Exoplanets, -moons, -comets

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

By Keith Cowing
Status Report
astro-ph.EP
June 24, 2025
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Multivariate Statistical Analysis of Exoplanet Habitability: Detection Bias and Earth Analog Identification
Three-dimensional PCA visualization of 517 exoplanets colored by habitability classification. PC1 (52.4% variance) captures stellar-planetary size coupling, PC2 (15.3% variance) reflects planetary composition gradients, and PC3 (9.4% variance) represents stellar metallicity relationships. Excellent Candidates (green) cluster in moderate parameter space, while ”Good Star, Poor Planet” systems (yellow) dominate high PC1 values, quantitatively demonstrating detection bias toward large planets around bright stars. — astro-ph.EP

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.

Distribution of planetary parameters across habitability categories. Earth’s position (red line) demonstrates validation of our classification framework. Green shaded regions
indicate habitability thresholds. The dominance of ”Good Star, Poor Planet” systems (blue)
reveals systematic detection bias. — astro-ph.EP

Caleb Traxler, Samuel Townsend, Abby Mori, Grace Newman, Kaitlyn Morenzone

Comments: 28 pages, 10 figures
Subjects: Earth and Planetary Astrophysics (astro-ph.EP); Instrumentation and Methods for Astrophysics (astro-ph.IM); Applications (stat.AP)
Cite as: arXiv:2506.18200 [astro-ph.EP] (or arXiv:2506.18200v1 [astro-ph.EP] for this version)
https://doi.org/10.48550/arXiv.2506.18200
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Submission history
From: Caleb Traxler
[v1] Sun, 22 Jun 2025 23:20:01 UTC (6,628 KB)
https://arxiv.org/abs/2506.18200
Astrobiology

Explorers Club Fellow, ex-NASA Space Station Payload manager/space biologist, Away Teams, Journalist, Lapsed climber, Synaesthete, Na’Vi-Jedi-Freman-Buddhist-mix, ASL, Devon Island and Everest Base Camp veteran, (he/him) 🖖🏻