{"knowledge_schema": {"broad_category": "Astronomy \u2192 Stellar Properties \u2192 Stellar Luminosity", "refinement": "This problem involves calculating the luminosity of a star based on its radius and temperature, using the Stefan-Boltzmann Law.", "specific_scope": "The focus is on a star with a radius twice that of the Sun and a surface temperature of 6000K, and how these factors influence its luminosity compared to the Sun.", "goal": "Determine the luminosity ratio of the star to the Sun and identify the correct answer from the given options."}, "summary": "This problem relates to astronomy and involves calculating the luminosity of a star using its radius and temperature. By applying the Stefan-Boltzmann Law, we can find the luminosity ratio of the star to the Sun, given that the star has a radius twice that of the Sun and a surface temperature of 6000K. The goal is to determine this ratio and select the correct answer from the provided options."}