Impacts Archives

Collision velocity as a function of the mass of the target in Earth masses. The lowest possible collision velocity without the presence of nebular gas is vcoll = 1 vesc, a gentle scenario that always results in a merger of the two bodies. Solar System formation simulations report velocities vcoll ≈ 1–1.6 vesc, with exceedingly few near 3 vesc (e.g., Agnor et al. 1999). For simplicity, sound speeds are shown for ∼0°C and ∼1 atm conditions, a constant density of 5 g/cm3 is assumed for the escape velocity calculation, and the impactor-to-target mass ratio is 0.7. The sizes of the planet images are not to scale. -- astro-ph.EP

Astrogeology, Exoplanets, -moons, -comets, Impact events, Moon, Status Report

The Role Of Giant Impacts In Planet Formation

by Keith CowingDecember 27, 2023December 27, 2023

Planets are expected to conclude their growth through a series of giant impacts: energetic, global events that significantly alter planetary composition and evolution.

Impact events, Press Release

Exploring the Diverse Outcomes of Large Asteroid Impacts During the Era of Terrestrial Planet Formation

by Keith CowingMarch 26, 2019

The most dramatic phases of terrestrial planet formation are thought to be oligarchic and chaotic growth, on timescales of up to 100-200 Myr, when violent impacts occur between large planetesimals […]