Download or read book Brown Dwarf Companions to Young Solar an written by Stanimir Metchev and published by Universal-Publishers. This book was released on 2006-02 with total page 255 pages. Available in PDF, EPUB and Kindle. Book excerpt: We present results from an adaptive optics survey conducted with the Palomar and Keck telescopes over 3 years, which measured the frequency of stellar and sub-stellar companions to Sun-like stars. The survey sample contains 266 stars in the 3-10000 million year age range at heliocentric distances between 8 and 200 parsecs and with spectral types between F5-K5. A sub-sample of 101 stars, between 3-500 million years old, were observed in deep exposures with a coronagraph to search for faint sub-stellar companions. A total of 288 candidate companions were discovered around the sample stars, which were re-imaged at subsequent epochs to determine physical association with the candidate host stars by checking for common proper motion. Benefitting from a highly accurate astrometric calibration of the observations, we were able to successfully apply the common proper motion test in the majority of the cases, including stars with proper motions as small as 20 milli-arcseconds/year. The results from the survey include the discovery of three new brown dwarf companions (HD 49197B, HD 203030B, and ScoPMS 214B), 43 new stellar binaries, and a triple system. The physical association of an additional, a priori-suspected, candidate sub-stellar companion to the star HII 1348 is astrometrically confirmed. The newly-discovered and confirmed young brown dwarf companions span a range of spectral types between M5 and T0.5, and will be of prime significance for constraining evolutionary models of young brown dwarfs and extra-solar planets. Based on the 3 new detections of sub-stellar companions in the 101 star sub-sample and following a careful estimate of the survey incompleteness, a Bayesian statistical analysis shows that the frequency of 0.012-0.072 solar-mass brown dwarfs in 30-1600 AU orbits around young solar analogs is 6.8% (-4.9%, +8.3%; 2-sigma limits). While this is a factor of 3 lower than the frequency of stellar companions to G-dwarfs in the same orbital range, it is significantly higher than the frequency of brown dwarfs in 0-3 AU orbits discovered through precision radial velocity surveys. It is also fully consistent with the observed frequency of 0-3 AU extra-solar planets. Thus, the result demonstrates that the radial-velocity "brown dwarf desert" does not extend to wide separations, contrary to previous belief.
Download or read book 50 Years of Brown Dwarfs written by Viki Joergens and published by Springer Science & Business Media. This book was released on 2013-11-27 with total page 174 pages. Available in PDF, EPUB and Kindle. Book excerpt: The years 2012/2013 mark the 50th anniversary of the theoretical prediction that Brown Dwarfs, i.e. degenerate objects which are just not massive enough to sustain stable hydrogen fusion, exist. Some 20 years after their discovery, how Brown Dwarfs form is still one of the main open questions in the theory of star formation. In this volume, the pioneers of Brown Dwarf research review the history of the theoretical prediction and the subsequent discovery of Brown Dwarfs. After an introduction, written by Viki Joergens, reviewing Shiv Kumar's theoretical prediction of the existence of brown dwarfs, Takenori Nakano reviews his and Hayashi's calculation of the Hydrogen Burning Minimum Mass. Both predictions happened in the early 1960s. Jill Tarter then writes on the introduction of the term 'Brown Dwarf', before Ben Oppenheimer, Rafael Rebolo and Gibor Basri describe their first discovery of Brown Dwarfs in the 1990s. Lastly, Michael Cushing and Isabelle Baraffe describe the development of the field to the current state of the art. While the book is mainly aimed at the Brown Dwarf research community, the description of the pioneering period in a scientific field will attract general readers interested in astronomy as well.
Download or read book Astroquizzical the Illustrated Edition written by Jillian Scudder and published by . This book was released on 2021-09-28 with total page 224 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Very Low Mass Stars and Brown Dwarfs written by Rafael Rebolo and published by Cambridge University Press. This book was released on 2000-11-27 with total page 284 pages. Available in PDF, EPUB and Kindle. Book excerpt: This volume provides a state-of-the-art review of our current knowledge of brown dwarfs and very low-mass stars. The hunt for and study of these elusive objects is currently one of the most dynamic areas of research in astronomy for two reasons. Brown dwarfs bridge the gap between stars and planets, and they may constitute an important part of the 'dark matter' of the Universe. This volume presents review articles from a team of international authorities who gathered at a conference in La Palma to assess the spectacular progress that has been made in this field in the last few years.
