  We examine the nature of RXJ0806.3+1527 and show that it is possible to
reconcile the observed period decrease and X-ray luminosity with the transfer
of mass between two white dwarfs provided that: either the system is (i) still
in the early and short-lived (less than ~100yr) stages of mass transfer due to
atmospheric Roche-lobe overflow, or (ii) in a standard, long-term,
quasi-stationary mass-transfer phase that is significantly (~90%)
non-conservative and the conversion of accretion energy to X-rays is quite
inefficient. In either of the two cases and for a wide range of physical
parameters, we find that orbital angular momentum is lost from the system at a
rate that is a factor of a few (less than ~4) higher than the rate associated
with the emission of gravitational waves. Although the physical origin of this
extra angular momentum loss is not clear at present, it should be taken into
account in the consideration of RXJ0806.3+1527 as a verification Galactic
source for LISA.
