On the nature of the mass-gap object in the GW190814 event

Abstract

In this work, we make a very extensive study on the conditions that allow the mass-gap object in the GW190814 event to be faced as a degenerate star instead of a black hole. We begin revisiting some parametrizations of the Quantum Hadrodynamics (QHD) and then study under which conditions the hyperons are present in such a massive star. Afterward, using a vector MIT based model, we study if self-bound quark stars, satisfying the Bodmer-Witten conjecture fulfill all the observational constraints. Finally, we study hybrid stars within a Maxwell construction and check for what values of the bag, as well as the vector interaction, a quark core star with only nucleons, and with nucleons admixed with hyperons can reach at least 2.50 M$_\odot$. We conclude that, depending on the choice of parameters, none of the possibilities can be completely ruled out, i.e., the mass-gap object can be a hadronic (either nucleonic or hyperonic), a quark, or a hybrid star. However, some cases are more probable than others.