Long-period transiting exoplanets: advances in detection and characterization

TL;DR

This paper discusses recent advances in detecting and characterizing long-period transiting exoplanets, emphasizing their importance for understanding planetary formation, evolution, and potential habitability.

Contribution

It highlights new detection methods, the significance of detailed characterization, and the potential for discovering moons and rings around these distant planets.

Findings

Detection of long-period transiting exoplanets has improved with space-based photometry.

Characterization enables insights into planetary composition, formation, and evolution.

Long-period planets are promising targets for studying moons and circumplanetary features.

Abstract

Most detected transiting planets have orbits which would fit within the one of Mercury, exposing them to intense stellar irradiation and interactions that significantly alter their properties. In contrast, colder planets with longer orbital periods are less affected, offering crucial insights into their formation and migration histories. Characterizing transiting warm and temperate planets is a key missing piece in the exoplanet puzzle. Dedicated photometric and spectroscopic follow-up of transiting events detected in space-based photometric data opened the way to detecting long-period transiting exoplanets. The wealth of information available for these transiting planets makes them golden targets for in-depth characterization. For giant planets, combining precise masses, radii, and ages with state-of-the-art planetary evolution models allows the estimation of their planetary bulk compositions, a crucial element to explore their formation and evolution pathways. Furthermore, these planets are compelling candidates for hosting moons and circumplanetary rings-features that could illuminate dynamical histories, satellite formation processes, and even potential habitable environments.