Publication Year: 2010
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.
Funding to make this important volume an affordable addition to anyone's library was provided by the National Aeronautics and Space Administration.
Published by: University of Arizona Press
Download PDF (72.6 KB)
List of Contributing Authors and Scientific Organizing Committee
Download PDF (47.0 KB)
Download PDF (70.7 KB)
The discovery of exoplanets is arguably the greatest scientific revolution since the time of Copernicus. Simply stated, humanity now knows for the first time as scientific fact: there actually are planets around other stars. Yet as profound as this discovery is, the trumpets have not blared and no theorists have been burned at the stake. (An early proponent of other planetary worlds, Giordano...
Download PDF (113.1 KB)
This is a unique time in human history — for the first time, we are on the technological brink of being able to answer questions that have been around for thousands of years: Are there other planets like Earth? Are they common? Do any have signs of life? The field of exoplanets is rapidly moving toward answering these questions with the discovery of hundreds of exoplanets now pushing toward lower and lower masses; the Kepler Space...
Part I: Introduction
Introduction to Exoplanets
Download PDF (834.1 KB)
The discovery of planets around other stars, which we call exoplanets, has emerged over the past two decades as a new, vibrant, fruitful field that spans the disciplines of astrophysics, planetary science, and even parts of biology. The study of exoplanets is now an important part of the curriculum for many graduate students, and this volume is intended to bridge the gap between single-article summaries...
Keplerian Orbits and Dynamics of Exoplanets
Download PDF (5.3 MB)
Understanding the consequences of the gravitational interaction between a star and a planet is fundamental to the study of exoplanets. The solution of the two-body problem shows that the planet moves in an elliptical path around the star and that each body moves in an ellipse about the common center of mass. The basic properties...
Part II: Exoplanet Observing Techniques
Radial Velocity Techniques for Exoplanets
Download PDF (2.9 MB)
The radial velocity technique was utilized to make the first exoplanet discoveries around Sun-like stars and continues to play a major role in the discovery and characterization of exoplanetary systems. In this chapter we describe how the technique works, and the current precision and limitations. We then review its major successes in the field of exoplanets...
Exoplanet Transits and Occultations
Download PDF (5.0 MB)
When we are fortunate enough to view an exoplanetary system nearly edge-on, the star and planet periodically eclipse each other. Observations of eclipses — transits and occultations — provide a bonanza of information that cannot be obtained from radial-velocity data alone, such as the relative dimensions of the planet and its host star, as well as the orientation...
Microlensing by Exoplanets
Download PDF (2.8 MB)
Gravitational microlensing occurs when a foreground star happens to pass very close to our line of sight to a more distant background star. The foreground star acts as a lens, splitting the light from the background source star into two images, which are typically unresolved. However, these images of the source are also magnified, by an amount that depends on the angular separation between the lens and source. The relative motion between the lens...
Direct Imaging of Exoplanets
Download PDF (15.1 MB)
A direct image of an exoplanet system is a snapshot of the planets and disk around a central star. We can estimate the orbit of a planet from a time series of images, and we can estimate the size, temperature, clouds, atmospheric gases, surface properties, rotation rate, and likelihood of life on a planet from its photometry, colors, and spectra in the visible and infrared. The exoplanets...
Astrometric Detection and Characterization of Exoplanets
Download PDF (3.6 MB)
Stars with planetary companions orbit the common center of mass. From astrometric measurements of this motion one can determine the mass and all orbital parameters of the planet. This has been done for a few planets previously known from radial-velocity surveys, using data from the Hipparcos satellite and the Hubble Space Telescope. New techniques are...
Planets Around Pulsars and Other Evolved Stars: The Fates of Planetary Systems
Download PDF (2.6 MB)
The first exoplanets ever discovered were found orbiting a pulsar, not a main-sequence star! The pulse timing technique used to detect these first planets has also powered searches for planets around eclipsing binaries, white dwarfs, and other evolved stars. In this chapter, we give a detailed description of this extraordinarily precise planet detection method, discuss...
Statistical Distribution of Exoplanets
Download PDF (5.1 MB)
This chapter discusses the current statistical sample of exoplanets. We discuss the selection effects in radial velocity and transit surveys, followed by a brief introduction to statistical techniques for characterizing the orbital properties of planets and how to include completeness corrections in population studies. We then highlight the major features of the planet population...