Download or read book The Census of Warm Debris Disks in the Solar Neighborhood from WISE and Hipparcos written by Rahul I. Patel and published by Universal-Publishers. This book was released on 2016-06-17 with total page 237 pages. Available in PDF, EPUB and Kindle. Book excerpt: Debris disks are optically thin circumstellar disks around mainsequence stars, comprised of micron-sized grains. The dust is generated from destructive collisions of planetesimals, induced from gravitational perturbations by large planets. Debris disks can as signposts for planetary systems, through which, a universal picture can be obtained that encompasses the evolution and architecture of the Solar System's own dust disk and planetary system. The dust in these disks can be detected by their thermal infrared flux, measured as an excess above the photospheric emission. Dust at different circumstellar locations, inferred from the peak wavelength of the detected emission, can act as a probe for local dynamical activity in the system. Over the last thirty years, cold disks, analogous to the Kuiper Belt, have constituted the bulk of debris disk detections. Warm disks, analogous to the Main Asteroid belt, can act as signposts for dynamical activity in the terrestrial planet zone, but are rare in contrast. The Wide-Field Infrared Survey Explorer (WISE) space telescope mapped the entire sky in two near-IR and two mid-IR bands in 2012. The two mid-IR bands are well placed to probe dust emission in the terrestrial planet zone of these stars, at sensitivities greater than the last all-sky IR survey in 1983. WISE also provides us for the first time an opportunity to contemporaneously measure the photospheric and IR excess wavelengths of the entire sky, increasing sensitivity to fainter levels of dust. In this thesis, I present an unbiased survey of warm disks around main-sequence Hipparcos stars in the solar neighborhood, detected using data from the WISE All-Sky Database. Our series of surveys builds upon each other to find previously undetected faint, warm debris disks by including bright photometrically saturated stars in WISE, using empirical photospheric colors, removing several non-trivial false-positive sources, and verifying and validating these detected excesses. This thesis adds a substantial number of new disk targets to the census of debris disks, as well as an assessment of the incidence rate of WISE disks in the solar neighborhood. The number and rate of detections can ultimately aid in enhancing our understanding of the formation and evolution of planetary systems.
Download or read book Ultracool Dwarfs written by Hugh R.A. Jones and published by Springer Science & Business Media. This book was released on 2012-12-06 with total page 199 pages. Available in PDF, EPUB and Kindle. Book excerpt: Once you have looked at the night sky on a moonless night it is not hard to realise why so much of our science and religion has its roots in the stars. Yet it took until 1850 to realise that fainter stars were not necessarily further away, nor the brighter ones closer. In fact within the magnitude range observable to the naked eye it is probable that the brighter star is in fact further away. Even today the measurement of stellar distances is relatively difficult and is gener ally only done using dedicated telescopes. In the early years of the 20th century Hertzsprung and Russell developed a powerful classification diagram which al lows stars to be distinguished using a plot of their colour versus magnitude. The construction of this diagram involved the use of spectroscopy which has become the cornerstone of modern astronomy. As telescopes become more powerful, de tectors more sensitive and more physics is added to astrophysics, astronomical spectroscopy becomes a more powerful tool. The concern of this book is the spectral classification of stars. With a single spectrum of a star it is possible to uniquely classify an object and find its place on the Hertzsprung-Russell diagram. This spectrum is thus equivalent to having the colour and the magnitude of the object which can in turn be related to mass and other quantities.
Download or read book Strange New Worlds written by Ray Jayawardhana and published by Princeton University Press. This book was released on 2013-04-21 with total page 278 pages. Available in PDF, EPUB and Kindle. Book excerpt: Describes the science of planet hunters, the prospects for the discovery of alien life, and discusses the controversies surrounding extrasolar-planet research.
Download or read book Worlds Beyond Our Own written by Sujan Sengupta and published by Springer. This book was released on 2014-10-28 with total page 163 pages. Available in PDF, EPUB and Kindle. Book excerpt: This is a book on planets: Solar system planets and dwarf planets. And planets outside our solar system – exoplanets. How did they form? What types of planets are there and what do they have in common? How do they differ? What do we know about their atmospheres – if they have one? What are the conditions for life and on which planets may they be met? And what’s the origin of life on Earth and how did it form? You will understand how rare the solar system, the Earth and hence life is. This is also a book on stars. The first and second generation of stars in the Universe. But in particular also on the link between planets and stars – brown dwarfs. Their atmospheric properties and similarities with giant exoplanets. All these fascinating questions will be answered in a non-technical manner. But those of you who want to know a bit more may look up the relevant mathematical relationships in appendices.
Download or read book Planet Quest written by Ken Croswell and published by Oxford University Press, USA. This book was released on 1999 with total page 348 pages. Available in PDF, EPUB and Kindle. Book excerpt: Are we alone? In 1995 planet hunters discovered the first alien solar system around a star like our own Sun. Ken Croswell tells the fascinating story of this discovery and the people who made it, then explores the possibility that one day we may have the technology to travel to different solar systems and find life.
