Expanding the ultracompacts: gravitational wave-driven mass transfer in the shortest-period binaries with accretion disks

Joheen Chakraborty, Kevin B. Burdge, Saul A. Rappaport +35

We report the discovery of three ultracompact binary white dwarf systems hosting accretion disks, with orbital periods of 7.95, 8.68, and 13.15 minutes. This significantly augments…