Lots of wild claims represented as facts. Settled science or more mathemagic?
Let’s see them put their hypothesis to a falsifiable test.
Figures don’t lie, but liars figure.
It's been known since the 1930s that it's totally dependent on mass, that's not something that was discovered last week. An older book I have that talks about the mathematical derivations (doesn't actually show the math but explains it) says that up to 1.4 solar masses, your star will become a white dwarf. (This is the Chandrasekhar Limit, named after an Indian astrophysicist who derived it it 1930.) From 1.4-3.3 solar masses, your star will become a neutron star. From 3.3 solar masses on, your star will become a black hole. Maybe the difference between the 3.3 and 2.16 solar masses is that 3.3 is for a normally shining star and the 2.16 is after it has exploded in a supernova and blown off some material.
Bottom line: conceptually, there's nothing new here except for a few numbers that are suspect. Must be a slow day at Popular Mechanics. The title Astronomers Find Mass Limit for Neutron Stars Before Collapsing Into Black Holes is a complete crock, this number was known back in the 1930s and was refined in the 1960s when calculating differential equations and integrals with computers became a lot better. These scientists may have tightened up some of the numbers using some new methods but they discovered something new? No, that's a total crock.