Green Bank Observatory Summary: Astronomers have discovered the most massive neutron star to date, a rapidly spinning pulsar approximately 4,600 light-years from Earth. This record-breaking object is teetering on the edge of existence, approaching the theoretical maximum mass possible for a neutron star.
Neutron stars are the compressed remains of massive stars gone supernova — are the densest “normal” objects in the known universe. They are also the source of all of the heavy elements (including gold, uranium, etc.) on our planet.
Many mysteries remain about the nature of the interior of neutron stars. Do crushed neutrons become “superfluid” and flow freely? Do they breakdown into a soup of subatomic quarks or other exotic particles? What is the tipping point when gravity wins out over matter and forms a black hole?
AND this particular star may not even be a neutron star (when referring to its size). It could be a boson star or a quark star or something even more exotic. (see exotic stars) Neutron stars do teeter on the edge of collapsing into black holes, which we know very little about beyond almost a grade-school understanding of things like spin rate/momentum and event horizon.
Neutron stars are also pulsars. Same with some black holes (Quasars – quasi-stellar objects). Pulsars get their name because of the twin beams of radio waves they emit from their magnetic poles. These beams sweep across space in a lighthouse-like fashion. Some rotate hundreds of times each second. Since pulsars spin with such phenomenal speed and regularity, astronomers can use them as the cosmic equivalent of atomic clocks. Such precise timekeeping helps astronomers study the nature of spacetime, measure the masses of stellar objects, and improve their understanding of general relativity.
In the case of this binary system, which is nearly edge-on in relation to Earth, this cosmic precision provided a pathway for astronomers to calculate the mass of the two stars.
And so it goes.