Exoplanet Atmospheres

Over the past twenty years, astronomers have identified hundreds of extrasolar planets--planets orbiting stars other than the sun. Recent research in this burgeoning field has made it possible to observe and measure the atmospheres of these exoplanets. This is the first textbook to describe the basic physical processes--including radiative transfer, molecular absorption, and chemical processes--common to all planetary atmospheres, as well as the transit, eclipse, and thermal phase variation observations that are unique to exoplanets. In each chapter, Sara Seager offers a conceptual introduction, examples that combine the relevant physics equations with real data, and exercises. Topics range from foundational knowledge, such as the origin of atmospheric composition and planetary spectra, to more advanced concepts, such as solutions to the radiative transfer equation, polarization, and molecular and condensate opacities. Since planets vary widely in their atmospheric properties, Seager emphasizes the major physical processes that govern all planetary atmospheres. Moving from first principles to cutting-edge research, Exoplanet Atmospheres is an ideal resource for students and researchers in astronomy and earth sciences, one that will help prepare them for the next generation of planetary science. The first textbook to describe exoplanet atmospheres Illustrates concepts using examples grounded in real data Provides a step-by-step guide to understanding the structure and emergent spectrum of a planetary atmosphere Includes exercises for students

Describes the basic physical processes, including radiative transfer, molecular absorption, and chemical processes, common to all planetary atmospheres as well as the transit, eclipse, and thermal phase variation observations that are unique to exoplanets.

Appendix B: Essential Formulae of Vector Calculus -- Appendix C: Essential Formulae of Thermodynamics -- Appendix D: Gibbs Free Energies of Various Molecules and Re-actions -- Appendix E: Python Scripts for Generating Figures -- Bibliography -- Index

Like planets in our solar system, exoplanets form, evolve, and interact with their host stars in many ways. As exoplanets acquire material and grow to the final size, their atmospheres are subjected to intense UV and X-radiation and high-energy particle bombardment from the young host star. Whether a planet can retain its atmosphere and the conditions for significant mass loss both depend upon the strength of the host star's high-energy radiation and wind, the distance of the exoplanet from its host star, the gravitational potential of the exoplanet, and the initial chemical composition of the exoplanet atmosphere. This introductory overview describes the physical processes responsible for the emission of radiation and acceleration of winds of host stars that together control the environment of an exoplanet, focusing on topics that are critically important for understanding exoplanetary atmospheres but are usually not posed from the perspective of host stars. Accordingly, both host stars and exoplanets are not studied in isolation but are treated as integrated systems. Stellar magnetic fields, which are the energy source for activity phenomena including high-energy radiation and winds, play a critical role in determining whether exoplanets are habitable. This text is primarily for researchers and graduate students who are studying exoplanet atmospheres and habitability, but who may not have a background in the physics and phenomenology of host stars that provide the environment in which exoplanets evolve. It provides a comprehensive overview of this broad topic rather than going deeply into many technical aspects but includes a large list of references to guide those interested in pursuing these questions. Nonspecialists with a scientific background should also find this text a valuable resource for understanding the critical issues of contemporary exoplanet research.

In this book, renowned scientists describe the complexity of exoplanetary atmospheres and all of the observational techniques that are employed to probe them. Readers will also find a panoramic description of the atmospheres of the planets within the Solar System, with explanation of considerations especially relevant to exoplanets. Over the past few years, thousands of exoplanets have been discovered orbiting around stars relatively close to the Solar System. Astronomers have revealed how varied these exoplanets are (rocky, icy, giant) and how diverse their architecture can be, confirming science fiction images in several cases and extending beyond the human imagination in others. The natural next step is to study their atmospheres and to understand their chemical composition and the physical processes taking place in their interiors, with the aim of detecting biomarkers. This book will appeal to all who seek a comprehensive, state-of-the-art account of the latest knowledge in the rapidly developing and highly interdisciplinary field of exoplanet research.

This book is a compendium of key scientific questions, challenges, and opportunities across different areas of exoplanetary science. The field is currently experiencing rapid growth, and the book provides a front-row view of the advancements at the cutting-edge of the field. Each chapter contains a short exposition on the most important open questions, challenges, and opportunities in a specific area from the perspective of one or more top experts in the area. It provides a starting point for researchers, experts and non-experts alike, to obtain a quick overview of the forefront of exoplanetary science and a vision for the future of the field. Topics range from observational developments and techniques, including exoplanet detection and characterisation methods and state-of-the-art and future missions, to exoplanet theory and modelling including planet formation, planetary interiors, atmospheres, habitability and the search for life. Key Features Provides a close-up view of the frontiers of exoplanetary science research Summarises key questions, challenges, and opportunities across different areas of the field Written by leading experts in the field Provides a valuable reference for early career researchers Topics span from state-of-the-art and emerging areas to long-term future directions

This PhD thesis details the development of a new 1D ionospheric model to describe the upper atmospheres of extrasolar giant plants. The upper atmospheres of Hot Jupiters are subject to extreme radiation conditions that can result in rapid atmospheric escape. The composition and structure of these planets’ upper atmospheres are affected by high-energy emissions from the host star. The nature of these emissions depends on the stellar type and age, making them important factors in understanding the behaviour of exoplanetary atmospheres.

For the first time in human history, we know for certain the existence of planets around other stars. Now the fastest-growing field in space science, the time is right for this fundamental source book on the topic which will lay the foundation for its continued growth. Exoplanets serves as both an introduction for the non-specialist and a foundation for the techniques and equations used in exoplanet observation by those dedicated to the field.