16694

AM CVns are double white dwarf binaries with orbital periods virgul5-65 mins. They have been predicted to exist in large amounts in globular clusters due to stellar interactions comma but while binaries harboring neutron stars and even black holes have been previously identified comma no single AM CVn has ever been confirmed to reside in any Galactic globular cluster. We propose to use 8 HST orbits to obtain FUV photometry and determine the sub-hour orbital period of a recently detected comma He-rich comma accreting binary in the globular cluster 47 Tuc. The system has multiwavelength characteristics that match well those expected for AM CVns. The confirmation of a sub-hour period comma as expected for AM CVns comma has profound implications for the dynamical evolution of globular clusters and whether they might be factories of SN Ia and ultracompact binaries that emit gravitational waves.