Fine-grained Material Associated with a Large Sulfide returned from Comet 81P/Wild 2

TL;DR

This study analyzes a large sulfide particle from comet Wild 2, revealing fine-grained material similar to interplanetary dust and evidence of thermal processing, shedding light on early Solar System materials.

Contribution

It reports the discovery of fine-grained material associated with a sulfide particle from Wild 2, providing insights into cometary composition and Solar nebula history.

Findings

FGM resembles interplanetary dust particles (IDPs) components

Sulfide shows Ni-rich lamellae indicating heating events

FGM was protected during hypervelocity capture

Abstract

In a consortium analysis of a large particle captured from the coma of comet 81P/Wild 2 by the Stardust spacecraft, we report the discovery of a field of fine-grained material (FGM) in contact with a large sulfide particle. The FGM was partially located in an embayment in the sulfide, so appears to have been largely protected from damage during hypervelocity capture in aerogel. Some of the FGM particles are indistinguishable in their characteristics from common components of chondritic-porous interplanetary dust particles (CP-IDPs), including glass with embedded metals and sulfides (GEMS) and equilibrated aggregates (EAs). The sulfide exhibits surprising Ni-rich lamellae, which may indicate that this particle experienced a long-duration heating event after its formation but before incorporation into Wild 2. We discuss the relationship of the FGM to the sulfide, to other Wild 2 particles and to the history of the Solar nebula.