  Radiative feedback is among the most important consequences of clustered star
formation inside molecular clouds. At the onset of star formation, radiation
from massive stars heats the surrounding gas, which suppresses the formation of
many low-mass stars. When simulating pre-main-sequence stars, their stellar
properties must be defined by a prestellar model. Different approaches to
prestellar modeling may yield quantitatively different results. In this paper,
we compare two existing prestellar models under identical initial conditions to
gauge whether the choice of model has any significant effects on the final
population of stars. The first model treats stellar radii and luminosities with
a ZAMS model, while separately estimating the accretion luminosity by
interpolating to published prestellar tracks. The second, more accurate
prestellar model self-consistently evolves the radius and luminosity of each
star under highly variable accretion conditions. Each is coupled to a
raytracing-based radiative feedback code that also treats ionization. The
impact of the self-consistent model is less ionizing radiation and less heating
during the early stages of star formation. This may affect final mass
distributions. We noted a peak stellar mass reduced by 8% from 47.3 Msun to
43.5 Msun in the evolutionary model, relative to the track-fit model. Also, the
difference in mass between the two largest stars in each case is reduced from
14 Msun to 7.5 Msun. The HII regions produced by these massive stars were also
seen to flicker on timescales down to the limit imposed by our timestep (< 560
years), rapidly changing in size and shape, confirming previous cluster
simulations using ZAMS-based estimates for prestellar ionizing flux.
