{"knowledge_schema": {"broad_category": "Astronomy \u2192 Stellar Properties \u2192 Interstellar Extinction", "refinement": "This problem involves understanding how interstellar dust affects the light from stars, specifically through the concept of color excess (E(B-V)).", "specific_scope": "The focus is on comparing the color excess values of different stars to determine which star experiences the least extinction due to interstellar dust.", "goal": "Identify the star with the lowest color excess value, indicating it experiences the least amount of extinction."}, "summary": "In this problem, we are examining the effects of interstellar dust on the light from stars, quantified by color excess (E(B-V)). The candidates are four stars with varying E(B-V) values. The star with the lowest E(B-V) value will experience the least extinction due to interstellar dust. In this case, Star A, with E(B-V) = 0.2, has the lowest value and therefore experiences the least amount of extinction."}