The star Regulus, in the constellation Leo, appears brighter through a blue filter than it does through a yellow filter. Suppose that a second star is found that has the same brightness as Regulus through the blue filter but is brighter than Regulus through the yellow filter. From this information, one can say conclusively that the second star has
A) a higher temperature.
B) the same temperature but a higher luminosity.
C) the same temperature but a lower luminosity.
D) a lower temperature.

Question

Quizplus · Accepted Answer

The second star appears brighter through a yellow filter and has the same brightness through a blue filter compared to Regulus. This indicates that the second star emits more light in the yellow part of the spectrum, which is characteristic of a star with a lower temperature than a star that appears brighter in the blue part of the spectrum. Stars that are cooler emit more of their light in the red and yellow part of the spectrum, while hotter stars emit more in the blue and ultraviolet parts.

The Star Regulus, in the Constellation Leo, Appears Brighter Through