# Habitability of Exoplanetary Systems

## TL;DR

This dissertation investigates habitability in exoplanetary systems by examining planets and moons, focusing on habitable zones, tidal heating effects, and methods to detect ice-covered satellites through photometric observations.

## Contribution

It provides a comprehensive analysis of habitability beyond planets, including moons, and explores new detection techniques for icy satellites in exoplanetary systems.

## Key findings

- Moons can be habitable due to tidal heating even if their planets are not.
- Tidal heating can sustain subsurface oceans on icy moons, supporting potential life.
- Photometric methods can identify ice-covered satellites by their high reflectance during occultation.

## Abstract

The aim of my dissertation is to investigate habitability in extra-Solar Systems. Most of the time, only planets are considered as possible places where extraterrestrial life can emerge and evolve, however, their moons could be inhabited, too. I present a comprehensive study, which considers habitability not only on planets, but on satellites, as well. My research focuses on three closely related topics. The first one is the circumstellar habitable zone, which is usually used as a first proxy for determining the habitability of a planet around the host star. The word habitability is used in the sense that liquid water, which is essential for life as we know it, may be present on the planetary surface. Whether the planet is habitable or not, its moon might have a suitable surface temperature for holding water reservoirs, providing that tidal heating is in action. Tidal heating is generated inside the satellite and its source is the strong gravitational force of the nearby planet. The second topic of my research explores tidal heating and the habitability of extra-solar moons with and without stellar radiation and other related energy sources. Life is possible to form even on icy planetary bodies, inside tidally heated subsurface oceans. The third topic probes the possibility of identifying an ice-covered satellite from photometric observations. A strong indication of surface ice is the high reflectance of the body, which may be measured when the moon disappears behind the host star, so its reflected light is blocked out by the star.