The Lifespan of a Star After Supernova

What happens after a star goes supernova can vary significantly depending on its initial mass and composition. When a massive star exhausts its nuclear fuel, it undergoes a catastrophic explosion, expelling most of its envelope back into intergalactic space. The core of the star then collapses under its own gravity, leading to the formation of a black hole, neutron star, or white dwarf. This article explores the various fates of stars post-supernova.

The Black Hole

For stars with an initial mass over about 20 solar masses, the core collapse leads to the formation of a black hole. Black holes are dense objects with mass equivalent to at least 3 3/5 solar masses and an event horizon from which nothing, not even light, can escape. Unlike neutron stars, black holes have a Hawking radiation which means they will over time, slowly evaporate. Theoretically, a black hole can evaporate entirely over many trillions of years, ultimately transitioning into a planck-scale object.

The Neutron Star

Stars with initial masses in the range of 8 to 20 solar masses form neutron stars. Neutron stars are incredibly dense remnants of supernovae, with the mass of the Earth packed into a sphere the size of a city. The cooling of a neutron star occurs over millions to billions of years. However, there is currently no definitive estimate of the exact time a neutron star will last, but it is believed that they are permanent until further astronomical events, such as a collisions with other stars or stellar collisions, might change their fate.

The White Dwarf

White dwarfs are the remnants of lower-mass stars, with initial masses below 8 solar masses. They are incredibly dense stars, with a mass comparable to that of the Sun, but only the size of the Earth. White dwarfs are hot for tens of billions of years and continue to cool and dim over billions of years, eventually becoming black dwarfs – hypothetical remnants that no longer emit significant radioactivity.

The Discovery of Direct Black Hole Formation

Recently, astronomers have made a fascinating discovery: some black holes may form directly from stars without visible supernova explosions. According to the latest research, these black holes can contain up to 98% of the star’s mass. In contrast, typical supernovae resulted in :~ 99.9% of the mass being ejected back into space. This new finding challenges our traditional understanding of how black holes form and highlights the complexity of stellar evolution.

In conclusion, while the ultimate fate of stellar remnants can vary, all forms of post-supernova stars, including black holes, neutron stars, and white dwarfs, play crucial roles in the evolution of our galaxy and the universe. The study of these objects continues to be a fascinating area of research, offering deeper insights into the nature of space and time.