Task: Question Generation
Input (English): Background Paragraph: A red giant star is a star with a mass like the Sun that is in the last phase of its life, when Hydrogen fusion reactions in the core decrease due to the lack of fuel. With the gravitational collapse of the core, the fusion reactions now occur in a shell surrounding the core. The outer layer of the star expands enormously up to 1000 times the size of the Sun. When the Sun becomes a red giant, its volume will include the orbit of Mercury and Venus and maybe even Earth. The increased size increases the luminosity even though the outer layer cools to only 3000 K or so. The cooler outer layer causes it to be a red star. After a few more million years, the star evolves into a white dwarf-planetary nebula system. 
Story: Two stars have just been discovered that are identical in terms of chemical composition. The scientist who discovered them was given the right to name them, and he chose the names Enterprise and Vader. As said before, these stars are very similar, but the main difference is that Vader is a red giant, and Enterprise is not. Scientists are very eager to study these two newly discovered stars and see if they can learn anything new from them.
Output (English): Which star's outer layer is cooler?