Lecture notes on the formation and early evolution of planetary systems

The initial conditions, physics, and outcome of planet formation are now constrained by detailed observations of protoplanetary disks, laboratory experiments, and the discovery of thousands of extrasolar planetary systems. These developments have broadened the range of processes that are considered important in planet formation, to include disk turbulence, radial drift, planet migration, and pervasive post-formation dynamical evolution. The N-body collisional growth of planet...

This pedagogical chapter covers the theory of planet formation, with an emphasis on the physical processes relevant to current research. After summarizing empirical constraints from astronomical and geophysical data, we describe the structure and evolution of protoplanetary disks. We consider the growth of planetesimals and of larger solid protoplanets, followed by the accretion of planetary atmospheres, including the core accretion instability. We also examine the possibilit...

The standard model for planet formation is a bottom-up process in which the origin of rocky and gaseous planets can be traced back to the collision of micron-sized dust grains within the gas-rich environment of protoplanetary disks. Key milestones along the way include disk formation, grain growth, planetesimal formation, core growth, gas accretion, and planetary system evolution. I provide an introductory overview of planet formation, emphasizing the main ideas and reviewing...

I attempt to summarize our knowledge of planet formation in evolving protoplanetary discs. I first review the physics of disc evolution and dispersal. For most of the disc lifetime evolution is driven by accretion and photoevaporation, and I discuss how the interplay between these processes shapes protoplanetary discs. I also discuss the observations that we use to test these models, and the major uncertainties that remain. I will then move on to consider planet formation and...

Following the groundbreaking discovery of the first extrasolar planet orbiting a sun-like star, 51 Pegasi b in 1995, the field of planet formation has become a cornerstone of modern astrophysics. This is in part due to the revelation of an astonishing diversity of planetary types and architectures, inferred from detailed astronomical observations. This diversity is driven by the interplay between the physical processes governing planet assembly and the environmental condition...

Understanding the origin and long-term evolution of the Solar System is a fundamental goal of planetary science and astrophysics. This chapter describes our current understanding of the key processes that shaped our planetary system, informed by empirical data such as meteorite measurements, observations of planet-forming disks around other stars, and exoplanets, and nourished by theoretical modeling and laboratory experiments. The processes at play range in size from microns...

The ensemble of now more than 250 discovered planetary systems displays a wide range of masses, orbits and, in multiple systems, dynamical interactions. These represent the end point of a complex sequence of events, wherein an entire protostellar disk converts itself into a small number of planetary bodies. Here, we present self-consistent numerical simulations of this process, which produce results in agreement with some of the key trends observed in the properties of the ex...

Discs of gas and dust around Myr-old stars are a by-product of the star formation process and provide the raw material to form planets. Hence, their evolution and dispersal directly impact what type of planets can form and affect the final architecture of planetary systems. Here, we review empirical constraints on disc evolution and dispersal with special emphasis on transition discs, a subset of discs that appear to be caught in the act of clearing out planet-forming materia...

Well before the existence of exo-solar systems was confirmed, it was accepted knowledge that most -- if not all -- stars possess circumstellar material during the first one-to-several million years of their pre-main sequence lives, and thus that they commonly have the potential to form planets. Here I summarize current understanding regarding the evolution of proto-planetary dust and gas disks, emphasizing the diversity in evolutionary paths.

This review is based on lectures given at the 45th Saas-Fee Advanced Course 'From Protoplanetary Disks to Planet Formation' held in March 2015 in Les Diablerets, Switzerland. Starting with an overview of the main characterictics of the Solar System and extrasolar planets, we describe the planet formation process in terms of the sequential accretion scenario. First the growth processes of dust particles to planetesimals and subsequently to terrestrial planets or planetary core...