Tähetüübi

Tähetüübi is an Estonian term that translates to "star type" or "star classification." In astronomy, it refers to the categorization of stars based on their physical characteristics, primarily their temperature, luminosity, and spectral properties. These classifications are essential for understanding stellar evolution, composition, and the broader structure of the universe.

The most common classification system used is the Morgan-Keenan (MK) system, which categorizes stars into spectral classes represented by letters: O, B, A, F, G, K, and M. These letters correspond to decreasing surface temperatures, with O-type stars being the hottest and M-type stars being the coolest. Each spectral class is further subdivided by numbers from 0 to 9.

In addition to spectral class, stars are also classified by luminosity class, which indicates their size and evolutionary stage. Luminosity classes range from I (supergiants) to V (main-sequence stars or dwarfs) to VII (white dwarfs). A star's full tähetüübi is typically given as a combination of its spectral and luminosity class, for example, G2V, which describes our Sun. Understanding a star's tähetüübi allows astronomers to infer its mass, age, and potential future development.