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.

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.

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.

This accessible text on classical celestial mechanics, the principles governing the motions of bodies in the Solar System, provides a clear and concise treatment of virtually all of the major features of solar system dynamics. Building on advanced topics in classical mechanics such as rigid body rotation, Langrangian mechanics and orbital perturbation theory, this text has been written for advanced undergraduates and beginning graduate students in astronomy, physics, mathematics and related fields. Specific topics covered include Keplerian orbits, the perihelion precession of the planets, tidal interactions between the Earth, Moon and Sun, the Roche radius, the stability of Lagrange points in the three-body problem and lunar motion. More than 100 exercises allow students to gauge their understanding and a solutions manual is available to instructors. Suitable for a first course in celestial mechanics, this text is the ideal bridge to higher level treatments.

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.

Binary systems of stars are as common as single stars. They are of fundamental importance because they allow stellar masses, radii and luminosities to be measured directly, and explain a host of diverse and energetic phenomena including X-ray binaries, cataclysmic variables, novae, symbiotic stars, and some types of supernovae. This 2001 book was the first to provide a pedagogical and comprehensive introduction to binary stars. It combines theory and observations at all wavelengths to develop a unified understanding of binaries of all categories. It comprehensively reviews methods for calculating orbits, the Roche model, ideas about mass exchange and loss, methods for analysing light curves, the masses and dimensions of different binary systems, and imaging the surfaces of stars and accretion structures. This book provides a thorough introduction to the subject for advanced undergraduate and graduate students. Researchers will also find this to be an authoritative reference.