Estimates of the total particulate mass of the plumes of Enceladus are important to constrain theories of particle formation and transport at the surface and interior of the satellite .
We revisit the calculations of , who estimated the particulate mass of the Enceladus plumes from strongly forward scattered light in Cassini ISS images .
We model the plume as a combination of spherical particles and irregular aggregates resulting from the coagulation of spherical monomers , the latter of which allows for plumes of lower particulate mass .
Though a continuum of solutions are permitted by the model , the best fits to the ISS data consist either of low mass plumes composed entirely of small aggregates or high mass plumes composed of mostly spheres .
The high particulate mass plumes have total particulate masses of ( 166 \pm 42 ) \times 10 ^ { 3 } kg , consistent with the results of .
The low particulate mass plumes have masses of ( 25 \pm 4 ) \times 10 ^ { 3 } kg , leading to a solid to vapor mass ratio of 0.07 \pm 0.01 for the plume .
If indeed the plumes are made of such aggregates , then a vapor-based origin for the plume particles can not be ruled out .
Finally , we show that the residence time of the monomers inside the plume vents is sufficiently long for Brownian coagulation to form the aggregates before they are ejected to space .