Year: 2026
Type: preprint
Abstract: We investigate the question whether compact objects in the so-called mass gap ($2.5 < M/M_\odot < 5.0$) can be neutron stars or hybrid stars. Using a generic hybrid star equation of state with a first-order deconfinement transition, we map the allowed parameter space in a Seidov-type diagram and confront it with modern mass-radius constraints. We find that mass-gap hybrid stars require an extremely early onset of deconfinement and very stiff quark matter. The Bayesian analysis, however, favors equations of state with deconfinement at typical neutron-star masses around $1.4\,M_\odot$ with mass-twin stars that, if confirmed, would rule out hybrid stars as candidates for observed mass-gap compact objects.
Source: arXiv (Cornell University)
Institutions: A. Alikhanyan National Laboratory, University of Wrocław
Language: English
Subfield: Astronomy and Astrophysics
Field: Physics and Astronomy
Domain: Physical Sciences
Open Access status: green
OpenAlex ID: W7163392501