Tiivistysvaiheissa

Tiivistysvaiheissa refers to a stage in the life cycle of a star, specifically a red giant or supergiant star. This phase occurs after the star has exhausted the hydrogen fuel in its core and begins to fuse heavier elements. During tiivistysvaiheissa, the star's core contracts and heats up, while the outer layers expand significantly. This expansion causes the star to become much larger and cooler, with a surface temperature that can drop to around 2,000-3,000 Kelvin. The star's luminosity also increases, making it one of the brightest objects in its galaxy. The exact duration of this phase varies depending on the star's mass, but it can last from a few hundred thousand to a few million years. After the tiivistysvaiheissa, the star may undergo further evolutionary stages, such as becoming a planetary nebula or a white dwarf, depending on its initial mass. This phase is an important stage in the life cycle of stars and provides insights into the processes that govern stellar evolution.