puhdistusvaiheisiin

Puhdistusvaiheisiin refers to a stage in the life cycle of a star, specifically a low- to intermediate-mass star like our Sun. This phase occurs after the star has exhausted the hydrogen fuel in its core and has transitioned from the main sequence. During the puhdistusvaiheisiin, the star begins to fuse hydrogen in a shell surrounding the core, while the core itself contracts and heats up.

The term "puhdistusvaiheisiin" is derived from the Finnish word for "cleansing" or "purification," reflecting the idea that the star is shedding its outer layers. This process is characterized by the star expanding significantly, becoming a red giant. The outer layers of the star are expelled into space, forming a planetary nebula. The remaining core, now a white dwarf, will slowly cool over billions of years.

This phase is crucial for the chemical enrichment of the interstellar medium. The expelled material, enriched with elements produced during the star's lifetime, contributes to the formation of new stars and planetary systems. The puhdistusvaiheisiin is a relatively short stage in the life of a star, lasting only a few tens of thousands of years, compared to the billions of years the star spends on the main sequence.