We present five epochs of near IR observations of the protoplanetary disk
around MWC 480 (HD31648) obtained with the SpeX spectrograph on NASA's Infrared
Telescope Facility (IRTF) between 2007 and 2013, inclusive. Using the measured
line fluxes in the Pa beta and Br gamma lines, we found the mass accretion
rates to be (1.43 - 2.61)x10^-8 Msun y^-1 and (1.81 - 2.41)x10^-8 Msun y^-1
respectively, but which varied by more than 50% from epoch to epoch. The
spectral energy distribution (SED)reveals a variability of about 30% between
1.5 and 10 microns during this same period of time. We investigated the
variability using of the continuum emission of the disk in using the
Monte-Carlo Radiative Transfer Code (MCRT) HOCHUNK3D. We find that varying the
height of the inner rim successfully produces a change in the NIR flux, but
lowers the far IR emission to levels below all measured fluxes. Because the
star exhibits bipolar flows, we utilized a structure that simulates an inner
disk wind to model the variability in the near IR, without producing flux
levels in the far IR that are inconsistent with existing data. For this object,
variable near IR emission due to such an outflow is more consistent with the
data than changing the scale height of the inner rim of the disk.Comment: 19 pages, 14 figure
