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A collapsing cloud of gas and dust destined to become a star; a stage before nuclear fusion begins. Duration ranges from a few hundred thousand to a few million years.

A cataclysmic explosion occurring at the end of a massive star's life, marked by a sudden increase in brightness followed by a gradual fade. The event lasts for a short period, typically on the order of months.

A region of spacetime exhibiting gravitational acceleration so strong that nothing—no particles or even electromagnetic radiation such as light—can escape from it. The lifespan of a black hole can be many billions of years.

A late phase in stellar evolution where a star expands and cools after exhausting hydrogen in its core. This stage can last from a few hundred thousand to a few billion years, depending on the star's mass.

An extremely energetic supernova associated with the creation of a black hole. Hypernovae are among the most energetic events in the universe and the duration of the visible phenomenon is similar to that of a supernova.

A type of stellar remnant that can result from the gravitational collapse of a massive star after a supernova. Neutron stars are incredibly dense and have very strong magnetic fields. They may exist for billions of years.

An expanding shell of ionized gas that is ejected from certain types of stars at the end of their lives. This stage usually lasts for tens of thousands of years before it disperses into space.

A dense, low-luminosity stellar remnant composed mostly of electron-degenerate matter. White dwarfs formed from low to medium mass stars can persist for billions of years before cooling completely.

A stable period of stellar evolution characterized by the fusion of hydrogen to form helium. Duration depends on mass but can range from a few million to tens of billions of years for smaller stars.