Terminatsioonifaasis

Terminatsioonifaasis is a phase in the life cycle of a star, occurring after the main sequence phase. This phase is characterized by the star's exhaustion of its nuclear fuel, leading to significant changes in its structure and luminosity. During this phase, the star undergoes dramatic transformations, ultimately leading to its demise.

In low to medium-mass stars, the terminatsioonifaasis begins with the star's outer layers expanding significantly, forming a red giant. This expansion is driven by the star's inability to sustain nuclear fusion in its core, causing it to contract and heat up. The outer layers, however, continue to expand due to the increased luminosity and reduced surface gravity. This phase is marked by the star's increased luminosity and the shedding of its outer layers, which can form planetary nebulae.

For more massive stars, the terminatsioonifaasis is more complex and violent. These stars may undergo multiple phases of nuclear burning, including carbon and oxygen burning, before finally collapsing under their own gravity. This collapse can lead to the formation of a supernova, one of the most energetic events in the universe.

The end of the terminatsioonifaasis varies depending on the star's mass. Low to medium-mass stars typically end their lives as white dwarfs, while more massive stars can become neutron stars or black holes. The terminatsioonifaasis is a crucial phase in stellar evolution, shaping the fate of stars and contributing to the enrichment of the interstellar medium with heavy elements.