# Seasonal changes of the volatile density in the coma and on the surface of comet 67P/Churyumov-Gerasimenko

## TL;DR

This study reconstructs the seasonal and spatial variations of gas density in the coma and surface activity of comet 67P/Churyumov-Gerasimenko using Rosetta data, revealing shifts in gas sources related to seasonal illumination changes.

## Contribution

It introduces a comprehensive inverse gas model that fits extensive measurements to identify gas sources across the comet's surface, capturing seasonal variations.

## Key findings

- High correlation between model and measurements (Pearson > 0.93)
- Systematic shift in gas sources before and after perihelion
- Revealed seasonal changes in surface activity and gas emission patterns

## Abstract

Starting from several monthly data sets of Rosetta's COmetary Pressure Sensor we reconstruct the gas density in the coma around comet 67P/Churyumov-Gerasimenko. The underlying inverse gas model is constructed by fitting ten thousands of measurements to thousands of potential gas sources distributed across the entire nucleus surface. The ensuing self-consistent solution for the entire coma density and surface activity reproduces the temporal and spatial variations seen in the data for monthly periods with Pearson correlation coefficients of 0.93 and higher. For different seasonal illumination conditions before and after perihelion we observe a systematic shift of gas sources on the nucleus.