Scientists have collected a wealth of physical and chemical data for the Sun, planets, and small bodies in our solar system, but until now this information has been scattered throughout the technical literature. The Planetary Scientist's Companion solves this problem, providing for the first time a single, extensive reference for the interdisciplinary fields of planetary science and cosmochemistry. The book begins with a summary of frequently used physical and chemical constants, unit conversion factors, properties of some compounds and minerals, thermodynamic data, partition coefficients, and useful formulas. This is followed by an overview of the solar system, including comparative data for the planets and their satellites and abundances of the elements. Much of the book is devoted to a series of chapters describing in turn the Sun, each of the planets, and the groups of small bodies (asteroids, comets, meteorites, and Kuiper Belt and Centaur objects). Each chapter includes an introduction, followed by tables of physical and chemical properties compiled from many sources, including data on planetary atmospheres, surfaces, and interiors. The book concludes with data on nearby stars, the interstellar medium, and recently discovered brown dwarfs and possible extrasolar planets, followed by a glossary. A unique and practical resource for anyone interested in contemporary planetary science and cosmochemistry, this volume is likely to be an essential tool in future research.