Autor(es)

Araujo, L. F. ; Lugones, G. ; Lima, J. A. S.

• Tipo de documento: Artigo Científico
• Fonte: PHYSICAL REVIEW D; v. 112, n. 8, p. 17-pg., 2025-10-06.

Resumo

The impact of energy exchange among the three relevant fluid components-baryonic matter, fermionic dark matter (DM), and dark energy (DE)-on the internal structure of neutron stars is investigated. Working with a representative DM mass m chi = 10 GeV and a barotropic DE relation pde = omega & varepsilon;de, we embed one or two phenomenological source terms Qi in the Tolman-Oppenheimer-Volkoff equations and analyze three hierarchical scenarios: (i) coexisting but noninteracting fluids (Model I); (ii) fully interacting fluids with independent baryon-DM and DM-DE exchanges and optional DM self-repulsion (Model II); and (iii) a unified dark sector that couples to baryons through a single exchange term while retaining an internal DM/DE partition (Model III). Across all models two complementary mechanisms dominate; softening by massive, pressure-poor DM, and vacuum softening/binding by the negative pressure of DE. Model I exhibits these effects in their purest form, yielding either softened or self-bound stars depending on the dark composition. In Model II the exchange terms self-regulate, cancelling the explicit dependence on the fluid coupling strength alpha, so that mass-radius curves are nearly invariant when alpha varies from 0.05 to 1000. Model III breaks this alpha-degeneracy; when the dark sector retains a substantial vacuum fraction, the baryonic pressure gradient is strongly suppressed and both the maximum mass and radii decrease appreciably, whereas a pure-DM core remains almost insensitive to the exchange strength. The study delineates the conditions under which dark interactions can (or cannot) imprint macroscopic signatures, thereby providing a theoretical baseline for future, more strongly constrained, microphysical models. (AU)

• Processo FAPESP: 11/51676-9 - Llama: um radiotelescopio para ondas mm/sub-mm nos andes, em colaboracao com a argentina.
• Beneficiário: Jacques Raymond Daniel Lépine
• Modalidade de apoio: Auxílio à Pesquisa - Temático