Spectral signatures from the habitable zone

TL;DR

This paper discusses methods for detecting spectroscopic signatures of habitable zone exoplanets, analyzing observational limitations, and estimating the feasibility of identifying biosignatures and technosignatures with future telescopes.

Contribution

It provides a framework for understanding detection capabilities and signal strength estimates for biosignatures and technosignatures on exoplanets in the habitable zone.

Findings

Earth-like planets are easily detectable with current methods.

Oxygen biosignatures can be characterized in about 20 hours.

Hydrogen iodine technosignatures require hundreds of hours to detect.

Abstract

This work describes the context and approach for the detection of spectroscopic signatures from planets in the habitable zone of nearby stars. By understanding the limitations of current observatories, future telescopes can be understood, and their ability to characterize the atmospheres of exoplanets estimated. An example calculation is given for the signal-to-noise analysis for a planet like the current Earth of oxygen as a biosignature, and (an enhanced abundance) of hydrogen iodine as a technosignature. In the optimistic estimate, Earth is easily detected, O2 characterized in 20 hours, but signals from enhance HI are only visible after hundreds of hours, indicating the signals are too weak to realistically constrain.