# Tracing the Origins and Evolution of Small Planets using Their Orbital Obliquities

## TL;DR

This paper emphasizes the importance of measuring the orbital obliquities of small exoplanets to understand their formation and migration, highlighting upcoming observational capabilities that will enable large-scale surveys.

## Contribution

It advocates for a comprehensive survey of small planet obliquities using future telescopes, which will provide new insights into planetary system evolution.

## Key findings

- Upcoming telescopes will enable obliquity measurements of small exoplanets.
- Measuring obliquities will shed light on planet formation and migration.
- This approach will improve understanding of the most common types of planets.

## Abstract

We recommend an intensive effort to survey and understand the obliquity distribution of small close-in extrasolar planets over the coming decade. The orbital obliquities of exoplanets--i.e., the relative orientation between the planetary orbit and the stellar rotation--is a key tracer of how planets form and migrate. While the orbital obliquities of smaller planets are poorly explored today, a new generation of facilities coming online over the next decade will make such observations possible en masse. Transit spectroscopic observations with the extremely large telescopes will enable us to measure the orbital obliquities of planets as small as $\sim2R_{\oplus}$ around a wide variety of stars, opening a window into the orbital properties of the most common types of planets. This effort will directly contribute to understanding the formation and evolution of planetary systems, a key objective of the National Academy of Sciences' Exoplanet Science Strategies report.