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arXiv · 2505.11591

Dust stars in the minimal exponential measure model

Reyhan D. Lambaga·Justin C. Feng·Norman Hsia·Pisin Chen
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Abstract

We report the existence of horizonless compact object solutions supported by dust in the Minimal Exponential Measure (MEMe) model, a theory which modifies the couplings between gravity and matter without introducing dynamical degrees of freedom. For a perfect fluid source, the field equations for the MEMe model can be rewritten as the Einstein field equations sourced by a perfect fluid with a transformed equation of state, which can endow a sufficiently dense cloud of dust with an effective pressure. The resulting dust-supported horizonless compact objects can have masses below $\sim 10^{-11}~M_\odot$, making them suitable as MACHOs comprising a significant mass fraction for dark matter. A necessary condition for the existence of these compact object solutions is that the single free parameter in the MEMe model is positive-valued. Additionally, we find that this positive sign for the parameter can provide a mechanism for suppressing the formation of (primordial) black holes from the gravitational collapse of matter below a certain mass scale.

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Reyhan D. Lambaga, Justin C. Feng, Norman Hsia, Pisin Chen. 2025-05-16. Dust stars in the minimal exponential measure model. https://doi.org/10.1103/qbsn-bt3y

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