Stars do not all have the same temperature. The color of light emitted by stars is characteristic of the light emitted by hot objects. Telescopic photos of three stars are shown below: (i) the Sun, which is classified as a yellow star, (ii) Rigel, in the constellation Orion, which is classified as a blue-white star, and (iii) Betelgeuse, also in Orion, which is classified as a red star. (a) Place these three stars in order of increasing temperature. (i) sun (ii) Rigel (iii) Betelguese

Key Concepts

Blackbody Radiation

Blackbody radiation refers to the electromagnetic radiation emitted by an idealized object that absorbs all incident radiation, regardless of frequency or angle. The temperature of the blackbody determines the spectrum of light it emits, with hotter objects radiating more energy at shorter wavelengths. This principle helps explain why stars of different colors have varying temperatures.

Stellar Classification

Stars are classified based on their spectral characteristics, which are closely related to their temperatures. The classification system includes categories such as O, B, A, F, G, K, and M, with O-type stars being the hottest and M-type stars being the coolest. The Sun, classified as a G-type star, is cooler than blue-white stars like Rigel (B-type) and hotter than red stars like Betelgeuse (M-type).

Color and Temperature Relationship

The color of a star is directly related to its surface temperature, a concept known as Wien's Displacement Law. As a star's temperature increases, it emits light that shifts from red to blue on the visible spectrum. Therefore, in the context of the stars mentioned, Rigel, being blue-white, is the hottest, followed by the Sun, and then Betelgeuse, which is red and the coolest.