ~ 40 keY, while at lower X-ray energies a steepening into a new component has been observed observed (e. g.
Download or read book Models of Classical Novae with MESA written by Oriol Abril Pla and published by . This book was released on 2017 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Classical novae are thermonuclear runaways at the envelope of a WD due to the piling up of H-rich accreted material. They have been observed to produce heavy elements during the explosion, and their role in galactical abundances for some specific elements may not be negligible. MESA (Modules for Experiments in Stellar Astrophysics) code has been thoroughly studied for its application to nova explosions. Detailed know-how of nova simulations with MESA has been achieved, leading the road of future studies using this tool. Its capablities in the field have been tested, demonstrating to reach further than what has been done in previous literature. MESA has been shown to give accurate nucleosynthesis yields for solar-like accreted material without any further postprocessing up to 50 nova bursts. The dependance of the nova outburst properties with the burst number have been anayzed. However, more simulations are needed in order to extract meaningful conclusions about the role of the burst number in the properties of novae outbursts. The key role of the nuclear reaction network has been highlighted, showing that simulations of consecutive novae outbursts require nuclear reactions networks specifically tested for the work. Many nuclear reaction networks that were thoroughly tested in a single nova explosion have not been capable of properly simulating 10 consecutive outbursts. The role of convective overshoot mixing as implemented in MESA has also been tested. It has been found that as shown in previous literature, it does account for dredge up. We plan to extend this work with simulations of consecutive nova outbursts implementing convective overshoot.
Download or read book Physics Briefs written by and published by . This book was released on 1990 with total page 1266 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Cataclysmic Variables and Related Objects pp i xc 1 342 written by Margherita Hack and published by . This book was released on 1993 with total page 438 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Literature 1980 Part 2 written by Siegfried Böhme and published by Springer Science & Business Media. This book was released on 2013-04-18 with total page 851 pages. Available in PDF, EPUB and Kindle. Book excerpt:
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 Novae and Related Stars written by Yozo Yokota and published by Springer Science & Business Media. This book was released on 2012-12-06 with total page 227 pages. Available in PDF, EPUB and Kindle. Book excerpt: Michael Friedjung Though known since antiquity, novae are still poorly under stood and present many problems. There has tended to be a lack of communication between theoreticians and observers and between different schools of thought, in spite of the advances of recent years in certain directions (observations of ordinary novae at minimum and of dwarf novae, theory of the causes of the explosion, etc ••• ). The meeting whose proceedings are contained in this volume was organized to stimulate a confron tation between the different ideas and results. The subject has changed a lot since 1963, when the previous international meeting was held. There were 61 participants at the conference from 17 countries, so very many groups ~oing research in the field of novae were represented. The reader will see that the subject has become more physical (we know for instance that the binary nature of novae is essential) but much work remains to be done. There is still a large gulf between theory and observation. May he find here many new ideas for future research! I would like to thank the French Centre National de la Recherche Scientifique for providing financial help. I must also thank the other members of the scientific committee (Profs and Drs Bath, Mustel, Payne-Gaposchkin, Sparks and Warner) and of the local committee (Audouze, Mrs Steinberg, Vauclair).
