Fuel Efficient Galaxies: Sustaining Star Formation with Stellar Mass
  Loss
  We examine the importance of secular stellar mass loss for fueling ongoing
star formation in disk galaxies during the late stages of their evolution. For
a galaxy of a given stellar mass, we calculate the total mass loss rate of its
entire stellar population using star formation histories derived from the
observed evolution of the M*-star formation rate relation, along with the
predictions of standard stellar evolution models for stellar mass loss for a
variety of initial stellar mass functions. Our model shows that recycled gas
from stellar mass loss can provide most or all of the fuel required to sustain
the current level of star formation in late type galaxies. Stellar mass loss
can therefore remove the tension between the low gas infall rates that are
derived from observations and the relatively rapid star formation occurring in
disk galaxies. For galaxies where cold gas infall rates have been estimated, we
demonstrate explicitly that stellar mass loss can account for most of the
deficit between their star formation and infall rates.
