  Members of widely-separated stellar binaries (> 0.1 pc) or loosely bound
stellar associations and clusters are born with small spreads in kinematics and
chemistry, but disrupt and dissociate on timescales comparable to their orbital
time within the Milky Way. The kinematic properties of comoving star
pairs---bound wide binaries or unbound but coeval stars---are therefore
sensitive to both the smooth tidal field and gravitational perturbation
spectrum of the Milky Way. In previous work, we identified >4,000 candidate
comoving pairs using only astrometric data from the Tycho-Gaia Astrometric
Solution (TGAS) catalog and find a large number of pairs with separations > 1
pc. Without radial velocity measurements for the vast majority of these pairs,
the false-positive rate at these separations is significant (~50%). Here we
present results from our own low-resolution radial-velocity survey of a random
sample of the candidate pairs to identify and validate true comoving star
pairs. Of the 311 observed comoving pairs, we confirm 127 comoving pairs with
separations as large as ~10 pc, our original search limit. Between separations
of 0.001 pc to ~0.5 pc, the number of confirmed pairs per separation decreases
with increasing separation (number per log separation is uniform). From ~0.5 pc
to 10 pc, the number per separation is approximately uniform (number per log
separation increases). We confirm the discovery of a population of comoving
star pairs at very large separations, suggesting that disrupted wide binaries
and stellar associations remain approximately spatially coherent.
