The star Betelgeuse appears red; the star Rigel appears blue. What accounts for this difference?
A) Betelgeuse and Rigel have different chemical compositions.
B) Betelgeuse is moving away from Earth, Rigel is moving toward Earth.
C) Betelgeuse is moving toward Earth, Rigel is moving away from Earth.
D) The surface of Betelgeuse is hotter than the surface of Rigel.
E) The surface of Betelgeuse is cooler than the surface of Rigel.

Question

Quizplus · Accepted Answer

The color of a star is primarily determined by its surface temperature, with cooler stars appearing red and hotter stars appearing blue. Betelgeuse is cooler than Rigel, which is why it appears red while Rigel appears blue.

The Star Betelgeuse Appears Red; the Star Rigel Appears Blue