Author: Timothy Dennis Stuit
Publisher:
ISBN:
Category : Planets
Languages : en
Pages : 156

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Book Description

Author: Pilat-lohinger Elke
Publisher: World Scientific
ISBN: 9813275146
Category : Science
Languages : en
Pages : 204

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Book Description
Astrophysical research has led to the detection of thousands of planets outside the Solar System. About one-tenth of the extrasolar planets discovered so far reside in binary- or multi-stellar systems, and some of the closest known rocky exoplanets populate these multiple-star systems. While such environments seem good places to look for a second Earth, can Earth-like planets with two or more suns be habitable? And do solar system-like configurations have to be detected to find a habitable exo-Earth?This book addresses these questions. Starting with a brief overview of the various types of double star-planet configurations that have been observed so far, the book discusses the intriguing variety of planetary motion in such environments, taking into account the stellar type, evolution, and activity, and elaborates on how the presence of an additional stellar companion affects planet formation, system architectures and the habitability of planets in binary star systems. New methodologies developed in this area of research are explained and demonstrated for systems such as Alpha-Centauri, HD41004, Kepler-35, and many others. This monograph provides a grand entry to the exciting results that we expect from new missions like TESS, CHEOPS and Plato.

Author: Suman Satyal
Publisher:
ISBN:
Category : Extrasolar planets
Languages : en
Pages : 139

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Book Description
The advancement in detection technology has substantially increased the discovery rate of exoplanets in the last two decades. The confirmation of thousands of exoplanets orbiting the solar type stars has raised new astrophysical challenges, including the studies of orbital dynamics and long-term stability of such planets. Continuous orbital stability of the planet in stellar habitable zone is considered vital for life to develop. Hence, these studies furthers one self-evident aim of mankind to find an answer to the century old question: Are we alone? This dissertation investigates the planetary orbits in single and binary star systems. Within binaries, a planet could orbit either one or both stars as S-type or P-type, respectively. I have considered S-type planets in two binaries, Cephei and HD 196885, and compute their orbits by using various numerical techniques to assess their periodic, quasi-periodic or chaotic nature. The Hill stability (HS) function, which measures the orbital perturbation induced by the nearby companion, is calculated for each system and then its efficacy as a new chaos indicator is tested against Maximum Lyapunov Exponents (MLE) and Mean Exponential Growth factor of Nearby Orbits (MEGNO). The dynamics of HD 196885 AB is further explored with an emphasis on the planet's higher orbital inclination relative to the binary plane. I have quantitatively mapped out the chaotic and quasi-periodic regions of the system's phase space, which indicates a likely regime of the planet's inclination. In, addition, the resonant angle is inspected to determine whether alternation between libration and circulation occurs as a consequence of Kozai oscillations, a probable mechanism that can drive the planetary orbit to a large inclination. The studies of planetary system in GJ 832 shows potential of hosting multiple planets in close orbits. The phase space of GJ 832c (inner planet) and the Earth-mass test planet(s) are analyzed for periodic-aperiodic orbits. The stability of the system is defined in terms of its lifetime and maximum eccentricity during the integration period then a regime is established for the known and injected planet's orbital parameters. The de-stabilizing resonances due to the outer planet extend by 1.36 AU towards the star, nonetheless, existence of two Earth-mass planets seems plausible. The radial velocity (RV) curves generated for the test planets reveals a weak RV signal that cannot be measured by currently available instruments. A theory has been developed by extrapolating the radio emission processes in the Jupiter-Io system, which could reveal the presence of exomoons around the giant exoplanets. Based on this theory, maximum distance, radius and masses of exoplanets and exomoons are calculated that could be detected by the available radio telescopes. Observation time at the Low Frequency Array (LOFAR) radio telescope has been proposed to detect exomoon in five different stellar systems. Subjects of my future studies include analysis of the data from LOFAR, search for the additional transiting planets in Kepler 47 circumbinary system and observation at the Subaru telescope to verify the predicted planets in GJ 832 system by the method of direct imaging.

