Very Low-Mass Stars and Brown Dwarfs

Very Low-Mass Stars and Brown Dwarfs PDF 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.

Very Low-Mass Stars and Brown Dwarfs

Very Low-Mass Stars and Brown Dwarfs PDF Author: Rafael Rebolo
Publisher: Cambridge University Press
ISBN: 9780521663359
Category : Science
Languages : en
Pages : 284

Get Book Here

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.

New Light on Dark Stars

New Light on Dark Stars PDF 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.

A Search for Pulsation in Young Brown Dwarfs and Very Low Mass Stars

A Search for Pulsation in Young Brown Dwarfs and Very Low Mass Stars PDF Author: Ann Marie Cody
Publisher: Universal-Publishers
ISBN: 1612334210
Category : Science
Languages : en
Pages : 318

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Book Description
In 2005, Palla & Baraffe proposed that brown dwarfs and very low mass stars (

New Light on Dark Stars

New Light on Dark Stars PDF Author: Neil Reid
Publisher: Springer
ISBN: 9783540808404
Category : Science
Languages : en
Pages : 560

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Book Description
There has been very considerable progress in research into low-mass stars, brown dwarfs and extrasolar planets during the past few years, particularly since the fist edtion of this book was published in 2000. In this new edtion the authors present a comprehensive review of both the astrophysical nature of individual red dwarf and brown dwarf stars and their collective statistical properties as an important Galactic stellar population. Chapters dealing with the observational properies of low-mass dwarfs, the stellar mass function and extrasolar planets have been completely revised. Other chapters have been significantly revised and updated as appropriate, including important new material on observational techniques, stellar acivity, the Galactic halo and field star surveys. The authors detail the many discoveries of new brown dwarfs and extrasolar planets made since publication of the first edition of the book and provide a state-of-the-art review of our current knowledge of very low-mass stars, brown dwarfs and extrasolar planets, including both the latest observational results and theoretical work.

New Light on Dark Stars

New Light on Dark Stars PDF Author: I. Neill Reid
Publisher:
ISBN: 9781447136651
Category : Astronomy
Languages : en
Pages : 470

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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.

Very Low Mass Stars and Brown Dwarfs in Galactic Clusters

Very Low Mass Stars and Brown Dwarfs in Galactic Clusters PDF Author: Nigel Charles Hambly
Publisher:
ISBN:
Category : Brown dwarf stars
Languages : en
Pages :

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Book Description


Rotation Studies of Young Very Low Mass Stars and Brown Dwarfs

Rotation Studies of Young Very Low Mass Stars and Brown Dwarfs PDF Author: María Victoria Rodríguez-Ledesma
Publisher:
ISBN:
Category :
Languages : en
Pages : 104

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Book Description


Evolutionary Scenario for Low-mass Stars and Substellar Brown Dwarfs

Evolutionary Scenario for Low-mass Stars and Substellar Brown Dwarfs PDF Author: Guy S. Stringfellow
Publisher:
ISBN:
Category : Brown dwarf stars
Languages : en
Pages : 596

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Book Description


1-10 Myr-old Low Mass Stars and Brown Dwarfs in Nearby Star Forming Regions

1-10 Myr-old Low Mass Stars and Brown Dwarfs in Nearby Star Forming Regions PDF Author: Catherine Louise Slesnick
Publisher:
ISBN:
Category : Electronic dissertations
Languages : en
Pages : 416

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Book Description


Brown Dwarf Companions to Young Solar an

Brown Dwarf Companions to Young Solar an PDF 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.