Exoplanet Atmospheric Escape Observations with the Habitable Worlds Observatory

TL;DR

This paper discusses using the Habitable Worlds Observatory's UV transit spectroscopy to study atmospheric escape in exoplanets, aiming to identify Earth-like planets and understand planetary atmospheric evolution.

Contribution

It proposes a UV spectrograph design for HWO to observe atmospheric escape and assess habitability potential of exoplanets.

Findings

Development of a UV spectrograph for exoplanet atmospheric studies

Methodology for detecting atmospheric escape via UV transit spectroscopy

Framework for identifying potentially Earth-like exoplanets

Abstract

The Decadal Survey on Astronomy and Astrophysics 2020 highlights the importance of advancing research focused on discovering and characterizing habitable worlds. In line with this priority, our goal is to investigate how planetary systems evolve through atmospheric escape and to develop methods for identifying potentially Earth-like planets. By leveraging the ultraviolet (UV) capabilities of the Habitable Worlds Observatory (HWO), we can use transit spectroscopy to observe atmospheric escape in exoplanets and explore the processes that shape their evolution, assess the ability of small planets to retain their atmospheres, and search for signs of Earth-like atmospheres. To achieve this, we support the development of a UV spectrograph with moderate- to high-resolution capabilities for point-source observations, coverage of key spectral features in the 100-300 nm range, and detectors that can register high count rates reliably. This article is an adaptation of a science case document developed for the Characterizing Exoplanets Steering Committee within HWO's Solar Systems in Context Working Group.