spektritüüp

Spektritüüp refers to the classification of stars based on their spectral characteristics, specifically the absorption lines present in their emitted light. This classification system is crucial for understanding a star's physical properties, such as its temperature, composition, and luminosity. The most common spectral classification scheme uses letters, arranged in the order O, B, A, F, G, K, and M, with O-type stars being the hottest and M-type stars being the coolest. Each letter class is further subdivided into numbers from 0 to 9, providing a more refined temperature scale.

The spectral type is determined by analyzing the spectrum of a star. When light from a star's hot interior passes through its cooler outer atmosphere, certain wavelengths of light are absorbed by the atoms and molecules present. These absorbed wavelengths appear as dark lines in the star's spectrum. The specific pattern of these absorption lines is unique to the star's atmospheric temperature and composition. For example, hot O-type stars show lines of ionized helium, while cooler M-type stars exhibit lines from molecules like titanium oxide.

Beyond temperature, spectral type also provides insights into a star's chemical makeup. While the temperature dictates which elements are ionized or in molecular form, the relative strengths of these spectral lines can indicate the abundance of different elements in the star's atmosphere. Luminosity classes, denoted by Roman numerals (e.g., Ia, Ib, II, III, IV, V, VI, VII), are often used in conjunction with spectral types to further refine stellar classification, distinguishing between giant stars, dwarf stars, and supergiants. This combined classification, known as the Yerkes spectral classification or MKK system, provides a comprehensive framework for categorizing stars.