  We present the results of a theoretical investigation aimed at testing
whether full amplitude, nonlinear, convective models account for the I-band
light curves of Bump Cepheids in the Large Magellanic Cloud (LMC). We selected
two objects from the OGLE sample that show a well-defined bump along the
decreasing (short-period) and the rising (long-period) branch respectively. We
find that current models do reproduce the luminosity variation over the entire
pulsation cycle if the adopted stellar mass is roughly 15 % smaller than
predicted by evolutionary models that neglect both mass loss and convective
core overshooting. Moreover, we find that the fit to the light curve of the
long-period Cepheid located close to the cool edge of the instability strip
requires an increase in the mixing length from 1.5 to 1.8 Hp. This suggests an
increase in the efficiency of the convective transport when moving toward
cooler effective temperatures. Current pulsation calculations supply a LMC
distance modulus ranging from 18.48 to 18.58 mag.

Astrophysics