Ablation and Chemical Alteration of Cosmic Dust Particles During Entry Into the Earth’s Atmosphere

Abstract

Most dust-sized cosmic particles undergo ablation and chemical alteration during atmospheric entry, which alters their original properties. A comprehensive understanding of this process is essential in order to decipher their preentry characteristics. The purpose of the study is to illustrate the process of vaporization of different elements for various entry parameters. The numerical results for particles of various sizes and various zenith angles are treated in order to understand the changes in chemical composition that the particles undergo as they enter the atmosphere. Particles with large sizes (> few hundred μm) and high entry velocities (>16 km s −1 ) experience less time at peak temperatures compared to those that have lower velocities. Model calculations suggest that particles can survive with an entry velocity of 11 km s −1 and zenith angles (ZA) of 30°-90°, which accounts for ∼66% of the region where particles retain their identities. Our results suggest that the changes in chemical composition of MgO, SiO 2 , and FeO are not significant for an entry velocity of 11 km s −1 and sizes <300 μm, but the changes in these compositions become significant beyond this size, where FeO is lost to a major extent. However, at 16 km s −1 the changes in MgO, SiO 2 , and FeO are very intense, which is also reflected in Mg/Si, Fe/Si, Ca/Si, and Al/Si ratios, even for particles with a size of 100 μm. Beyond 400 μm particle sizes at 16 km s −1 , most of the major elements are vaporized, leaving the refractory elements, Al and Ca, suspended in the troposphere.

Comparison of global datasets of sodium densities in the mesosphere and lower thermosphere from GOMOS, SCIAMACHY and OSIRIS measurements and WACCM model simulations from 2008 to 2012

“…These meteoric smoke particles are thought to play a significant role in the formation of noctilucent clouds (see, e.g., Rapp and Thomas, 2006) in the summer polar mesosphere and for aerosols and clouds in the stratosphere (see, e.g., Murphy et al, 1998;Voigt et al, 2005;Curtius et al, 2005). However, to quantify the impact of meteoric smoke on the middle atmosphere, it is important to understand the changes in chemical composition of the incoming particles during their entry into the Earth's atmosphere (e.g., Rudraswami et al, 2016) and how much meteoric material is on average deposited into the Earth's atmosphere. The rate of daily influx of meteoric material into the upper atmosphere has a large uncertainty, with estimates varying between 1 and 300 t day −1 (see, e.g., Table 1 of Plane, 2012).…”

Oxygen isotopic and chemical composition of chromites in micrometeorites: Evidence of ordinary chondrite precursors

“…; Rudraswami et al. , , , ). This could be due to either (1) a population deprived of S‐type asteroids in the asteroid belt or (2) an underrepresentation of dust related to ordinary chondrites in Earth resonant orbits.…”

Rare, metal micrometeorites from the Indian Ocean

“…Slightly different angles, velocities, physical properties, and chemical compositions of the incoming particles would make the transition between melted and unmelted particles (Rudraswami et al. ). The more evolved meteorites such as the high metamorphic grade ordinary chondrites find lesser representation among the micrometeorites because they have greater tensile strengths and therefore do not fragment into smaller sized pieces during asteroidal collisions (Rudraswami et al.…”