  We have discovered two extended half-ring structures in a far-ultraviolet
image taken with the GALEX satellite of the well-known mass-losing carbon star
CIT 6 (RW LMi). The northern (southern) ring is brighter (fainter) with a
diameter of about 15 arcmin (18 arcmin). These structures most likely represent
the astrosphere resulting from the shock interaction of CIT 6's molecular wind
with the Warm Interstellar Medium, as it moves through the latter. These data
provide a direct estimate of the size of CIT 6's circumstellar envelope that is
a factor ~20 larger than previous estimates based on CO millimeter-wave line
data. We find that CIT 6 has been undergoing heavy mass-loss for at least
93,000 yr and the total envelope mass is 0.29 Msun or larger, assuming a
constant mass-loss rate of 3.2 x 10^(-6) Msun/yr. Assuming that the shock front
has reached a steady-state and CIT 6's motion relative to the ISM is in the
sky-plane, we measure the termination-shock standoff distance directly from the
image and find that CIT 6 is moving at a speed of about 39 (0.17
cm^(-3)/n_ISM)^(1/2) km/s through the interstellar medium around it. However,
comparisons with published numerical simulations and analytical modelling shows
that CIT 6's forward shock (the northern ring) departs from the parabolic shape
expected in steady-state. We discuss several possible explanations for this
departure.
