  We investigate the observational signatures of super-Earths (i.e.,
Earth-to-Neptune mass planets) in their natal disks of gas and dust. Combining
two-fluid global hydrodynamics simulations with a radiative transfer code, we
calculate the distributions of gas and of sub-mm-sized dust in a disk perturbed
by a super-Earth, synthesizing images in near-infrared scattered light and the
mm-wave thermal continuum for direct comparison with observations. In low
viscosity gas ($\alpha\lesssim10^{-4}$), a super-Earth opens two annular gaps
to either side of its orbit by the action of Lindblad torques. This double gap
and its associated gas pressure gradients cause dust particles to be dragged by
gas into three rings: one ring sandwiched between the two gaps, and two rings
located at the gap edges farthest from the planet. Depending on system
parameters, additional rings may manifest for a single planet. A double gap
located at tens of AUs from a host star in Taurus can be detected in the dust
continuum by the Atacama Large Millimeter Array (ALMA) at an angular resolution
of ~0".03 after two hours of integration. Ring and gap features persist in a
variety of background disk profiles, last for thousands of orbits, and change
their relative positions and dimensions depending on the speed and direction of
planet migration. Candidate double gaps have been observed by ALMA in systems
like HL Tau (D5 and D6) and TW Hya (at 37 and 43 AU); we submit that each
double gap is carved by one super-Earth in nearly inviscid gas.
