The lower mass, however following the protostar stage
The final category used in stellar evolution contains, massive stars (Astronomy & Space, Stellar). These are stars with masses greater than three suns, thereby permanently changing their live cycles (Earth Science). These stars live much shorter than their lower mass competitors, as they burn through their hydrogen and heavier element fuel much faster (Earth Science). For example, the largest most massive stars in the cosmos will fuse their entire cores after only several million years (Earth Science). Massive stars begin their lives similarly to stars of lower mass, however following the protostar stage they evolve to become red supergiants as they near death (Earth Science). The supergiants are formed identically to regular giants yet differ with their ability to fuse carbon into heavier elements. (NASA, Supernovae).
Oxygen, Neon, Sulfur, and nitrogen are examples of these elements that are able to be formed because of the extreme size and temperature of red supergiants (NASA, Supernovae). This nuclear fusion continues up until iron, “no element heavier can be synthesized to create energy to keep the star alive” (World of Scientific Discovery). In order to fuse elements heavier then iron, the star would need an insert of energy rather than the actual energy being unleashed from the star’s core (NASA, Supernovae). There is now an absence of nuclear fusion in the star, thus no energy is being released to support further fusion (Earth Science). Therefore, the star embarks on a catastrophic collapsing as stellar balance is no longer in place and the cores weight surpasses it’s own gravity (NASA, Supernovae).
Supernovas explain the apocalyptic deaths of massive stars (Earth Science). Following the termination of fusion in the star’s core, powerful shock waves are sent from the interior to break the stars outer shells and blast them into space (Earth Science). During this explosion, materials found in the outer layers fuse into heavier elements and radioactive isotopes as the extreme temperature from the core heats them (NASA, Supernova). Throughout the supernova, the star’s luminosity notably increases to become one million times brighter than what it previously was (Earth Science). In other words, if a star in close proximity to the solar system were to explode in a supernova, it’s light would exceed the luminosity of all the stars in the galaxy, including the sun (NASA, Life).
The next step in massive star demise consists of the collapsing into neutron stars or black holes, another factor also dictated by mass (Earth Science). If the iron core remaining from the supernova is one and a half to three times as massive as the sun then it will become a neutron star (NASA, Supernovae). In these stars, the electrons and protons combine to become neutrons, hence the name, neutron star (Earth Science). Neutron stars remain fairly small in size, yet similar to white dwarfs are unimaginably dense (Earth Science). To better comprehend the extreme density present in these stars, take the earth for example, if it were packed into a neutron star it would have a diameter equivalent to the size of a football field (Earth Science). To take it further, a pupil size of the matter in this neutron star would weigh a hundred million tons (Earth Science).
In addition to neutron stars, black wholes can be the fate of many massive stars of the cosmos