{"knowledge_schema": {"broad_category": "Astrophysics \u2192 Stellar Composition \u2192 Elemental Abundance Ratios", "refinement": "This problem involves calculating the relative abundances of elements in the photospheres of two stars based on given elemental abundance ratios and solar composition.", "specific_scope": "The focus is on determining the ratio of calcium atoms between two stars (Star_A and Star_B) using the provided abundance data and solar reference values.", "goal": "Calculate the ratio of calcium atoms in the photospheres of Star_A and Star_B based on their elemental abundances."}, "summary": "This problem requires understanding stellar elemental abundances and how to calculate ratios based on given data. We are tasked with finding the ratio of calcium atoms in the photospheres of two stars, Star_A and Star_B, using their respective abundance ratios and solar composition references. The goal is to derive the ratio of calcium atoms, which leads to the answer of 10^0.9."}