# Exoplanet Reflected Light Spectroscopy with PICASO

## TL;DR

PICASO is an open-source Python radiative transfer model for simulating exoplanet reflected light, incorporating advanced scattering methods and Raman features, enabling detailed atmospheric characterization across diverse conditions.

## Contribution

This work introduces PICASO, the first open-source radiative transfer code for exoplanet reflected light, with new features like Raman scattering and comprehensive benchmarking.

## Key findings

- PICASO accurately reproduces results from independent codes.
- Model sensitivity varies with phase function choices.
- Information content analysis reveals parameter detectability limits.

## Abstract

Here we present the first open-source radiative transfer model for computing the reflected light of exoplanets at any phase geometry, called PICASO: Planetary Intensity Code for Atmospheric Scattering Observations. This code, written in Python, has heritage from a decades old, well-known Fortran model used for several studies of planetary objects within the Solar System and beyond. We have adopted it to include several methodologies for computing both direct and diffuse scattering phase functions, and have added several updates including the ability to compute Raman scattering spectral features. Here we benchmark PICASO against two independent codes and discuss the degree to which the model is sensitive to a user's specification for various phase functions. Then, we conduct a full information content study of the model across a wide parameter space in temperature, cloud profile, SNR and resolving power.