Author: Nader Haghighipour
Publisher: Springer Science & Business Media
ISBN: 9048186870
Category : Science
Languages : en
Pages : 334

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Book Description
In 1988, in an article on the analysis of the measurements of the variations in the radial velocities of a number of stars, Campbell, Walker, and Yang reported an - teresting phenomenon;the radial velocity variations of Cephei seemed to suggest the existence of a Jupiter-like planet around this star. This was a very exciting and, at the same time, very surprising discovery. It was exciting because if true, it would have marked the detection of the ?rst planet outside of our solar system. It was surprising because the planet-hosting star is the primary of a binary system with a separation less than 19 AU, a distance comparable to the planetary distances in our solar system. The moderatelyclose orbit of the stellar companionof Cephei raised questions about the reality of its planet. The skepticism over the interpretation of the results (which was primarily based on the idea that binary star systems with small sepa- tions would not be favorable places for planet formation) became so strong that in a subsequent paper in 1992, Walker and his colleagues suggested that the planet in the Cephei binary might not be real, and the variations in the radial velocity of this star might have been due to its chromospheric activities.

Author: Sverre Aarseth
Publisher: Springer
ISBN: 1402084315
Category : Science
Languages : en
Pages : 405

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Book Description
Published under the auspices of the Royal Astronomical Society, this volume contains a set of extensive school tested lectures, with the aim to give a coherent and thorough background knowledge of the subject and to introduce the latest developments in N-body computational astrophysics. The topics cover a wide range from the classical few-body problem with discussions of resonance, chaos and stability to realistic modelling of star clusters as well as descriptions of codes, algorithms and special hardware for N-body simulations. This collection of topics, related to the gravitational N-body problem, will prove useful to both students and researchers in years to come. 1) Published under the auspices of the Royal Astronomical Society.

Author: David J. Eicher
Publisher: Cambridge University Press
ISBN: 1316558665
Category : Science
Languages : en
Pages : 299

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Book Description
Over the past decade, astronomers, planetary scientists, and cosmologists have answered - or are closing in on the answers to - some of the biggest questions about the universe. David J. Eicher presents a spectacular exploration of the cosmos that provides a balanced and precise view of the latest discoveries. Detailed and entertaining narratives on compelling topics such as how the Sun will die, the end of life on Earth, why Venus turned itself inside-out, the Big Bang Theory, the mysteries of dark matter and dark energy, and the meaning of life in the universe are supported by numerous color illustrations including photos, maps and explanatory diagrams. In each chapter the author sets out the scientific history of a specific question or problem, before tracing the modern observations and evidence in order to solve it. Join David J. Eicher on this fascinating journey through the cosmos!

Author: Katherine Michele Deck
Publisher:
ISBN:
Category :
Languages : en
Pages : 201

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Book Description
A large population of low-mass exoplanets with short orbital periods has been discovered using the transit method. At least 40% of these planets are actually part of compact systems with more than one planet. The closeness of the planetary orbits in these multi-planet systems leads to strong dynamical interactions that imprint themselves on the transit light curve as transit timing variations (TTVs). By modeling the orbital evolution of these planetary systems, one can fit the observed variations and strongly constrain the masses and orbits of the interacting planets, parameters which, given the faintness of the host stars, cannot be determined using other techniques. This type of analysis is performed for KOI- 984, a system with a single transiting planet perturbed by a non-transiting companion. By modeling the gravitational interaction between the planets using our code TTVFast, we are able to infer the masses and orbits of the two planets and to show that the orbits are distinctly non-coplanar. This discovery, a first for the low-mass multi-planet systems, indicates that dynamical processes that excite mutual inclinations can be important for such systems. The dynamical interactions that lead to observable TTVs can also lead to orbital instability and chaos. The Kepler 36 system has the closest confirmed pair of planets to date, with unique TTVs that tightly constrain the orbits, in turn allowing for detailed analysis of the long-term dynamics of the system. We find the system to be strongly chaotic, characterized by the very human timescale of -10 years. We are able to understand the source of this rapid chaos, and to show that despite its presence, the system can be long-lived. But how compact can two planetary orbits be before being unstable? We consider more generally the long-term stability of two-planet systems within the framework of first-order resonance overlap. We determine a stability criterion for close pairs of planets which we then compare to other analytic criteria and to numerical integrations. This work provides a step towards understanding the long-term evolution of more complex planetary systems.

