Why won’t the Sun eventually become a neutron star?
Neutron stars can only form after the explosive deaths of stars with masses between about eight and 25 times the mass of the Sun. In contrast, our star, after approaching the end of its life in approximately 5 billion years from now, will evolve through a series of expansions and contractions and will quietly transform into a very small and dense object known as a white dwarf.
This very compact object will contain approximately half of the Sun’s mass densely packed in a sphere, with a diameter of roughly 10,000 kilometres (6,200 miles).
The other half of the Sun’s mass – its outer layers – will be thrown into the surrounding environment, creating a so-called planetary nebula, a fascinating bubble of expanding and glowing gas. While the gas of the planetary nebula will disperse into space, disappearing within about 10,000 years, the white dwarf will keep shining for several thousand billion years before turning into a cold, dark, inert remnant known as a black dwarf.