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 Stellar Spectral Classification written by Richard O. Gray and published by Princeton University Press. This book was released on 2009-03-29 with total page 620 pages. Available in PDF, EPUB and Kindle. Book excerpt: Written by leading experts in the field, Stellar Spectral Classification is the only book to comprehensively discuss both the foundations and most up-to-date techniques of MK and other spectral classification systems. Definitive and encyclopedic, the book introduces the astrophysics of spectroscopy, reviews the entire field of stellar astronomy, and shows how the well-tested methods of spectral classification are a powerful discovery tool for graduate students and researchers working in astronomy and astrophysics. The book begins with a historical survey, followed by chapters discussing the entire range of stellar phenomena, from brown dwarfs to supernovae. The authors account for advances in the field, including the addition of the L and T dwarf classes; the revision of the carbon star, Wolf-Rayet, and white dwarf classification schemes; and the application of neural nets to spectral classification. Copious figures illustrate the morphology of stellar spectra, and the book incorporates recent discoveries from earth-based and satellite data. Many examples of spectra are given in the red, ultraviolet, and infrared regions, as well as in the traditional blue-violet optical region, all of which are useful for researchers identifying stellar and galactic spectra. This essential reference includes a glossary, handy appendixes and tables, an index, and a Web-based resource of spectra. In addition to the authors, the contributors are Adam J. Burgasser, Margaret M. Hanson, J. Davy Kirkpatrick, and Nolan R. Walborn.
Download or read book Brown Dwarfs written by International Astronomical Union. Symposium and published by Astronomical Society of the Pacific. This book was released on 2003 with total page 608 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Planets Outside the Solar System Theory and Observations written by Jean-Marie Mariotti and published by Springer Science & Business Media. This book was released on 2012-12-06 with total page 440 pages. Available in PDF, EPUB and Kindle. Book excerpt: The question of the existence of other worlds and other living beings has been present in the human quest for knowledge since as far as Epicurus. For centuries this question belonged to the fields of philosophy and theology. The theoretical problem of the formation of the Solar System, and hence of other planetary systems, was tackled only during the 18th century, while the first observational attempts for a detection started less than one hundred years ago. Direct observation of an extra-solar planetary system is an extraordinarily difficult problem: extra-solar planets are at huge distances, are incredibly faint and are overwhelmed by the bright light of their own stars. With virtually no observational insight to test their models, theoreticians have remained for decades in a difficult position to make substantial progress. Yet, the field of stellar formation has provided since the 1980s both the the oretical and observational evidences for the formation of discs at the stage of star birth and for debris materials orbiting the very young stellar systems. It was tempting to consider that these left-overs might indeed later agglomerate into planetary systems more or less similar to ours. Then came observational evidences for planets outside the Solar System.
Download or read book A Question and Answer Guide to Astronomy written by Pierre-Yves Bely and published by Cambridge University Press. This book was released on 2017-03-23 with total page 361 pages. Available in PDF, EPUB and Kindle. Book excerpt: Contains 250 questions and answers about astronomy, particular for the amateur astronomer.
Download or read book Particles And The Universe Proceedings Of The Johns Hopkins Workshop On Current Problems In Particle Theory 17 written by Zalan Horvath and published by World Scientific. This book was released on 1994-07-15 with total page 514 pages. Available in PDF, EPUB and Kindle. Book excerpt: An accelerating convergence of interests of particle physics and modern experimental and theoretical astrophysics has been witnessed in the past few years. One of the focal points is the observation and phenomenological characterization of Dark Matter from Galactic to the large scale structure of the Universe. Particle physics provides detailed predictions for the cosmological impact of various dark matter candidates. The other central subjects are neutrino astronomy and cosmic ray reactions which provide valuable information both on stellar structure (solar neutrinos) and on the nature of extreme high energy particle interactions. The lectures presented here represent important new contributions to all these fields.
Download or read book Solar System Astrophysics written by Eugene F. Milone and published by Springer Science & Business Media. This book was released on 2014-01-30 with total page 496 pages. Available in PDF, EPUB and Kindle. Book excerpt: The second edition of Solar System Astrophysics: Planetary Atmospheres and the Outer Solar System provides a timely update of our knowledge of planetary atmospheres and of the bodies of the outer solar system and their analogs in other planetary systems. This volume begins with an expanded treatment of the physics, chemistry, and meteorology of the atmospheres of the Earth, Venus, and Mars, moving on to their magnetospheres and then to a full discussion of the gas and ice giants and their properties. From here, attention switches to the small bodies of the solar system, beginning with the natural satellites. The comets, meteors, meteorites, and asteroids are discussed in order, and the volume concludes with the origin and evolution of our solar system. Finally, a fully revised section on extrasolar planetary systems puts the development of our system in a wider and increasingly well understood galactic context. All of the material is presented within a framework of historical importance. This book and its sister volume, Solar System Astrophysics: Background Science and the Inner Solar system, are pedagogically well written, providing clearly illustrated explanations, for example, of such topics as the numerical integration of the Adams-Williamson equation, the equations of state in planetary interiors and atmospheres, Maxwell’s equations as applied to planetary ionospheres and magnetospheres, and the physics and chemistry of the Habitable Zone in planetary systems. Together, the volumes form a comprehensive text for any university course that aims to deal with all aspects of solar and extra-solar planetary systems. They will appeal separately to the intellectually curious who would like to know how just how far our knowledge of the solar system has progressed in recent years.
Download or read book Newsletter written by and published by . This book was released on 1998 with total page 668 pages. Available in PDF, EPUB and Kindle. Book excerpt:
