Debris Disks and Planet formation
The MIRI will produce images at wavelengths which give high star/debris disk constrast and also perform Coronagraphy at key wavelengths for planet detection and identification. Planetary debris disks provide a unique look at the early stages of the evolution of planetary systems. Understanding them requires measurements of both scattered and thermally emitted light.
The MIRI spectroscopy of protoplanetary disks and of their descendents, the debris disks, will reveal the mineralogy of the dust and the physical conditions of the gas. There may be a close correspondence of mineralogy between these disks and that of outer solar solar system objects. For example, a suitable set of imaging filters can probe the composition of comet grains. The MIRI spectra can also constrain the forms of material on the surfaces of solar system objects, such as particle size or the effects of weathering.
Volatile compounds, hydrocarbons, and simple organic ices have all been found in dark clouds and regions of star formation. There are a variety of complex organic materials that are important for conducting physical and chemical processes required for life as we know it, and several of these compounds may be discovered in different ISM environments with MIRI.
The spectrum below of CR618 is from Chernicharo et al (2001). Although this spectrum is from an evolved and dying star, its spectrum illustrates the richness of this spectral region for the study of gas-phase organics.
The stability of the PSF that can be achieved from space is critical, but so are the low backgrounds. Since they are intrinsically extended, the gain with very large telescopes is modest and can easily be canceled by image instability.
