On the Nature of the Mass-gap Object in the GW190814 Event

In this work, we conduct an extensive study of 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 by revisiting some parameterizations of quantum hadrodynamics and then study under which conditions hyperons are present in such a massive star. Afterward, using a vector MIT-based model, we study whether 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 ⊙. 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, although some cases are more probable than others.