Dust stars in the minimal exponential measure model

TL;DR

This paper demonstrates the existence of dust-supported horizonless compact objects in the MEMe model, which could serve as dark matter candidates and influence black hole formation.

Contribution

It introduces a novel class of dust-supported horizonless objects in the MEMe model, linking modified gravity to potential dark matter constituents.

Findings

Existence of dust-supported horizonless objects with masses below 10^{-11} M_sun.

Positive model parameter enables these solutions and suppresses small black hole formation.

Potential role as MACHOs in dark matter composition.

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.