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Author: Subhanjoy Mohanty
Publisher:
ISBN:
Category :
Languages : en
Pages : 582
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Book Description
Author: Subhanjoy Mohanty
Publisher:
ISBN:
Category :
Languages : en
Pages : 582
Get Book Here
Book Description
Author: Hugh R.A. Jones
Publisher: Springer Science & Business Media
ISBN: 3642566723
Category : Science
Languages : en
Pages : 199
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Book Description
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.
Author: Rafael Rebolo
Publisher: Cambridge University Press
ISBN: 9780521663359
Category : Science
Languages : en
Pages : 284
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Book Description
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.
Author: Nirmala Prakash
Publisher: World Scientific
ISBN: 9814304530
Category : Science
Languages : en
Pages : 674
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Book Description
This book describes these issues in terms of links, between cosmology, particle and nuclear physics, as well as between cosmology, atmospheric and terrestrial physics. It studies the constituents of dark matter (classified as hot warm and cold) first in terms of their individual structures, and second, in terms of facilities available to detect these structures. Neutrinos are treated as a separate entity. The last chapter details the real-time stories about the "regions" that were not explored thus far, for lack of advanced technology. Their untold stories (which span up to 2010) are illustrated here datewise in full. The book concludes with the latest news that the Large Hadron Collider team at CERN has finally succeeded in producing 7 trillion electronic Volts of energy by creating head-on-collisions of protons and more protons (in search of God-particle).
Author: Stanimir Metchev
Publisher: Universal-Publishers
ISBN: 158112290X
Category : Science
Languages : en
Pages : 255
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Book Description
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.
Author: Joachim E. Trümper
Publisher: Springer Science & Business Media
ISBN: 3540344128
Category : Science
Languages : en
Pages : 499
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Book Description
With contributions from leading scientists in the field, and edited by two of the most prominent astronomers of our time, this is a totally authoritative volume on X-ray astronomy that will be essential reading for everyone interested – from students to astrophysicists and physicists. All the aspects of this exciting area of study are covered, from astronomical instrumentation to extragalactic X-ray astronomy.
Author: Harley A. Thronson
Publisher: Springer Science & Business Media
ISBN: 1402094574
Category : Science
Languages : en
Pages : 523
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Book Description
NASA’s James Webb Space Telescope (JWST), planned for operation in about five years, will have the capability to investigate – and answer – some of the most challenging questions in astronomy. Although motivated and designed to study the very early Universe, the performance of the observatory’s instruments over a very wide wavelength range will allow the world’s scientific community unequaled ability to study cosmic phenomena as diverse as small bodies in the Solar System and the formation of galaxies. As part of preparation to use JWST, a conference was held in Tucson, Arizona in 2007 that brought together astronomers from around the world to discuss the mission, other major facilities that will operate in the coming decade, and major scientific goals for them. This book is a compilation of those presentations by some of the leading researchers from all branches of astronomy. This book also includes a “pre-history” of JWST, describing the lengthy process and some of the key individuals that initiated early work on the concepts that would evolve to become the premier space observatory of the next decade.
Author: Neill I. Reid
Publisher: Springer Science & Business Media
ISBN: 1447136632
Category : Science
Languages : en
Pages : 492
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Book Description
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.
Author: International Astronomical Union. Symposium
Publisher: Cambridge University Press
ISBN: 9780521874700
Category : Science
Languages : en
Pages : 620
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Book Description
State-of-the-art review of the growing field of astrometry, for researchers and graduate students.
Author: Chris Impey
Publisher: MIT Press
ISBN: 0262373084
Category : Science
Languages : en
Pages : 375
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Book Description
The science of finding habitable planets beyond our solar system and the prospects for establishing human civilization away from our ever-less-habitable planetary home. Planet Earth, it turns out, may not be the best of all possible worlds—and lately humanity has been carelessly depleting resources, decimating species, and degrading everything needed for life. Meanwhile, human ingenuity has opened up a vista of habitable worlds well beyond our wildest dreams of outposts on Mars. Worlds without End is an expertly guided tour of this thrilling frontier in astronomy: the search for planets with the potential to host life. With the approachable style that has made him a leading interpreter of astronomy and space science, Chris Impey conducts readers across the vast, fast-developing field of astrobiology, surveying the dizzying advances carrying us ever closer to the discovery of life beyond Earth—and the prospect of humans living on another planet. Since the first exoplanet, or planet beyond our solar system, was discovered in 1995, over 4,000 more have been pinpointed, including hundreds of Earth-like planets, many of them habitable, detected by the Kepler satellite. With a view spanning astronomy, planetary science, geology, chemistry, and biology, Impey provides a state-of-the-art account of what’s behind this accelerating progress, what’s next, and what it might mean for humanity’s future. The existential threats that we face here on Earth lend urgency to this search, raising the question: Could space be our salvation? From the definition of habitability to the changing shape of space exploration—as it expands beyond the interests of government to the pursuits of private industry—Worlds without End shows us the science, on horizons near and far, that may hold the answers.
