{"knowledge_schema": {"broad_category": "Astronomy \u2192 Planetary Science \u2192 Planetary Atmospheres and Tails", "refinement": "This problem focuses on the behavior of Mercury's sodium tail in relation to its position in the solar orbit (aphelion vs perihelion) and the effects of solar radiation on the tail's characteristics.", "specific_scope": "The specific context involves observing Mercury's sodium tail using a narrow bandpass filter, which affects the perceived color and visibility of the tail at different orbital positions.", "goal": "Determine the appearance and color of Mercury's sodium tail at aphelion and perihelion based on the physical principles of solar radiation and atmospheric interactions."}, "summary": "This problem examines the differences in the appearance of Mercury's sodium tail at aphelion and perihelion, focusing on its length and color as observed through a specific bandpass filter. The tail's characteristics are influenced by Mercury's distance from the Sun, with the expectation that it may be longer and potentially different in color at aphelion compared to perihelion. The goal is to identify the correct description of the tail's appearance based on these orbital positions."}