Substellar Strange Quark Matter Objects: Predicting a New Class of Highly Compact Candidates

Zapata Campos J.J.; Negreiros R. · Astrophysical Journal (2026) · DOI: 10.3847/1538-4357/ae95f4

Resumen

We investigate the existence of highly compact substellar objects composed of strange quark matter (SQM), focusing on finite-size strangelets with baryon number A ≤ 100. Motivated by the emergence of mass–radius outliers in the Gaia DR3 era, we employ a Bayesian exploration of the MIT bag model parameter space, explicitly accounting for finite-size surface and curvature contributions that become relevant at low baryon number. Enforcing the bulk absolute stability requirement for SQM (E/A < 930 MeV), we find that self-gravitating equilibrium sequences are confined to the substellar regime, with typical masses ∼10−6–10−2 M⊙ and characteristic radii of order 102–∼103 km. We further show that rapid rotation, treated through a self-consistent framework that incorporates relativistic thermodynamics, can substantially inflate the equatorial radius and extend the accessible mass–radius domain. Although rotation does not eliminate the intrinsic high-density compactness of these configurations, it shifts the most extended models closer to the observational parameter space of massive exoplanets. A comparison with objects from the NASA Exoplanet Archive reveals a pronounced density gap separating standard atomic-matter planets and brown dwarfs from the strangelet-rich branch predicted here. We conclude that light strangelets cannot account for solar-mass white dwarfs, but they robustly predict a previously unexplored population of highly compact substellar objects, offering testable targets for future microlensing searches and high-cadence photometric surveys.

Instituciones: Universidad Tecnológica del Perú