Simulations of micrometeoroid interactions with the Earth atmosphere

Abstract

Aims. Micrometeoroids (cosmic dust with size between a few μm and ∼1 mm) dominate the annual extraterrestrial mass flux to the Earth. We investigate the range of physical processes occurring when micrometeoroids traverse the atmosphere. We compute the time (and altitude) dependent mass loss, energy balance, and dynamics to identify which processes determine their survival for a range of entry conditions. Methods. We develop a general numerical model for the micrometeoroid-atmosphere interaction. The equations of motion, energy, and mass balance are simultaneously solved for different entry conditions (e.g. initial radii, incident speeds and angles). Several different physical processes are taken into account in the equation of energy and in the mass balance, in order to understand their relative roles and evolution during the micrometeoroid-atmosphere interaction. In particular, to analyze the micrometeoroid thermal history we include in the energy balance: collisions with atmospheric particles, micrometeoroid radiation emission, evaporation, melting, sputtering and kinetic energy of the ablated mass. Results. Low entry velocities and grazing incidence angles favor micrometeoroid survival. Among those that survive, our model distinguishes (1) micrometeoroids who reach the melting temperature and for which melting is the most effective mass loss mechanism, and (2) micrometeoroids for which ablation due to evaporation causes most of the the mass loss. Melting is the most effective cooling mechanism. Sputtering-induced mass loss is negligible.

Oxygen isotopes in cosmic spherules and the composition of the near Earth interplanetary dust complex

“…Micrometeorite accumulation rates evaluated from different collections vary significantly from 2700 ± 1400 t y À1 at AD 1100-1500 years (Taylor et al, 1998) to 11,000 ± 6600 to 16,000 ± 9300 t y À1 at 27-33 kyr BP (Yada et al, 2004). A significant proportion of micrometeoroids impacting the Earth's atmosphere (60-90 wt.%, Love and Brownlee, 1991;Briani et al, 2013) are, however, lost through melting and evaporation occurring during atmospheric entry.…”

Kinetics of White Soft Minerals (WSMs) Decomposition under Conditions of Interest for Astrobiology: A Theoretical and Experimental Study

“…Usually, the "limit" angle is in the range of 83.0 • to 83.7 • . Moreover, grazing trajectories represent the main scenario in which larger grains can survive the atmospheric entry without melting [33,50]: it must be noted that the peak temperatures in grazing entries are lower (top right panel in Figure 2).…”

Evaluation of CaSO4micrograins in the context of organic matter delivery: thermochemistry and atmospheric entry

“…On entering Earth's atmosphere, MMs experience several physical and chemical modifications (Genge et al 1997 (Flynn 1989;Love and Brownlee 1991;Briani et al 2013;Bisceglia et al 2017;Micca Longo and Longo 2017a,b) in order to simulate the various interactions between the MMs and Earth's atmosphere. These previous works focus on more common micrometeorites materials, i.e.…”