Question

1. aldebaran is a relatively cool, orange/red star, yet it has a very high luminosity. how can this be?

Explanation:

Luminosity depends on both temperature and surface - area. Aldebaran is large in size. Despite its relatively low temperature for a star, its large surface - area allows it to emit a high amount of energy, resulting in high luminosity.

Answer:

Its large size compensates for its lower temperature to give it high luminosity.