The temperatures of the stars can be classified using the Wien displacement law, which is in section formulas that relate the light and matter. The great diversity of observed stellar spectra gave rise to the classification of the stars in seven spectral classes:
OBAFGKM
Oh, Be A Fine Girl, Kiss Me!
Moreover, each class is divided into 10 subclasses designated spectral types: B2; B5; A0; A5, for example. Out of curiosity, the sun is a star that is contemplated in the G2 class.
Depending on the constitution of the atmosphere of stars, we can relate the spectra with the previous absorption temperatures and the respective spectral classes (with a predominant color).
| Classe | Temperatura (kelvin) |
Cor convencional | Cor aparente | |||||
|---|---|---|---|---|---|---|---|---|
| O | ≥ 33 000 K | azul | azul | |||||
| B | 10 000–33 000 K | azul-branco | azul-branco | |||||
| A | 7 500–10 000 K | branco | branco a azul-branco | |||||
| F | 6 000–7 500 K | amarelo-branco | branco | |||||
| G | 5 200–6 000 K | amarelo | amarelo-branco | |||||
| K | 3 700–5,200 K | laranja | amarelo-laranja | |||||
| M | 2 000–3 700 K | vermelho | laranja-vermelho |