Mass Distribution and "Mass Gap" of Compact Stellar Remnants in Binary Systems

TL;DR

This paper reviews the mass distribution of neutron stars and black holes, discusses the existence of a mass gap, and introduces gravidynamics as a model to explain the observed mass spectrum and fill the gap.

Contribution

It proposes a scalar-tensor gravidynamics model to explain the mass distribution and the presence of the mass gap between neutron stars and black holes.

Findings

Maximum neutron star mass estimated at 2.2-2.9 M_Sun

Mass gap between 2-5 M_Sun discussed and addressed

Gravidynamics model predicts objects filling the mass gap

Abstract

The highest critical mass of neutron stars (NSs) was reviewed in the context of equation of state and observationsl results/ It was predicted that the maximum NS mass (MNS) exists in the range MNS ~ 2.2-2.9 M_Sun. However, recent observations of gravitationsl waves and other studies had suggested the higher mass limit of NSs, MNS ~ 3/2 M_Sun. The NS mass up to the value of MNS ~ 2 M_Sun is well understood, and with such a mass value it was meaning ful to discuss the "mass gap" ("m-gap") between the NS and black hole (BH) collapsars.The "m-gap" exists in between the highest mass of NS and the lowest mass of BH collapsars (Mm-gap ~ 2-5 M_Sun). in the mass distribution, the maximim population of NSs and BHs is located at MNS = 1.4 M_Sun and MBH = 6.7 M_Sun, respectively. However, recent ofservational results predicted filling the "m-gap" by the compact objects. In this paper, the concept of gravidynamics was reported to resolve the problem of peak likelihood value of gravitational mass at Mpeak = 6.7 M_Sun and the "m-gap" (Mm-gap ~ 2-5 M_Sun). This concept was based on a non-metric scalar-tensor model of gravitational interaction with localizable field energy. The gravidynamics model shows the total mass (MQ) of a compact relativistic object filled with matter of quark-gluon plasma of the radius r* = GMQ/c2 ~ 10 km, consistent with the "m-gap". It was conceptualized that the total measurable gravitational mass of such an extremely dense object consists of both matter and field, which is described by scalar-tensor components. This model is also useful for predicting the collapsars within the "m-gap".