What types of stellar objects has the greatest desity?

The stellar objects with the greatest density are neutron stars. These remnants of supernova explosions are composed primarily of densely packed neutrons, resulting in extraordinarily high densities, often exceeding that of an atomic nucleus. A sugar-cube-sized amount of neutron star material can weigh about as much as a mountain on Earth. Additionally, black holes, while not traditionally measured by density in the same way, can also have immense gravitational effects that suggest extreme density within their event horizons.