SIMULATION OF COMET IMPACT AND SURVIVABILITY OF ORGANIC COMPOUNDS

Comets have long been proposed as a potential means for the transport of complex organic compounds to early Earth. For this to be a viable mechanism, a significant fraction of organic compounds must survive the high temperatures due to impact. We have undertaken three‐dimensional numerical simulations to track the thermodynamic state of a comet during oblique impacts. The comet was modeled as a 1‐km water‐ice sphere impacting a basalt plane at 11.2 km/s; impact angles of 15° (from horizontal), 30°, 45°, 65°, and 90° (normal impact) were examined. The survival of organic cometary material, modeled as water ice for simplicity, was calculated using three criteria: (1) peak temperatures, (2) the thermodynamic phase of H2O, and (3) final temperature upon isentropic unloading. For impact angles greater than or equal to 30°, no organic material is expected to survive the impact. For the 15° impact, most of the material survives the initial impact and significant fractions (55%, 25%, and 44%, respectively) satisf...