  The total amount of dust grains in protoplanetary disks is one of the key
properties that characterize the potential for planet formation. With
(sub-)millimeter flux measurements, literature studies usually derive the dust
mass using an analytic form under the assumption of optically thin emission,
which may lead to substantial underestimation. In this work, we conduct a
parameter study with the goal of investigating the effects of disk structure
and dust properties on the underestimation through self-consistent radiative
transfer models. Different dust models, scattering modes and approaches for
dust settling are considered and compared. The influences of disk
substructures, such as rings and crescents, on the mass derivation are
investigated as well. The results indicate that the traditional analytic method
can underestimate the mass by a factor of a few to hundreds, depending on the
optical depth along the line of sight set mainly by the true dust mass, disk
size and inclination. As an application, we perform a detailed radiative
transfer modeling of the spectral energy distribution of DoAr 33, one of the
observed DSHARP disks. When the DSHARP dust opacities are adopted, the most
probable dust mass returned from the Bayesian analysis is roughly 7 times
higher than the value given by the analytic calculation. Our study demonstrates
that estimating disk dust masses from radiative transfer modeling is one
solution for alleviating the problem of insufficient mass for planet formation
raised in the ALMA era.
