We report on the detection in the combined Gaia -DR1/RAVE data of a lack of disk stars in the solar neighbourhood with velocities close to zero angular momentum .
We propose that this may be caused by the scattering of stars with very low angular momentum onto chaotic , halo-type orbits when they pass through the Galactic nucleus .
We model the effect in a Milky-Way like potential and fit the resulting model directly to the data , finding a likelihood ( \sim 2.7 \sigma ) of a dip in the distribution .
Using this effect , we can make a dynamical measurement of the Solar rotation velocity around the Galactic center : v _ { \odot } = 239 \pm 9 \mathrm { km s } ^ { -1 } .
Combined with the measured proper motion of Sgr A ^ { * } , this measurement gives a measurement of the distance to the Galactic centre : R _ { 0 } = 7.9 \pm 0.3 \mathrm { kpc } .