  Chandra observations of elliptical galaxies have revealed large numbers of
Low Mass X-ray Binaries (LMXBs) accreting at rates above 10^-9 solar masses per
year. One scenario which generates this transfer rate from an old stellar
population is nuclear driven mass transfer onto a neutron star or black hole
from a Roche lobe filling red giant. However, in our Galaxy, most of these
systems accrete sporadically as transients due to a thermal instability in the
accretion disk. Using the common criterion for disk instability (including
irradiation), we find that this mode of mass transfer leads to transient
accretion for at least 75% of the binary's life. Repeated Chandra observations
of elliptical galaxies should reveal this population. The recurrence times
might exceed 1000 years (depending on the orbital period at the onset of mass
transfer), and outbursts might last for 1-100 years. Mass transfering binaries
can also be formed in old populations via interactions in dense stellar
environments, such as globular clusters. These tend to have shorter orbital
periods and are more likely stable accretors, making them apparently a large
fraction of the elliptical's LMXB population.
