# Giant Planet Atmospheres and Spectra

## TL;DR

This paper discusses the importance of spectral measurements of extrasolar giant planets and reviews the physics, chemistry, and spectroscopy needed to interpret current and future exoplanet atmospheric data.

## Contribution

It provides a comprehensive overview of the theoretical tools and models essential for understanding exoplanet atmospheres from spectral observations.

## Key findings

- Analysis of hot Jupiter atmospheres using Spitzer and HST data
- Development of models for atmospheric composition and temperature profiles
- Preparation for future observations of wide-separation exoplanets

## Abstract

Direct measurements of the spectra of extrasolar giant planets 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 {\em Spitzer} and HST data of transiting "hot Jupiters," we have now dramatically entered the era of remote sensing. We are probing their atmospheric compositions and temperature profiles, are constraining their atmospheric dynamics, and are investigating their phase light curves. Soon, many non-transiting exoplanets with wide separations (analogs of Jupiter) will be imaged and their light curves and spectra measured. In this paper, we present the basic physics, chemistry, and spectroscopy necessary to model the current direct detections and to develop the more sophisticated theories for both close-in and wide-separation extrasolar giant planets that will be needed in the years to come as exoplanet research accelerates into its future.