An Informational-Entropic Approach to Exoplanet Characterization

TL;DR

This paper introduces an informational-entropic metric based on exoplanet spectra to quantitatively assess how Earth-like a planet is, aiding in identifying potential Earth 2.0 candidates.

Contribution

The work presents a novel spectral entropic metric that objectively measures exoplanet Earth-likeness using high-resolution spectroscopy data.

Findings

The metric successfully differentiates Earth-like planets from others in simulated spectra.

It provides a quantitative, data-driven measure of planetary similarity to Earth.

The approach can be applied to real telescope data for exoplanet characterization.

Abstract

In the past, measures of ``Earth-likeness'' of exoplanets have been qualitative, considered an abiotic Earth, or required discretionary choices of what parameters make a planet Earth-like. With the advent of high-resolution exoplanet spectroscopy, there is a growing need for a method of quantifying the Earth-likeness of a planet that addresses these issues while making use of the data available from modern telescope missions. In this work, we introduce an informational-entropic metric that makes use of the spectrum of an exoplanet to directly quantify how Earth-like the planet is. To illustrate our method, we generate simulated transmission spectra of a series of Earth-like and super-Earth exoplanets, as well as an exoJupiter and several gas giant exoplanets. As a proof of concept, we demonstrate the ability of the information metric to evaluate how similar a planet is to Earth, making it a powerful tool in the search for a candidate Earth 2.0.