{"knowledge_schema": {"broad_category": "Astronomy \u2192 Stellar Observation \u2192 Spectroscopy", "refinement": "This problem involves determining which stars can be observed using two different spectrographs based on their apparent magnitudes and distances.", "specific_scope": "The focus is on comparing the apparent magnitudes of stars with the observational limits of the ESPRESSO and HIRES spectrographs to identify which stars can be detected by both.", "goal": "Identify the stars that meet the brightness criteria for both the ESPRESSO and HIRES spectrographs."}, "summary": "In this problem, we need to determine which stars can be observed with both the ESPRESSO spectrograph at the Paranal Observatory and the HIRES spectrograph at the Keck Observatory based on their apparent magnitudes. ESPRESSO can observe stars brighter than 17 mag, while HIRES can observe stars brighter than 16 mag. By calculating the apparent magnitudes of the stars based on their absolute magnitudes and distances, we find that Star3 (apparent V magnitude of 15.5 mag) and Star5 (apparent V magnitude of 16.5 mag) are the only candidates that meet the criteria for both spectrographs."}