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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: 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: Detlev Koester
Publisher:
ISBN: 9781583811979
Category : Science
Languages : en
Pages : 722
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Book Description
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: Andy Adamson
Publisher: Springer Science & Business Media
ISBN: 940077432X
Category : Science
Languages : en
Pages : 336
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Book Description
These are the proceedings of an international meeting hosted by the Royal Observatory, Edinburgh, to commemorate the 30th anniversary of the dedication of the UKIRT, the United Kingdom InfraRed Telescope. The volume comprises 31 professional level papers. The first part of the book has 10 thorough reviews of the conception, design and build of the telescope, as well as accounts of some its key instruments such as IRCAM (the common-user infrared camera), CGS4 (the fourth Cooled Grating Spectrometer) and the Wide Field Camera. The second part of the book comprises 14 reviews of scientific achievements during its twenty years of visitor mode operations. The final part of the book is a series of 7 reviews of the results from the multiple surveys being done as part of UKIDSS (UKIRT Infrared Deep Sky Survey). The authors are all experts in their respective fields, for example instrument scientists, operations staff and leading astronomers.
Author: Lisa J. Storrie-Lombardi
Publisher: AIP Conference Proceedings / A
ISBN:
Category : Science
Languages : en
Pages : 272
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Book Description
The Spitzer Space Telescope will complete its prime cryogenic mission in early 2009. A workshop for the astronomical community was held in June 2007 to explore science drivers and a new operations philosophy for the ‘warm’ Spitzer mission, operating the mid-infrared camera on the observatory when the telescope is no longer ‘cold’. This volume will be of interest to professional astronomers in both academic and industry positions.
Author: Swetlana Hubrig
Publisher: Springer Science & Business Media
ISBN: 3540747451
Category : Science
Languages : en
Pages : 304
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Book Description
This volume presents results from the ESO workshop Multiple Stars across the H-R Diagram, held in Garching in July 2005. It covers observations of multiple stars from ground and space, dynamical and stellar evolution in multiple systems, formation and early evolution of multiple stars, and special components of multiple stars. The book reviews the current state of observational and theoretical knowledge and discusses future studies for further progress in the field.
Author: Dany Vanbeveren
Publisher: Springer Science & Business Media
ISBN: 9780792371045
Category : Science
Languages : en
Pages : 612
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Book Description
This book reviews recent observations of non-evolved and evolved binary populations in clusters and the field with special emphasis on statistical biases, incompleteness, and distribution functions. It considers different binary types and presents and discusses recent results in the field.
Author: Natalie R. Hinkel
Publisher: Walter de Gruyter GmbH & Co KG
ISBN: 1501520814
Category : Science
Languages : en
Pages : 612
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Book Description
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.
Author: Caitlin A. Griffith
Publisher:
ISBN:
Category : Science
Languages : en
Pages : 400
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Book Description
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)
Author: Viki Joergens
Publisher: Springer Science & Business Media
ISBN: 3319011626
Category : Science
Languages : en
Pages : 174
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Book Description
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.
