Dust porosity may affect the analysis of debris disc observations

Debris discs are often modelled assuming compact dust grains, but there is increasing evidence that dust may be porous. We quantify which systematic errors would be introduced when modelling debris discs composed of porous dust with a disc model that assumes spherical, compact grains. The figure shows the results as functions of stellar luminosity for different degrees of porosity. The inferred disk radius (top left) and density slopes (top right) are barely affected. However, the minimum grain size (also known as 'blowout size', bottom left) is overestimated or underestimated by up to a factor of two. The slope of the grain size distribution (bottom right) derived using compact grains is significantly overestimated as well.

Details: http://adsabs.harvard.edu/abs/2017MNRAS.464.4383B