Investigations of the Formation and Evolution of Planetary Systems

TL;DR

This paper reviews observational evidence on how planetary systems form and evolve, emphasizing the importance of long-wavelength observations for understanding the processes and characteristics of planet formation.

Contribution

It discusses the potential of high-resolution, long-wavelength imaging to distinguish between different planet formation mechanisms and to analyze the evolution of planetary systems.

Findings

High-resolution images can resolve planet formation scales.

Long-wavelength observations reduce opacity issues.

Observations can reveal the influence of stellar metallicity.

Abstract

Stars and planets are the fundamental objects of the Universe. Their formation processes, though related, may differ in important ways. Stars almost certainly form from gravitational collapse and probably have formed this way since the first stars lit the skies. Although it is possible that planets form in this way also, processes involving accretion in a circumstellar disk have been favored. High fidelity high resolution images may resolve the question; both processes may occur in some mass ranges. The questions to be answered in the next decade include: By what process do planets form, and how does the mode of formation determine the character of planetary systems? What is the distribution of masses of planets? In what manner does the metallicity of the parent star influence the character of its planetary system? In this paper we discuss the observations of planetary systems from birth to maturity, with an emphasis on observations longward of 100 $\mu$m which may illuminate the character of their formation and evolution. Advantages of this spectral region include lower opacity, availability of extremely high resolution to reach planet formation scales and to perform precision astrometry and high sensitivity to thermal emission.