A dense 0.1-solar-mass star in a 51-minute-orbital-period eclipsing binary.

Of more than a thousand known cataclysmic variables (CVs), where a white dwarf is accreting from a hydrogen-rich star, only a dozen have orbital periods below 75 minutes. One way to achieve these short periods requires the donor star to have undergone substantial nuclear evolution before interacting with the white dwarf, and it is expected that these objects will transition to helium accretion. These transitional CVs have been proposed as progenitors of helium CVs.

A 62-minute orbital period black widow binary in a wide hierarchical triple.

Over a dozen millisecond pulsars are ablating low-mass companions in close binary systems. In the original 'black widow', the eight-hour orbital period eclipsing pulsar PSR J1959+2048 (PSR B1957+20), high-energy emission originating from the pulsar is irradiating and may eventually destroy a low-mass companion. These systems are not only physical laboratories that reveal the interesting results of exposing a close companion star to the relativistic energy output of a pulsar, but are also believed to harbour some of the most massive neutron stars, allowing for robust tests of the neutron star equation of state.

General relativistic orbital decay in a seven-minute-orbital-period eclipsing binary system.

General relativity predicts that short-orbital-period binaries emit considerable amounts of gravitational radiation. The upcoming Laser Interferometer Space Antenna (LISA) is expected to detect tens of thousands of such systems but few have been identified, of which only one is eclipsing-the double-white-dwarf binary SDSS J065133.338+284423.

Bringing the visible universe into focus with Robo-AO.

The angular resolution of ground-based optical telescopes is limited by the degrading effects of the turbulent atmosphere. In the absence of an atmosphere, the angular resolution of a typical telescope is limited only by diffraction, i.e.