{"knowledge_schema": {"broad_category": "Physics \u2192 Astronomy \u2192 Orbital Mechanics", "refinement": "This problem involves understanding the relationship between the mass of a planet, its orbital period, and the gravitational effects it has on its host star as observed through spectral line shifts.", "specific_scope": "The focus is on comparing the orbital periods of two planets based on the periodic shifts they cause in the spectral lines of their respective stars.", "goal": "Determine the ratio of the orbital periods of Planet A to Planet B based on the observed spectral shifts."}, "summary": "This problem falls under the category of orbital mechanics in astronomy, where we analyze the effects of planetary masses on their host stars. The periodic shifts in spectral lines caused by the planets provide information about their orbital characteristics. The goal is to calculate how many times longer the orbital period of Planet A is compared to that of Planet B, based on the given shifts in miliangstroms. The answer indicates that Planet A's orbital period is 1.68 times longer than that of Planet B."}