Planet Formation

A self-contained graduate-level introduction to the physical processes that shape planetary systems, covering all stages of planet formation.

When this book was published in 2006, it had been just over ten years since the first planet outside our solar system was detected. Since then, much work has focused on understanding how extrasolar planets may form, and discovering the frequency of potentially habitable Earth-like planets. This volume addresses fundamental questions concerning the formation of planetary systems in general, and of our solar system in particular. Drawing from advances in observational, experimental and theoretical research, it summarises our understanding of the planet formation processes, and addresses major open questions and research issues. Chapters are written by leading experts in the field of planet formation and extrasolar planet studies. The book is based on a meeting held at Ringberg Castle in Bavaria, where experts gathered together to present and exchange their ideas and findings. It is a comprehensive resource for graduate students and researchers, and is written to be accessible to newcomers to the field.

This book's interdisciplinary scope aims at bridging various communities: 1) cosmochemists, who study meteoritic samples from our own solar system, 2) (sub-) millimetre astronomers, who measure the distribution of dust and gas of star-forming regions and planet-forming discs, 3) disc modellers, who describe the complex photo-chemical structure of parametric discs to fit these to observation, 4) computational astrophysicists, who attempt to decipher the dynamical structure of magnetised gaseous discs, and the effects the resulting internal structure has on the aerodynamic re-distribution of embedded solids, 5) theoreticians in planet formation theory, who aim to piece it all together eventually arriving at a coherent holistic picture of the architectures of planetary systems discovered by 6) the exoplanet observers, who provide us with unprecedented samples of exoplanet worlds. Combining these diverse fields the book sheds light onto the riddles that research on planet formation is currently confronted with, and paves the way for a comprehensive understanding of the formation, evolution, and dynamics of young solar systems. The chapters ‘Chondrules – Ubiquitous Chondritic Solids Tracking the Evolution of the Solar Protoplanetary Disk’, ‘Dust Coagulation with Porosity Evolution’ and ‘The Emerging Paradigm of Pebble Accretion’ are published open access under a CC BY 4.0 license via link.springer.com.

Graduate-level textbook providing a basic understanding of the astrophysical processes for readers in planetary science, and observational and theoretical astronomy.

An in-depth view of the panspermia hypothesis examined against the latest knowledge of planetary formation and related processes. Panspermia is the concept that life can be passively transported through space on various bodies and seed, habitable planets and moons, which we are beginning to learn may exist in large numbers. It is an old idea, but not popular with those who prefer that life on Earth started on Earth, an alternative, also unproven hypothesis. This book updates the concept of panspermia in the light of new evidence on planet formation, molecular clouds, solar system motions, supernovae ejection mechanisms, etc. Thus, it is to be a book about newly understood prospects for the movement of life through space. The novel approach presented in this book gives new insights into the panspermia theory and its connection with planetary formation and the evolution of galaxies. This offers a good starting point for future research proposals about exolife and a better perspective for empirical scrutiny of panspermia theory. Also, the key to understanding life in the universe is to understand that the planetary formation process is convolved with the evolution of stellar systems in their galactic environment. The book provides the synthesis of all these elements and gives the readers an up-to-date insight on how panspermia might fit into the big picture. Audience Given the intrinsic interdisciplinary nature of the panspermia hypothesis the book will have a wide audience across various scientific disciplines covering astronomy, biology, physics and chemistry. Apart from scientists, the book will appeal to engineers who are involved in planning and realization of future space missions.

Is the Sun and its planetary system special? How did the Solar system form? Are there similar systems in the Galaxy? How common are habitable planets? What processes take place in the early life of stars and in their surrounding circumstellar disks that could impact whether life emerges or not? This book is based on the lectures by Philip Armitage and Wilhelm Kley presented at 45th Saas-Fee Advanced Course „From Protoplanetary Disks to Planet Formation“ of the Swiss Society for Astrophysics and Astronomy. The first part deals with the physical processes occurring in proto-planetary disks starting with the observational context, structure and evolution of the proto-planetary disk, turbulence and accretion, particle evolution and structure formation. The second part covers planet formation and disk-planet interactions. This includes in detail dust and planetesimal formation, growth to protoplanets, terrestrial planet formation, giant planet formation, migration of planets, multi-planet systems and circumbinary planets. As Saas-Fee advanced course this book offers PhD students an in-depth treatment of the topic enabling them to enter on a research project in the field.

Two models for the origin of the Solar System, the Nebula Theory and the Capture Theory, are discussed by protagonists, Simon and Steven respectively, in the presence of Solomon, who oversees the discussions. Modelled on Galileo's Dialogue Concerning the Two Chief World Systems, this book provides new insight into different theories of cosmogony. The Nebula Theory, at present the standard model of planet formation, proposes that a star and planets are derived from a single spinning nebula. Woolfson here introduces an alternative, the Capture Theory, in which planets are produced from a protostar tidally disrupted by a condensed star which 'captures' most of the formed planets into orbits. These complex ideas are simplified and presented in an easily understandable, accessible way for all students of physics, astronomy, cosmology and those interested in the beginning of our world as we know it.

The book begins with a historical review of four major theories for the origin of the Solar System in particular, or of planets in general, which highlight the major problems that need to be solved by any plausible theory. In many theories, including that which form the major theme of this book, the formation of planets and stars is intimately linked, so four chapters are devoted to the processes that can be described as the birth, life and death of stars. Recent observations that have revealed the existence of planets around many Sun-like stars are described in detail, followed by a clear exposition of the Capture Theory for the origin of planets. Many aspects of this theory are illustrated with sophisticated computer modelling that convincingly demonstrates the plausibility of the theory. The Capture Theory is in complete accord with all observations, including the estimate it gives for the proportion of Sun-like stars with planets. It is the only theory that sits comfortably with all present observational and theoretical constraints. The general theory of planet formation does not explain the detailed structure of the Solar System. An early postulated collision of two major planets is shown to explain many disparate features of the Solar System the nature of the terrestrial planets, surface features of the Moon and its relationship with Earth, asteroids, comets and dwarf planets, the relationship between Neptune, Triton and Pluto and the characteristics of meteorites, including the isotopic anomalies found in them. The postulate of a planetary collision is given support by a 2009 NASA observation of the residue of such an event around a distant young star.