Not exactly. Certainly it is a black hole once a neutron star's mass fits within a certain radius, but since it is then not a neutron star any longer, the quest

Not exactly. Certainly it is a black hole once a neutron star's mass fits within a certain radius, but since it is then not a neutron star any longer, the question is how that condition came about. Neutron stars have an effective outward pressure that is caused by the Pauli exclusion principle [1]; two or more fermions such as neutrons cannot be in the same state (which includes location). A strong enough inward counter force from internal gravity (or from an external force) will cause a net motion inward, overcoming the outward force, such that enough matter (more accurately, enough mass-energy, not just matter) is within the critical region. See for instance [2] [1] https://en.wikipedia.org/wiki/Pauli_exclusion_principle https://en.wikipedia.org/wiki/Pauli_exclusion_principle [2] https://www.forbes.com/sites/startswithabang/2018/06/13/the-surprising-reason-why-neutron-stars-dont-all-collapse-to-form-black-holes/?sh=587230a7159c https://www.forbes.com/sites/startswithabang/2018/06/13/the-...