Author: G.E.O. Giacaglia
Publisher: Springer Science & Business Media
ISBN: 9401033234
Category : Science
Languages : en
Pages : 540

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Book Description
The subjects of resonance and stability are closely related to the problem of evolution of the solar system. It is a physically involving problem and the methods available to mathematics today seem unsatisfactory to produce pure non linear ways of attack. The linearization process in both subjects is clearly of doubtful significance, so that, even if very restrictive, numerical solutions are still the best and more valuable sources of informations. It is quite possible that we know now very little more of the entire problem that was known to Poincare, with the advantage that we can now compute much faster and with much more precision. We feel that the papers collected in this Symposium have contributed a step forward to the comprehension of Resonance, Periodic Orbits and Stability. In a field like this, it would be a surprise if one had gone a long way toward that comprehension, during the short time of two weeks. But we are sure that the joint efforts of all the scientists involved has produced and will produce a measurable acceleration in the process. If this is true it will be a great satisfaction to us that this has happened in Brasil. The Southern Hemisphere in America has now begun to participate actively in the Astro nomical Society and for this, we are grateful to everyone who has helped.

Author: Billy Lee Quarles
Publisher:
ISBN:
Category : Celestial mechanics
Languages : en
Pages :

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Book Description
Planetary science in various forms has become interwoven into human culture during all of known human history. The need and desire to expand our horizons has brought humans from basic forms of observation to the development of space satellites that have (in)directly observed other worlds. A major feat of this enterprise during the last half century has been the development of numerical tools and theories to determine the orbital stability of multiple objects orbiting a central body. In this dissertation I have examined two special cases of the gravitational N body problem (N = 3,4) along with the development of a stability criterion based upon the method of Lyapunov exponents. This Lyapunov criterion has shown the existence of a resonance plateau and instability islands within the coplanar circular restricted three body problem (CRTBP). Additionally, the Lyapunov criterion has been used in the determination of resonances for the case of large mass ratios in the CRTBP. I have demonstrated that the 2:1 resonance occurs most frequently as a primary resonance and 3:1 as a secondary resonance within the framework of the coplanar CRTBP. My established methods of using the Lyapunov criterion and determination of resonances have been used to address a controversial system Octantis to ascertain possible ranges of stability that would account for the present observations of a Jupiter-mass planet. The determined stability limits of the planet in Octantis has unveiled the evidence supporting the possibility of a retrograde planet existing in the binary star system and demonstrated the desert of stability when considering a traditional prograde planet. Orbital stability is but one part in the bigger question of habitability. To this end, I have addressed the concerns of habitability within the newly discovered circumbinary system Kepler-16 for possible habitable planets and moons. This exploration has considered many di erent orbital, formation, and habitability scenarios for which a habitable world could exist. I have shown that an Earth-mass object could exist as a Trojan or an exomoon within the standard habitable zone. Furthermore, the orbital stability region resumes for planetary orbits superior to 0.95 AU from Kepler-16A which resides in the extended habitable zone. Finally, the habitability of possible Trojan planets and exomoons in HD 23079 has been addressed and I have shown the improbability of an exomoon from taking excursions from the habitable zone as well as a stable orbit for such an object. My future work will better investigate the possibility of habitable moons in HD 23079. This work will aid in broadening the regions to be considered as habitable since such objects would orbit a Jupiter-like planet within the habitable zone. In addition, I plan to develop theoretical tools to investigate the regions of habitability within multi-stellar environments. I plan to use this new framework to further the investigation of circumbinary planets in Kepler-16, Kepler-34, Kepler-35, and Kepler- 38. Data from the Kepler mission will soon be made public and I will search the public data for the existence of habitable objects within these systems.

Author: Zdzislaw Musielak
Publisher: Springer
ISBN: 3319582267
Category : Science
Languages : en
Pages : 115

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Book Description
This brief book provides an overview of the gravitational orbital evolution of few-body systems, in particular those consisting of three bodies. The authors present the historical context that begins with the origin of the problem as defined by Newton, which was followed up by Euler, Lagrange, Laplace, and many others. Additionally, they consider the modern works from the 20th and 21st centuries that describe the development of powerful analytical methods by Poincare and others. The development of numerical tools, including modern symplectic methods, are presented as they pertain to the identification of short-term chaos and long term integrations of the orbits of many astronomical architectures such as stellar triples, planets in binaries, and single stars that host multiple exoplanets. The book includes some of the latest discoveries from the Kepler and now K2 missions, as well as applications to exoplanets discovered via the radial velocity method. Specifically, the authors give a unique perspective in relation to the discovery of planets in binary star systems and the current search for extrasolar moons.