Part III: Exoplanet Dynamics
Non-Keplerian Dynamics of Exoplanets
Download PDF (3.9 MB)
Exoplanets are often found with short periods or high eccentricities, and multiple-planet systems are often in resonance. They require dynamical theories that describe more extreme motions than those of the relatively placid planetary orbits of the solar system. We describe the most important dynamical processes in fully formed planetary systems and how...
Tidal Evolution of Exoplanets
Download PDF (12.0 MB)
Tidal effects arise from differential and inelastic deformation of a planet by a perturbing body. The continuous action of tides modify the rotation of the planet together with its orbit until an equilibrium situation is reached. It is often believed that synchronous motion is the most probable outcome of the tidal evolution process, since synchronous rotation is observed for the majority...
Part IV: Exoplanet Formation and Protoplanetary Disk Evolution
Protoplanetary and Debris Disks
Download PDF (1.1 MB)
The discovery of protoplanetary and debris disks around young stars, together with the discovery of exoplanets, confirmed the longstanding notion that planet formation in rotating circumstellar disks is a natural consequence of the star formation process. Disk studies both challenge and inform modern planet formation theories, providing insights on the birth of the solar system...
Terrestrial Planet Formation
Download PDF (2.2 MB)
The standard planetesimal model of terrestrial planet formation is based on astronomical and cosmochemical observations, and the results of laboratory experiments and numerical simulations. In this model, planets grow in a series of stages beginning with the micrometersized dust grains observed in protoplanetary disks. Dust grains readily stick together to form millimeter- to centimeter-sized aggregates,...
Giant Planet Formation
Download PDF (7.3 MB)
Gas giant planets play a fundamental role in shaping the orbital architecture of planetary systems and in affecting the delivery of volatile materials to terrestrial planets in the habitable zones. Current theories of gas giant planet formation rely on either of two mechanisms: the core accretion model and the disk instability model. In this chapter,...
Download PDF (2.2 MB)
Planet migration is the process by which a planet’s orbital radius changes in time. The main agent for causing gas giant planet migration is the gravitational interaction of the young planet with the gaseous disk from which it forms. We describe the migration rates resulting from these interactions based on a simple model for disk properties. These migration rates are higher than is reasonable for planet survival. We discuss...
Part V: Exoplanet Interiors and Atmospheres
Terrestrial Planet Interiors
Download PDF (3.3 MB)
The discovery and study of exoplanets has always motivated the question of the existence and nature of terrestrial exoplanets, especially habitable planets. Exoplanet mass and radius measurements (yielding average density) are possible for a growing number of exoplanets, including terrestrial planets. The mass and radius provide a constraint for terrestrial planet interior models and, via models, enable interpretation...
Giant Planet Interior Structure and Thermal Evolution
Download PDF (2.3 MB)
We discuss the interior structure and composition of giant planets, and how this structure changes as these planets cool and contract over time. Here we define giant planets as those that have an observable hydrogen-helium envelope that includes Jupiter-like planets, which are predominantly H/He gas, and Neptune-like planets, which are predominantly composed of elements heavier than H/He. We describe...
Giant Planet Atmospheres
Download PDF (2.0 MB)
Direct measurements of the spectra of giant exoplanets are the keys to determining their physical and chemical nature. The goal of theory is to provide the tools and context with which such data are understood. It is only by putting spectral observations through the sieve of theory that the promise of exoplanet research can be realized. With the new Spitzer and Hubble...
Terrestrial Planet Atmospheres and Biosignatures
Download PDF (2.4 MB)
The search for terrestrial exoplanets — rocky worlds in orbit around stars other than the Sun — is one of humanity’s most exciting science goals. The discovery of super Earths, terrestrial planets more massive than Earth, has opened a new era in exoplanet science, confirming the basic idea that our solar system is not the only planetary system to harbor terrestrial planets...
Atmospheric Circulation of Exoplanets
Download PDF (3.0 MB)
We survey the basic principles of atmospheric dynamics relevant to explaining existing and future observations of exoplanets, both gas giant and terrestrial. Given the paucity of data on exoplanet atmospheres, our approach is to emphasize fundamental principles and insights gained from solar system studies that are likely to be generalizable to exoplanets. We begin...
Download PDF (132.5 KB)
Publication Year: 2010