Determine the composition of dust in the Crab Nebula

Determine the mineralogical composition and size distribution of dust grains in the Crab Nebula’s ejecta filaments by obtaining mid-infrared spectra that unambiguously isolate continuum emission from contaminating lines and mitigate current MIRI/MRS detector artifacts.

Background

Dust has been inferred in the Crab Nebula from infrared excess and extinction features, and JWST imaging reveals warm dust concentrated in dense inner filaments. Polarization measurements hint at a carbonaceous component, but line contamination in broadband filters and detector artifacts in current MIRI/MRS spectra hinder definitive compositional identification.

The authors attempted to use MRS to constrain grain composition but found that bright lines induce detector effects that contaminate the continuum, deferring a detailed grain-property analysis.