  We present a simple model for gas and dust flow from
67P/Churyumov-Gerasimenko that can be used to understand the grain impact
observed by the DIM instrument on Philae (Krueger et al. 2015) We show how
model results when applied to the GIADA measurements (Rotundi et al. 2015;
Della Corte et al. 2015) can be used, in conjunction with the results found by
the MIRO (Schloerb et al. 2015) and VIRTIS (De Sanctis et al. 2015) instruments
to infer surface properties such as surface temperature and surface ice
fraction.
