Multivariate Statistical Analysis of Exoplanet Habitability: Detection Bias and Earth Analog Identification

TL;DR

This study uses multivariate statistical methods on 517 exoplanets to identify Earth-like candidates, revealing significant detection biases and emphasizing the rarity of truly habitable worlds while highlighting promising targets for future observation.

Contribution

It introduces a novel multivariate classification framework for exoplanet habitability and quantifies detection bias in current surveys.

Findings

Only 0.6% of exoplanets meet all habitability criteria.

Significant observational bias favors unsuitable planetary systems.

Earth is a statistical outlier among exoplanets.

Abstract

We present a comprehensive multivariate statistical analysis of 517 exoplanets from the NASA Exoplanet Archive to identify potentially habitable worlds and quantify detection bias in current surveys. Using eight key parameters (planetary radius, equilibrium temperature, insolation flux, density, and stellar effective temperature, radius, mass, metallicity), we developed a classification framework that successfully identifies Earth as an "Excellent Candidate" for habitability. Our analysis reveals that only 0.6% (3 planets including Earth) meet all habitability criteria under relaxed thresholds, while 75.0% exhibit "Good Star, Poor Planet" characteristics, indicating significant observational bias toward unsuitable planetary systems. Hotelling's T2 test demonstrates that potentially habitable planets are statistically significantly different from the general exoplanet population (p = 0.015). Mahalanobis distance analysis places Earth in the 69.4th percentile for statistical unusualness, confirming that Earth-like planets are genuine outliers in parameter space. We identify Kepler-22 b as a compelling Earth analog with remarkable parameter similarity, and reveal that 1.2% of planets represent "edge cases" orbiting M-dwarf stars with suitable planetary but marginal stellar conditions. These findings demonstrate systematic detection bias in exoplanet surveys and provide quantitative evidence for the rarity of Earth-like worlds while identifying high-priority targets for atmospheric characterization with JWST.