Fragment-collision model for compound chondrule formation: Estimation of collision probability

TL;DR

This paper introduces the fragment-collision model for compound chondrule formation, estimating collision probabilities of ejectors from disrupted molten dust particles, aligning well with observed chondrule characteristics.

Contribution

The study presents a novel collision-based formation scenario for compound chondrules within the shock-wave heating framework, supported by analytic modeling of collision probabilities.

Findings

Collision probability matches observed compound chondrule fractions

Model aligns with isotopic and textural observational data

Proposes a viable alternative to existing formation theories

Abstract

We propose a new scenario for compound chondrule formation named as "fragment-collision model," in the framework of the shock-wave heating model. A molten cm-sized dust particle (parent) is disrupted in the high-velocity gas flow. The extracted fragments (ejectors) are scattered behind the parent and the mutual collisions between them will occur. We modeled the disruption event by analytic considerations in order to estimate the probability of the mutual collisions assuming that all ejectors have the same radius. We found that the estimated collision probability, which is the probability of collisions experienced by an ejector in one disruption event, can account for the observed fraction of compound chondrules. In addition, the model predictions are qualitatively consistent with other observational data (oxygen isotopic composition, textural types, and size ratios of constituents). Based on these results, we concluded that this new model can be one of the strongest candidates for the compound chondrule formation. It should be noted that all collisions do not necessarily lead to the compound chondrule formation. The formation efficiency and the future works which should be investigated in the forthcoming paper are also discussed.