  We present the discovery of an extended ring of ultraviolet emission
surrounding the AGB star U Hya in archival observations performed by the Galaxy
Evolution Explorer (GALEX). This is the third discovery of extended UV emission
from a carbon AGB star and the first from an AGB star with a detached shell.
From imaging and photometric analysis of the FUV and NUV images, we determined
that the ultraviolet ring has a radius of $\sim 110^{\prime\prime}$, thus
indicating that the emitting material is likely associated with the detached
shell seen in the infrared. We find that scattering of the central point source
of NUV and FUV emission by the dust shell is negligible. Moreover, we find that
scattering of the interstellar radiation field by the dust shell can contribute
at most $\sim10%$ of the FUV flux. Morphological and photometric evidence
suggests that shocks caused by the star's motion through space and, possibly,
shock-excited H$_2$ molecules are the most likely origins of the UV flux. In
contrast to previous examples of extended UV emission from AGB stars, the
extended UV emission from U Hya does not show a bow shock-like structure, which
is consistent with a lower space velocity and lower interstellar medium
density. This suggests the detached dust shell is the source of the UV emitting
material and can be used to better understand the formation of detached shells.
