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Author: Ann Marie Cody
Publisher: Universal-Publishers
Published: 2013-08
Total Pages: 318
ISBN-13: 1612334210
DOWNLOAD EBOOK →In 2005, Palla & Baraffe proposed that brown dwarfs and very low mass stars (
Author: Michael J. Thompson
Publisher: Springer Science & Business Media
Published: 2013-04-17
Total Pages: 302
ISBN-13: 9401707995
DOWNLOAD EBOOK →We stand at the threshold of an exciting era of Asteroseismology. In a few months' time, the Canadian small-satellite asteroseismology mission MOST will be laun ched. Danish and French missions MONS and COROT should follow, with the ESA mission Eddington following in 2007/8. Helioseismology has proved spec tacularly successful in imaging the internal structure and dynamics of the Sun and probing the physics of the solar interior. Ground-based observations have detected solar-like oscillations on alpha Centauri A and other Sun-like stars, and diagnostics similar to those used in helioseismology are now being used to test and constrain the physics and evolutionary state of these stars. Multi-mode oscillations are being observed in an abundance of other stars, including slowly pulsating B stars (SPB stars), delta Scuti stars, Ap stars and the pulsating white dwarfs. New classes of pulsators continue to be discovered across the Hertzsprung-Russell diagram. For good reason it was decided to entitle our conference 'Asteroseismology Across the HR Diagram' . Yet the challenges still to be faced to make asteroseismology across the HR diagram a reality are formidable. Observation, data analysis and theory all pose hard problems to be overcome. In conceiving this meeting, the aim of the organisers was to facilitate a cross-fertilization of ideas and approaches between researchers working on different pulsators and with different areas of expertise. We venture to suggest that in this the conference was a great success.
Author: Richard J. Stancliffe
Publisher:
Published: 2007
Total Pages: 552
ISBN-13:
DOWNLOAD EBOOK →This volume is comprised of a series of papers dealing with some of the current unsolved problems in the field of stellar physics. It is also a celebration of the many contributions that Prof. Douglas Gough has made to this subject. Topics discussed include: stars, interiors, stars: evolution, asteroseismology, helioseismology, and fluid dynamics.
Author: Quinn Morgan Konopacky
Publisher:
Published: 2009
Total Pages: 474
ISBN-13:
DOWNLOAD EBOOK →Author: Eric Stempels
Publisher: American Institute of Physics
Published: 2009-03-09
Total Pages: 1042
ISBN-13:
DOWNLOAD EBOOK →The series of ‘Cool Star’ meetings concentrates on the astrophysics of low-mass stars (with masses similar to that of the Sun and lower), including the Sun. The meeting in St. Andrews, Scotland, was the 15th in this series, and focused in particular on the origin of low-mass stars and their planets, as well as the properties of their atmospheres. This volume provides a comprehensive overview of the science presented by the 350 participants of this meeting. The book is suitable for researchers and graduate students interested in the astrophysics of cool stars and the Sun.
Author: Joyce Ann Guzik
Publisher: Frontiers Media SA
Published: 2021-08-17
Total Pages: 269
ISBN-13: 2889711838
DOWNLOAD EBOOK →Author: Viki Joergens
Publisher: Springer Science & Business Media
Published: 2013-11-27
Total Pages: 174
ISBN-13: 3319011626
DOWNLOAD EBOOK →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.
Author: Stanimir Metchev
Publisher: Universal-Publishers
Published: 2006-02
Total Pages: 255
ISBN-13: 158112290X
DOWNLOAD EBOOK →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.
