A Search for Distant Giant Planets and Low Mass Brown Dwarfs in Solar Orbits PDF Download
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Author: Suzanne Bushnell
Publisher:
ISBN:
Category : Brown dwarf stars
Languages : en
Pages : 136
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Book Description
Author: Suzanne Bushnell
Publisher:
ISBN:
Category : Brown dwarf stars
Languages : en
Pages : 136
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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: Hans Deeg
Publisher: Cambridge University Press
ISBN: 1139468049
Category : Science
Languages : en
Pages : 269
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Book Description
This 2007 volume presents the lectures from the sixteenth Winter School of the Instituto de Astrofísica de Canarias, which was dedicated to extrasolar planets. Research into extrasolar planets is one of the most exciting fields of astrophysics, and the past decade has seen a research leap from speculations on the existence of planets orbiting other stars to the discovery of around 200 planets to date. The book covers a wide range of issues, from the state-of-the-art observational techniques used to detect extrasolar planets, to the characterizations of these planets, and the techniques used in the remote detection of life. It also looks at the insights we can gain from our own Solar System, and how we can apply them. The contributors, all of high-standing in the field, provide a balanced and varied introduction to extrasolar planets for research astronomers and graduate students, bridging theoretical developments and observational advances.
Author: Sujan Sengupta
Publisher: Springer
ISBN: 3319098942
Category : Science
Languages : en
Pages : 163
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Book Description
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.
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: John Christian Wilson
Publisher:
ISBN:
Category :
Languages : en
Pages : 278
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Book Description
Author: David S. Stevenson
Publisher: Springer Science & Business Media
ISBN: 1461481333
Category : Science
Languages : en
Pages : 331
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Book Description
Gliese 581 is a red dwarf star some 20.3 light years from Earth. Red dwarfs are among the most numerous stars in the galaxy, and they sport diverse planetary systems. At magnitude 10, Gliese 581 is visible to amateur observers but does not stand out. So what makes this star so important? It is that professional observers have confirmed that it has at least four planets orbiting it, and in 2009, Planet d was described in the letters of The Astrophysical Journal as “the first confirmed exoplanet that could support Earth-like life.” Under a Crimson Sun looks at the nature of red dwarf systems such as Gliese as potential homes for life. Realistically, what are prospects for life on these distant worlds? Could life evolve and survive there? How do these planetary surfaces and geology evolve? How would life on a red dwarf planet differ from life on Earth? And what are the implications for finding further habitable worlds in our galaxy? Stevenson provides readers with insight into the habitability of planets and how this changes as time progresses and the central star evolves. Explore with him in this engaging, fascinating book the possibilities for finding life, from bacteria to more complex and even intelligent organisms, on red dwarf system planets.
Author: Shubham Kanodia
Publisher:
ISBN:
Category :
Languages : en
Pages : 0
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Book Description
We do not understand the largest planets around the smallest and most numerous stars in the Galaxy. M dwarfs are the most common type of stars in the Galaxy. Empirical studies show that they also play host to more inner planets than FGK stars, despite this, of the currently $\sim 5000$ confirmed exoplanets, only about 250 orbit M dwarfs, of which only $\sim 65$ have precise mass and radii measurements! The population of planets around M dwarfs is poorly understood. In this thesis I will discuss our efforts to detect and obtain precise measurements for planets around M dwarfs, and then to place this sample of M dwarfs in context of the larger sample of planets around FGK stars. The first part of my dissertation focusses on the instrumentation efforts for the Habitable zone Planet Finder (HPF), and NEID. HPF is a stabilized near-infrared (NIR) fiber-fed radial velocity (RV) spectrograph at the 10 m Hobby Eberly Telescope (HET) at McDonald Observatory, Texas, USA, while NEID is a new high-precision spectrograph in the red-optical installed at the 3.5 m WIYN telescope at Kitt Peak, Arizona, USA. I was in charge of developing, integrating and testing the fiber-feed for HPF, as well as the optical simulations to verify the alignment of the instrument. For NEID, not only did I lead a similar effort for the fiber-feed and simulations, but was also responsible for the chromatic exposure meter which is essential to measure exposure midpoints for barycentric corrections. In conjunction, I developed the algorithm for performing these corrections, which are now used in HPF, NEID and numerous other RV spectrographs. HPF with its large aperture and near-infrared bandpass, and NEID with its red-optical coverage have already started to enable the RV follow up of planets around mid-to-late and early M dwarfs respectively. I then discuss some results from the HPF RV survey, where first I test the scrambling performance of HPF on the fixed altitude HET using on-sky data on an M dwarf. Then I present the results of a serendipitous observation of a flare around the ultracool dwarf vB 10. The HPF spectra taken during the flare show a red excess in the He 10830 \AA~triplet which is similar to observations of coronal rain for the Sun, while also placing a limit on the atmospheric mass loss from flares for planets orbiting such stars. Alongside the instrumentation and observational efforts, I also built upon a nonparametric framework to model exoplanet masses and radii (M-R), which was then applied to a sample of planets around M dwarfs. By comparing the results for M dwarf planets with those from FGK stars we notice some systemic differences in their distributions. However, further inferences were deterred by the small sample of transiting M dwarf planets with mass measurements. I then discuss the efforts to use HPF and NEID to follow up on M dwarf planet candidates discovered by TESS. Not only do these planets help fill in the M-R plane for M dwarfs, but also highlight interesting correlations with stellar properties. Finally, I conclude by giving an overview of how my work on instrumentation, algorithms and novel statistical frameworks has helped develop our understanding of the M dwarf planet population. The ongoing transiting gas giant follow-up will be continued in the future, which will help us shed further light on how these giant planets form around the smallest stars.
Author: C. Eiroa
Publisher: Springer Science & Business Media
ISBN: 9401154686
Category : Science
Languages : en
Pages : 333
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Book Description
The past year has produced some of the most exciting results in the history of astronomy, particularly in the area of planets outside our solar system. Only a half-year before our meeting in Toledo, Spain, the first unambiguous detection of planet-sized masses orbiting main sequence stars were reported. Since that time, evidence for a new exo planet has been reported almost at the rate of about once per month. Some of these objects are likely to turn out to be very low-mass stars, but something like half show characteristics - Jupiter-like mass and near-zero orbital eccentricity - which appear to be unique to planets. Almost at the same time that giant planets were being discovered regularly, the two major space agencies, ESA and NASA, have iden tified searches for and detailed study of Earth-like planets as a major priority for the future. In ESA's "Horizon 2000 Plus" programme, an infrared interferometer has been proposed as a possible future Cor nerstone mission. Similarly, scientists in the US produced the "Road Map for the Exploration of Neighboring Planetary Systems (ExNPS)", which provided NASA with a long-term plan which leads also to an infrared interferometer in space to study hypothetical Earth-like worlds beyond our Solar System. Such an observatory is designed to search for the thermal emission from a family of planets, using interferometric nulling to remove the contaminating light from the central star.
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.
